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Migraine headache. Oral caffeine in combination with acetaminophen, aspirin, and/or sumatriptan is approved by the US Food and Drug Administration (FDA) for treating migraine headache. Details: Taking caffeine 100-260 mg orally in combination with acetaminophen 500-2000 mg, aspirin 500 mg, and/or sumatriptan 50-100 mg is effective for treating migraine headache (2715,2716,2717,37614,37626,37816,91068). Some evidence shows that caffeine in combination with aspirin and acetaminophen may be more effective than sumatriptan in treating a migraine attack (37666). However, taking caffeine 200 mg plus ergotamine seems to be less effective than sumatriptan or calcium carbasalate plus metoclopramide (37685,38312). Caffeine is an FDA-approved product for use with analgesics for the treatment of migraine.
Neonatal apnea. Oral or intravenous caffeine citrate is approved by the US Food and Drug Administration (FDA) for the short-term treatment of neonatal apnea in very preterm infants. Details: Using caffeine orally or intravenously improves apnea of prematurity in very preterm infants and reduces the risk of bronchopulmonary dysplasia, invasive mechanical ventilation, and neurodevelopmental impairment (6023,6371,37857,37906,38124,38344,98807,100364,114658). The dosage approved in the FDA labeling is a single loading dose of caffeine citrate 20 mg/kg (10 mg/kg caffeine base), followed by 5 mg/kg of caffeine citrate (2.5 mg/kg caffeine base) every 24 hours for maintenance. Clinical research shows that caffeine citrate dose-dependently reduces the number of apnea episodes by at least 50% over 7-10 days of treatment (6371). Most research suggests that doses above 10 mg/kg daily reduce the risk of apnea, bronchopulmonary dysplasia, and problematic extubation when compared with doses below 10 mg/kg/day (98807,100364,114658). Additional clinical research shows that reinitiating caffeine treatment after termination of the original caffeine regimen, and continuing until 40 weeks postmenstrual age, reduces the incidence of intermittent hypoxia in premature infants by 46% when compared to standard care (91073). At 18-21 months of age, a history of neonatal caffeine treatment reduces the risk of long-term complications of apnea of prematurity, such as cerebral palsy or cognitive delay (37722,38340). At 11 years of age, individuals born prematurely and treated with caffeine have improved visuomotor, visuoperceptual, and visuospatial abilities when compared to those who received placebo (97452). At 6-11 years of age, these individuals may also have a reduced risk of motor impairment (114658). Data on the prophylactic use of caffeine in very low birth-weight infants (less than 1500 grams and 32 weeks' gestation) are conflicting. In a meta-analysis of 11 studies, 5 show a reduced risk of apnea of prematurity, oxygen therapy, bronchopulmonary dysplasia, patent ductus arteriosus, and retinopathy of prematurity, and a reduced duration of mechanical ventilation (111491). However, other studies do not show any benefit (38125,111491). A study of infants born at 34-36 weeks' gestation shows that caffeine citrate, 10 or 20 mg/kg orally daily, reduces the number of intermittent hypoxemia episodes per hour by 61% and 67% respectively, when compared with placebo (111493). Caffeine and aminophylline have similar effectiveness for management of apnea, bradycardia, and hypoxemia, but caffeine has a wider range of safe plasma levels and lower rates of tachycardia and feeding intolerance (111492).
Postoperative headache. Oral or intravenous caffeine is approved by the US Food and Drug Administration (FDA) for preventing headache in postoperative patients who regularly consume caffeinated products. Details: Clinical research shows that using caffeine is effective for preventing postoperative headache in patients who regularly consume caffeinated products. Intravenous caffeine does not seem to be effective in non-regular caffeine consumers. Studied doses have included 200 mg intravenously or oral doses calculated based on average daily consumption (2725,2726). Caffeine is an FDA-approved product for preventing headache in postoperative patients who regularly consume caffeinated products.
Tension headache. Oral caffeine in combination with analgesics is approved by the US Food and Drug Administration (FDA) for treating tension headache. Details: Taking caffeine orally in combination with analgesics is effective for treating simple tension headache. Taking caffeine 100 mg alone is more effective at reducing tension headache pain when compared with placebo, but less effective than the combination of caffeine and analgesics. Caffeine 130 mg has been used with acetaminophen 1000 mg or with acetaminophen 500 mg and aspirin 500 mg. Caffeine 50 mg has been used with acetylsalicylic acid 250 mg and acetaminophen 200 mg (2718,11832,37668,37773).

Athletic performance. Oral caffeine taken as a single dose of at least 2-3 mg/kg can modestly improve endurance, muscle strength, power output, and overall athletic performance when taken prior to certain forms of athletic activity or exercise. However, the magnitude and duration of effect is variable and may be dependent on the form and dose of caffeine, as well as various individual- and activity-specific factors. Caffeine intake in excess of 800 mg daily can result in blood levels greater than those allowed by the National Collegiate Athletic Association. Details: Clinical research and meta-analyses of clinical research show that taking caffeine 2-10 mg/kg modestly improves work produced, aerobic endurance, muscle strength and endurance, power output, and overall athletic performance (10203,11832,37648,37894,38054,38063,95955,100362,100365,100371)(103701,103703,108798,111250,114655,114657,114661,114673). According to the International Society of Sports Nutrition, the most consistent and measurable effects are seen in aerobic endurance; the minimal effective dose for any form of exercise is unclear, but benefits have been most consistent at doses of 3-6 mg/kg (114673). Meta-analyses of studies using caffeine 3-9 mg/kg as a single dose prior to endurance time trials report variability in results. Sports studied included running, rowing, cycling, swimming, and Nordic skiing, and included both recreational and trained athletes. Overall there was a small positive effect on time to exhaustion, endurance performance, and mean power output, and a decrease in the time needed to complete the trials when compared with placebo (98808,111497,114655). One meta-analysis of studies that evaluated cycling time trial performance found that doses of 4-6 mg/kg, but not doses of 1-3 mg/kg, improved performance (114655). A separate meta-analysis of 14 clinical studies shows that taking caffeine 2-11 mg/kg approximately 45-60 minutes before exercise improves muscle strength and endurance in the upper and lower body when compared with placebo. However, a sub-group analysis shows that muscle strength only improves with caffeine doses of at least 6 mg/kg (114657). Another meta-analysis of small clinical trials shows that the benefit of caffeine on athletic performance seems to increase with increased duration of activity. This suggests that caffeine can improve physical endurance during athletic activities (100371). In these trials, caffeine is typically provided as a single dose 30-150 minutes prior to testing (98808), although one study suggests that taking caffeine 60 minutes prior to peak activity has the most consistent ergogenic benefits (104577). Caffeine might improve performance in some athletic activities but not others. Some research shows that caffeine does not improve performance during athletic activities requiring a high amount of exertion over a short period of time. Such activities include sprinting and lifting (11832,37564,37758,37837,37841,37890,38319,95963,97459,112740). However, it is possible that the negative lifting studies were underpowered. Ballistic exercise, such as jumping or throwing, requires rapid increases in velocity, force, and muscle activation. A meta-analysis of 10 studies shows that caffeine in a range of doses (mean: 3 mg/kg) has a significant ergogenic effect on throwing performance and velocity (111488). A meta-analysis of small studies shows that caffeine modestly improves bench press repetitions and maximum strength, but not perceived exertion, when compared with placebo. Caffeine also tends to improve these parameters for leg presses, but the improvement does not reach significance when compared with placebo (103701). A meta-analysis of small clinical studies in female team-sport athletes shows that caffeine improves specific team-sport skills but has no effect on perceived exertion or agility tests performed after exertion (108799). Conversely, a small individual clinical study shows that taking caffeine 6.5 mg/kg 60 minutes before strength training decreases perceived exertion while increasing the number of repetitions of both upper and lower limb exercises by 17% to 33% over placebo (104581). Some clinical research also shows that taking caffeine can decrease subjective feelings of exertion and fatigue during exercise such as fencing and cycling (17618,37656,91026,91058,91062). Although some other clinical studies show that caffeine does not affect perceived exertion, caffeine does seem to improve performance and cause small increases in the amount of physical work done when compared with placebo in various athletes, including cyclists, runners, basketball players, and golfers (37702,37860,37872,38031,38119,38320,91037,91077,97457,97459)(104580,108800,108804). These effects do not seem to be dependent upon the dose of caffeine (97459), although some research shows that the timing of caffeine intake and exercise may alter overall benefit, with a greater effect seen in the morning compared to the evening (97457,104580). Most research has investigated the acute effects of a single dose of caffeine. The evidence is mixed as to whether chronic intake of caffeine could induce tolerance and reduce any acute ergogenic benefits (114673). One study shows that the consistent consumption of caffeine 3 mg/kg daily for 28 days eliminates the acute benefits of caffeine in work produced when compared with placebo, suggesting the development of tolerance (95955). However, chronic use of caffeine at a dose of 6 mg/kg for 4 days does not seem to induce tolerance to an acute dose of caffeine 6 mg/kg taken 60 minutes prior to a cycling time trial in males who are moderate to high users of caffeine (104576). Similarly, a small clinical study in trained individuals shows that acute supplementation with oral caffeine 6 mg/kg about 1 hour prior to performance improves strength and endurance when compared with placebo or control, regardless of habitual caffeine consumption (108804). Differences may be due to the type of exercise, the acute dose of caffeine, the length of the chronic intake period, and/or the normal caffeine intake of the athlete. Most studies suggest that there is significant inter-individual variability in response to caffeine for improvement of athletic performance (100365). These differences might be due, at least in part, to genotype (100370,114673), although research is conflicting. Caffeine is metabolized by the cytochrome P450 1A2 (CYP1A2) enzyme. One small clinical trial in resistance-trained males shows that taking caffeine 6 mg/kg improves resistance exercise performance in those homozygous for the CYP1A2 rs762551 polymorphism (AA) when compared with those without or heterozygous for that polymorphism (CC or A/C, respectively) (100370). However, another clinical study in trained male athletes shows that taking oral caffeine 4 mg/kg about 30 minutes prior to performance decreases handgrip strength by about 13% in individuals with the CC genotype when compared with placebo, but not in those with the AA or A/C genotypes. No groups experienced an improvement in vertical jump performance (108803). Another small clinical study suggests that CYP1A2 genotype does not affect exercise performance in athletes 60 minutes after taking caffeine 3 mg/kg. In addition, the ADORA2A genotype, which plays a role in caffeine sensitivity, does not seem to affect exercise performance benefits from caffeine (104578). However, these studies are small and used different performance protocols; further research is needed to clarify how these polymorphisms may impact the athletic performance benefits of caffeine (114673). Limited research has also evaluated the use of a caffeine mouth rinse, with mixed findings. Two very small clinical studies in healthy trained males shows that rinsing the mouth with 25 mL of water containing caffeine 85 or 300 mg for 5-10 seconds does not affect athletic performance or time to exhaustion while cycling when compared with placebo (103709,108801). However, another small study in healthy Taekwondo athletes fasting for Ramadan suggests that using a mouth rinse containing caffeine 6 mg/kg, ten seconds prior to exertion, modestly reduces perceived exertion and modestly improves kick performance when compared with using a placebo rinse (103710). Similarly, another small clinical study in healthy, resistance-trained males shows that rinsing the mouth with 25 mL of a solution containing caffeine 3%, but not 1% or 2%, reduces perceived exertion and increases muscular endurance, but not strength, when compared with placebo. The mouth rinse was used for 5 seconds immediately prior to a strength test or once per minute for 2 minutes during a muscular endurance test (108802). Preliminary clinical research has also investigated the use of caffeine in combination with other ingredients, such as sodium bicarbonate or creatine. However these studies have not demonstrated clear benefits in athletic performance over taking caffeine alone (112740,114673).
Mental alertness. Oral caffeine increases mental alertness. However, it might not improve performance or accuracy to the same extent achieved through adequate sleep. Details: Consumption of caffeinated beverages or caffeine supplements seems to prevent a decline in alertness and cognitive capacity when consumed throughout the day (4221,4224,36439,37727,37757,37759,38070,38075,38158,91093)(91075). Caffeine appears to be especially effective in individuals that are not regular users (91074). Taking caffeine 100-600 mg can improve alertness and speed following prolonged sleep deprivation but usually does not affect mental performance or accuracy (10205,37716,37755,37806,37992,38007,38035,38139,91049,91072)(103706,112736). Drinking coffee containing caffeine 100 mg prior to a cognitive performance test improves reaction times in people with recent poor sleep quality, and in those with adequate sleep. However, the increase in vigilance occurring in the sleep-deprived people does not bring their performance up to the level seen with adequate sleep. Also, the number of errors made by sleep-deprived people seems to increase, suggesting that caffeine may have a detrimental effect on inhibitory control (98809). Caffeine also appears to reduce cognitive impairment caused by medications such as chlorpheniramine (91058). Combining caffeine with certain other supplements may improve mental performance. Taking caffeine 80 mg with taurine seems to provide a small improvement in mental performance (9899), although this effect is not observed in sleep deprived subjects (38154). Some clinical research shows that combining caffeine 40-75 mg with glucose 37.5 grams or L-theanine 97-100 mg improves mental performance better than placebo or either substance alone (13732,37762,37903,38116); however, other clinical research shows no additional benefit from combining L-theanine and caffeine (91045).

Bronchopulmonary dysplasia. Intravenous caffeine may reduce the risk for bronchopulmonary dysplasia in preterm infants. Details: Population research has found that initiating caffeine treatment prior to the third day of life in premature infants is associated with a reduced risk of developing bronchopulmonary dysplasia compared to later initiation of treatment with caffeine. Additionally, a meta-analysis of available clinical research shows that high-dose caffeine (40-80 mg/kg loading dose, 20 mg/kg daily maintenance) lowers the risk of bronchopulmonary dysplasia when compared with standard dosing (20 mg/kg loading dose, followed by 5-10 mg/kg daily maintenance). However, small sample sizes and high heterogeneity limit the validity of these findings (97462,100364).
Diabetes. Dietary caffeine seems to be beneficial for the prevention of type 2 diabetes; it is unclear if it is beneficial for the prevention of gestational diabetes. Also, it is unclear if oral caffeine is beneficial in patients with type 1 or type 2 diabetes. Details: Total caffeine consumption from beverages such as coffee or tea is associated with a lower risk of developing type 2 diabetes. This effect appears to be dose-dependent (11353,14313,37850,37871,91040,100368). For example, an increase of 200 mg daily caffeine intake seems to be associated with a 14% decrease in the incidence of type 2 diabetes (91055). Additionally, in North American males, consuming caffeine 417 mg daily from coffee or tea is associated with a 20% lower risk of developing type 2 diabetes when compared with those consuming less than 37 mg daily. North American females consuming at least 258 mg of caffeine daily from coffee or tea seem to have a 10% to 30% lower risk of developing type 2 diabetes when compared with those consuming less than 140 mg daily (11353). Japanese adults who consume at least 416 mg of caffeine daily from beverages including coffee or green tea seem to have a 33% lower risk of developing type 2 diabetes compared to those who consume no more than 57 mg daily. The risk reduction appears to be more pronounced in Japanese females when compared with males (14313). It is unclear if caffeine is beneficial in adults with diabetes. A few small studies show that caffeine consumption may further reduce insulin sensitivity in patients with type 2 diabetes, gestational diabetes, or those at risk for developing diabetes (13744,37653,37820). Caffeine consumption has also been evaluated during pregnancy. An observational study has found that self-reported consumption of beverages containing up to 100 mg of caffeine at 16-22 weeks' gestation is associated with a 47% lower risk of developing gestational diabetes when compared with no intake (108814). Research regarding the effects of caffeine in patients with type 1 diabetes shows conflicting results. One study shows that taking caffeine 250 mg twice daily for 2 weeks can reduce the incidence of elevated blood sugar at night in patients with type 1 diabetes (37660). However, another study in patients with type 1 diabetes shows that taking caffeine 200 mg daily for 3 months may increase the ability to perceive hypoglycemic symptoms when compared with placebo, although overall glycemic control does not seem to be affected (6024). A small clinical crossover study evaluated caffeine for the prevention of exercise-induced hypoglycemia in adults with type 1 diabetes using ultra-long-acting insulin. This study shows that consuming a beverage containing caffeine 250 mg, glucose 10 grams, and aspartame 30 minutes before a moderate intensity cycling exercise does not reduce the risk of exercise-related hypoglycemia, alter the time to hypoglycemia, or increase peak plasma glucose levels during exercise when compared with taking glucose and aspartame (114662).
Memory. Oral caffeine seems to be beneficial for short-term memory recall in college students and extroverted personalities. It is unclear if oral caffeine is beneficial for introverted personalities or other populations. Details: Taking a single dose of caffeine 65-200 mg orally daily seems to improve memory function in some individuals such as college students and people with extroverted personalities. A small study shows that taking caffeine does not improve memory function in individuals with introverted personalities (37845,38071,91080).
Obesity. Oral caffeine, when taken in combination with ephedrine or as a component of green tea, seems to be beneficial for weight loss, short-term. Details: Taking caffeine orally, in combination with ephedrine or as a component of green tea, seems to help reduce weight, short-term (695,696,1704,8647,16892,37617,37831). Caffeine 192 mg in combination with ephedra 20-90 mg per day for 6 months seems to cause a modest weight reduction (5.3 kg) in people with a body mass index (BMI) between 25-40 kg/m². This combination, along with limiting fat intake to 30% of calories and moderate exercise, also seems to reduce body fat, decrease low-density lipoprotein (LDL) cholesterol, and increase high-density lipoprotein (HDL) cholesterol. However, even in carefully screened and monitored otherwise healthy adults, caffeine/ephedra combinations can cause small changes in blood pressure and heart rate (8647). Preliminary clinical research also shows that taking 1000 mg of a proprietary combination product containing caffeine and multiple other ingredients (Prograde Metabolism) twice daily for 8 weeks in conjunction with dieting reduces body weight, fat mass, waist circumference, and hip circumference by 1.5%, 5%, 1.8%, and 1.3%, respectively, when compared with dieting alone (40802).
Pain (acute). Oral caffeine, when taken in combination with acetaminophen, propyphenazone, ibuprofen, or other pain-relieving agents, seems to be beneficial for acute pain. Details: Clinical research shows that taking caffeine 50-130 mg in combination with acetaminophen, propyphenazone, ibuprofen, or other pain-relieving agents can reduce acute pain when compared with the effects of pain-relieving agents alone (37587,37904,38036,38303,91038). Adding ≥100 mg caffeine to treatment with acetaminophen or ibuprofen results in 5% to 10% more patients that achieve at least 50% of maximum pain relief for over 4 hours when compared to treatment with acetaminophen or ibuprofen alone (91038).
Postdural puncture headache. Oral or intravenous caffeine seem to be beneficial for preventing postdural puncture headache. Details: Using caffeine 300 mg orally or 500 mg in 1,000 mL normal saline intravenously seems to help treat and prevent postdural puncture headache (2727,2728). Using a combination of ergotamine and caffeine seems to be less effective than gabapentin for treating this condition (38147). Lower doses of oral caffeine may not be beneficial. Clinical research shows that oral caffeine, 75-125 mg, does not decrease the risk of postdural headache (91022).

Atrial fibrillation. Oral caffeine does not seem to prevent atrial fibrillation after cardiopulmonary bypass. In addition, it might increase the risk of gastrointestinal side effects. Details: In adults undergoing surgery with cardiopulmonary bypass, taking caffeine 400 mg every 8 hours for 6 doses does not seem to reduce the risk of developing atrial fibrillation during the first three post-operative days. This clinical study was stopped prior to the completion of recruitment after an interim analysis showed increased incidence of postoperative nausea and vomiting, and no effect on the incidence of atrial fibrillation (97451).
Attention deficit-hyperactivity disorder (ADHD). Oral caffeine does not seem to reduce symptoms of ADHD in children. Details: Most research suggests caffeine does not significantly reduce ADHD symptoms in children when used at tolerable doses (10755,10756,10757,10758,10759,10760). The use of caffeine in adolescents and adults with ADHD has not been studied.

Age-related cognitive decline. It is unclear if oral caffeine prevents cognitive decline with aging. Details: Population research from a small cohort of elderly females shows that caffeine intake of more than 371 mg daily is associated with an attenuation in cognitive decline when compared to less than 30 mg daily. This is equivalent to the difference seen over a 7 year span of age. Caffeinated coffee consumption, but not caffeinated chocolate, tea, or cola, was associated with this attenuation in cognitive decline (91088).
Alzheimer disease. It is unclear if oral caffeine is beneficial for preventing dementia; the available research is conflicting. Details: Population research from the UK Biobank has found that caffeine intake up to 400 mg daily is associated with a 24% to 34% reduced risk of developing Alzheimer disease when compared with lower intake. Conversely, population research from the Rush Memory and Aging Project in the US has found that caffeine intake of more than 100 mg daily is associated with a 41% increased risk of developing Alzheimer disease when compared with lower intake. However, when those with mild cognitive impairment at baseline or cases diagnosed within 2 years of follow-up are excluded, these findings become insignificant (108810).
Asthma. Oral caffeine seems to modestly improve airway function for up to 4 hours in patients with mild to moderate asthma. However, it is unclear if oral caffeine has a clinically significant effect on asthma symptoms or quality of life. Details: Taking caffeine 9 mg/kg orally appears to modestly improve airway function for up to 4 hours in people with mild to moderate asthma (37907,37915). However, more research is needed to determine the appropriate dose, whether any benefit is clinically significant, or whether tolerance occurs with chronic dosing.
Cancer pain. It is unclear if intravenous caffeine is beneficial for cancer pain. Details: Clinical research shows that receiving caffeine 200 mg intravenously once daily for 2 days results in a significant reduction in pain intensity by 0.833 points on the NRS scale when compared with control in patients receiving opioids for pain from advanced cancer (91081).
Cognitive function. It is unclear if oral caffeine improves cognitive performance in trained athletes. Details: A meta-analysis of small studies in trained adult athletes shows that consumption of a low to moderate amount of caffeine 15-60 minutes prior to exercise and during exercise improves attention performance, but not reaction time or inhibitory control, when compared with placebo (108797). The validity of these findings is limited by unclear reporting.
Dementia. It is unclear if oral caffeine is beneficial for preventing dementia or improving behavior in patients with dementia. Details: Population research from the Women's Health Initiative has found that caffeine intake of more than 175 mg daily is associated with a 26% reduced risk of developing probable dementia or global cognitive impairment when compared to less than 175 mg daily in postmenopausal adults 65-80 years of age (97458). Population research from the UK Biobank has found that caffeine intake up to 400 mg daily is associated with a 17% to 26% reduced risk for developing all-cause dementia when compared with lower intake. Conversely, population research from the Rush Memory and Aging Project in the US has found that caffeine intake of more than 100 mg daily is associated with a 35% increased risk of developing all-cause dementia when compared with lower intake. However, when those with mild cognitive impairment at baseline or cases diagnosed within 2 years of follow-up are excluded, these findings become insignificant (108810). Caffeine consumption has also been evaluated in patients with dementia. A cross-sectional study in patients with dementia in a care home has found that intake of 'normal' to 'high' amounts of caffeine are associated with reduced agitation and other behavioral symptoms when compared to 'low' intakes of caffeine (104574).
Depression. It is unclear if oral caffeine is beneficial for depression prevention. Details: Some population research found that caffeine intake is associated with an increased incidence of depressive symptoms in pediatric patients (37839,38162). However, other population research found that caffeinated beverage intake is associated with a decreased incidence of depression in adults (37969,38165,91067,100366).
Electroconvulsive therapy (ECT) augmentation. Although there has been interest in using intravenous caffeine sodium benzoate to augment electroconvulsive therapy, there is insufficient reliable information about the clinical effects of caffeine for this condition.
Exercise-induced hypoxemia. It is unclear if oral caffeine is beneficial for hypoxemia associated with exercise. Details: Preliminary clinical research in athletes experiencing exercise-induced hypoxemia shows that taking caffeine 8 mg/kg can improve exercise ventilation, but not ventilatory response or oxygen saturation, when compared with placebo (37750).
Exercise-induced muscle soreness. It is unclear if oral caffeine is beneficial for reducing muscle soreness during exercise. Details: There is conflicting clinical evidence as to whether caffeine can reduce exercise-induced muscle pain. Some evidence shows that taking caffeine 100 mg or 10 mg/kg can reduce muscle pain during exercise when compared with placebo (37622,38146). However, the effect of lower doses is unclear. Some evidence shows that taking caffeine 5 mg/kg may reduce exercise-induced muscle pain when compared with placebo (37747,91050), while other evidence suggests that taking caffeine 2-5 mg/kg does not affect muscle pain during exercise (38141).
Gallbladder disease. It is unclear if increased dietary caffeine intake reduces the risk of developing gallstones. Details: Consumption of caffeinated beverages that provide 400 mg or greater of caffeine per day is associated with a significantly reduced risk of developing symptomatic gallstone disease (3345,8032). The effect seems to be dose-dependent; consumption of 800 mg caffeine per day has the greatest reduction in risk (3345).
Hepatitis C. It is unclear if increased dietary caffeine reduces the risk for hepatitis C-associated severe liver inflammation, although it may reduce the risk of developing advanced fibrosis. Details: A meta-analysis of population research has found that regular consumption of caffeine at doses of at least 123 mg daily is associated with a 48% reduced risk of advanced liver fibrosis when compared to lower caffeine intake in patients with hepatitis C virus (95947). An individual population study also found that higher intake of caffeine from coffee is associated with reduced severity of liver fibrosis in patients with chronic hepatitis C virus. For these patients, the risk of advanced fibrosis is reduced by 14% for each 67 mg of caffeine (37896). However, caffeine intake does not appear to be associated with a reduced risk of moderate to severe liver inflammation in patients with hepatitis C (95947).
Hypnic headache. It is unclear if oral caffeine reduces the pain associated with this rare condition. Details: Anecdotal evidence suggests that drinking a cup of coffee containing caffeine before bed or upon waking up may help alleviate pain associated with hypnic headaches (38078).
Hypotension. It is unclear if oral caffeine is beneficial in people with low blood pressure. Details: Preliminary clinical research shows that consuming caffeinated beverages increase blood pressure in elderly people with postprandial hypotension (11834,11835).
Intermittent claudication. It is unclear if oral caffeine is beneficial for intermittent claudication. Details: Taking a single dose of caffeine 6 mg/kg orally seems to improve walking distance, muscular strength, and endurance in patients with intermittent claudication; however, balance seems to be reduced (38038).
Liver disease. It is unclear if oral caffeine is beneficial for liver disease prevention. Details: Population research found that there is an inverse association between intake of coffee and the incidence of liver cirrhosis (37576,37608). However, it is unclear if this effect of coffee is attributable to caffeine, since other caffeinated beverages do not show this effect.
Multiple sclerosis (MS). It is unclear if oral caffeine is beneficial for the symptoms of multiple sclerosis (MS). Details: A small crossover study in adults with MS shows that taking caffeine 200 mg daily for 12 weeks may modestly improve balance, functional mobility, and MS-related quality of life, but not walking function, when compared to a 2-week placebo run-in period. All patients were told to eliminate all other forms of caffeine from their diets; however, baseline caffeine intake was not recorded (114663). The validity of this study is limited by the small size and heterogeneous nature of the study population, which included patients with various forms of MS at varying levels of severity.
Narcolepsy. It is unclear if oral caffeine is beneficial for narcolepsy. Details: A small clinical study in patients with narcolepsy shows that taking caffeine 200 mg daily in the morning for 1 week does not affect reaction time, but modestly reduces drowsiness, when compared with baseline (103698). The validity of this finding is limited by the lack of a statistical comparison between the treatment and placebo groups.
Neonatal resuscitation. It is unclear if oral caffeine improves the likelihood for successful extubation in preterm infants. Details: Preliminary clinical research in extremely preterm infants requiring mechanical ventilation within the first 5 days of birth shows that early administration of caffeine, given as a loading dose of caffeine citrate 20 mg/kg followed by a maintenance dose of 5 mg/kg daily until extubation, does not reduce mortality or shorten time to first successful extubation when compared to giving a bolus dose of caffeine citrate 20 mg/kg just prior to extubation (97461).
Nocturnal enuresis. Reducing caffeine intake might reduce the frequency of nocturnal enuresis episodes in children. Details: Preliminary clinical research in children aged 6-15 years with primary nocturnal enuresis shows that limiting caffeine intake to less than 30 mg daily reduces the mean number of bedwetting episodes from 3.5 to 2.4 per week, when compared with no change in the group with intakes of 80-100 mg daily. The probability of bedwetting in the caffeine restricted group was about 14% lower than that in the control group (111495).
Nonmelanoma skin cancer. It is unclear if oral caffeine is beneficial for nonmelanoma skin cancer prevention. Details: A review of available population research shows that increased caffeine intake from any source is associated with a 14% reduction in the risk of developing nonmelanoma skin cancer. Consumption of caffeinated coffee, but not decaffeinated coffee, is associated with an 18% reduced risk (97465).
Parkinson disease. Although consuming caffeinated beverages might reduce the risk of developing Parkinson disease, it is unclear if oral caffeine is beneficial for improving symptoms. Also, oral caffeine does not seem to prevent tardive dyskinesia. Details: It is unclear whether caffeine improves some symptoms of Parkinson disease, as results from clinical research are conflicting (91069,95951,95954,103705). One clinical study in Parkinson disease patients with extreme daytime somnolence shows that taking caffeine 100 mg twice daily for 3 weeks and then 200 mg twice daily for 3 weeks results in modest improvements in rigidity and bradykinesia, but inconsistent improvements in drowsiness, when compared with placebo (91069). Other clinical research shows that caffeine 200 mg twice daily does not lead to improvements in motor severity, cognition, or somnolence after 6, 12, or 18 months when compared with placebo (95954). Furthermore, a large retrospective study has found that caffeine consumption of more than 300 mg daily for 18 months in conjunction with dopaminergic therapy does not slow the rate of Parkinson disease progression. This research also shows that a reported consumption of caffeine greater than 300 mg, in conjunction with creatine 10 grams daily for 18 months, may accelerate the rate of Parkinson disease progression (95951). The retrospective nature of this study limits the validity of these findings. Caffeine does not appear to be helpful for reducing the risk of tardive dyskinesia. A retrospective analysis has found no definitive difference in onset of tardive dyskinesia in Parkinson patients consuming more than 204 mg caffeine daily when compared with those consuming less than 68 mg daily (91090). Despite these mainly negative findings, large-scale epidemiological studies have found that people who consume caffeinated beverages, such as coffee, tea, and cola, have a decreased risk of Parkinson disease (37931,91060,91071,103705). Males consuming 3-4 cups (28 oz) of caffeinated coffee per day, or 421-2716 mg total caffeine, seem to have the lowest risk of developing this condition. However, a lower risk is also associated with consumption of as little as 124-208 mg of caffeine (6022). In females, more moderate caffeinated coffee consumption, such as 1-3 cups per day, seems to be best (1238). Caffeine does not appear to provide additional protection from Parkinson disease in cigarette smokers (9236,91060).
Postoperative ileus. It is unclear if oral caffeine is beneficial for improving bowel recovery following colorectal surgery. Research is conflicting and may vary depending on the type of procedure performed. Details: A meta-analysis of two small clinical trials in adults undergoing elective laparoscopic colorectal resection shows that taking caffeine 100-200 mg three times daily, starting on postoperative day 1, does not reduce the time to the first stool, time to first flatus, or length of hospital stay (LOS) when compared with placebo (112732). Another meta-analysis of 8 trials, including the 2 trials discussed previously, pooled 610 patients undergoing open and laparoscopic colorectal procedures. The analysis shows that caffeine taken three times daily, starting either on the day of surgery or on postoperative day 1, reduces LOS and the time to first bowel movement when compared with placebo, tea, or decaffeinated coffee. However, a sub-analysis of only laparoscopic procedures shows no difference in LOS between groups. These findings are limited by high heterogeneity, which appears to be due primarily to differences between open and laparoscopic procedures (114660).
Postoperative pain. It is unclear if intravenous caffeine is beneficial for reducing opioid consumption in adults undergoing surgery. Details: A small clinical study in adults undergoing laparoscopic colorectal and gastrointestinal surgery shows that intravenous caffeine citrate 200 mg at the initiation of surgical closure has no effect on cumulative opioid consumption through postoperative day 3 when compared with placebo. In fact, post-hoc analysis with adjustment for age, sex, comorbidities, history of anxiety or depression, and open surgical conversion suggests an increase in opioid consumption with administration of caffeine when compared with placebo (108809).
Pre-eclampsia. It is unclear if oral caffeine intake affects the risk of gestational hypertension or pre-eclampsia. Details: a meta-analysis of 10 observational studies including about 115,000 pregnant people did not find an association between the level of caffeine intake during pregnancy and the risk of developing gestational hypertension or pre-eclampsia (111485).
Stroke. It is unclear if oral caffeine is beneficial for stroke prevention. Details: Population research has found that increased intake of either caffeinated or decaffeinated coffee is associated with a decreased risk of stroke in females (37804). However, it is not clear if the effect of coffee is attributable to the caffeine component.
Tinnitus. It is unclear if oral caffeine is beneficial in patients with chronic tinnitus. Details: A small clinical study in adults with chronic tinnitus shows that taking a single dose of caffeine 300 mg improves mood and quality of life at 1 hour when compared with baseline. (108805). The lack of statistical comparison to the placebo group limits the validity of these findings. More evidence is needed to rate the effectiveness of caffeine for these uses.

CALCIUM

Dyspepsia. Oral calcium carbonate is approved by the US Food and Drug Administration (FDA) as an antacid. Details: Taking calcium carbonate orally as an antacid is effective for treating dyspepsia (1843). Calcium carbonate has FDA approval as an antacid.
Hyperkalemia. Intravenous calcium gluconate is approved by the US Food and Drug Administration (FDA) for preventing hyperkalemia-induced cardiac abnormalities. Details: Administering calcium gluconate intravenously can reverse electrocardiographic changes and arrhythmias induced by hyperkalemia (12946). Intravenous calcium gluconate is FDA-approved for preventing hyperkalemia-induced cardiac abnormalities.
Hypocalcemia. Oral calcium treats and prevents hypocalcemia. Intravenous calcium is used to treat severe hypocalcemia. Details: Taking calcium orally is effective for treating and preventing hypocalcemia. Intravenous calcium gluconate, acetate, gluceptate, or chloride is effective for severe hypocalcemia or hypocalcemic tetany (12928).
Kidney failure. Oral calcium carbonate or calcium acetate is used as a phosphate binder during kidney failure. Details: Taking calcium carbonate or calcium acetate orally is effective as a phosphate binder. Calcium acetate (PhosLo) appears to control hyperphosphatemia better than sevelamer (Renagel) (12943,12944,38990). Calcium citrate is not recommended for this purpose because it increases aluminum absorption and does not bind phosphate as efficiently as calcium acetate or calcium carbonate (21631). Some clinical research also shows that taking calcium orally reduces blood pressure in patients with kidney failure (975).

Corticosteroid-induced osteoporosis. Oral calcium in combination with vitamin D prevents bone density loss that occurs during long-term treatment with corticosteroids. Details: Taking calcium in combination with vitamin D as adjunctive therapy seems to be effective for reducing bone mineral density loss in people using corticosteroids long-term (982,1046,1830,1831,1832,4462,4463,4464,4465,4466)(4467,12945,38493). One specific product used in clinical research is Oscal (Marion Merrel Dow Inc.), which contains elemental calcium 500 mg per tablet plus vitamin D 125 IU per tablet (982). Another product used is Oscal 250 + D (SmithKline Beecham Healthcare), which contains elemental calcium 250 mg and vitamin D 125 IU per tablet (1046).
Hyperparathyroidism. Oral calcium reduces parathyroid hormone levels in patients with secondary hyperparathyroidism due to kidney failure. Details: Taking calcium orally reduces parathyroid hormone levels in patients with kidney failure and secondary hyperparathyroidism (1827,1828,1829,39174,39425). In elderly women, the combination of calcium and vitamin D reverses secondary hyperparathyroidism and reduces hip fracture risk (8818). Also, population research suggests increased calcium intake from the diet and supplements reduces the risk of primary hyperparathyroidism in women. Supplemental intakes of at least 500 mg/day and dietary intakes of approximately 1100 mg/day are considered to be protective (91353).
Osteoporosis. Adequate calcium intake, from the diet and/or supplements, is recommended for the prevention and treatment of osteoporosis. Details: The Bone Health and Osteoporosis Foundation (BHOF) recommends ensuring adequate calcium intake in line with the recommended dietary allowance (RDA) by age, along with adequate vitamin D intake, for the prevention and treatment of osteoporosis in adults over 50 years of age. Supplementation can be used to augment dietary intake when adequate dietary intake is not feasible (109425). In the US and Canada, foods containing at least 200 mg calcium with less phosphorous content than calcium can be labelled with a health claim regarding the relationship between adequate calcium intake and a reduced risk for osteoporosis (11940,102148). However, calcium supplementation is not recommended specifically for the primary prevention of osteoporosis. The US Preventive Task Force (USPSTF) states that the current evidence is insufficient to assess the balance of benefits and harms of vitamin D and calcium supplementation, alone or in combination, for the primary prevention of fractures in community dwelling adults without osteoporosis (95695). Also, calcium supplements do not seem to be effective for preventing loss of bone mineral density (BMD) during lactation (988), in patients who have had bone marrow transplantation (1817), or in patients who have had renal transplantation (4823,38736,38871). Maximal bone growth occurs in the teenage years, and then BMD in females remains relatively constant until age 30-40. After age 40, bone loss typically occurs at rates of 0.5% to 1% per year. In males, this occurs several decades later. Bone loss is more pronounced if dietary calcium intake is below the RDA, which is the case for many Americans (2571,2578). One meta-analysis of randomized controlled trials in healthy children 7-14 years old shows that fortifying food with calcium 250-1000 mg daily for up to 24 months modestly improves femoral neck BMD, but not hip or spine BMD. However, the included trials did not supplement vitamin D (107232). During the 5 years immediately after menopause, calcium supplementation has very little effect on bone loss (2569,2570,2575,2576). The rapid loss of estrogen causes a high bone resorption rate, which increases serum calcium levels and therefore decreases intestinal absorption of calcium (2570). After this period, the typical rate of bone loss is 2% per year (2572,2576). Taking calcium 1000-1600 mg daily as carbonate, citrate, lactate gluconate, or citrate malate salt decreases this rate by 0.25% to 1% annually (977,979,981,2569,2571,2572,2575,2576,2578,6850)(38978,38980,39064). The greatest reductions (1% or more) are seen in the first 1-2 years of supplementation when bone remodeling foci can be filled (2569,2576). After this period, the differences in rate of loss between supplemented and non-supplemented females are closer to 0.25% per year (2569,2577). A meta-analysis of clinical evidence suggests that there is no additional benefit after 4 years (38980). Small clinical studies have found that continuous calcium supplementation at an average daily dose of 1050 mg, started after menopause and continued for 1.5-4 years, may reduce fracture rates by 26% when compared with no calcium supplementation. The largest of these studies was conducted in nursing home residents who also received daily vitamin D; the benefits of calcium, specifically, are unclear (39386). Some research also suggests that calcium and vitamin D improves primary prevention of osteoporotic fractures in some older individuals with osteoporosis, particularly the elderly and those who are no longer community dwelling (12930,38875,38849,39026,109471). However, not all research is positive. One large clinical trial in elderly adults with a low-trauma fracture show that taking calcium 1000 mg daily with or without vitamin D 800 IU daily for 2-7 years does not reduce the risk of a second fracture when compared with placebo (13073). Another clinical study shows that taking calcium 1000 mg daily plus vitamin D 800 IU daily does not prevent a second fracture in elderly patients, or prevent a first fracture in elderly patients with other risk factors such as low body weight (less than 58 kg, 127.6 pounds), smoking, family history of hip fracture, or fair or poor self-reported health (12929). Also, some exploratory research suggests that supplements may need to be continued indefinitely; in adults over 68 years of age, any effects of 2 years of calcium supplements on BMD appear to be lost within 2 years after discontinuing supplements (6853). Calcium has additive effects when used with other agents such as vitamin D, estrogens, or calcitonin. Whereas calcium alone generally reduces or prevents loss of BMD, combination with other agents can produce small increases in BMD ranging from 0.3% to 3.3% depending on the combination and dosages used (978,980,1836,2570,2571,2572,2576). However, one meta-analysis in healthy adults shows that fortifying foods with calcium 250-1000 mg daily, in conjunction with vitamin D supplementation, for up to 24 months does not improve BMD when compared with control (107232). The full potential of osteoporosis treatments cannot be realized without adequate calcium intake (2569,2570,2571,2572). Advise patients taking agents such as estrogens, calcitonin, bisphosphonates, or raloxifene (Evista) to ensure that their daily calcium intake meets the RDA. Use supplements if necessary. The usefulness of calcium in preventing osteoporosis in males is not as well-studied. Some observational research has found that calcium 870 mg daily is not associated with changes in BMD and bone loss in males (97201). However, clinical evidence suggests that taking calcium 1000 mg daily for 2 years might improve trabecular or cortical bone mass by 2% to 4% (980,8827,8873). Dietary supplementation with calcium and vitamin D seems to moderately reduce bone loss measured in the femoral neck, spine, and total body, and seems to reduce the incidence of nonvertebral fractures in older patients with osteopenia or low BMD (980).
Premenstrual syndrome (PMS). Adequate calcium intake seems to prevent symptoms of PMS. Details: There seems to be a link between low dietary calcium intake and symptoms of PMS (2004,6847,39007). Taking calcium 1000-1336 mg daily seems to significantly reduce depressed mood, water retention, and pain, especially if daily calcium intake is inadequate (1822,1823,1824,2004,95821). Calcium carbonate 1200 mg daily seems to decrease PMS symptom scores by about 18% when compared with placebo (1822). Increasing dietary calcium intake is also associated with a decreased risk of developing PMS. Consuming an average of 1283 mg of calcium per day from foods is associated with about a 30% lower risk of developing PMS compared with consuming an average of 529 mg daily (13094); however, taking calcium supplements does not appear to be associated with the risk of developing PMS.

Colorectal cancer. Oral calcium seems to be beneficial for preventing colorectal cancer, especially in those with adequate vitamin D levels and normal body mass index (BMI). Details: Population studies have found that increased intake of dietary or supplemental calcium is associated with a reduced risk of colorectal cancer and colorectal adenomas (1047,8820,12120,38951,98898,98899). Clinical trials and meta-analyses of clinical research also show that taking calcium supplements 1.2-2 grams daily for up to 4 years can reduce the risk of colorectal adenoma recurrence by up to 29% (970,12118,12950,15267,34596,38718,39042,95817). However, not all research has been positive. Some meta-analyses of clinical research or observational studies suggest that taking calcium does not reduce the risk of familial adenomatous polyposis or colorectal cancer (34596,39042,39349). Other contradictory research suggests that postmenopausal females who take calcium 1000 mg daily plus vitamin D 400 IU daily do not have a reduced risk of developing colorectal cancer (14290); however, this finding may not be reliable due to the high baseline intake of calcium in study participants. The reason for these conflicting findings is not entirely clear. Vitamin D might be an important factor. People with lower than average vitamin D levels do not seem to get any benefit from calcium supplements (12118). Also, one meta-analysis of previous trials suggests that taking calcium 1200 mg daily reduces the risk of colorectal adenomas in people with a normal BMI, but not in those who are overweight or obese (99715). Despite this conflicting evidence, the US Food and Drug Administration (FDA) approved a qualified health claim in 2005 stating that calcium supplements may reduce the risk of colorectal cancer and colorectal adenomas. However, the FDA has determined that there is little scientific evidence to support this claim (102366).
Fetal bone mineralization. If calcium intakes are low during pregnancy, oral calcium seems to be beneficial for increasing fetal bone density. Details: With low dietary calcium intake (less than 562 mg elemental calcium daily) during pregnancy, calcium supplementation increases fetal bone mineralization and density. However, calcium supplementation does not offer any additional benefit if calcium intakes are adequate (3263,3264).
Hypertension. Oral calcium seems to reduce blood pressure by a small amount. However, it is unclear if this reduction is clinically significant. Details: Many clinical trials and observational studies show that intake of calcium supplements or dietary calcium modestly reduces blood pressure in patients with or without hypertension, usually around 1-2 mmHg. Calcium seems to be more effective for certain subpopulations of patients, such as salt-sensitive people and patients with low baseline dietary calcium intake (945,972,974,976,984,1818,1819,1820,1821,6852)(13138,14406,38803,39063,39094,39221). Also, a meta-analysis of clinical research shows that calcium intake during pregnancy reduces systolic blood pressure in offspring by 1-2 mmHg (38852). However, a large-scale clinical trial in postmenopausal females shows that taking vitamin D (cholecalciferol) 400 IU daily in combination with elemental calcium 1000 mg daily does not lower blood pressure or reduce the risk of developing hypertension (16714). Additionally, a meta-analysis of 8 clinical trials shows that taking calcium in combination with vitamin D for up to 7 years has no effect on blood pressure (98861). The validity of this finding is limited by the poor methodological quality of the included studies. Some observational research suggests that calcium can reduce the risk for hypertension. Population research in females aged 45 years and older suggests that higher intake of calcium from both diet and supplement sources is linked to a lower risk of developing hypertension when compared to lower calcium intake (14265). In 2005, the US Food and Drug Administration (FDA) approved a qualified health claim stating that calcium supplements may reduce the risk of hypertension. However, the FDA has concluded that this claim is based on supporting, rather than conclusive, evidence (102367).
Osteomalacia. Oral calcium seems to reverse osteomalacia caused by very low calcium intakes. Details: Osteomalacia is commonly caused by vitamin D deficiency; however, very low calcium intake can also lead to osteomalacia in children and adults. Calcium supplementation can reverse osteomalacia caused by calcium deficiency. Along with appropriate vitamin D supplementation, individuals at risk of osteomalacia need sufficient calcium intake (94819).
Pre-eclampsia. Oral calcium seems to reduce the risk of pre-eclampsia in high risk pregnancies, especially if calcium intakes are low. Details: Although there is some conflicting evidence (971,38756), most clinical research shows that taking calcium orally 1-2 grams daily reduces pregnancy-related hypertension and pre-eclampsia (973,1833,8828,39043,39319,39426,96480). Calcium appears to reduce the risk of pre-eclampsia by about 50% when compared with placebo. One meta-analysis of 19 controlled trials involving over 29,000 pregnancies found that for every 19 females treated with calcium, one episode of pre-eclampsia would be avoided (96480). Calcium appears to have the greatest effect in individuals at high-risk of pre-eclampsia or with low calcium levels, and when taken at greater than or equal to 20 weeks of gestation (15029,38497,96480,99714). In 2005, the US Food and Drug Administration (FDA) approved a qualified health claim regarding the use of calcium supplements to reduce the risk of pregnancy-induced hypertension and pre-eclampsia. However, due to the limited and conflicting research available at that time, the FDA stated that this outcome was highly unlikely. Since then, large, high-quality clinical research has supported this finding. In fact, in 2016 the World Health Organization (WHO) released a recommendation to prescribe oral calcium supplementation 1.5-2 grams daily during pregnancies at high risk of pre-eclampsia if dietary calcium intakes are low, in order to prevent pre-eclampsia (97347).
Rickets. Oral calcium seems to reverse rickets caused by very low calcium intakes. Details: Rickets is commonly caused be vitamin D deficiency; however, very low calcium intake can also lead to rickets. Calcium supplementation can reverse rickets caused by calcium deficiency (94819). A small clinical study in children with nutritional rickets shows that taking calcium 500-2000 mg daily for 24 weeks improves radiographically measured rickets caused by calcium deficiency. Rickets seems to improve more rapidly with calcium 1000 mg compared to calcium 500 mg. However, increasing the calcium dose to 2000 mg daily is not more beneficial than calcium 1000 mg daily (98904).
Tooth retention. Oral calcium with vitamin D seems to help with tooth retention in the elderly population. Details: A clinical trial in the elderly population shows that taking calcium citrate malate 500 mg daily along with vitamin D3 (cholecalciferol) 700 IU daily orally for 3 years reduces the risk of tooth loss by about 52% when compared with placebo (8816).

Breast cancer. Oral calcium does not seem to be beneficial for breast cancer prevention. Details: Although some population research disagrees (15631,39041,95811,107237), most research shows that increased calcium intake is not associated with a reduced risk of breast cancer (15631,16715,98895,107236,107237). Subgroup analyses of population research suggest that calcium intake may reduce the risk of breast cancer in postmenopausal, but not pre-menopausal, adults (15631,107237). Another subgroup analysis in a large meta-analysis of population research also suggests that dietary intake may reduce estrogen receptor(ER)-negative breast cancer, but not ER-positive breast cancer (107236). However, most other research has not evaluated the effects of calcium supplementation or intake on breast cancer subtypes. The best evidence to date, from a large scale clinical trial (Women's Health Initiative), shows that taking vitamin D (cholecalciferol) 400 IU daily plus calcium 1000 mg daily for 7 years after menopause does not reduce the risk of developing invasive breast cancer at the end of the study and 5 years after the end of the intervention (16715,98895).
Fractures. Although oral calcium prevents fractures in osteoporosis, most evidence shows that calcium does NOT prevent factures in people who do not have osteoporosis. See Osteoporosis discussion for more information on the use of calcium for this purpose. Details: The most recent and robust meta-analysis of clinical research shows that calcium supplementation with or without vitamin D is NOT associated with reduced fractures in older adults without osteoporosis (95822). A large-scale study in postmenopausal females aged 50-79 years suggests calcium 1000 mg plus vitamin D 400 IU daily for 7 years only modestly improves bone mineral density (BMD) and does not significantly reduce fracture risk. This lack of effect may have been due to low adherence to the treatment regimen. In those who were 80% adherent, the combination of calcium plus vitamin D reduced the risk of hip fracture by about 29% (14282). Also, some clinical research shows that taking calcium carbonate 1000 mg and vitamin D 400 IU for 5 years does not attenuate loss of height after menopause when compared with placebo (95810). Additional meta-analyses of clinical and observational evidence suggest that calcium supplementation is not associated with a reduced risk of vertebral or nonvertebral fractures, such as hip fractures (38589,38888,98895). Some other research has suggested that calcium in combination with vitamin D reduces fracture risk in older patients without osteoporosis (980,1836,8818,12930,12933,12952,38849,102145,107235); however, this research is confounded by a number of variables, including the presence of hormonal therapy and differing levels of fracture risk at baseline (1836,8818,95822). Conflicting findings on this topic might also be due to genetic differences in patient populations. A population analysis of the Women's Health Initiative study found that, in older females with the lowest genetic susceptibility to low bone mineral density (BMD), taking calcium with vitamin D is associated with a reduction in fracture risk. However, in females with a higher genetic susceptibility to low BMD, there is no association between supplementation and fracture risk. This might be because individuals with a lower susceptibility to low BMD are also more responsive to calcium and vitamin D supplementation (97357). As of April 2018, the U.S. Preventative Services Task Force (USPSTF) concludes that there is insufficient evidence to determine whether supplementing with vitamin D >400 IU daily along with calcium >1000 mg daily is safe and effective for preventing fractures in community dwelling adults without vitamin D deficiency, osteoporosis, or a history of fracture. USPSTF recommends against supplementing with calcium 1000 mg daily or less along with vitamin D 400 IU daily or less for preventing primary fractures in community-dwelling postmenopausal females (95695).
Obesity. Oral calcium does not seem to improve weight loss. Details: Observational research has found that adults and children with low calcium intake are more likely to gain weight, have a higher body mass index (BMI), and be overweight or obese when compared to people with high calcium intake (12124,12125,12126,12127,14265). Additional observational research has found that increasing calcium intake is associated with weight loss in females; the results in males have been conflicting (12127,15602,15603). Despite these findings from observational research and a few small clinical studies (12128,15397,14438,98905), most clinical research has found that increased calcium intake does not increase weight loss (12052,13138,15396,15399,38985,39004,97356). The most recent meta-analysis of 20 clinical studies shows that daily dietary and supplemental calcium intake that meets the dietary reference intake (DRI) of 1000 mg or more daily does not increase weight loss in overweight individuals or patients with obesity when compared with intake below the DRI (95813). An older meta-analysis of 13 clinical trials also shows that increased dietary and supplemental calcium intake does not increase weight loss (15605).
Overall mortality. Oral calcium does not seem to reduce overall mortality. Details: While some population research has found that calcium taken in combination with vitamin D in older females is associated with a lower risk of death (97353), most evidence shows that calcium, with or without vitamin D, has no effect on all-cause mortality (93533,97308).

INEFFECTIVE

Cardiovascular disease (CVD). Oral calcium does not reduce the risk of developing CVD and may actually increase risk in some patients. Details: Clinical research shows that calcium does not decrease CVD risk. Several separate meta-analyses of clinical and population research involving over 50,000 patients show that taking calcium 600-1200 mg daily for up to 7 years does not reduce the risk of CVD-related outcomes, including stroke and myocardial infarction, cardiovascular death, or overall mortality (39018,91350,92994,93533,97308,98902,107231,107233). No association was found between total dietary or supplemental calcium intake with or without vitamin D and the risk of CVD or mortality (91350,93533,97308). In fact, some population and clinical research has found that when calcium is used alone or with vitamin D, there is an INCREASED risk of CVD and coronary heart disease (38077,107233). However, other clinical research disagrees (93533). One meta-analysis of high-quality randomized controlled trials shows that taking calcium for 2-7 years increases the risk of CVD and coronary heart disease by 1.1-1.2 times when compared with control. However, the majority of the included research evaluated postmenopausal females and it is unclear if this finding is applicable to other populations (107233).
Chemotherapy-induced peripheral neuropathy. Intravenous calcium does not prevent nerve pain in patients given oxaliplatin. Oral calcium has not been evaluated for this purpose. Details: While pooled analyses of cohort studies and randomized controlled trials suggest that calcium and magnesium infusion decreases the incidence of oxaliplatin-induced neurotoxicity, a meta-analysis of only randomized controlled trials shows that the infusion has no effect in preventing neurotoxicity (90028,90029,90031). Additionally, clinical trials show that administering calcium gluconate 1 gram with magnesium sulfate 1 gram intravenously immediately before, or before and after, the administration of a single oxaliplatin cycle (90005), or over the entire 6-cycle course of oxaliplatin, does not improve symptoms of neurotoxicity when compared with placebo (96474).
Myocardial infarction (MI). Oral calcium does not prevent MI. When taken in the absence of vitamin D, oral calcium may increase the risk of MI. Details: Population research has found that increased dietary intake of calcium is associated with a decreased risk of MI (91350). However, a 2010 meta-analysis of clinical research shows that taking calcium at a dose of at least 500 mg daily is associated with an approximate 30% INCREASE in the risk of MI in patients over the age of 40. According to this analysis, one additional case of MI will occur for every 69 patients that take calcium for 5 years (17482). A more recent meta-analysis of high-quality randomized controlled trials shows that taking calcium for 2-7 years increases the risk of MI by 1.2 times when compared with control. However, the majority of the included research studied postmenopausal females and it is unclear if this finding is applicable to other populations (107233) In contrast, other meta-analyses of clinical research have shown that taking calcium for up to 7 years is NOT associated with an increased risk of MI, including a meta-analysis that only included postmenopausal females (93533,107231). Reasons for these discrepancies are not entirely clear. It may relate to whether calcium is taken as monotherapy or in combination with vitamin D. When taken with vitamin D, which is commonly recommended, calcium supplementation does not appear to be associated with an increased risk of MI in postmenopausal females (93533). Also, the association between calcium supplementation and MI risk may be influenced by the amount of calcium consumed as part of the diet. Supplementation with calcium may be associated with an increased risk of MI in people with dietary calcium intake above 805 mg daily, but not in those with dietary calcium intake below 805 mg daily (17482)

Alcohol use disorder. It is unclear if oral calcium is beneficial for alcohol use disorder. Details: Preliminary clinical research shows that taking calcium carbonate 800 mg and vitamin D 200 IU orally daily for 14 days modestly reduces alcohol craving scores and withdrawal scores when compared with placebo in adults with alcohol dependence that are undergoing withdrawal. Taking calcium carbonate did not reduce the need for diazepam; however, the study may have been inadequately powered to detect a difference between groups (107234).
Atherosclerosis. It is unclear if oral calcium is beneficial for atherosclerosis. Details: A population study has found that taking calcium 1.2 grams daily for 3 years has no effect on carotid intima thickness or carotid atherosclerosis incidence. A total calcium intake (dietary and supplemental) of at least 1794 mg daily in older females may be associated with a decreased risk of carotid atherosclerosis when compared with a total calcium intake below 1010 mg daily (97351).
Autism spectrum disorder. It is unclear if oral calcium during pregnancy is beneficial for reducing the odds of autism spectrum disorder in the offspring. Details: A small observational study found that calcium supplementation during pregnancy is associated with a 52% reduced odds of an autism spectrum disorder in the offspring (98900).
Cancer. Oral calcium alone does not seem to prevent cancer. It is unclear if oral calcium with vitamin D is beneficial for preventing cancer. Details: Taking calcium alone does not seem to significantly reduce the risk of cancer (12118,15629). The role of calcium in cancer prevention when taken along with vitamin D is controversial, as conflicting results exist. One clinical trial shows that healthy postmenopausal females who take supplemental calcium 1400-1500 mg daily plus vitamin D3 (cholecalciferol) 1100 IU daily have a 60% lower relative risk for developing cancer of any type. Approximately 25 postmenopausal females would need to take this combination for 4 years to prevent one occurrence of cancer (15629). However, a more recent clinical study shows that healthy postmenopausal females who take supplemental calcium 1500 mg daily plus vitamin D3 (cholecalciferol) 2000 IU daily do not have a reduced risk of cancer at 4 years (93943). Reasons for the disparate results are not entirely clear. The discrepancies do not appear to be related to baseline vitamin D levels or different study populations. It is possible that, given the 10-year time lapse between the two publications, the discrepancies result from differences in cancer detection capability. Also, since cancer risk was a secondary outcome measure in the earlier study and a primary outcome measure in the more recent study, it is possible that the discrepancies result from differences in statistical methodologies. The effect of vitamin D and calcium on cancer risk in males and younger patients is not known. There is also interest in using calcium for reducing the risk of hematological malignancies. An analysis of the Women's Health Initiative study shows that taking calcium 1000 mg daily in combination with vitamin D3 400 IU for up to 10 years is associated with a 20% reduction in the risk of hematologic malignancies when compared with placebo. However, no effect on hematologic malignancy related mortality was seen (97354).
Depression. It is unclear if oral calcium is beneficial for depression prevention. Details: Population research has found no association between a higher dietary intake of calcium and the risk of depression when compared with a lower dietary intake of calcium (96480).
Diabetes. It is unclear if oral calcium is beneficial for type 2 diabetes prevention. Details: Some population research has found that a higher intake of calcium from diet or supplements, alone or in combination with vitamin D, is associated with a lower risk of developing type 2 diabetes when compared with lower calcium intake (14265,16713,96473). However, population research is often limited by confounding variables. For example, one analysis found that any beneficial effect might be influenced by concomitant magnesium intake (96473). Furthermore, other population research has found that serum calcium levels higher than 9.6 mg/dL are associated with greater risk of developing diabetes in Chinese adults with osteoporosis. This study is limited because it was not determined whether increased serum calcium was due to increased calcium intake or another factor such as parathyroid function (95815).
Dysmenorrhea. It is unclear if oral calcium is beneficial for reducing pain associated with dysmenorrhea. Details: Clinical research shows that taking calcium carbonate 1000 mg with vitamin D 5000 IU daily for three menstrual cycles does not reduce pain when compared with placebo in patients with primary dysmenorrhea (95821). However, calcium carbonate 1000 mg taken alone seems to reduce pain when compared with placebo.
Endometrial cancer. It is unclear if oral calcium is beneficial for endometrial cancer prevention. Details: A meta-analysis of population research suggests that calcium supplements may reduce the risk of endometrial cancer, but dietary calcium does not seem to have any effect (38893).
Fall prevention. It is unclear if oral calcium with vitamin D is beneficial for preventing falls. Details: Research suggests that calcium in combination with vitamin D, but not calcium alone, might prevent falls by decreasing body sway and normalizing systolic blood pressure (6362,11939,39038). Some experts think the combination of calcium and vitamin D may be important (11916). Preliminary clinical research in adults residing in a health care facility shows that taking vitamin D supplements while increasing dietary calcium and protein for 2 years reduces falls by 11% when compared with standard diets. Intervention diets were supplemented with milk, yogurt, and cheese to provide calcium 1142 mg and protein 69 grams daily (107235). There might also be different effects in females compared to males. In one study, females aged 65 years or older who took vitamin D 700 IU plus calcium citrate 500 mg daily over a 3-year period had a 46% lower risk of falling. However, this combination did not decrease falls in males (14291).
Fluorosis. Oral calcium has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Taking calcium orally, in combination with ascorbic acid (vitamin C) and vitamin D, seems to be effective for reducing excessive fluoride levels in children and improving symptoms of fluorosis in children aged 6-12 years (990).
Heart failure. It is unclear if oral calcium in combination with vitamin D is beneficial for preventing heart failure. Details: Based on a secondary analysis of a large-scale clinical trial (Women's Health Initiative), taking calcium 1000 mg with vitamin D 400 IU daily does not reduce the risk of heart failure in the overall population or in individuals at high risk. However, in a subgroup of postmenopausal females without risk factors for heart failure, calcium and vitamin D supplementation might reduce the risk of developing heart failure by about 37% (97307).
Hypercholesterolemia. It is unclear if oral calcium is beneficial for hypercholesterolemia. Details: Some evidence shows that taking calcium carbonate 400 mg three times daily reduces low-density lipoprotein (LDL) cholesterol levels by 4% and increases high-density lipoprotein (HDL) cholesterol levels by 4% after 6 weeks of treatment when used in combination with a low-fat diet (American Heart Association Step 1) (2557). In contrast, a study in females with dyslipidemia shows that taking calcium 800 mg daily for 2 years might INCREASE total cholesterol levels by about 12 mg/dL when compared with placebo. This same study showed an association between calcium supplementation and an increase in total cholesterol levels and carotid intimal thickness in postmenopausal females, but not premenopausal females (97350). A recent meta-analysis of randomized controlled trials which included both healthy patients and patients with dyslipidemia shows that taking calcium 500-2000 mg daily and vitamin D 200-7142 IU daily modestly improves HDL cholesterol and triglyceride levels, but not LDL cholesterol levels, when compared with placebo. Subgroup analyses suggest that calcium and vitamin D supplementation is more effective in patients with dyslipidemia at baseline. It is unclear if this effect is due to calcium, vitamin D, or the combination (107227). However, other research shows that taking a specific supplement containing calcium 600 mg plus vitamin D 200 IU (Caltrate 600 D, Wyeth Consumer Healthcare Inc.) twice daily in combination with calorie restriction does not reduce total or LDL cholesterol levels when compared with placebo (15601).
Lead toxicity. It is unclear if oral calcium is beneficial for reducing blood levels of lead. Details: Lead is mobilized along with calcium from bone during pregnancy and lactation, resulting in increased serum concentrations of lead. One clinical study suggests that calcium supplementation does not significantly decrease these elevated lead concentrations (1586). However, another clinical study suggests that taking calcium reduces blood lead levels by 11% when compared with placebo, with greatest effects observed in those with high baseline levels of lead (38957).
Lyme disease. Although there is interest in using oral calcium for Lyme disease, there is insufficient reliable information about the clinical effects of calcium for this condition.
Metabolic syndrome. It is unclear if oral calcium alone or with vitamin D is beneficial for metabolic syndrome prevention. Details: Population research has found that a higher intake of calcium from diet and supplements alone, or in combination with vitamin D, is associated with a lower risk of developing metabolic syndrome when compared with lower calcium intake (14265,16713).
Nephrotic syndrome. It is unclear if oral calcium with vitamin D is beneficial for preventing nephrotic syndrome. Details: Clinical research shows that taking calcium 500-1000 mg daily for 3 months in combination with vitamin D3 60,000 IU daily or weekly for 4 weeks has no effect on bone mineral density or the risk of relapse in children with steroid-sensitive nephrotic syndrome (97355).
Nonmelanoma skin cancer. It is unclear if oral calcium is beneficial for preventing keratinocyte carcinomas. Details: In middle aged and older adults recently diagnosed with a colorectal adenoma, clinical research shows that taking calcium 1200 mg daily as calcium carbonate for 3-5 years does not reduce the incidence of keratinocyte cancer when compared with placebo over a median of 8 years. A sub-group analysis shows that taking calcium alone or with vitamin D3 1000 IU daily reduced the risk of invasive cutaneous squamous cell carcinoma by a moderate amount, but had no effect on the risk of basal cell carcinoma (104622).
Oral mucositis. When used in combination with fluoride treatments, a calcium phosphate mouth rinse seems to prevent and reduce mucositis-related pain in patients undergoing hematopoietic stem cell transplantation (HSCT). Details: A small clinical study in patients undergoing HSCT shows that using a particular mouth rinse (Caphosol, EUSA Pharma) containing calcium phosphate, in combination with fluoride treatments, reduces days of mucositis, the duration of pain, and the dose and days of morphine used when compared with placebo and fluoride treatment (38611).
Ovarian cancer. It is unclear if oral calcium is beneficial for ovarian cancer prevention. Details: An older meta-analysis of 12 cohort studies found that dietary calcium intake is not associated with a reduced risk of ovarian cancer (38792). However, a more recent pooled analysis of 15 cohort and case-control studies has found that the highest intake of dietary or dairy calcium is associated with a 20% lower risk of ovarian cancer when compared to the lowest intake (97349).
Postpartum depression. It is unclear if oral calcium is beneficial for reducing postpartum depression risk. Details: Preliminary clinical research shows that taking calcium 2 grams daily beginning at 11-21 weeks gestation reduces depression at 12 weeks postpartum when compared with placebo. However, no benefit is seen at 6 weeks postpartum (39447).
Pregnancy-related leg cramps. It is unclear if oral calcium is beneficial for preventing leg cramps during pregnancy. Details: A small clinical study shows that taking calcium 1 gram twice daily (as a mixture of salts) for 2 weeks can reduce pregnancy-related leg cramps during the second half of pregnancy when compared with no treatment (2567).
Prostate cancer. It is unclear if oral calcium is beneficial for prostate cancer prevention. Details: Some clinical research shows that taking calcium 1200 mg daily might decrease the risk of developing prostate cancer (14133). However, some epidemiological research suggests that consuming very high doses of calcium, over 2000 mg daily, might actually increase the risk of developing prostate cancer (14134). Some epidemiological research also suggests that doses greater than 1500 mg daily increase the risk of poorly differentiated, clinically advanced, and fatal prostate cancer (14132). Consumption of dairy products has also been weakly linked to a modest increase in risk of prostate cancer (98894). However, contradictory research suggests that there is no association between dietary intake of calcium and overall risk of prostate cancer (14131,14132,104630).
Stroke. It is unclear if oral calcium is beneficial for stroke prevention. Details: Some population research has found that increasing dietary calcium intake is associated with a decreased risk of ischemic stroke (4822,38678). However, other population research has found that increasing dietary calcium intake is not associated with a decreased risk of stroke (91350). One meta-analysis of high-quality randomized controlled trials shows that taking calcium for 2-7 years does not affect the risk of stroke when compared with control. However, the majority of the included research evaluated postmenopausal females, and it is unclear if this finding is applicable to other populations (107233).
Vertigo. Oral calcium with vitamin D might reduce positional vertigo; the effect of calcium when used alone is unclear. Details: A large clinical study in adults with recurrent benign paroxysmal positional vertigo shows that taking calcium 500 mg and vitamin D 400 IU twice daily for one year reduces annual recurrence of vertigo by 27% when compared with no treatment. The number needed to treat to prevent vertigo was 3.7 (103681). It is unclear if this benefit is due to vitamin D, calcium, or the combination. More evidence is needed to rate calcium for these uses.

COFFEE (natural Coffee bean extract powder, Coffeeberry organic Coffee (fruit) extract)

Mental alertness. Consumption of caffeinated coffee attenuates changes in alertness and cognitive capacity that occur throughout the day. It also improves mental performance and alertness following sleep deprivation. Details: Consumption of coffee and other caffeinated beverages seems to prevent a decline in alertness and cognitive capacity when consumed throughout the day (4221,4224). Caffeine can improve mental performance and alertness following prolonged sleep deprivation (10205). With respect to mental alertness while driving, some research shows that drinking a single cup of coffee containing 80 mg caffeine in 180 mL during a 15-minute rest after simulated driving for 2 hours reduces the amount of weaving and increases speed consistency in the 3rd and 4th hours of driving when compared with drinking decaffeinated coffee. Overall, the mental effort needed to drive, driving quality, and feelings of sleepiness appear to improve with caffeine consumption (93875).

Diabetes. Population research has found that consumption of caffeinated coffee is associated with a reduced risk of developing type 2 diabetes. Consumption of coffee also seems to be associated with a reduced risk of mortality in patients with type 2 diabetes. Details: Population research suggests that consumption of caffeinated coffee is associated with a dose-dependent reduced risk of developing type 2 diabetes (11353,11731,14313,38174,91040,91055,111040). Some research suggests that increasing coffee consumption by 1 cup daily is associated with a 6% to 9% reduction in the incidence of type 2 diabetes (91040,91055). In North American adults, consuming 6 or more cups of coffee daily is associated with a 29% lower risk of developing diabetes in females and a 54% lower risk in males (11353). Research in European adults suggests that drinking 5-6 cups of coffee daily appears to reduce diabetes risk by 61% in females and 30% in males. Drinking 10 or more cups daily reduces diabetes risk by 79% in females and 55% in males (11731). Additional research suggests that drinking 3-4 cups of coffee daily reduces the risk of diabetes by 23% to 42% when compared with drinking just 1 cup daily (14343,38174). An analysis of these and other cohort studies involving over 457,000 patients suggests that drinking 3-4 cups of coffee or decaffeinated coffee daily is associated with a 25% to 35% reduced risk of type 2 diabetes when compared with drinking 2 cups or less daily. Each additional cup of coffee consumed each day is associated with a 5% to 10% reduction in the incidence of type 2 diabetes (97368). Some population research in patients with previous gestational diabetes has also investigated the association between consumption of coffee and risk of developing type 2 diabetes. Research suggests that consumption of at least 4 cups of caffeinated coffee daily is associated with a 54% reduced risk of type 2 diabetes when compared with drinking no coffee. There is no association between consumption of decaffeinated coffee and type 2 diabetes risk (111040). Coffee consumption has also been evaluated in patients with type 2 diabetes, with mixed findings. Most population research suggests that coffee consumption is associated with a reduced risk of mortality in patients with type 2 diabetes. In one meta-analysis of observational studies, drinking high amounts of coffee was associated with a 24% reduction in mortality risk, with a 9% reduction for each additional cup of coffee (104595). In another meta-analysis, drinking up to 4 cups of coffee daily was associated with a 19% reduction in all-cause mortality and a 34% reduction in coronary heart disease (CHD) mortality when compared with not drinking coffee. Reductions in cardiovascular disease (CVD) mortality were only significant when one large study was excluded during sensitivity analyses (107836). Results of individual studies are conflicting (37805,97374,104589,104594). Additionally, a cross-sectional study in older adults with type 2 diabetes has examined the relationship between coffee consumption and CVD risk factors. This study suggests that higher coffee consumption is associated with lower fasting plasma glucose and diastolic blood pressure and higher high-density lipoprotein (HDL) cholesterol and triglyceride levels (107825). Population research has examined the relationship between coffee consumption and change in kidney function in patients with type 2 diabetes. One study in patients with normal kidney function suggests that drinking any coffee is associated with up to a 25% prevention in kidney function decline when compared with no coffee consumption. Kidney function decline was based on estimated glomerular function rate (eGFR) measurements (111043).
Heart failure. Consumption of caffeinated coffee seems to reduce the long-term risk of heart failure in those without cardiovascular disease (CVD) at baseline. Details: A meta-analysis of three large population studies, the Framingham Heart Study (FHS), Cardiovascular Heart Study (CHS), and Atherosclerosis Risk in Communities (ARIC) study, has found that increased daily coffee consumption is associated with a reduced long-term risk of heart failure in individuals without CVD at baseline. Drinking at least 2 cups of coffee daily is associated with a 29% to 31% reduced risk of heart failure. In the analysis, total caffeine intake, but not decaffeinated coffee intake, was associated with a reduced risk of heart failure (104597).
Overall mortality. Consumption of coffee seems to reduce all-cause mortality. The effects of coffee on specific causes of mortality are variable. Details: Population research conducted in almost 4 million international individuals suggests that long-term, daily consumption of coffee is associated with an 8% to 28% reduction in all-cause mortality when compared to low or no coffee consumption (97373,97374,103997,103998,104594,104595,105308,105311,105314,107826)(107833,107839,111033), though not all research agrees (107822). The strongest association is seen for individuals consuming 2-4 cups of coffee daily and in never smokers. Most research suggests that consuming ground, instant, or decaffeinated coffee is associated with similar reductions in mortality (97373,97374,103997,103998,104594,104595,105308,105311,105314,107833)(111033). The use of sweeteners might affect the association of coffee consumption with all-cause mortality. Population research suggests that consumption of unsweetened coffee, in amounts ranging from any to up to 4.5 cups daily depending on type of coffee, is associated with a reduction in mortality of 14% to 39% when compared with no coffee consumption. Consumption of 1.5 to 3.5 cups of sugar-sweetened coffee is associated with a reduction in mortality of approximately 30%; however, this association does not occur with higher coffee intakes or the consumption of decaffeinated coffee. Any association between the consumption of artificially sweetened coffee and mortality is unclear. When subgroup analyses were conducted to determine the association of coffee consumption with cause-specific mortality, coffee consumption was associated with a reduction in cardiovascular mortality. In some analyses, this association is for ground or decaffeinated, but not sweetened, instant, or unfiltered, coffee (97373,97374,103997,103998,104594,104595,105308,105311,105314,107833)(111032). In another analysis, consumption of coffee was inversely associated with deaths from chronic respiratory diseases, diabetes, pneumonia and influenza, and intentional self-harm. There were no associations between coffee consumption and deaths from accidents, Alzheimer disease, or kidney disease (105311). The association between coffee consumption and cancer-related mortality is less clear. Although one large meta-analysis of population research suggests that consumption of approximately 2 cups of coffee daily is associated with a 4% decrease in cancer-related mortality, the results of individual studies are mixed. One large population cohort suggests that ground or instant caffeinated coffee consumption is associated with up to a 27% reduction in cancer mortality (97374), while other analyses show no association (97373,103994,105308,105311,107822). The reasons for this discrepancy are not clear but may be related to smoking status or use of sweeteners. In one meta-analysis, consumption of each additional cup of coffee daily is associated with a 2% decrease in cancer-related mortality in non-smokers, as opposed to an increased risk in smokers (105308). Other population research suggests that only intake of unsweetened coffee, and not sugar-or artificially-sweetened coffee, is associated with a reduced risk of cancer-related mortality (111032).
Parkinson disease. Consumption of coffee seems to reduce the risk of developing Parkinson disease. This effect seems to be dose related in males, but not in females. Details: There is evidence that the risk of Parkinson disease is lower in people who consume caffeinated beverages such as coffee, tea, and cola. For males, the effect seems to be dose related. Males consuming the greatest amount of caffeinated coffee, 28 ounces (three to four cups) or a total of 421-2716 mg of caffeine from any source daily, seem to have the greatest reduction in risk. However, a significant reduction in risk exists even with consumption of as little as approximately 1-2 cups of coffee, or 124-208 mg of caffeine, daily (6022). In females, the effect does not seem to be dose related. Moderate consumption of caffeinated coffee, 1-3 cups daily, provides the greatest reduction in risk (1238). Coffee does not appear to provide additional protection from Parkinson disease in cigarette smokers (9236).
Postoperative ileus. Consumption of coffee seems to decrease the time to first stool and first flatus, and possibly time to discharge, after gynecological or colorectal surgeries. Details: Meta-analyses of mainly small clinical trials in patients who have undergone gynecological or colorectal surgeries show that drinking coffee decreases the time to the first stool and time to tolerating solid food by about 10-15 hours when compared with no treatment or drinking water or tea (103991,111035,112732). Although one meta-analysis found that drinking coffee does not reduce the length of hospital stay (103991), other research shows that hospital stay is reduced by up to 1.5 days; however, the validity of these results are limited by high heterogeneity. In addition, sub-analyses suggest that benefit is limited to gynecological surgery and not colorectal surgery or caesarian section (97386,111035,112732). Sub-analyses also suggest that drinking coffee does not improve bowel function after caesarian section (103991,111035). Caffeinated coffee has been most commonly consumed as 100 mL three times daily starting after surgery and until the first stool. Some studies have used decaffeinated coffee (93876,97386,103991,111035,111039).

Esophageal cancer. Consumption of coffee does not seem to be associated with a reduced risk of esophageal cancer. Details: Population research has found that coffee intake is not associated with the incidence of esophageal cancer (9222,90186,100874). However, subgroup analyses have found coffee consumption may be associated with a reduced risk of esophageal cancer in patients from East Asia (100874).

Attention deficit-hyperactivity disorder (ADHD). Although there has been interest in consuming coffee for ADHD, there is insufficient reliable information about the clinical effects of coffee for this purpose.
Atherosclerosis. It is unclear if consuming coffee is beneficial for atherosclerosis. Details: Population research has found that drinking coffee is not associated with prevalent coronary-artery calcium, a subclinical marker of atherosclerosis, in patients without known coronary heart disease (97371).
Atrial fibrillation. It is unclear if consuming coffee affects the risk of atrial fibrillation. The available research is conflicting. Details: A meta-analysis of observational research suggests that coffee intake is not associated with the incidence of atrial fibrillation (100860). However, a more recent observational study suggests that drinking at least 1 cup of coffee per week is associated with a 40% increased risk of atrial fibrillation, with the highest incidence of atrial fibrillation occurring in adults consuming at least 6 cups daily. A sub-analysis found that this association remained only for White participants and not other ethnicities (111042). This study was limited by its relatively small sample size and a higher than general proportion of smokers. Some observational research in elderly persons following the Mediterranean diet suggests that consuming 4-28 cups of coffee monthly (up to 1 cup daily) is associated with a lower risk of atrial fibrillation when compared with 3 cups or less monthly. Consuming more than 1 cup of coffee daily was not associated with reduced risk (103988). However, it is unclear if this association was due to moderate coffee consumption, the Mediterranean diet, or other, unidentified factors.
Bladder cancer. Population research suggests that coffee consumption does not reduce the risk of bladder cancer. Details: Although earlier evidence has been conflicting (97375,97376), the most comprehensive analysis of cohort and case control studies has found that coffee consumption is not associated with bladder cancer risk. In subgroup analyses of females, males, or non-smokers, coffee did not affect risk (103992).
Brain tumor. It is unclear if consuming coffee reduces the risk of brain cancer. Details: Observational research has found that consumption of coffee is associated with a lower risk of brain cancer in Asian populations, but not in American populations (100870).
Breast cancer. Population research suggests that coffee consumption does not reduce the risk of breast cancer. Details: Population research has found that consumption of coffee is not associated with a reduced incidence of breast cancer (9235,97377,107823).
Cancer. Although there has been interest in using rectal coffee enemas for the treatment of cancer, there is insufficient reliable information about the clinical effects of coffee for this purpose.
Cardiovascular disease (CVD). Some population research has found that drinking coffee is associated with a reduced risk of heart failure, but not with a reduced risk of major adverse cardiac events, coronary heart disease, or CVD in general. In patients with a history of CVD, coffee consumption may reduce CVD-related mortality. However, at least some evidence suggests that there is a J-shaped association between coffee consumption and the risk of acute coronary syndromes. Details: A meta-analysis of three large population studies, the Framingham Heart Study (FHS), Cardiovascular Heart Study (CHS), and Atherosclerosis Risk in Communities (ARIC) study, suggests that increased daily coffee consumption is associated with a reduced long-term risk of heart failure in individuals without CVD at baseline. Drinking at least 2 cups of coffee daily is associated with a 29% to 31% reduced risk of heart failure. However, there was no association between coffee consumption and risk of stroke, coronary heart disease, or CVD in general. In the analysis, total caffeine intake, but not decaffeinated coffee intake, was associated with a reduced risk of heart failure (104597). In one cohort study, there was no association between past coffee-drinking and the prevalence of having coronary heart disease as determined by a coronary angiography (104588). However, a large population study suggests that drinking up to 5 cups daily of instant, ground, or decaffeinated coffee is associated with a reduced risk of incident CVD, including coronary heart disease, cardiac failure, and/or ischemic stroke, of approximately 11% (111033). The association between coffee consumption and arrhythmia has also been investigated. In one population study, there was a 3% reduced risk of arrhythmia for each additional cup of habitual coffee consumed. Similar effects were seen when atrial fibrillation and supraventricular tachycardia, but not ventricular tachycardia, were independently analyzed (105310). More recent population research suggests that consuming 1-5 cups daily of ground or instant coffee, but not decaffeinated coffee, is associated with up to a 17% reduced risk of arrhythmia when compared with not consuming coffee. Intake of more than 5 cups was no longer associated with a reduced risk of arrhythmia (111033). Some population research suggests a J-shaped association between regular coffee consumption and the risk of developing acute coronary syndromes. Moderate consumption of less than 300 mL daily (about 1.3 cups) was associated with a lower risk of developing acute coronary syndromes, whereas regular consumption of 300 mL daily or more was associated with an increased risk (11318). However, other population research in people without a history of CVD suggests that drinking more than 6 cups of coffee daily does not appear to be associated with an increased risk of developing coronary heart disease (14343). The association between coffee consumption and CVD-related mortality has also been evaluated in people with CVD. Population research suggests that coffee consumption is associated with a reduction in CVD-related mortality. In some analyses, this association is for ground or decaffeinated coffee only (97373,97374,103997,103998,104594,104595,105308,105311,105314). A meta-analysis of a small number of population studies suggests that consuming coffee for at least 1 year after a myocardial infarction (MI) is associated with a small reduction in risk of CVD-related mortality and no increased risk of all-cause mortality or major cardiac events, such as a recurrent MI or stroke (104882). In patients with a history of acute coronary syndrome, including acute MI or unstable angina, consumption of 1-3 cups of coffee daily is associated with a reduced risk of overall mortality over a 4-year period, especially in never or former smokers. However, in those who are current smokers, consuming more than 3 cups daily is associated with a more than 2-fold increased risk of overall mortality (8533,105313). A large observational study which followed patients with stable coronary artery disease for 5 years also suggests that there is no association between coffee consumption and CVD-related mortality, myocardial infarction, or stroke (112735).
Chronic kidney disease (CKD). It is unclear if consuming coffee is beneficial for the prevention or management of CKD. Details: A small meta-analysis of population research has found that coffee consumption is associated with a 14% reduced incidence of CKD; drinking at least 2 cups daily seems to have the most benefit. Coffee consumption is also associated with an 18% reduced incidence of progression to kidney failure, as well as lower odds of having albuminuria. In addition, coffee consumption is associated with a reduced risk of CKD-related death, with at least 4 cups daily providing the most benefit when compared with drinking no coffee (104586). The validity of these findings is limited by the heterogeneous definitions of CKD, kidney failure, and albuminuria in the individual studies, as well as the comparisons of coffee consumption.
Cognitive function. It is unclear if consuming coffee is beneficial for cognitive function. Details: Some population research has found that higher lifetime coffee consumption might positively affect cognitive function among females aged 80 years or older (10620). Additionally, a small clinical study in healthy adults shows that consuming a single dose of regular coffee 220 mL containing 100 mg of caffeine improves reaction time and working memory, but not episodic memory, when compared with placebo (100864).
Colorectal cancer. It is unclear if consuming coffee is beneficial for the prevention or treatment of colorectal cancer. Details: A meta-analysis of cohort studies conducted in North America and Europe suggests that there is no association between coffee intake and the incidence of colorectal cancer (97385). However, population research conducted in Japan and Korea suggests that drinking coffee is associated with a lower risk of colorectal cancer, with the greatest reduction seen in patients consuming 3 or more cups of coffee daily (9222,97384,107832,111041). In one study, risk reduction increased from 32% to 78% when adjusted for the use of coffee additives, including cream and sugar (107832). In addition, drinking coffee is associated with a reduced risk of disease progression and death in patients with advanced or metastatic colorectal cancer. Each additional cup daily is associated with a 5% reduced risk of cancer progression and a 7% reduced risk of death. The greatest benefits were associated with drinking at least 4 cups daily when compared with no coffee consumption (104591).
Constipation. Although there has been interest in consuming coffee for constipation, there is insufficient reliable information about the clinical effects of coffee for this purpose.
Dementia. It is unclear if consuming coffee is beneficial for preventing dementia. Details: One meta-analysis of observational studies including nearly 329,000 adults has found that drinking coffee is not associated with a lower risk of dementia or Alzheimer disease (100866). Conversely, other observational research has found evidence of benefit, but results are conflicting. A meta-analysis of observational studies in nearly 334,000 adults has found a reduced risk of any cognitive deficit (including mild cognitive impairment and dementia) or dementia alone in those drinking less than 2.8 or 2.3 cups of coffee daily, respectively, when compared with not drinking coffee (107829). The validity of these findings is limited by a lack of discussion of heterogeneity and variability in sensitivity analyses. An individual observational study in nearly 14,000 adults has found that coffee and caffeine consumption is associated with dose-dependent reductions in dementia risk, especially in males, and that drinking at least 3 cups of coffee daily is associated with a 50% lower risk of dementia when compared with not drinking coffee (107841). Coffee consumption has also been studied in combination with tea. An observational study has found that drinking 0.5-1 cup of coffee with at least 4 cups of tea or 2-3 cups of coffee and tea each daily is associated with a 28% to 30% reduced risk of dementia when compared with not drinking coffee and tea (107204).
Depression. It is unclear if consuming coffee is beneficial for reducing the risk of depression. Details: Observational research has found that higher coffee consumption is associated with a 24% lower risk of depression when compared with lower coffee consumption. Drinking 400-600 mL of coffee daily is associated with 16% lower risk of depression when compared with not consuming coffee (100863).
Endometrial cancer. It is unclear if consuming coffee is beneficial for the prevention of endometrial cancer; the available research is conflicting. Details: One meta-analysis of prospective cohort studies suggests that drinking coffee is associated with a dose-dependent reduction in the risk of endometrial cancer. Increasing coffee consumption by 4 cups daily is associated with a 20% reduction in endometrial cancer risk (97381). Another meta-analysis of population research suggests that the highest intake of caffeinated coffee, but not decaffeinated coffee, is associated with a 34% reduced risk of endometrial cancer when compared with the lowest. A sub-analysis suggests that this association is limited to individuals with a high body mass index (111036). In contrast, earlier meta-analyses and one large prospective cohort study conducted in the United Kingdom suggests that drinking coffee is not associated with a reduced risk of endometrial cancer in general; however, there may be some protection in obese females drinking at least 2 cups of caffeinated coffee daily (93873,97381,97382).
Fractures. It is unclear if consuming coffee is beneficial for fracture prevention. Details: Multiple meta-analyses of observational research suggest that the highest intake of coffee is not associated with a difference in the odds of fracture when compared with the lowest intake. However, any association may be dependent on the dose of coffee and/or the location of research (111034,112734). A dose-response analysis in one meta-analysis suggests that consuming 0.5 to 4 cups daily, but not higher amounts, is associated with a small reduction in the incidence of hip fracture when compared with no coffee consumption. Additional sub-analyses suggest that while the highest coffee consumption was associated with a 25% reduced risk of fracture in studies conducted in Europe and North America, the opposite is true in studies conducted in Asia where the risk is increased by 37% (111034).
Gallbladder disease. Population research suggests that consuming coffee may reduce the risk of developing symptomatic gallstone disease. Details: Population research has found that the consumption of caffeinated beverages, including coffee, that provide at least 400 mg of caffeine (two or more cups of coffee) daily is associated with a significantly reduced risk of developing symptomatic gallstone disease (3345,8032). The effect seems to be dose-dependent; consumption of 800 mg caffeine (four or more cups of coffee) daily is associated with the greatest reduction in risk (3345).
Gastric cancer. It is unclear if consuming coffee reduces the risk of gastric cancer. Details: Overall, meta-analyses of observational research suggest that coffee consumption does not affect gastric cancer risk. However, subgroup analyses of patients living in the United States suggest that consuming coffee is associated with an increased risk of gastric cancer (100873,111038). One sub-analysis suggests that consuming 6.5 or more cups of coffee daily was associated with a 36% greater risk of gastric cancer (100873).
Gout. It is unclear if consuming coffee is beneficial for preventing gout. Details: Epidemiological research has found that the risk of developing gout over a 12-year period is 40% lower in males aged 40-75 years who drink 4-5 cups of caffeinated coffee daily, compared with those who don't drink coffee. In people who drink 6 cups or more daily, the risk of developing gout is 59% lower. Drinking decaffeinated coffee is also associated with a reduced risk of developing gout, but the risk reduction is more modest than with caffeinated coffee (15540).
Headache. Although caffeine is an established treatment for certain types of headache, there is insufficient reliable information about the clinical effects of coffee, specifically, for this purpose.
Hearing loss. It is unclear if consuming coffee is beneficial for hearing loss. Details: Population research has found that consuming at least one cup of coffee daily is associated with a reduced risk of hearing impairment in males, but not females, when compared with less than one cup of coffee daily. In males, each additional cup consumed daily was associated with a 15% lower risk of hearing impairment (104592).
Hepatitis B. It is unclear if consuming coffee is beneficial for hepatitis B. Details: Population research in patients being treated for chronic hepatitis B suggests that drinking at least 3 cups of coffee a day is associated with a reduced risk of having liver fibrosis when compared to not consuming coffee. However, this association was not present in untreated patients (111044). This study is limited by its cross-sectional design and use of blood markers, rather than the gold standard liver biopsy, for diagnosing fibrosis.
Hyperlipidemia. It is unclear if consuming caffeinated coffee is beneficial for hyperlipidemia. Details: A meta-analysis of small, randomized, controlled trials shows that consuming caffeinated coffee for up to about 11 weeks reduces total cholesterol by 8 mg/dL, low-density lipoprotein (LDL) cholesterol by 5 mg/dL, and triglycerides by 13 mg/dL when compared with a control group. These effects appear to be dose-dependent, with the greatest reduction observed in individuals consuming 6-8 cups of coffee daily. Every additional cup of caffeinated coffee consumed daily is associated with a 3-4 mg/dL additional reduction in total and LDL cholesterol and a 6-7 mg/dL additional reduction in triglyceride levels. Decaffeinated coffee had no effect on any markers of cholesterol (97370). However, population research has found that coffee consumption is associated with slightly higher total cholesterol, LDL cholesterol, and triglyceride levels when compared with no coffee consumption (104590).
Hypertension. Epidemiologic research suggests that consuming coffee reduces the risk of developing hypertension. Details: Some epidemiological research suggests that coffee consumption might reduce the risk of developing hypertension. A meta-analysis of epidemiologic research suggests that long-term coffee intake is associated with a modest 9% reduction in the risk of developing hypertension. However, smoking may diminish any potential benefit (97372). This analysis did not investigate the likelihood of a dose-response relationship and did not adjust for smoking status. Another epidemiologic study in a Brazilian population that did adjust for sociodemographic factors such as smoking suggests that drinking 1-3 cups of coffee daily is associated with a reduced risk of hypertension by about 18% when compared with never or almost never drinking coffee. Drinking more than 3 cups of coffee did not impact risk (103993). However, this study defined 1 cup of coffee as 50 mL; it is unclear how this intake compares with typical use in other countries. The best evidence comes from a meta-analysis of observational research which suggests that coffee intake was not associated with hypertension risk. However, coffee intake was associated with a modest reduction in hypertension risk in studies conducted in the United States (111037). In patients with hypertension, a meta-analysis of epidemiologic research suggests that habitual coffee intake is not associated with the risk of developing CVD (105312). However, other prospective population research in patients with severe hypertension, but not mild hypertension, suggests that drinking at least two cups of coffee daily is associated with a 2-fold increase in CVD mortality compared with non-coffee drinkers (111027).
Hypotension. It is unclear if consuming caffeinated coffee is beneficial in older adults with postprandial hypotension. Details: Preliminary clinical research in older adults with postprandial hypotension shows that consuming caffeinated beverages like coffee seems to increase blood pressure (11835).
Irritable bowel syndrome (IBS). It is unclear if consuming coffee is beneficial for preventing IBS. Details: A meta-analysis of mostly small, low-quality, observational and population research suggests that coffee consumption is associated with a modestly lower odds of developing IBS when compared with no coffee consumption. However, the validity of this result is limited by high heterogeneity (112739).
Kidney failure. It is unclear if consuming coffee is beneficial for preventing progression to kidney failure or reducing the risk of chronic kidney disease (CKD)-related death. Details: A small meta-analysis of population research has found that coffee consumption is associated with an 18% reduced incidence of progression from CKD to kidney failure. Coffee consumption is also associated with a reduced risk of CKD-related death, with at least 4 cups daily providing the most benefit when compared with not drinking coffee (104586). This analysis is limited by the heterogeneous definitions of CKD and kidney failure in the individual studies, as well as the comparisons of coffee consumption.
Liver cancer. It is unclear if consuming coffee reduces the risk of liver cancer. Details: A meta-analysis of observational research in approximately 2.5 million adults in Asia, North America, and Europe suggests that consuming at least 1 cup of coffee daily is associated with a 27% to 48% reduced risk of liver cancer (111016). An earlier meta-analysis of observational research suggests that regular coffee consumption is associated with a 31% lower risk of hepatocellular carcinoma when compared with no consumption. Higher coffee consumption seems to have a greater preventative effect when compared with lower coffee consumption (103989).
Liver disease. It is unclear if consuming coffee reduces the risk of chronic liver disease. Details: Observational research has found that regular coffee consumption is associated with a 38% lower risk of chronic liver disease when compared with no consumption. Higher coffee consumption seems to have a greater preventative effect when compared with lower coffee consumption (100862).
Lung cancer. It is unclear if consuming caffeinated coffee reduces the risk of lung cancer; the available research is conflicting. Details: Epidemiological research has found that males who consume a higher amount of dietary phytoestrogens, such as the lignan precursors found in coffee and tea, have up to a 27% lower risk of developing lung cancer when compared with those who consume smaller amounts (13190). However, conflicting evidence suggests that people who consume 2-4 or more cups of caffeinated coffee daily have a significantly increased risk of developing lung cancer (13191,90177). But drinking decaffeinated coffee seems to be associated with a decreased risk of lung cancer (13191).
Melanoma. It is unclear if consuming coffee reduces the risk of malignant melanoma. Details: Population research has found that high coffee intake is associated with a 19% to 25% reduction in the risk of malignant melanoma when compared with low consumption. However, after adjusting for confounders, most data show no significant reduction. Drinking decaffeinated coffee is not associated with a reduced incidence of malignant melanoma (97378,97379).
Metabolic syndrome. It unclear if consuming decaffeinated coffee is beneficial in patients with metabolic syndrome. Details: A meta-analysis of mostly small randomized controlled studies in patients with metabolic syndrome shows that consumption of decaffeinated coffee modestly reduces systolic and diastolic blood pressure when compared with control. The validity of these findings is limited by the high heterogeneity and small size of the included studies (107830).
Nonalcoholic fatty liver disease (NAFLD). Observational research suggests that consuming coffee may reduce the risk of NAFLD. Observational and clinical research on liver fibrosis is conflicting. Details: A meta-analysis of observational research in over 50,000 patients has found that drinking 1-2 cups of coffee daily does not affect NAFLD incidence when compared with drinking less than 1 cup of coffee. However, drinking more than 3 cups of coffee daily was associated with a reduced risk of NAFLD when compared with less than 2 cups daily (103990). Other observational research has found a reduced risk of NAFLD and/or fibrosis in those who drink coffee when compared with those who do not drink coffee (100872,107831). However, the validity of these findings is limited by a relatively small population size and the lack of dose-response analyses. Two of the primary bioactive constituents of coffee, caffeine and chlorogenic acid, also have been evaluated. A small study in patients with NAFLD and type 2 diabetes shows that taking caffeine 200 mg and/or chlorogenic acid 200 mg for 6 months has no effect on the reduction of hepatic fat and fibrosis when compared with placebo (107835).
Nonmelanoma skin cancer. It is unclear if consuming caffeinated coffee reduces the risk of nonmelanoma skin cancer. Details: Population research has found that the highest intake of coffee or caffeine is associated with an 18% reduction in nonmelanoma skin cancer risk when compared with the lowest intake. However, the benefit appears to be limited to the incidence of basal cell carcinoma. Drinking decaffeinated coffee is not associated with a reduced incidence of nonmelanoma skin cancer. The effect, if any, appears to be due to caffeine rather than coffee (97380).
Obesity. It is unclear if consuming coffee is beneficial for weight loss in patients who are overweight or obese; the available research is conflicting. Details: Some clinical research in males who are overweight or obese and are receiving dietary counseling shows that taking coffee mannooligosaccharides 2 grams twice daily for 12 weeks reduces body weight by 6%, compared with 2.3% with placebo. The product also reduces body fat in males, but not females (93877). Additional clinical research in patients with pre-obesity shows that drinking a dark roast coffee 500 mL daily, enriched with N-methylpyridinium ions, for 4 weeks results in weight loss of 3.5%, compared with 0% with a light roast coffee enriched in chlorogenic acids. The dark roast coffee appears to reduce caloric intake (93874). However, other clinical research in adults who are overweight or obese shows that drinking caffeinated or decaffeinated coffee 885 mL daily for 8 weeks does not appear to improve glycemic control or reduce weight (93879).
Osteoporosis. It is unclear if consuming coffee is beneficial for osteoporosis prevention. Details: A meta-analysis of observational research suggests that the highest coffee consumption is associated with a 21% reduced odds of osteoporosis when compared with the lowest (111034).
Pancreatitis. It is unclear if consuming coffee reduces the risk of pancreatitis. Details: Observational research has found that drinking three or more cups of coffee daily is associated with a 22% lower risk of pancreatitis when compared with drinking less coffee (100871).
Pharyngeal cancer. It is unclear if consuming coffee reduces the risk of pharyngeal cancer. Details: Observational research has found that high coffee consumption is associated with a 28% reduced odds of pharyngeal cancer when compared with low coffee consumption (100869).
Pregnancy-induced hypertension. It is unclear if consuming coffee reduces the risk of pregnancy-induced hypertension. Details: A large prospective cohort study in pregnant patients in Japan has found that the highest total caffeine intake is associated with a 26% increased risk of pregnancy-induced hypertension when compared with no intake, but that a higher coffee intake (at least 2 cups daily) is associated with a 21% reduced risk of pregnancy-induced hypertension when compared with no intake, even when adjusted for total caffeine intake (107827). The validity of these findings may be limited by the fact that detailed information on proteinuria and hypertension were unavailable.
Pneumonia. It is unclear if consuming coffee is beneficial for reducing the risk of pneumonia. Details: A case-control study in elderly patients has found a 50% reduced risk of pneumonia in those consuming 2 or more cups of coffee daily over the past month (107840). The validity of this finding may be limited by differences in the baseline characteristics between the matched control subjects and the cases, specifically the higher prevalence of hypertension and diabetes in the control group.
Prostate cancer. Population research has found that coffee consumption is associated with a modestly reduced risk of prostate cancer. Details: Although some individual studies disagree (107834), population research has found that the highest coffee consumption is associated with a small reduction in the risk of prostate cancer when compared with the lowest consumption (97383,97384,104587). Sub-analyses show that coffee consumption is associated with a 7% reduced risk of localized, but not advanced or fatal, prostate cancer (97383,97384,104587).
Stroke. It is unclear if coffee consumption, alone or in combination with tea, is beneficial for stroke, post-stroke dementia, all-cause mortality, or stroke-related mortality. The available research is conflicting. Details: Several meta-analyses of population research in patients with and without cardiovascular disease (CVD) have found no association between coffee consumption and risk of stroke (104597,104882). However, another meta-analysis of population research and an individual observational study have found that coffee consumption (e.g., 2-3 cups of coffee daily) is associated with an 8% to 12% reduced risk of stroke, especially ischemic stroke, when compared with no consumption (107204,107828). The validity of the findings from the meta-analysis is limited by the lack of a dose-response analysis. Additionally, this analysis found that consumption of 2-3 cups of coffee daily is associated with a 20% reduced risk of post-stroke dementia when compared with not drinking coffee (107204). The consumption of coffee in combination with tea has also been evaluated. An observational study has found that consumption of 2-3 cups daily each of coffee and tea, including black tea, is associated with a 32% reduced risk of stroke when compared with not drinking coffee and tea. Additionally, consumption of 0.5-1 cup of coffee and 2-3 cups of tea, including black tea, daily is associated with a 50% reduced risk of post-stroke dementia when compared with not drinking coffee and tea (107204). Coffee consumption has also been evaluated for its effects on stroke-related and all-cause mortality. One observational study has found that consumption of 1-2 cups of coffee daily is associated with a 50% reduced risk of stroke-related mortality (107822). However, another observational study in patients with a history of stroke has found no association between coffee consumption and all-cause mortality (107839).
Thyroid cancer. It is unclear if consuming coffee reduces the risk of thyroid cancer. Details: Population research has found that high coffee consumption is associated with a 25% lower risk of thyroid cancer when compared with low consumption. Every additional cup of coffee was associated with a 5% reduction in risk (103996). More evidence is needed to rate coffee for these uses.

MAGNESIUM

Bowel preparation. Various magnesium salts are used for cleansing the bowel prior to procedures such as colonoscopy. Details: Various magnesium salts, including citrate, hydroxide, oxide, and sulfate, are ingredients in bowel preparation products available over-the-counter or by prescription only.
Constipation. Magnesium salts are effective when used short-term orally to treat constipation and chronic idiopathic constipation (CIC). Details: Magnesium citrate, hydroxide, oxide, and sulfate salts are commonly used as laxatives. Magnesium citrate 11.3-17.45 grams has been used; magnesium hydroxide 2.4-4.8 grams, as 30-60 mL of milk of magnesia, has also been used (113483,113484). Magnesium sulfate, also known as Epsom salt, which seems to have the most potent effect, has been used as 10-30 grams (6430,113485). Magnesium salts should only be used for occasional treatment of constipation, and doses should be taken with a full 8-ounce glass of water. Magnesium oxide seems to be beneficial in adults with CIC when taken short-term. Clinical guidelines published by the American Gastroenterology Association and American College of Gastroenterology in 2023 give a conditional recommendation suggesting the use of magnesium oxide over managing CIC without magnesium oxide based on low-quality studies conducted over 4 weeks. The recommended starting dose is 400-500 mg daily with dose titration per symptom response and side effects (112859). A small clinical study in patients with CIC who are not taking chronic medications shows that taking magnesium oxide 1.5 grams in three divided doses daily for 28 days increases spontaneous bowel movements when compared with placebo (104397). It is unknown if magnesium is beneficial for CIC when used long-term.
Dyspepsia. Magnesium salts are effective when used orally as antacids. Details: Magnesium carbonate, hydroxide, oxide, or trisilicate salts are used orally as antacids to reduce symptoms of gastric hyperacidity or gastroesophageal reflux. Magnesium hydroxide has the fastest onset of action. The onset for magnesium carbonate is slower due to its crystal structure. Magnesium trisilicate has the slowest onset and longest duration of action due to poor solubility (6844). Doses used include magnesium hydroxide 400-1200 mg (5-15 mL of milk of magnesia) up to four times daily, or magnesium oxide 800 mg daily (15).
Eclampsia. Magnesium sulfate is considered the drug of choice for control of seizures. Details: Intravenous (IV) and/or intramuscular (IM) magnesium sulfate is considered the agent of choice for seizure prophylaxis during eclampsia by the American College of Obstetricians and Gynecologists (ACOG) (15,12591,12592,61012,61184). Typical doses include 4-6 grams of magnesium sulfate by IV infusion in 250 mL of dextrose 5% or normal saline solution, followed by 4-5 grams of magnesium sulfate IM every 4 hours, or 1-3 grams per hour by continuous IV infusion. Doses should be adjusted according to serum levels and urinary excretion, and should not exceed 30-40 grams of magnesium sulfate daily (15,12591). Meta-analyses of clinical research show that treatment with IV or IM magnesium reduces the risk of seizure recurrence by 33% to 69% when compared with phenytoin, and by 47% to 60% when compared with diazepam (19960,60818,60954,60964,61105). One preliminary clinical study shows that lower doses of IV magnesium sulfate (9 grams loading dose and maintenance of 2.5 grams every 4 hours for 24 hours) are as effective as higher doses (14 grams loading dose and maintenance of 5 grams every 4 hours for 24 hours) for reducing the recurrence of eclamptic seizures (89383). It is generally recommended that treatment be continued for at least 24 hours after the last seizure (15). Oral magnesium has not been evaluated for eclampsia.
Hypomagnesemia. Hypomagnesemia can be effectively treated with oral or parenteral magnesium. Details: Taking magnesium orally or parenterally is helpful for treating and preventing hypomagnesemia associated with alcoholism, cirrhosis of the liver, congestive heart failure (CHF), severe or prolonged diarrhea or vomiting, kidney dysfunction, inflammatory bowel disease (IBD), pancreatitis, malabsorption syndromes, and other conditions (6280,6281,8088,8089). The dose and salt of magnesium for oral replacement therapy should be chosen carefully to avoid causing diarrhea. The gluconate and chloride salts cause less diarrhea, while the oxide salt is more likely to cause diarrhea and should be avoided. Magnesium chloride should also be avoided due to poor solubility which decreases absorption (6430,8099,10664). Orally, magnesium sulfate 3 grams every 6 hours for four doses has been used for hypomagnesemia (15). Parenteral magnesium doses must be individualized according to serum magnesium levels, but a typical starting dose for mild deficiency is 1 gram of magnesium sulfate intramuscularly (IM) every 6 hours for 4 doses (15). For more severe deficiency, 5 grams of magnesium sulfate may be given as an intravenous (IV) infusion in 1 liter of dextrose 5% or normal saline solution over 3 hours (15).
Pre-eclampsia. Magnesium sulfate is considered the drug of choice for seizure prophylaxis in patients with pre-eclampsia. Details: Intravenous (IV) and/or intramuscular (IM) magnesium sulfate is considered the agent of choice for seizure prophylaxis during pre-eclampsia by the American College of Obstetricians and Gynecologists (ACOG) (12591,12592,61012,61184). Some meta-analyses show that IV administration of magnesium sulfate reduces the risk of eclampsia when compared with placebo, phenytoin, or diazepam in patients with pre-eclampsia (19960,60818,60960,60979). A typical initial dose is 4-5 grams of magnesium sulfate by IV infusion in 250 mL of dextrose 5% or normal saline solution, followed by 4-5 grams of magnesium sulfate IM every 4 hours, or 1-3 grams of magnesium sulfate per hour by continuous IV infusion. Doses should be adjusted according to serum levels and urinary excretion, and should not exceed 30-40 grams of magnesium sulfate daily (15,12591). The optimal duration of prophylaxis has not been determined. A meta-analysis suggests that using a shorter duration of 12 hours or less is not associated with an increase in risk of eclamptic seizures when compared with regimens of 24 hours or longer (108732). However, studies are likely underpowered due to the low incidence of eclampsia. Oral magnesium has been evaluated for the prevention of pre-eclampsia in healthy adults, but taking magnesium citrate 300 mg daily, starting at 12-20 weeks' gestation and continuing until delivery, does not reduce the incidence of pre-eclampsia when compared with placebo (103724).

Cerebral palsy. Most evidence shows that antenatal magnesium reduces the risk of cerebral palsy in preterm infants, although there are some inconsistent results. Details: Most clinical studies and meta-analyses show that antenatal magnesium sulfate reduces the risk of cerebral palsy by about 32% and the risk of motor dysfunction by about 45% in preterm infants (60915,60927,60931,61001,97485,103734,103754,114675,114681). The lowest effective dose of magnesium sulfate seems to be 4 grams intravenously, with or without a maintenance dose of 1 gram/hour until birth or for 24 hours. In obese females, a higher dose, based on body weight, may be needed (97485,97495,103734,103754). However, some studies have inconsistent results (8093,19998,98293,98295,112784). Giving females at risk of imminent preterm birth (prior to 32 weeks), intravenous magnesium sulfate 4.5 grams over 20 minutes followed by 1 gram per hour until birth or for 24 hours, in addition to a standard treatment protocol, does not reduce the incidence of cerebral palsy (112784). Oral magnesium has not been evaluated for this purpose.
Seizures. Intravenous magnesium sulfate is used for treating seizures of various etiologies. Details: Intravenous magnesium sulfate may be useful for controlling seizures associated with epilepsy, glomerulonephritis, hypothyroidism, and acute nephritis in children (15). Oral magnesium has not been evaluated for this purpose.
Torsades de pointes. Intravenous magnesium sulfate is the first-line treatment for torsades de pointes after measures to correct precipitating factors have been unsuccessful. Details: Intravenous magnesium sulfate has been used successfully to treat the life-threatening ventricular tachycardia, torsades de pointes (15,6844). The Advanced Cardiac Life Support (ACLS) guidelines of the American Heart Association recommend a dose of 1 to 2 grams diluted in 50-100 mL Dextrose 5% solution given IV over 5-60 minutes, followed by a continuous IV infusion of 0.5-1 gram/hour.

Arrhythmia. Magnesium sulfate is effective for the specific type of ventricular tachycardia known as torsades de pointes, and seems to be helpful for treating other types of arrhythmias. Evidence for the role of oral or intravenous magnesium in preventing postoperative arrhythmias is conflicting. Details: Administering magnesium intravenously or orally may be helpful for treating atrial and ventricular tachycardia and fibrillation, and supraventricular tachycardia (9497,13352,13354,13355,13356,60804,60829,60877,61113,111696). Arrhythmias associated with congestive heart failure have been treated with magnesium sulfate 8 grams infused over 12 hours (9497). For rate control in atrial fibrillation, magnesium sulfate 2.5 grams IV over 20 minutes, followed by 2.5 grams IV over 2 hours has been used (13356). For paroxysmal supraventricular tachycardia, single doses of 1-4 grams of magnesium chloride have been used (13352). For atrial tachycardia, 2 grams of magnesium sulfate in 10 mL of dextrose 5% solution has been given IV over 1-10 minutes, followed by 5-10 grams of magnesium sulfate in 250-500 mL dextrose 5% solution as an IV infusion over 5 hours (13354,13355). Research on the effects of intravenous magnesium for preventing arrhythmias after cardiac surgery is conflicting. Some meta-analyses show that intravenous magnesium reduces the risk of atrial fibrillation, ventricular arrhythmias, or supraventricular arrhythmias following cardiac surgery by 23% to 48% when compared with placebo (60814,60826,60828,60838,61008,61033,61181,97487,97490). Doses of magnesium sulfate used include 30 mg/kg in 500 mL normal saline (97490), or 80-100 mg/kg added to the cardioplegia solution (97487). Also, one small study in adults after CABG surgery suggests that taking magnesium hydroxide 1600 mg orally reduces arrhythmia as effectively as receiving magnesium sulfate 2000 mg intravenously (99315). However, other meta-analyses that only include higher-quality trials show that magnesium supplementation does not reduce the risk of ventricular or supraventricular arrhythmias following cardiac surgery (61010,61024,61031,105081). A meta-analysis of clinical trials of intravenous magnesium for prevention of new-onset atrial fibrillation after non-cardiac surgeries shows that it does not reduce the incidence significantly when compared with placebo (112778). However, there was a high risk of bias in the analysis, and variability in types of surgery, and the salt and dose of magnesium used.
Asthma. Parenteral magnesium sulfate can help to reverse severe acute asthma attacks and reduce the need for hospital admission. It is unclear if nebulized magnesium is beneficial for acute asthma attacks. However, oral magnesium does not seem to be beneficial. Details: Overall, a single dose of intravenous magnesium seems to improve pulmonary function in acute asthma exacerbation and reduce the risk of hospitalization, particularly in patients with severe asthma, and those who have failed initial treatment with nebulized albuterol and intravenous corticosteroids (60888,90023,96483,104398,107365). The typical dose used for adults is 2 grams of magnesium sulfate infused over 20 minutes (15). For children, 25-75 mg/kg, to a maximum of 2 grams, infused over 20-30 minutes has been used (15,96483,107365). However, a post-hoc analysis of one large clinical trial (104400) designed to assess nebulized magnesium in children with acute asthma has found that adding IV magnesium to nebulized magnesium is associated with greater odds of hospitalization when compared with no IV magnesium (105919). This post-hoc analysis did not differentiate between precautionary and necessary hospitalizations. Although some clinical research and a meta-analysis in patients with acute asthma exacerbation show that nebulized magnesium in combination with standard treatment improves airway function, respiratory rate, and clinical asthma severity when compared with standard treatment alone, it is unclear whether these findings are clinically relevant (90016,113466). Most evidence, including larger clinical trials and meta-analyses, has not shown benefit of adjunct nebulized magnesium for acute asthma in adults or children (60888,90002,96484,104400,105920,113466,114674). Oral magnesium also does not seem to be beneficial. A meta-analysis of small clinical trials in children and adults with asthma shows that taking magnesium supplements orally does not improve lung function or reduce bronchodilator use when compared with control (104404).
Colorectal cancer. Increasing dietary magnesium intake seems to lower the risk of colon cancer but not rectal cancer. Details: Epidemiological research shows that increased dietary magnesium intake is associated with a reduced risk of colon cancer, but the risk of rectal cancer is not affected (89387,90017,90027,101355).
Diabetes. Low dietary magnesium may increase the risk of developing type 2 diabetes, but evidence on the use of supplements for treating type 2 diabetes is conflicting. Details: Higher dietary magnesium intake is associated with lower fasting insulin concentrations and a reduced risk of developing type 2 diabetes in adults and obese children (13369,15548,96473,97486,98294,103736,105918,106920). In people with existing type 2 diabetes, hypomagnesemia is found in 25% to 38% of patients, especially in those with poorly controlled diabetes (1172). Population research in adults with type 2 diabetes also shows that a dietary magnesium intake of less than 250 mg daily is associated with a 56% higher risk of mortality. Preliminary subgroup analyses suggest that the risk of mortality is higher in those with glycated hemoglobin (HbA1C) levels above 7% (110051). A meta-analysis of small, heterogeneous clinical studies in adults with type 2 diabetes suggests that magnesium may modestly reduce HbA1C in patients with hypomagnesemia, but not in patients with normal magnesium levels, when compared with control (105075). Individual clinical studies using magnesium supplements in patients with type 2 diabetes or insulin resistance have shown mixed results. Some research suggests magnesium supplements can decrease fasting blood glucose and improve insulin sensitivity, as well as reduce the risk of developing diabetes in high-risk patients (10664,12582,13376,60854,99313,106920), but other research shows no effect (1171,1172,13379,13380,112780). Discrepancies in these findings might reflect differences in magnesium salts and doses used, or differences in baseline magnesium status in study subjects.
Hypercholesterolemia. Magnesium may help improve lipid levels by a small amount in people with this condition. Details: There is some evidence that taking magnesium oxide 1 gram orally daily for 6 weeks can produce small decreases in low-density lipoprotein (LDL) and total cholesterol levels, and small increases in high-density lipoprotein (HDL) levels in patients with hypercholesterolemia. However, magnesium does not seem to improve lipoprotein (a) levels (1193). Magnesium may also lower triglycerides in people with hypertriglyceridemia (97494).
Metabolic syndrome. Low dietary and serum levels of magnesium seem to be associated with the development of metabolic syndrome. Details: Higher magnesium intake from diet and supplements is associated with a 27% lower risk of developing metabolic syndrome in healthy females (13371) and a 31% lower risk in healthy young adults (14304). Additional epidemiological research suggests that people with low serum magnesium levels are 6-7 times more likely to have metabolic syndrome than people with normal magnesium levels (13372). In a population analysis of over 6000 individuals without metabolic syndrome at baseline, the risk of developing this condition over a 6-year follow-up period was reduced by 16% in the highest quintile of dietary magnesium intake (median intake 371 mg daily) when compared with the lowest quintile (median intake 203 mg daily). Some, but not all, research suggests that the hazard ratio for metabolic syndrome in relation to magnesium intake may be U-shaped, with higher risk at intakes below about 150 mg daily and above 600 mg daily (108963). A combination of magnesium 20 mEq daily and potassium 40 mEq daily (magnesium potassium citrate) taken orally for 16 weeks reverses metabolic side effects of chlorthalidone, such as increased fasting plasma glucose and hypokalemia, more effectively than potassium chloride 40 mEq daily alone (112932).
Osteoporosis. Increased dietary and supplemental magnesium intake seems to increase bone mineral density and decrease bone loss in postmenopausal patients. Details: Preliminary clinical research shows that taking magnesium hydroxide orally, 300-1800 mg daily for 6 months, then 600 mg daily for 18 months, or magnesium citrate orally 1830 mg daily for 30 days, might reduce bone loss and bone turnover in postmenopausal patients with osteoporosis (9104,60928). Some epidemiological research also suggests that magnesium intake is related to increased bone mineral density (12501,12502,12503,12504,90014), although not all studies have found an association (12505,98286).
Postoperative pain. Injectable magnesium has been used with promising results for reducing pain and the need for other analgesics postoperatively. Details: A meta-analysis of 25 clinical trials shows that intravenous (IV) magnesium sulfate, 5-50 mg/kg bolus followed by a continuous infusion of 6 mg/kg or 500 mg hourly during surgery, seems to reduce the 24-hour postoperative use of IV morphine by 24% when compared with placebo (19968). Adding IV magnesium sulfate 3.7-5.5 grams to patient-controlled analgesia for 24 hours after surgery has also been used (19968). Additionally, meta-analyses support that adjunctive IV or intrathecal administration of magnesium reduces post-operative pain scores, improves pain relief and sensory nerve block, and decreases the need for other analgesics, when compared with control (89390,90012,90015,98287,103728,114676,114677,114678). However, some data are conflicting. In a meta-analysis of 7 trials, IV magnesium was not associated with lower pain scores over the first 48 hours postoperatively. The reasons for these discrepant findings are unclear but may be explained by differences in magnesium regimens, anesthesia protocols, and surgical populations studied. Additionally, IV magnesium appears to be less effective than dexmedetomidine (105082). Two moderate-sized clinical studies in patients undergoing total knee arthroplasty in China show that adding magnesium sulfate 2.5 mg/mL to the periarticular infiltration analgesia (PIA) cocktail or administering IV magnesium sulfate 40 mg/kg before anesthesia induction then as a 15 mg/kg infusion during surgery reduces pain scores, increases comfort levels, limits and delays the use of postoperative opioids, prolongs analgesia, and reduces markers of inflammation when compared with the usual PIA cocktail or control (111181,113677). Administering magnesium intravenously also seems to be helpful for pain control after hysterectomy. A 3-gram IV bolus of magnesium sulfate followed by an infusion of 0.5 grams per hour for 20 hours has been used. Lower doses were not effective (6848). In males undergoing laparoscopic radical resection for gastrointestinal cancer, administering IV magnesium intraoperatively, as a loading dose of 40 mg/kg followed by 15 mg/kg/hour through the end of surgery, reduces postoperative catheter-related bladder discomfort and analgesic requirements, when compared with placebo (112783). However, IV magnesium might not alleviate postoperative pain in children. Two small clinical studies show that administering a magnesium IV infusion does not reduce pain when compared with saline in children after tonsillectomy or after elective strabismus surgery (98282,105077).
Premenstrual syndrome (PMS). Taking magnesium orally seems to relieve symptoms of PMS. Details: There is some evidence that magnesium supplementation can improve symptoms, including mood changes and fluid retention, in some patients with PMS (1187,1188,6847). Doses used include magnesium oxide 333 mg daily for 2 menstrual cycles, or magnesium pyrrolidone carboxylic acid equivalent to 360 mg elemental magnesium three times daily, from the 15th day of the menstrual cycle until onset of menstrual flow (1187,1188). Taking magnesium orally in a dose of 360 mg (elemental magnesium) three times daily for 2 months seems to prevent premenstrual migraine (1186,6847). A combination of magnesium 200 mg daily plus vitamin B6 50 mg daily seems to reduce anxiety-related premenstrual symptoms, including nervous tension, mood swings, irritability, and anxiety, when compared with placebo (8555).
Vasospastic angina. Intravenous magnesium seems to prevent coronary spasm in patients with this condition. Details: Clinical research shows that administration of intravenous magnesium sulfate 65 mg/kg infused over 20 minutes dilates coronary arteries and suppresses acetylcholine-induced coronary spasms when compared with infusion of a dextrose solution in patients with vasospastic angina (8091).

Altitude sickness. Taking magnesium citrate orally does not seem to reduce acute altitude sickness risk. Details: Clinical research shows that taking magnesium citrate 1200 mg daily orally in three divided doses, beginning 3 days prior to mountain ascent and continuing until mountain descent, does not reduce the risk of acute altitude sickness when compared with placebo (60801).
Athletic performance. Taking magnesium orally does not seem to improve energy or endurance during athletic activity. Details: Most evidence suggests that taking magnesium orally doesn't increase energy and endurance during athletic activity. Magnesium oxide, aspartate, and orotate salts do not seem to improve exercise performance when used alone or in combination with potassium, vitamin B6, or zinc (2825,2826,2828,2829,2830,60751,113655).
Bronchiolitis. Intravenous or nebulized magnesium is not beneficial in infants with this condition. Details: Clinical research shows that administering a single IV dose of magnesium sulfate 100 mg/kg to infants with acute bronchiolitis does not improve, and may actually worsen, symptoms when compared with placebo (97482). A clinical study in infants with moderate to severe bronchiolitis shows that adding nebulized magnesium sulfate 40 mg/kg to nebulized epinephrine does not reduce hospital stay or the need for ventilator or oxygen support when compared with epinephrine alone (99317). Oral magnesium has not been evaluated for this use.
Chemotherapy-induced peripheral neuropathy. Research on the effects of intravenous infusions of magnesium and calcium for preventing oxaliplatin neurotoxicity are inconsistent, but higher quality studies seem to show no benefit. Details: Pooled analyses of cohort studies and clinical trials show that calcium and magnesium infusions can decrease the incidence of severe oxaliplatin-induced neurotoxicity (90028,90029,90031). However, when only clinical trials are considered, the infusions do not appear to be helpful (90005,90029,90031,96474,96479).
Complex regional pain syndrome. Intravenous magnesium is not beneficial in complex regional pain syndrome type 1. Details: Clinical research shows that receiving magnesium sulfate 70 mg/kg intravenously at the rate of 25 mL/hour for 4 hours each day for 5 days does not improve pain or level of impairment when compared with placebo in patients with chronic complex regional pain syndrome type 1 (89395).
Emergence delirium. The majority of small clinical studies in adults and children undergoing various surgeries suggest that intravenous (IV) magnesium doesn't reduce the risk of emergence delirium. However, most clinical studies in adults suggest that IV magnesium reduces emergence agitation. Details: A small clinical study in adults undergoing surgery for endovascular aortic aneurysm repair shows that administering IV magnesium 30 mg/kg as a loading dose, followed by a 10 mg/kg/hour infusion for the duration of surgery, does not improve agitation or delirium scores when compared with administering saline (111182). Similarly, a small clinical study in children ages 2-5 years undergoing elective strabismus surgery shows that administering IV magnesium during anesthesia does not seem to prevent the occurrence of emergence delirium when compared with administering saline (105077). In a meta-analysis of 8 clinical trials in children aged 2-16 years undergoing general anesthesia for oral or ophthalmic surgery, giving IV magnesium as a 30 mg/kg loading dose followed by a 10 mg/kg/hour infusion, or as a single dose of 15-30 mg/kg, does not reduce emergence delirium scores, and may actually prolong emergence times (108729). However, there is some conflicting evidence. In patients undergoing radical mastectomy, giving intraoperative magnesium sulfate 30mg/kg over 1 hour, followed by 10 mg/kg/hour until the end of surgery, reduces emergence agitation (odds ratio 0.26) when compared with placebo (112781).
Menopausal symptoms. Oral magnesium oxide does not seem to be beneficial for menopausal hot flashes. Details: A small, low quality study in postmenopausal patients with a history of breast cancer shows that taking magnesium oxide 400-800 mg orally daily reduces hot flashes when compared with baseline (102454). However, a larger, higher quality clinical study using magnesium oxide 800-1200 mg daily did not show any benefit when compared with placebo (98290).
Muscle cramps. Oral magnesium does not seem to improve muscle cramp frequency or intensity. Details: Meta-analyses of small clinical trials show that magnesium supplementation for 3-6 weeks does not decrease the frequency or intensity of skeletal muscle cramps, whether the cramps are idiopathic or due to liver cirrhosis or pregnancy, when compared with placebo (90022,104395).
Sickle cell disease. Intravenous magnesium does not add any benefit to standard therapy for sickle cell disease in children. Details: Clinical research shows that giving magnesium sulfate 40-100 mg/kg (maximum of 2 grams per dose) intravenously every hour for 6-8 doses as an adjunct to standard therapy does not decrease hospital stay, pain, or opioid use, or improve quality of life, when compared with standard therapy and placebo in children with sickle cell disease (89399,98283,101356). Oral magnesium has not been evaluated for this purpose.
Stillbirth. Magnesium administered during pregnancy does not reduce stillbirth risk. Details: A meta-analysis of clinical research shows that magnesium supplementation does not significantly decrease the risk of stillbirths when administered during pregnancy (60925,60978).
Tetanus. Intravenous magnesium sulfate does not seem to improve outcomes in patients with this condition. Details: A meta-analysis of clinical research shows that intravenous magnesium sulfate does not reduce mortality when compared with placebo or diazepam in patients with tetanus (61020). While some research shows that magnesium reduces the duration of hospitalization and the need for ventilation when compared with diazepam (61170), magnesium does not seem to improve these outcomes when compared with placebo (60860).
Traumatic brain injury (TBI). Magnesium does not improve clinical outcomes in patients with moderate to severe TBI. Its effect in patients with concussions is unclear. Details: A meta-analysis of four clinical trials shows that treatment with magnesium does not significantly improve neurological outcomes or reduce the risk of mortality when compared with placebo in patients with moderate to severe TBI (60905). A small observational cohort study in adolescents with concussions has found that adding oral magnesium 400 mg twice daily for 5 days to standard treatment with acetaminophen and ondansetron is associated with a trend toward reduced symptom severity when compared with standard treatment alone (104401). The validity of this study is limited by its observational nature and small cohort size.

Alcohol use disorder. Intravenous magnesium does not seem to help reduce symptoms of alcohol withdrawal but may reduce the duration of alcoholic delirium. Details: Preliminary clinical research shows that administration of four intramuscular injections of magnesium sulfate 2 grams at 6-hour intervals does not reduce symptoms of alcohol withdrawal when compared with saline (61063). A small observational study in patients with alcoholic delirium has found that administering magnesium sulfate IV 50 mg/kg every 8 hours, in addition to usual sedation, is associated with a reduction of delirium by approximately 2 days, or 4 days when given every 12 hours in addition to dexmedetomidine, when compared with usual sedation alone (111180). However, half of patients had hypomagnesemia at baseline; it is unclear if effects would be similar for patients with normal magnesium levels. Oral magnesium has not been evaluated for this purpose.
Allergic rhinitis (hay fever). Although there has been interest in using oral magnesium for allergic rhinitis, there is insufficient reliable information about the clinical effects of magnesium for this purpose.
Attention deficit-hyperactivity disorder (ADHD). It is unclear if oral magnesium is beneficial in children with ADHD. Details: Children with ADHD seem to have lower magnesium levels in their blood and hair (9969,100262,100263). A small clinical study in children aged 7-12 years with ADHD and magnesium deficiency shows that taking magnesium aspartate and lactate 6 mg/kg daily for 6 months might improve hyperactivity and magnesium levels when compared with control (1189). Another small clinical study in children with ADHD but without magnesium deficiency shows that taking magnesium 6 mg/kg daily along with vitamin D 50,000 IU weekly for 8 weeks may modestly improve emotional problems, but not inattention or hyperactivity, as measured on the strength and difficulties questionnaire (SDQ), when compared with placebo (105914).
Back pain. It is unclear if oral or intravenous magnesium is beneficial for acute or chronic back pain in adults. Details: One open-label clinical study in adults with acute low-back pain shows that taking magnesium 365 mg once daily in addition to taking etodolac 400 mg twice daily for 10 days does not further reduce pain when compared with taking etodolac alone (105913). Magnesium has also been tried for chronic back pain. A small clinical study in patients with chronic low-back pain shows that receiving magnesium sulfate 1 gram in 250 mL normal saline intravenously every 4 hours for 2 weeks, followed by magnesium gluconate 100 mg and magnesium oxide 400 mg by mouth daily for 4 weeks, reduces pain severity when compared with placebo (90035). It is unclear if oral magnesium used alone is beneficial.
Bariatric surgery complications. It is unclear if oral magnesium supplementation improves metabolic parameters after bariatric surgery. Details: A retrospective study of over 3000 post-bariatric surgery patients suggests that those who take oral magnesium supplements providing 100-450 mg elemental magnesium daily may have improved metabolic parameters over 4 years of follow-up. When patients taking magnesium supplements were compared with those not taking supplements, 11% and 18% had type 2 diabetes, respectively, 30% and 42% had hypertension, respectively, and 16% and 23% had elevated low-density lipoprotein (LDL) cholesterol levels, respectively. For patients with hypomagnesemia at baseline, supplementation seemed to result in greater benefits (108968).
Bipolar disorder. Taking magnesium orally might improve manic symptoms in some people with bipolar disorder; however, it is unclear how it compares to current standard of care. Details: One preliminary clinical study shows that magnesium 40 mEq daily (Magnesiocard) for 32 weeks has similar effects to lithium in up to 50% of patients treated for rapid cycling bipolar affective disorder (61022). Another preliminary clinical study shows that magnesium oxide 375 mg orally daily plus verapamil 80 mg taken four times daily reduces manic symptoms more effectively than verapamil alone in patients with mania (60742).
Cancer-related neuropathic pain. It is unclear if intravenous magnesium is beneficial for this condition. Details: Single 500 mg to 1 gram doses of magnesium sulfate seem to relieve neuropathic pain for up to four hours when compared to baseline (6846). The validity of this finding is limited by the lack of a comparator group.
Chemotherapy-induced leukopenia. It is unclear if oral magnesium is beneficial in pediatric patients at risk for cisplatin-induced febrile neutropenia. Details: A small clinical study in children with solid tumors aged 9 years and older shows that taking magnesium 250 mg daily while receiving cisplatin-based chemotherapy reduces febrile neutropenia by 47% and septic shock by 57% when compared with not receiving magnesium. Results from this study suggest that four pediatric patients need to take oral magnesium to avoid one case of febrile neutropenia (104394).
Cardiac arrest. Intravenous magnesium does not seem to be helpful in cardiac arrest; however, the risk of sudden cardiac death seems to be inversely correlated to higher plasma magnesium levels or dietary intake. It is unclear if magnesium supplementation is associated with similar risk reduction. Details: Administering magnesium intravenously doesn't seem to improve successful resuscitation in people with cardiac arrest (1190). However, higher plasma magnesium levels and higher dietary magnesium intake might reduce the risk of sudden cardiac death, possibly by protecting against fatal ventricular arrhythmias. In the Nurses' Health Study, the risk of sudden cardiac death was 77% lower in females with the highest quartile of plasma magnesium levels when compared with the lowest quartile. Also, the risk was 37% lower in females with the highest quartile of dietary magnesium intake when compared with the lowest quartile (17132).
Cardiovascular disease (CVD). Evidence regarding the effect of dietary magnesium on CVD risk is conflicting. Details: Epidemiological research in some populations shows that increased dietary magnesium intake is associated with decreased mortality due to strokes, coronary heart disease, ischemic heart disease, and heart failure, but other epidemiological research does not show any effect on these risks (89391,90003,90009,90030,90036,103735). Reasons for the discrepancies may be related to serum levels of magnesium at baseline, risk of cardiovascular disease at baseline, use of concomitant medications such as diuretics, or the presence of concomitant conditions such as kidney dysfunction. A population analysis conducted in Denmark has found that magnesium intake from drinking water may be associated with cardiovascular mortality. The overall risk of cardiovascular death and death due to stroke was reduced by 4% in the lowest 3 quintiles of intake when compared with the highest quintile. However, the risk of death due to acute myocardial infarction was increased by 22% in the lowest quintile when compared with the highest (108726). The relevance of these results is unclear, given that the main dietary source of magnesium is food rather than drinking water.
Chronic fatigue syndrome (CFS). Limited evidence suggests that magnesium may help improve CFS symptoms, but this is controversial. Details: In people with low red blood cell magnesium, there is some evidence that intramuscular injections of 1 gram magnesium sulfate given once weekly for 6 weeks might improve CFS symptoms (7556). However, there is additional evidence that most patients with CFS have normal magnesium stores, and measurement of red cell magnesium is a poor indicator of total magnesium stores (7557,8084,8085,8086,8087).
Chronic obstructive pulmonary disease (COPD). Intravenous, but not nebulized, magnesium may be helpful in acute exacerbations of COPD. Details: Administering magnesium sulfate intravenously, 1.2-2.5 grams over 20 minutes, might be helpful for treating acute exacerbations of COPD (1208,6844,103733). Also, giving magnesium sulfate 2 grams intravenously seems to improve exercise capacity when compared with placebo (89384). A meta-analysis of studies using intravenous magnesium sulfate for COPD exacerbations shows that it reduces hospital admission and mean length of stay and improves dyspnea scores when compared with placebo. Based on the relative risk identified in the included studies, seven patients would need to receive intravenous magnesium to prevent one hospitalization. However, intravenous magnesium sulfate does not change the need for non-invasive ventilation and the available research did not evaluate intensive care unit (ICU) admission (108967). Nebulized magnesium has also been evaluated. In patients experiencing a COPD exacerbation, clinical research shows that administering nebulized magnesium sulfate with albuterol three times at 30-minute intervals does not improve pulmonary function as measured by the forced expiratory volume in 1 second (FEV1) when compared with placebo (89393). Also, a meta-analysis of a small number of low-quality studies shows that nebulized magnesium does not reduce hospital admission or the need for ventilatory support, although it might modestly improve dyspnea scores and reduce ICU admissions, when compared with placebo (108967).
Cluster headache. It is unclear if a single intravenous dose of magnesium sulfate is beneficial for cluster headaches. Details: Administering magnesium sulfate intravenously, 1 gram over 5 minutes, seems to improve cluster headaches when compared with baseline(1184). The validity of this finding is limited by the lack of a comparator group.
Cognitive impairment. It is unclear if oral magnesium is beneficial for cognitive impairment. Details: A large observational study in adults with end-stage renal disease on hemodialysis suggests that serum magnesium levels of 20.2-22.3 mg/dL are associated with the lowest odds of mild cognitive impairment, while serum magnesium levels below and above that range of values are associated with increased odds of mild cognitive impairment (111695).
Coronary heart disease (CHD). It is unclear if magnesium supplementation is beneficial for CHD. Details: Clinical research shows that magnesium oxide 800-1200 mg daily for 3 months reduces platelet-dependent thrombosis by 35% when compared with placebo in patients with CHD (60759). It is unclear if this effect improves clinical outcomes. The effect of magnesium supplementation on coronary artery calcium has also been studied. A meta-analysis of 3 clinical studies in 196 patients with chronic kidney disease (CKD) shows that taking magnesium or increasing the concentration of magnesium in dialysate does not improve coronary artery calcification (CAC) scores when compared with standard therapy. However, magnesium reduced carotid intima-media thickness (111179). Similarly, a large clinical study in patients with CKD shows that taking slow-release magnesium hydroxide (Mablet, Denmark) 360 mg twice daily for 12 months does not slow the progression of CAC scores when compared with placebo (111178). This study may not have been adequately powered to detect a difference between groups.
Coronavirus disease 2019 (COVID-19). It is unclear if oral magnesium is beneficial for COVID-19. Details: A small clinical study in patients hospitalized with moderate COVID-19 shows that taking magnesium 300 mg daily for the duration of hospitalization reduces the number of patients requiring oxygen therapy but not the duration of hospital stay when compared with placebo (114680).
Depression. It is unclear if magnesium is beneficial for the treatment or prevention of depression in adults. Details: Some population research shows that dietary intake of elemental magnesium between 76-360 mg daily is associated with a reduced risk of depression, but there was no association with greater amounts of magnesium, and other population research shows no association at any intake level (96480,98289). For treatment of mild to moderate depression, one preliminary clinical study shows that taking magnesium chloride 2 grams orally daily for 6 weeks reduces depression scores by 56% and anxiety scores by about 52% when compared to baseline (96477). The validity of these findings is limited by the lack of a comparator group. However, a small clinical study in adults with recurrent depression shows that taking magnesium aspartate 120 mg daily for 8 weeks, along with fluoxetine, does not improve depression scores when compared with patients taking fluoxetine and placebo (111185). Similarly, a very small crossover clinical study in adults with mild or moderate treatment-resistant depression shows that administering a single dose of IV magnesium sulfate 4 grams does not improve depression scores when compared with an infusion of 5% dextrose (96481). However, scores were evaluated 24 hours post-infusion which may be too soon to detect improvement. Guidelines from The World Federation of Societies of Biological Psychiatry (WFSBP) and Canadian Network for Mood and Anxiety Treatments (CANMAT) Taskforce state that elemental magnesium in doses of 100-400 mg is not recommended for adjunctive or monotherapy use in patients with depression (110318).
Diabetic foot ulcers. Oral magnesium has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in patients with grade 3 diabetic foot ulcers shows that taking magnesium oxide 250 mg plus vitamin E 400 IU daily for 12 weeks modestly reduces ulcer size when compared with placebo (101436). It is unclear if this effect is due to magnesium, vitamin E, or the combination.
Exercise-induced muscle soreness. It is unclear if oral magnesium reduces muscle soreness in adults after resistance training. Details: A very small study in healthy adults, ages 19-23, shows that taking magnesium glycinate 350 mg daily for 10 days seems to reduce muscle soreness after bench press exercise when compared with placebo (104399).
Fetal and premature infant mortality. It is unclear if antenatal intravenous (IV) magnesium sulfate administration reduces the risk of fetal and premature infant mortality. Details: Two meta-analyses of up to 7 clinical studies in patients at risk of preterm birth shows that antenatal IV magnesium sulfate administration does not reduce the risk of fetal or neonatal death when compared with placebo (114675,114681).
Fibromyalgia. It is unclear if oral magnesium is beneficial for this condition. Details: A small clinical study shows that taking magnesium chloride orally 100 mg once daily for one month reduces mild to moderate, but not severe, stress associated with fibromyalgia when compared with placebo. It also reduces pain levels, but not to a clinically significant extent, and it does not affect sleep, fatigue, or quality of life (108964). Another small clinical study shows that taking magnesium citrate 300 mg daily for 8 weeks improves some symptoms of fibromyalgia, such as number of tender points and depression, when compared to baseline (89385). The validity of this finding is limited by the lack of a comparator group. A small clinical study shows that taking a combination of magnesium hydroxide and malic acid (Super Malic tablets) orally decreases fibromyalgia-related pain and tenderness in some patients when compared with placebo (3262). It is unclear if this effect is due to magnesium, malic acid, or the combination.
Fractures. Population research suggests that higher intakes of magnesium may reduce fracture risk. Details: Observational research has found that higher dietary and supplemental magnesium intake is associated with a 34% lower odds of fracture when compared with lower magnesium intake (101395).
Gastric cancer. Population research suggests that higher intakes of magnesium may reduce gastric cancer risk. Details: Observational research has found that higher dietary and supplemental magnesium intake is not associated with a reduced risk for gastric cancer when compared with lower intake (103730).
Hearing loss. Oral magnesium may prevent and improve hearing loss due to environmental factors or loud noises. Details: Clinical research in healthy military recruits shows that taking magnesium aspartate 167 mg daily for 2 months prevents hearing loss from exposure to loud noises during basic military training when compared with placebo (1205). Also, in patients with acute-onset hearing loss that was not caused by environmental factors, taking magnesium aspartate 167 mg daily for 8 weeks seems to improve hearing loss when compared with placebo (60813).
Hypertension. Oral magnesium supplementation may modestly reduce blood pressure, although these changes are not likely to be considered clinically significant. Details: Most research shows that taking oral magnesium supplements in daily doses that are at least as high as the Recommended Dietary Allowance (RDA) for adults and up to 1000 mg daily can lower diastolic blood pressure by about 2 mmHg in adults with or without hypertension (1192,1199,9465,15165,18111,96482). Significantly lower doses do not seem to have this effect (1180,1195,1197,8098). The effect of magnesium on systolic blood pressure is conflicting. One meta-analysis shows that taking magnesium 240-970 mg daily does not lower systolic blood pressure (15165). However, more recent meta-analyses show that taking magnesium 120-970 mg daily can lower systolic blood pressure in a dose-dependent manner by about 2-4 mmHg in patients with or without hypertension (18111,96482). In 2022, the US Food and Drug Administration (FDA) approved a qualified health claim stating that inconsistent and inconclusive evidence suggests that diets with adequate magnesium may reduce the risk of high blood pressure. Products bearing this claim must provide at least 84 mg of magnesium daily, but no more than 350 mg daily (107451).
Hypokalemia. It is unclear if intravenous or oral magnesium is beneficial for hypokalemia in patients with normal magnesium levels. Details: A preliminary retrospective observational study in patients with hypokalemia and unknown serum magnesium levels has found that administering oral or intravenous magnesium is not associated with improved time to normalization of serum potassium levels when compared with no magnesium treatment (110049). However, hypokalemia with concurrent hypomagnesemia can impede potassium repletion and exacerbate hypokalemia-induced rhythm disturbances. Standard of care in patients with hypokalemia and known hypomagnesemia includes prompt treatment with magnesium (110063).
Impaired glucose tolerance (prediabetes). It is unclear if oral magnesium is beneficial for prediabetes. Details: Preliminary clinical research in patients with prediabetes shows that taking magnesium oxide 250 mg orally daily for 12 weeks does not improve fasting blood glucose levels, insulin resistance, or glycated hemoglobin (HbA1C) levels when compared with placebo. Taking magnesium also did not affect blood pressure, body weight, triglyceride levels, or low-density lipoprotein cholesterol levels; however, it did modestly improve high-density lipoprotein cholesterol levels (110053).
Insomnia. Oral magnesium may modestly improve sleep complaints in adults, but evidence is conflicting. Details: A meta-analysis of two small clinical studies in healthy older adults with or without insomnia suggests that taking magnesium reduces the time to fall asleep by an average of 17 minutes when compared with placebo (105917). However, it does not increase the time spent asleep. Also, these findings are limited by imprecision and a high risk of bias. Studies included in the analysis used elemental magnesium 500-729 mg daily (as magnesium oxide) for up to 8 weeks (102458,105917). Another small clinical study in patients with poor sleep quality and low magnesium status shows that taking elemental magnesium 320 mg (as magnesium citrate) in divided doses daily for 7 weeks does not improve sleep quality, as measured by the Pittsburgh Sleep Quality Index (PSQI), when compared with a sodium citrate placebo (102456). Magnesium has also been evaluated in combination with other ingredients. A very small crossover clinical study in patients aged 18-40 years without a sleep disorder shows that taking a combination of magnesium 300 mg, L-tryptophan 1000 mg, glycine 3000 mg, tart cherry 220 mg, and theanine 200 mg for 3 days reduces the time to fall asleep by about 24 minutes, increases total time asleep by about 22 minutes, and improves sleep efficiency, but does not improve the total time in bed or wakefulness after falling asleep when compared with cellulose placebo (111184). Another small crossover clinical study in adults with sleep disturbances shows that taking a combination of magnesium 200 mg and melatonin nightly for 4 weeks improves sleep quality, as measured by the PSQI, reduces the length of time it takes to fall asleep by about 17 minutes, and improves some other measures of sleep, such as sleep efficiency and number of awakenings, when compared with placebo. However, despite these improvements, overall sleep quality was still categorized as poor after the intervention (113670). It is unclear if these effects are due to magnesium, other ingredients, or the combination.
Intraventricular hemorrhage. It is unclear if antenatal intravenous (IV) magnesium sulfate can reduce the risk for intraventricular hemorrhage in neonates. Details: A meta-analysis of clinical research in premature infants shows that if the mother received antenatal intravenous magnesium sulfate, the infant had a non-significant trend toward a reduced risk of intraventricular hemorrhage when compared with infants whose mothers received placebo (103727). This analysis may have been insufficiently powered to detect a difference between groups. Another meta-analysis of up to 6 clinical studies, some of which are included in the previously referenced meta-analysis, in patients at risk of preterm birth shows that maternal antenatal (IV) magnesium sulfate administration does not reduce the risk of intraventricular hemorrhage, but does reduce the risk of severe intraventricular hemorrhage by about 24% when compared with placebo (114681).
Kidney stones (nephrolithiasis). Taking magnesium orally may prevent the recurrence of kidney stones, although evidence is conflicting. Details: Prophylactic treatment with magnesium hydroxide, 200 mg twice daily for one year, followed by 500 mg daily for another year, might decrease the recurrence rate of calcium stone formation (2007). However, magnesium oxide does not seem to benefit patients considered to be recurrent calcium stone formers when compared with placebo, no treatment, or chlorthalidone (8097,38501,61199). Magnesium oxide 300 mg in combination with vitamin B6 10 mg daily seems to decrease urinary oxalate levels in people with hyperoxaluria who have previously had kidney stones (1201), but it is unclear if this effect translates into a reduced incidence of kidney stones.
Liver cancer. Increased dietary magnesium intake is linked with a lower risk of liver cancer. Details: Observational research in retired older Americans has found that higher dietary magnesium intake is associated with a 35% lower risk of liver cancer when compared with lower intake. This association was especially strong in persons who were moderate or heavy alcohol users (105080).
Lung cancer. Supplemental or dietary magnesium intake does not seem to reduce the risk of lung cancer. Details: A large epidemiological cancer screening trial with a mean follow-up of over 12 years suggests there is no association between dietary or supplemental magnesium intake and the risk of lung cancer. However, dietary magnesium seems to play an important yet unclear role in lung cancer prevention when taken as part of the diet with alpha-carotene, vitamin C, vitamin E, lycopene, selenium, lutein, and zeaxanthin (112096).
Migraine headache. Oral magnesium may help prevent migraine in some adults and children. Also, intravenous magnesium may help treat migraine in adults, but evidence is conflicting. Details: Small clinical studies in adults with migraine suggest that taking oral high-dose magnesium citrate 600-1830 mg daily in divided doses for up to 3 months seems to modestly reduce the frequency and severity of headaches when compared with baseline or placebo (4891,9498,60902). Limited evidence suggests that adding oral magnesium to conventional treatment may also be beneficial. A clinical study in adults with migraine living in Iran shows that taking magnesium oxide 250 mg twice daily in addition to sodium valproate 200 mg twice daily for 12 weeks modestly reduces severity and duration of migraine, but not migraine frequency, when compared with taking sodium valproate alone (105915). It is unclear if these improvements would be considered clinically significant. In contrast, one small clinical study shows that taking magnesium does not reduce migraine frequency and severity by at least 50% in adults when compared with placebo (10661). For treatment of migraine, some adults with normal magnesium levels respond to intravenous (IV) magnesium sulfate 1 gram over 5 minutes, but most patients who benefit have low magnesium levels at baseline (1185,6844). Effects of IV magnesium in patients with unknown magnesium levels are conflicting. Some preliminary clinical research shows that magnesium 1-2 grams IV alleviates acute migraine for up to 2 hours, but other research has found no benefit (89388,97493,98285). In children, treatment with magnesium oxide orally 15 mg/kg daily in 3 divided doses for up to 16 weeks reduces the frequency and severity of migraine headaches when compared with placebo (10663). However, adding magnesium sulfate 400 mg orally daily to ibuprofen or acetaminophen does not further reduce migraine severity in children (89396).
Miscarriage. Oral magnesium has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in pregnant adults with threatened miscarriage between the 6th and 13th week of gestation shows that taking a specific combination product (DAV HA, Lo.Li pharma s.r.l) containing magnesium 450 mg, alpha-lipoic acid, hyaluronic acidvitamin B6, and vitamin D daily in combination with conventional treatment of vaginal progesterone over 2 weeks of observation results in a faster resorption of the subchorionic hematoma and faster decrease of patient-reported vaginal bleeding, abdominal pain, and uterine contractions when compared with vaginal progesterone alone (113893). It is unclear if these effects are due to magnesium, other ingredients, or the combination. Additionally, the validity of these findings is limited by the lack of a placebo in the control group.
Myocardial infarction (MI). Research on the effects of intravenous or oral magnesium after myocardial infarction are conflicting. Details: Administering magnesium intravenously doesn't seem to reduce mortality after an acute MI (8999,13357,13358,13359,13360,19990,60872,61082), although there is some conflicting evidence from a meta-analysis of clinical research that shows that intravenous magnesium sulfate may reduce short-term mortality by 55% when compared with placebo (60795,60895). Clinical research with oral magnesium supplementation has found no benefit (1198,6844).
Neonatal encephalopathy. Intravenous magnesium may improve short-term outcomes in neonates with encephalopathy. Details: A meta-analysis of clinical research shows that intravenous magnesium may improve short term outcomes of neonatal encephalopathy (hypoxic ischemic encephalopathy, HIE). However, long term outcomes are not affected (90025).
Nocturnal leg cramps. It is unclear if oral magnesium is helpful for nocturnal leg cramps. Details: Some clinical research in adults with nocturnal leg cramps shows that taking magnesium oxide 865 mg daily at bedtime for 4 weeks does not reduce the frequency of leg cramping episodes when compared with placebo (96478). However, four weeks may be too short a time to see a benefit. In other clinical research, taking oral magnesium oxide monohydrate 226mg daily at bedtime for 60 days reduces the frequency of leg cramps when compared with placebo. This reduction was not seen after 30 days. Magnesium also reduced cramp duration and improved sleep quality, but did not affect pain scores, at 60 days when compared with placebo (106919).
Nonalcoholic fatty liver disease (NAFLD). Oral magnesium hydroxide has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in adults with NAFLD shows that taking magnesium hydroxide 150 mg and L-carnitine 2000 mg daily for 16 weeks does not improve liver stiffness scores when compared with baseline or controls who took placebo for 8 weeks followed by this magnesium and L- carnitine combination for 8 weeks. Taking magnesium and L-carnitine also did not improve levels of aspartate aminotransferase (AST) or alanine transaminase (ALT) when compared to baseline (111177).
Obesity. Evidence on the use of magnesium for weight loss in obese patients is conflicting; any benefit is likely small at best. Details: A meta-analysis of 7 clinical studies in obese patients shows that taking magnesium reduces body mass index (BMI) by 0.3 when compared with control (103723). Another meta-analysis of 7 studies in obese patients shows that while magnesium supplementation does not reduce weight, it reduces waist circumference by 2 cm when compared with placebo (103729). Interestingly, subgroup analyses did not find that the dose of magnesium or baseline magnesium levels impacted effectiveness. One subgroup analysis found that magnesium supplementation lasting 12 weeks or less seemed to be more beneficial for obesity than supplementation lasting longer than 12 weeks (103723).
Overall mortality. It is unclear if oral or IV magnesium reduces the risk of overall mortality. Details: A meta-analysis of heterogeneous observational studies has found that increased dietary magnesium intake, but not supplemental magnesium intake, is associated with a modestly reduced risk of overall mortality (105073). A meta-analysis of 3 small, low-quality clinical studies in ICU patients shows that administering IV magnesium 24-30 mmol or as a target-directed dose for 3 days reduces overall mortality when compared with patients who did not receive magnesium (111290). However, some studies included patients with hypomagnesemia; it is unclear if effects would be similar for patients with normal levels of magnesium.
Osteoarthritis. Population research has not found a link between magnesium intake and osteoarthritis risk. Details: Observational research has found that dietary and supplemental magnesium intake is not associated with the risk of developing osteoarthritis (101395).
Pain (acute). It is unclear if intravenous magnesium is helpful for acute pain associated with kidney dysfunction. Details: Preliminary clinical research in patients with renal colic shows that intravenous (IV) magnesium sulfate, 50 mg/kg infused over 20 minutes, is as effective as IV morphine sulfate 0.1 mg/kg for controlling acute renal pain at 20 minutes after the dose (107367).
Pain (chronic). Population research suggests that higher intakes of magnesium may modestly reduce the risk for chronic pain. Details: A cross-sectional observational study has found that increased magnesium intake is associated with a 7% to 8% reduced risk for chronic pain. The association was found to be stronger in females than in males (103732).
Perioperative anxiety. It is unclear if oral magnesium is beneficial for perioperative anxiety. Details: Preliminary clinical research in adults undergoing open heart surgery shows that taking magnesium oxide 250 mg orally twice daily during hospitalization moderately improves anxiety and depression scores when compared with no magnesium therapy. Magnesium therapy was held for the 2 days immediately following surgery (110054).
Physical performance. Oral magnesium may modestly improve physical performance in otherwise healthy, elderly females. Details: Clinical research in otherwise healthy elderly females shows that taking a magnesium oxide supplement (Easymag, Sanofi-Aventis) 900 mg daily for 12 weeks modestly improves walking speed and chair stand speed in elderly females when compared with no treatment (90026).
Polycystic ovary syndrome (PCOS). It is unclear if oral magnesium is beneficial for improving metabolic indices in patients with PCOS. Details: Two small clinical studies in patients with PCOS show that taking magnesium oxide orally, 250 mg daily for 8 weeks, does not affect insulin resistance, beta-cell function, lipid levels, or insulin sensitivity when compared with placebo (103725,105887). Other clinical research in patients with PCOS shows that taking magnesium oxide orally, 250 mg daily for 10 weeks, improves subjective measures of quality of life, fatigue, and emotional functioning, but not objective measures such as alopecia, abnormal uterine bleeding, or acne, when compared with placebo (108965). A clinical study using a combination of magnesium 250 mg with vitamin E 400 mg daily for 12 weeks shows a modest reduction in insulin resistance, insulin levels, and triglyceride levels, but not other lipid levels, when compared with placebo (100264). It is unclear if these beneficial effects are due to magnesium, vitamin E, or the combination.
Postoperative nausea and vomiting (PONV). It is unclear if intravenous (IV) magnesium is beneficial for PONV due to mixed results from clinical research. Details: A meta-analysis of 5 clinical studies in adults undergoing surgery with general anesthesia shows that administering IV magnesium sulfate intraoperatively reduces PONV (114676). However, a meta-analysis of 20 clinical studies in adults undergoing surgery with general anesthesia shows that administering IV magnesium perioperatively does not reduce the incidence of PONV (114678). A moderate-sized clinical study conducted in China in older adults undergoing total knee arthroplasty shows that administering intravenous magnesium sulfate 40 mg/kg prior to anesthesia induction then 15 mg/kg during surgery reduces the incidence of postoperative vomiting but not postoperative nausea when compared with control (113677). The reasons for these discrepant findings are unclear but may be explained by differences in magnesium regimens, anesthesia protocols, and surgical populations studied.
Postoperative recovery. It is unclear if intravenous (IV) magnesium is beneficial for postoperative recovery. Details: A moderate-sized clinical study conducted in China in older adults undergoing total knee arthroplasty shows that administering IV magnesium sulfate 40 mg/kg prior to anesthesia induction then 15 mg/kg during surgery does not reduce extubation time, time spent in the post-anesthesia care unit (PACU), or duration of hospital stay when compared with control (113677). Additionally, a meta-analysis of 3 different clinical studies in adults undergoing surgery with general anesthesia shows that administering IV magnesium intraoperatively does not reduce extubation time (114676).
Postoperative sleep disturbance. It is unclear if oral magnesium is beneficial for postoperative sleep disturbances. Details: Preliminary clinical research in adults undergoing open heart surgery shows that taking magnesium oxide 250 mg orally twice daily during hospitalization moderately improves sleep scores when compared with no magnesium therapy. Magnesium therapy was held for the 2 days immediately following surgery (110054).
Postoperative sore throat. It is unclear if topical magnesium sulfate is beneficial for reducing sore throat pain after endotracheal intubation. Details: Preliminary clinical research in patients undergoing endotracheal intubation for surgery shows that using a gargle containing magnesium sulfate 20% with lidocaine, 20 minutes before anesthesia induction, is less effective for reducing sore throat pain than a gargle containing dexmedetomidine and lidocaine (112779). The study did not include a comparison to lidocaine alone.
Pregnancy-related leg cramps. It is unclear if oral magnesium reduces leg cramps during pregnancy; evidence is conflicting. Details: One small clinical study in patients with pregnancy-related leg cramps shows that taking magnesium bisglycinate chelate 300 mg daily for 4 weeks reduces the frequency and intensity of leg cramps when compared with placebo (99318). A smaller clinical study in this population shows that taking a specific mixture of magnesium lactate and citrate (Nycoplus Magnesium) providing elemental magnesium 120 mg in the morning and 240 mg in the evening for 3 weeks reduces the frequency of cramps when compared with placebo (1194). However, not all research agrees. One small clinical study using this same supplement and dose for 2 weeks found no benefit when compared with placebo (17463). It is possible that a 2-week duration of treatment is too short to be beneficial. Finally, a meta-analysis of these studies and one other more recent clinical study shows that taking magnesium does not reduce the frequency or improve the resolution of pregnancy-related leg cramps when compared with placebo (105916). This analysis may not have been adequately powered to detect a difference between treatment groups.
Pre-procedural sedation. It is unclear if intravenous magnesium is beneficial when administered in addition to other medications used for sedation during surgery. Details: A moderate-sized study of adults aged 65-79 years old undergoing endoscopic retrograde cholangiopancreatography (ERCP) shows that administering a single intravenous bolus of magnesium sulfate 40 mg/kg prior to the procedure reduces intraoperative propofol requirements by about 21% and reduces some peri-procedural adverse events including the incidence of respiratory depression and involuntary movement when compared with control. However, there were no differences in recovery time, hemodynamic parameters, or the incidence of hypotension, bradycardia, perioperative nausea or vomiting, lethargy, or arrythmias (111694). Another moderate-sized study in older adults undergoing total knee arthroplasty shows that administering intravenous magnesium sulfate 40 mg/kg prior to anesthesia induction then 15 mg/kg during surgery does not reduce the need for medications used for anesthesia induction, intraoperative maintenance propofol requirements, or recovery time when compared with control. However, magnesium sulfate does seem to reduce the amount of remifentanil required for intraoperative anesthesia maintenance and increase norepinephrine requirements when compared with control (113677).
Preterm labor. The use of magnesium sulfate to inhibit uterine contractions in preterm labor (tocolysis) is controversial. However, its use for the purpose of fetal neuroprotection for up to 48 hours is supported by the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine. Details: Magnesium is given intravenously during preterm labor in an effort to improve fetal neurological outcomes. The typical dosage of magnesium sulfate is 4 grams infused IV over 10-30 minutes, followed by a maintenance infusion of 1-4 grams/hour for 48 hours or until birth. Use beyond 5-7 days has been associated with hypocalcemia and bone abnormalities in the fetus (15,12590,12594). Some meta-analyses of clinical research suggest that magnesium sulfate is more effective at delaying delivery by 48 hours when compared with oxytocin receptor blockers, nitrates, beta-mimetics, and/or placebo (20263,61021). Administration of magnesium during preterm labor has been shown to reduce the risk of cerebral palsy and motor dysfunction in the infant (60915,60927,60931,61001,97485,103734,103754,114681).
Pseudoxanthoma elasticum (PXE). It is unclear if oral magnesium is beneficial for PXE. Details: Preliminary clinical research in patients with PXE shows that taking magnesium oxide 800 mg (500 mg of elemental magnesium) twice daily for one year tends to reduce calcification of elastic skin fibers when compared with placebo, but the effect is not statistically significant (101393). This study was limited by small size and insufficient power to detect smaller effects.
Restless legs syndrome (RLS). It is unclear if oral magnesium is beneficial for RLS. Details: Some observational research has found that hypomagnesemia is associated with RLS; however, not all research agrees (8096,9472). Preliminary clinical research in adults with RLS who are beginning treatment with pramipexole shows that also taking magnesium oxide 250 mg orally daily for 2 months moderately improves RLS scores and sleep quality scores when compared with pramipexole and placebo (110052). Other low-quality clinical research in adults with RLS or periodic limb movement during sleep shows that taking magnesium 12.4 mmol orally in the evening for 4-6 weeks decreases movement and increases sleep when compared with baseline (9466). The validity of this finding is limited by the lack of a comparator group.
Sarcopenia. It is unclear if oral magnesium is beneficial for the prevention or treatment of sarcopenia. Details: Population research in older adults has found that lower dietary intake of magnesium is associated with sarcopenia. However, the effect of magnesium supplementation on sarcopenia prevention or treatment has not been evaluated (110055). Magnesium has been evaluated in combination with other ingredients for treatment of sarcopenia. A small clinical study in elderly individuals with sarcopenia undergoing a diet and exercise program shows that taking a combination supplement containing magnesium 300 mg, carnosine, hydroxymethylbutyrate, lactoferrin, and sodium butyrate daily for 4 months increases muscle mass, as measured by the skeletal muscle index, and improves measures of muscle function, including handgrip muscle strength, chair test, and walking speed, when compared with placebo (114682). It is unclear if these effects are due to magnesium, other ingredients, or the combination.
Sepsis. It is unclear if intravenous magnesium is beneficial for sepsis. Details: A very large observational study in patients with sepsis and hypomagnesaemia or normomagnesemia in the intensive care unit (ICU) suggests that administering intravenous magnesium sulfate 2 or 4 grams within 24 hours of admission reduces 28-day all-cause mortality from 25% in patients who did not use magnesium sulfate to 20% in those who were administered magnesium sulfate, regardless of baseline serum magnesium level and other baseline characteristics. Administration of intravenous magnesium sulfate in this population may also reduce ICU mortality by 4%, in-hospital mortality by 3%, and the use of renal replacement therapy by 3% but also seems to increase the length of ICU and hospital stay when compared with patients who did not use magnesium sulfate (113676). The validity of these results is limited by the observational nature of the study.
Sleep deprivation. Oral magnesium has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A very small clinical study in sleep-deprived recreational athletes shows that taking a combination of magnesium 1350 mg, zinc 90 mg, and vitamin B6 31.5 mg for 3 nights at bedtime does not change sleep quality, subjective sleepiness, mood, or fatigue the next day when compared with placebo (113655).
Stroke. Increased dietary magnesium may decrease stroke risk, and using a magnesium-containing salt substitute may improve neurological performance post-stroke. However, intravenous magnesium has not demonstrated benefit. Details: Most population research has found that increased dietary intake of magnesium is associated with decreased stroke risk and decreased mortality from stroke (9001,9002,90013,90030,90036,92107,103736). In patients who have had a stroke, a preliminary clinical study shows that using a salt substitute providing the Dietary Reference Intake (DRI) of magnesium and potassium for 6 months improves neurological performance when compared with using regular salt (97491). However, intravenous (IV) magnesium does not seem to be beneficial in patients who have had a stroke. Large prospective clinical trials show that IV magnesium given within 12 hours of acute stroke does not reduce mortality or disability in most patients when compared with placebo. However, one subgroup analysis suggested that IV magnesium might benefit patients with lacunar (non-cortical) stroke (13361,90021). IV magnesium also doesn't seem to reduce cardiovascular complications after acute stroke. A secondary analysis of a clinical trial in patients after ischemic and hemorrhagic stroke shows that giving IV magnesium does not reduce serious cardiac adverse events when compared with placebo (104393). Another secondary analysis of this trial shows that giving IV magnesium prior to arrival at the hospital and within 2 hours of a hemorrhagic stroke does not reduce hematoma volume on hospital arrival, hematoma expansion during hospital admission, or functional outcomes at 3 months (108733).
Subarachnoid hemorrhage. Intravenous magnesium sulfate may reduce the risk of adverse outcomes in people with subarachnoid hemorrhage, but evidence is conflicting. Details: There is mixed evidence regarding the effect of magnesium sulfate in managing aneurysmal subarachnoid hemorrhage. One meta-analysis of clinical research shows that intravenous magnesium sulfate 64-144 mmol/day for 10-18 days reduces the risk of poor outcomes following aneurysmal subarachnoid hemorrhage, including death, vegetative state, or dependency, by 46% when compared with control (60932). Also, meta-analyses of clinical research show that intravenous magnesium reduces the risk of delayed cerebral ischemia by 27% when compared with placebo (60944,89398). However, these results were not confirmed in other meta-analyses (60973,90034).
Thrombocytopenia. It is unclear if intravenous magnesium sulfate is beneficial in patients with thrombotic thrombocytopenic purpura (TTP). Details: Addition of intravenous magnesium sulfate as a 6-gram loading dose followed by 6 grams infused over 24 hours for 3 days, to standard treatment for TTP does not reduce the time to normalization of the platelet count, the incidence of TTP-related organ dysfunction, or the recurrence rate, when compared with standard treatment alone (112777). This study may have been underpowered to detect a difference.
Urinary incontinence. Although there has been interest in using oral magnesium for urinary incontinence, there is insufficient reliable information about the clinical effects of magnesium for this purpose. More evidence is needed to rate magnesium for these uses.

Bowel preparation. Oral sodium phosphate is effective for cleansing the colon in preparation for colonoscopy; however, it is unclear whether sodium phosphate is as effective as polyethylene glycol (PEG) solution. Some products are approved by the US Food and Drug Administration (FDA) for this use. However, due to the potential for kidney damage, sodium phosphate is not recommended as first-line therapy. Details: Sodium phosphate tablets (OsmoPrep, Salix Pharmaceuticals; Visicol, Salix Pharmaceuticals) are FDA-approved for cleansing the colon in preparation for colonoscopy. Clinical research shows that using the OsmoPrep formulation can achieve an "excellent" or "good" response rate, which is defined as having 90% of the mucosa visible with only some or little suctioning needed, in 94% to 97% of patients (88133). Similarly, using the specific product Visicol has been shown to achieve an excellent or good response rate in 82% to 86% of patients (94674). Non-FDA-approved sodium phosphate products have also been investigated. One such product (Fleet Phospho-soda, C. B. Fleet Co.) has been shown to achieve adequate bowel cleansing in 23% to 89% of patients (93846,94673). Another sodium phosphate tablet preparation (Clicolon tablets, Korea Pharma Co.) has been shown to achieve adequate bowel cleansing in 63% to 93% of patients (93848,93850,93853). Excellent or good bowel cleansing was found in 98.6% of patients using a 32-tablet regimen of other sodium phosphate tablets (Quiklean, Universal Integrated Corporation) (107008). Reasons for the differences in the percentage of patients who achieve adequate bowel cleansing with the same sodium phosphate product may relate to the method used to analyze bowel cleansing, differences in diet followed during bowel cleansing, and demographic factors (93846,93848,93850,93853). Various preparations (OsmoPrep, Salix Pharmaceuticals; Visicol, Salix Pharmaceuticals; Clicolon tablets, Korea Pharma Co.; Quiklean, Universal Integrated Corporation) have been used which contain 1.102 grams of sodium phosphate monobasic monohydrate and 0.398 grams of sodium phosphate dibasic anhydrous. These products have been taken as 3-4 tablets with 8 ounces of water every 15 minutes for a total of 20 tablets the evening before colonoscopy, and 3-4 tablets with 8 ounces of water every 15 minutes for a total of 12-20 tablets the morning of a colonoscopy (88133,93848,93850,94674,107008). Also, sodium phosphate solution (Fleet Phospho-soda, C. B. Fleet Co.) containing sodium hydrogen phosphate 24.4 grams and disodium phosphate dodecahydrate 10.8 grams has also been used the morning and evening before the procedure (93846). Numerous publications have compared the bowel cleansing activity of sodium phosphate with PEG solution. When given as a split-overnight dosage, sodium phosphate is about as effective as PEG solutions in achieving adequate bowel cleansing. However, when day-before dosage is used, PEG is more effective for bowel cleansing than sodium phosphate (93861,93862,107008). Sodium phosphate and PEG may have different effectiveness depending on the colonic site assessed. When only trials assessing descending colon cleansing are considered, sodium phosphate is found to work similarly to PEG solutions. When only studies assessing ascending colon cleansing are considered, PEG is more effective for bowel cleansing than sodium phosphate (93861). Also, a large clinical trial in outpatients scheduled for non-sedated colonoscopy shows that receiving PEG resulted in an easier insertion and a less painful colonoscopy when compared with receiving sodium phosphate (104473). However, in patients with chronic constipation, sodium phosphate seems to be preferable. A meta-analysis of three small clinical studies in adults with chronic constipation shows that using sodium phosphate has an 87% greater chance of a successful bowel preparation when compared with using PEG (104472). Sodium phosphate is not recommended as first-line therapy for bowel preparation prior to colonoscopy due to the potential for kidney damage (93863,94672). In fact, one sodium phosphate preparation (Fleet Phospho-soda, C. B. Fleet Co.) that was previously approved as an over-the-counter supplement for bowel preparation in the US was withdrawn from the market for this indication in December 2008 due to concerns for phosphate-induced kidney disease (94672). Of the sodium phosphate products that are still approved by the FDA, current guidelines recommend that these products not be used for bowel cleansing in patients with kidney disease, pre-existing electrolyte disturbances, congestive heart failure, cirrhosis, ascites, or inflammatory bowel disease. Guidelines also recommend that caution should be used if these products are prescribed for patients who are elderly, hypertensive, or taking certain classes of drugs (94672). For small bowel preparation for endoscopy, a meta-analysis suggests that sodium phosphate is no more effective than fasting alone (93860).
Hypophosphatemia. Oral or intravenous phosphate salts are effective for the prevention or treatment of hypophosphatemia. Some products are approved by the US Food and Drug Administration (FDA) for this use. Details: Taking sodium or potassium phosphate orally is effective for preventing and treating hypophosphatemia (15). Treating hypophosphatemia with oral phosphates requires monitoring of serum electrolyte levels to determine appropriate dosing (15). The FDA-approved intravenous (IV) product is also used for the correction of hypophosphatemia (8302,8303,88135). FDA-approved intravenous (IV) sodium phosphate or potassium phosphate 15-30 mmol is typically given over 2-12 hours. Higher doses have been used if needed to increase efficacy (8302,8303,88135).

Constipation. Oral or rectal sodium phosphate is approved by the US Food and Drug Administration (FDA) as an ingredient in over-the-counter (OTC) products to treat constipation. Details: Sodium phosphate is an FDA-permitted ingredient of oral and rectal OTC products intended for the treatment of constipation (88107).
Dyspepsia. Oral aluminum phosphate and calcium phosphate are approved by the US Food and Drug Administration (FDA) as ingredients in over-the-counter (OTC) antacids. Details: Aluminum phosphate and calcium phosphate are FDA-permitted ingredients of oral OTC products intended for use as antacids (88107).
Hypercalcemia. Although other treatments are preferred, oral non-calcium phosphate salts are beneficial for treatment of mild to moderate hypercalcemia. Details: Taking phosphate salts (except calcium phosphate) orally is effective for treating mild to moderate hypercalcemia (88144,88145). Treating hypercalcemia with oral phosphates requires monitoring of serum electrolyte levels to determine appropriate dosing (15); other agents are now preferred (6479). Intravenous phosphates should be avoided due to the risk of calcium precipitation in vital organs (metastatic calcification) (15,88144,88145).

Kidney stones (nephrolithiasis). Oral potassium phosphate seems to be beneficial for prevention of kidney stones in individuals with hypercalciuria. Details: Taking potassium phosphate orally may help prevent calcium oxalate kidney stones in patients with hypercalciuria (6470). Clinical research in adults with absorptive hypercalciuria and at high risk for stone formation shows that taking a specific slow-release potassium phosphate product (Uro-Phos-K, Mission Pharmacal), providing phosphate 620 mg orally twice daily for 4 days, reduces urinary calcium excretion by 35% to 40% (2208,2209). Potassium and sodium phosphate salts providing 1200-1500 mg of elemental phosphate daily have been used (2209,6470).

Athletic performance. The evidence is mixed as to whether oral sodium phosphate improves cycling or running performance. Most research suggests that oral calcium phosphate and potassium phosphate are not beneficial. Details: Clinical research shows that taking calcium phosphate or potassium phosphate orally does not improve running or cycling performance (2499,9300,8301). Evidence for the use of sodium phosphate to improve cycling performance is mixed. One very small clinical study shows that taking sodium phosphate as tribasic sodium phosphate dodecahydrate for 6 days before a 10-mile cycling trial increases mean power output by about 10% and decreases the time needed to complete the trial by 3% in trained male cyclists (88150). Other small clinical trials in trained cyclists show that taking the same form of sodium phosphate as 50 mg/kg of fat-free mass in four divided doses daily for 6 days modestly improves work, power output, and peak oxygen uptake and reduces heart rate during high-intensity cycling exercise when compared to baseline (93857,93858,93859,107007). However, conflicting research shows that taking a similar dosage of this form of sodium phosphate does not improve time trial performance, work accomplished relative to energy expenditure, power output, or oxygen uptake in trained cyclists (93855,93856,107007). Sodium phosphate has also been evaluated for improving running performance, with mixed findings. Two small clinical trials in female athletes show that tribasic sodium phosphate dodecahydrate 50 mg/kg of fat-free mass taken in four divided doses daily for 6 days moderately improves repeated sprint times when compared with placebo (93843,93844). However, taking the same dosage does not significantly improve sprint times in male athletes (93849). Also, sodium phosphate does not seem to improve endurance or aerobic capacity in treadmill tests (8301,93854). Reasons for the discrepancies regarding the effects of sodium phosphate on athletic performance are not entirely clear, but likely relate to the very small number of participants in the included trials.
Diabetic ketoacidosis. Potassium phosphate infusion is not recommended as first-line therapy for adults with diabetic ketoacidosis. Details: Clinical research shows that intravenous infusion of potassium phosphate 8.5 mmol/hour (approximately 6 grams of phosphate over 24 hours) along with potassium chloride 12.5 mEq/hour provides no benefit over potassium chloride alone in adults with diabetic ketoacidosis (88149). Guidelines for the treatment of diabetic ketoacidosis in the both the US and UK do not recommend phosphate replacement for most patients. However, it may be considered in specific cases, such as cardiac dysfunction, anemia, respiratory depression, and serum phosphate concentrations below 1 mg/dL (107349,107350A).
Osteoporosis. Calcium phosphate seems to be beneficial for bone density improvement; however, it does not seem to be more beneficial than calcium carbonate. Details: In postmenopausal adults with osteoporosis and low phosphate intakes, taking calcium 1800 mg daily as tricalcium phosphate for 12 months improves lumbar spine and hip densities. However, it is no more effective than taking the same amount of calcium as calcium carbonate (93847). The calcium products were used in combination subcutaneous teriparatide and oral vitamin D (cholecalciferol) 1000 IU daily.
Refeeding syndrome. It is unclear if intravenous potassium phosphate or sodium phosphate is beneficial for prevention of refeeding syndrome. Details: Preliminary clinical research shows that giving intravenous sodium and potassium phosphates, 50 mmol (1.56 grams) phosphate over 24 hours, prevents the refeeding syndrome seen when restarting adequate nutrition after severe malnutrition or starvation when compared with historical controls (88148). More evidence is needed to rate phosphate salts for these uses.

POTASSIUM

Hypokalemia. Oral or intravenous potassium can treat and prevent hypokalemia. Details: Administering potassium orally or intravenously is effective for treating and preventing hypokalemia (15,107970). Oral potassium 20 mEq (780 mg of elemental potassium) is typically taken once daily to prevent hypokalemia (15,95010). Oral potassium 40-100 mEq (1560-3900 mg of elemental potassium) is typically taken in 2-5 divided doses daily to treat hypokalemia (95010). Doses should be limited to 40 mEq (1560 mg of elemental potassium), and the total dose should not exceed 200 mEq (7800 mg of elemental potassium) in 24 hours (95010). Potassium supplementation and route of administration should be individualized based on serum potassium level and patient status (15,107970).

Hypertension. Oral potassium, via dietary intake or supplementation, reduces blood pressure. Details: Population research has found that higher dietary potassium consumption is associated with a lower risk of developing hypertension (1310,8817,69512). Additionally, most clinical research shows that potassium, taken orally as part of the diet or as a supplement, reduces systolic blood pressure by about 3-9.5 mmHg and diastolic blood pressure by about 2-6.4 mmHg in patients with or without hypertension (3385,92104,92106,95624,107974). In most of these studies, daily intake of potassium typically ranged from about 1500-7800 mg, with the most common intake being about 2340-2540 mg daily (92104,95624). However, some research shows that taking potassium does not lower systolic or diastolic blood pressure (69541,69550,107966). Differences in the patient populations, potassium intake, and salt intake could have contributed to the conflicting results. Potassium seems to be more effective for people with hypertension, low potassium levels, high daily sodium intake, and for Black adults (3384,3385,3386,92104,92106). Some research also shows that the greatest blood pressure-lowering effects of potassium occur at doses of about 3900-7800 mg daily (95624). A meta-analysis of clinical trials using a novel computational technique to assess both potassium intake and excretion suggests that the optimal blood pressure reduction occurs when taking about 1500 mg supplemental potassium daily or an overall intake of 4500-6500 mg potassium daily (105448). This analysis is limited by the heterogeneity and short duration of the included trials. There is also interest in utilizing low-sodium, high-potassium food substitutes to treat hypertension. Research shows that using salt substitutes containing 25% to 30% potassium chloride reduces systolic and diastolic blood pressure by 3-4.6 mmHg and 1 mmHg, respectively, when compared with regular table salt (107971,107976). In 2017, the American College of Cardiology and the American Heart Association (ACC/AHA) published guidelines recommending that patients with hypertension consume 3500-5000 mg of potassium daily (95680). This intake of potassium is expected to lower systolic blood pressure by about 4-5 mmHg in patients with hypertension and by about 2 mmHg in normotensive patients (3385). Although potassium supplements and dietary potassium both seem to be beneficial, the guidelines recommend getting potassium from dietary sources, since potassium-rich diets are usually heart-healthy (95680). Additionally, the US Food and Drug Administration (FDA) has determined that foods containing at least 350 mg potassium and that are low in sodium, saturated fat, and cholesterol can state that "diets containing foods that are good sources of potassium and low in sodium may reduce the risk of high blood pressure and stroke" (1310,8817).
Kidney stones (nephrolithiasis). Oral prescription potassium citrate reduces the risk of kidney stone recurrence. It is unclear if non-prescription potassium citrate would be beneficial. Details: The American Urological Association (AUA) recommends potassium citrate therapy for patients with recurrent calcium stones and low urinary citrate, those with recurrent calcium or calcium oxalate stones without current metabolic abnormalities, and those with uric acid or cystine stones. The citrate component reduces urine calcium excretion and increases urine citrate and urine pH, which in turn alleviates crystal growth, formation, and aggregation. Sodium citrate may also be used to prevent stone recurrence; however, due to sodium's propensity to increase urine calcium excretion, potassium citrate remains the preferred salt formulation (107972). It is important to note that potassium citrate supplements are not equivalent to prescription potassium citrate products. Dose and duration of treatment is determined by a healthcare professional and individualized based on a patient's urinary citrate levels (107975,107989). Serum potassium levels should be monitored prior to starting potassium citrate, within 2 weeks of treatment initiation, and every 12 months (107975).

Cardiovascular disease (CVD). Eating foods high in potassium and low in sodium might reduce the risk of cardiovascular disease. It is unclear if taking potassium supplements has the same benefit. Details: Large population studies in adults without prior CVD have found that higher dietary potassium intake is associated with a lower risk of cardiovascular events (109395,109399). One study found that daily potassium intake of about 3300 mg is associated with a 13% reduction in CVD risk when compared with intake of about 1920 mg (109399). The other study found that each additional 1000 mg of daily urinary potassium excretion, which is a marker of dietary intake, is associated with an 18% reduction in CVD risk (109395). Another observational study in over 15,000 adults with history of stroke or hypertension shows that replacing regular table salt with a substitute product containing 75% sodium chloride and 25% potassium chloride for an average of 5 years decreases the rate of stroke, major cardiovascular events, or death (107976). High quality clinical trials are needed to confirm this association. The US Food and Drug Administration (FDA) has determined that foods containing at least 350 mg potassium and that are low in sodium, saturated fat, and cholesterol can state that "diets containing foods that are good sources of potassium and low in sodium may reduce the risk of high blood pressure and stroke" (1310,8817).
Stroke. Eating foods high in potassium and low in sodium might reduce the risk of stroke. It is unclear if taking potassium supplements has the same benefit. Details: Higher dietary intake of potassium seems to be associated with a lower risk of stroke. Population research has found that increasing dietary potassium intake by 1-1.5 grams daily is associated with up to a 20% reduced risk of stroke (92105,92107). Some population research has found that higher supplemental intake of potassium is associated with a 29% reduced risk of ischemic stroke. However, supplemental potassium intake is not found to be associated with a lower risk of hemorrhagic or total stroke (92107). An observational study in over 15,000 adults with history of stroke or hypertension shows that replacing regular table salt with a substitute product containing 75% sodium chloride and 25% potassium chloride for an average of 5 years decreases the rate of stroke, major cardiovascular events, or death (107976). High quality clinical trials are needed to confirm this association. The US Food and Drug Administration (FDA) has determined that foods containing at least 350 mg potassium and that are low in sodium, saturated fat, and cholesterol can state that "diets containing foods that are good sources of potassium and low in sodium may reduce the risk of high blood pressure and stroke" (1310,8817).

Dental hypersensitivity. It is unclear if topical potassium improves dental hypersensitivity. Details: One meta-analysis of clinical research shows that using a dentifrice containing 5% potassium nitrite reduces dentin sensitivity when compared with a dentifrice that does not contain potassium nitrite (69549). Other clinical research published in a systematic review shows that potassium-containing toothpastes might reduce dentin sensitivity more than controls that do not contain potassium. However, these toothpastes might be less effective than other active toothpastes, such as those containing sodium monofluorophosphate, and the effect may result from a placebo effect, since the mechanism of action of potassium is unclear (69456).
Diabetes. It is unclear if increasing dietary potassium reduces the risk of diabetes. Details: A meta-analysis of 7 large population studies has found that consuming dietary potassium 3300-3500 mg daily is associated with a 20% reduction in the risk of diabetes when compared with consumption below 1000 mg daily. Results were similar when studies that measured potassium intake with a dietary questionnaire were analyzed separately from those that measured intake based on urinary potassium excretion (110776). However, the validity of this finding is limited by the heterogeneity of the included studies. Furthermore, despite use of data from various databases, most studies included in the analysis were conducted by the same author.
Impaired glucose tolerance (prediabetes). It is unclear if oral potassium improves glycemic control in prediabetes. Details: A small clinical study in Black patients with prediabetes shows that taking extended-release potassium (Klor-Con M10, Cardinal Health) 40 mEq daily as potassium chloride for 3 months does not improve glucose tolerance when compared with placebo. Although fasting glucose levels were slightly reduced in the potassium group when compared with placebo, both groups experienced a worsening of glucose intolerance, with no change in insulin levels or glycated hemoglobin (98533).
Osteoporosis. Although there is interest in using oral potassium for osteoporosis, there is insufficient reliable information about the clinical effects of potassium for this condition.
Physical performance. It is unclear if oral potassium improves physical performance in older adults. Details: Observational research in older adults has found that decreased dietary potassium intake and increased dietary sodium intake over 5 years is associated with worsened physical performance (105450).
Systemic lupus erythematosus (SLE). It is unclear if oral potassium is beneficial in patients with SLE. Details: Observational research in patients with SLE has found that increased dietary potassium intake is not associated with improvements in disease activity scores or markers of cardiovascular disease, including lipid levels and blood pressure, when compared with low dietary potassium intake. However, higher potassium intake does seem to reduce the odds of having elevated levels of C-reactive protein, a marker of inflammation, in these patients (109397). More evidence is needed to rate potassium for these uses.

SODIUM

Cystic fibrosis. Long-term nebulized hypertonic sodium chloride improves lung function and reduces pulmonary exacerbations in patients with cystic fibrosis. Details: Meta-analyses of clinical research in adults with cystic fibrosis show that, when taken along with a bronchodilator and other standard therapies, nebulized hypertonic sodium chloride in concentrations of 3% to 7%, up to 10 mL twice daily for 4 weeks, increases forced expiratory volume at one second (FEV1) when compared with isotonic saline (sodium chloride 0.9%) (26230,26230). This benefit was not seen at 48 weeks. Other clinical research in adults with cystic fibrosis shows that inhaling sodium chloride 7%, 4 mL twice daily for 48 weeks, does not improve FEV1 when compared with isotonic saline. However, chronic treatment with hypertonic saline does reduce the number of pulmonary exacerbations and increase the number of patients without pulmonary exacerbations when compared with isotonic saline (29402). It is not clear if this benefit occurs in children with cystic fibrosis. The Pulmonary Clinical Practice Guidelines Committee of the Cystic Fibrosis Foundation recommends that individuals with cystic fibrosis aged 6 years or older use nebulized hypertonic saline long-term to improve lung function, reduce the number of exacerbations, and improve quality of life (29403).

Amphotericin B nephrotoxicity. Oral sodium chloride seems to prevent nephrotoxicity associated with use of amphotericin B. Details: Clinical research shows that administering oral or intravenous sodium chloride 150 mEq daily during treatment with amphotericin B can attenuate the rise in serum creatinine levels and preserve renal function when compared to treatment with amphotericin B alone (26226).

Bipolar disorder. It is unclear if oral sodium is beneficial in preventing lithium level fluctuations in patients with bipolar disorder. Details: A moderate-sized open-label clinical study in adults with type I bipolar disorder receiving lithium carbonate shows that taking sodium chloride 1 gram daily for 12 weeks along with dietary salt restriction of 1 gram daily reduces the percentage of patients with lithium level fluctuations above 0.8 mEq/L, but does not significantly affect serum sodium, potassium, aldosterone, or creatinine levels when compared with controls who were not salt restricted, but were advised not to consume additional salt at the table (112909). However, the interpretation of these findings is limited by missing data in both groups.
Canker sores. Although there is interest in using topical sodium chloride for canker sores, there is insufficient reliable information about the clinical effects of sodium chloride for this condition.
Congestive heart failure. It is unclear if oral sodium is beneficial in patients with acute decompensated heart failure requiring decongestive therapy with diuretics. Details: A moderate-sized clinical study in adults hospitalized with acute decompensated heart failure requiring high-dose intravenous furosemide shows that taking sodium chloride 2 grams three times daily for up to 96 hours does not affect patient weight or serum creatinine levels when compared with placebo (112911). However, the clinical relevance of this study is unclear and it may have been inadequately powered to detect a difference between groups.
Conjunctivitis. Although there is interest in using ophthalmic sodium chloride for conjunctivitis, there is insufficient reliable information about the clinical effects of sodium chloride for this condition.
Hyponatremia. Although there is interest in using oral sodium chloride for hyponatremia, there is insufficient reliable information about the clinical effects of oral sodium chloride for this condition.
Pharyngitis. Although there is interest in using topical sodium chloride for pharyngitis, there is insufficient reliable information about the clinical effects of sodium chloride for this condition.
Prematurity. It is unclear if oral sodium is beneficial for premature infants. Details: Preliminary clinical research in infants born at less than 32 weeks' gestation shows that adding sodium 4 mEq/kg daily to enteral feedings, starting from the 7th day after birth and continuing through the 35th day, reduces the risk of developing hyponatremia and improves weight gain when compared with adding water (98180). A small, open-label clinical study in newborns less than 35 weeks gestation shows that high sodium intake, defined as an average of 0.25% sodium in maintenance fluids, for 48 hours on day 2 and 3 after birth results in less weight loss within the first 72 hours of life when compared with control, but does not improve mortality, length of hospital stay, or complications from prematurity (112908). However, interpretation of these findings is limited by varied concentrations of sodium as an intervention. More evidence is needed to rate sodium for these uses.

Athletic performance. Regular consumption of whey protein in conjunction with exercise may improve muscle strength and performance. However, inconsistent consumption of whey protein, as well as intake of whey protein without concomitant exercise, may not be beneficial. Details: Most clinical research shows that taking whey protein 1.2-1.5 grams/kg or 30-33 grams daily in combination with strength training for 6-21 weeks can increase lean body mass, strength, and muscle hypertrophy in healthy young adults (16728,16729,16748,46552,85765,85910,91806,96025,102173). Higher doses of whey protein, such as 46-77 grams daily, have also been shown to increase strength when combined with athletic training (98886,98888). Some clinical research shows that whey protein hydrolysate (Lacprodan HYDRO.365, Arla Food Ingridiens Group P/S) twice daily for 1 week may slightly improve running speed (91793). However, less frequent intake or lower doses of whey protein do not seem to be beneficial for muscle strength. Some clinical research in middle-aged males shows that taking whey protein 35 grams three times weekly with resistance training for 14 weeks does not improve strength or muscle mass when compared with placebo (46736,85893). A small clinical study in trained males shows that taking whey protein 25 grams daily has no effect on body mass or strength after 2 weeks of detraining and 4 weeks of retraining when compared with maltodextrin (96021). Also, consuming whey protein without concomitant exercise does not seem to improve body composition or strength. Some clinical research shows that whey protein does not improve muscle mass or strength in obese postmenopausal patients who are losing weight through diet without exercise (98889). Some research has compared whey protein to other types of protein. A meta-analysis of preliminary clinical research, as well as individual clinical studies, show that whey protein is similarly beneficial to soy, beef, chicken, and dairy (casein with whey) protein for improving muscle strength (85941,98871,98888,105591). However, the validity of these findings is limited by the small size and high heterogeneity of the studies.

Chronic obstructive pulmonary disease (COPD). Oral whey protein does not seem to improve COPD symptoms. Details: Clinical research in adults with COPD shows that taking a specific whey protein supplement (ImuPower) 12 grams twice daily for 6 weeks can improve shortness of breath, but not lung function, exercise tolerance, or quality of life, when compared with placebo (86302). Other clinical research shows that taking a pressurized whey protein supplement 20 grams daily for 16 weeks, in combination with strength training for weeks 8-16, does not improve exercise tolerance, lung function, or muscle function when compared with placebo (86025).
Osteoporosis. Oral whey protein does not seem to improve bone mineral density in older adults. Details: Clinical research shows that taking whey protein 30-45 grams daily for up to 2 years does not improve bone density when compared with a low-protein placebo in postmenopausal patients and males over 70 years of age (86074,91796). Taking whey protein 20-60 grams daily for 36 weeks also does not improve bone density when compared with an isoenergetic placebo in overweight or obese adults undergoing an exercise program (96027). The effect of whey protein in patients with osteoporosis has not been evaluated.

Age-related cognitive decline. It is unclear if oral whey protein is beneficial for age-related cognitive impairment. Details: Preliminary clinical research in older adults with subjective cognitive decline shows that taking whey peptide 1 gram for 12 weeks does not improve memory, executive functioning, or attention when compared with placebo. However, in a subgroup of patients with high levels of fatigue, whey peptide modestly improved memory (98885).
Asthma. It is unclear if oral whey protein is beneficial in children with asthma. Details: A very small clinical study in children with asthma shows that taking a specific type of whey protein (HMS 90, Immunotec Inc.) 20 grams daily for 30 days does not improve lung function when compared to baseline (85833). The validity of this finding is limited by the lack of a comparator group.
Atopic dermatitis (eczema). It is unclear if consuming infant formula containing whey protein reduces the risk of developing eczema. Details: A high-quality meta-analysis of small clinical studies shows that use of infant formula containing hydrolyzed whey protein for 4-6 months is no better than standard milk formula for reducing the risk of eczema (105585). This is in contrast to older meta-analyses that found benefit after consumption of fully or partially hydrolyzed whey protein (85987,86007,86048). However, these older publications had notable conflicts of interest and did not include small negative studies (105585). In 2011, the US Food and Drug Administration (FDA) allowed a qualified health claim in healthy infants with a family history of allergy who are not solely breastfed. It stated that feeding a formula of 100% partially hydrolyzed whey protein instead of formula containing intact cow's milk proteins from birth up to 4 months of age may reduce the risk of atopic dermatitis throughout 1-3 years of age. However, the FDA has concluded that there is very little scientific evidence to support this claim (102311).
Atopic disease. It is unclear if consuming infant formula containing whey protein reduces the risk of developing atopic disease. Details: A high-quality meta-analysis of small clinical studies shows that use of infant formula containing hydrolyzed whey protein for 4-6 months is no different than standard milk formula for reducing the risk of atopic disease. However, there was a non-significant trend to reduced risk in the hydrolyzed whey protein group (105585). This finding conflicts with older meta-analyses which found benefit with hydrolyzed whey protein formula (85987,86007). However, these older publications had notable conflicts of interest and did not include small negative studies (105585).
Cystic fibrosis. It is unclear if oral whey protein is beneficial for children or adults with cystic fibrosis. Details: A small clinical study in patients with cystic fibrosis shows that taking pressurized whey protein, 20 grams in children and 40 grams in adults, daily for 28 days, improves lung function in children, but not adults, when compared with baseline (85995). The validity of this finding is limited by the lack of a comparator group.
Diabetes. It is unclear if oral whey protein is beneficial for improving glycemic control in people with type 2 diabetes. Details: A small clinical study in patients with well-controlled diabetes shows that consuming a 220 kcal drink containing whey protein concentrate 50 grams (Beit Haemek Advanced Technologies, Beit Haemek) before a meal lowers blood glucose levels by 28% and increases insulin levels in the first 3 hours after a meal when compared with drinking water (91795). However, whey protein does not seem to have long-term benefit on glycemic control when added to an exercise regimen. Another small clinical study in middle-aged males with type 2 diabetes shows that adding 20 grams of whey protein daily for 10 weeks to high-intensity mixed-mode interval training (MMIT) does not further improve glycemic control or body composition when compared to MMIT with placebo (98883).
Exercise-induced asthma. It is unclear if oral whey protein is beneficial for exercise-induced asthma. Details: A small clinical study in patients with exercise-induced asthma shows that taking whey protein 30 grams daily for 10 days improves lung function when compared to baseline (85791). The validity of this finding is limited by the lack of a comparator group.
Exercise-induced muscle damage. It is unclear if oral whey protein is beneficial for attenuating exercise-induced muscle damage; evidence is conflicting. Details: A meta-analysis of small heterogeneous clinical studies in trained and untrained adults shows that supplementation with a median dose of whey protein 25 grams (range 20-120 grams) given after and/or before exercise modestly improves muscle recovery measured over 3 days when compared with control (98881). Individual studies included in the analysis used whey protein 1.5 grams/kg daily for up to 2 weeks (86044), and whey protein isolate or whey protein hydrolysate (NatraPro or NatraBoost XR, MG Nutritionals) 25 grams three times in 24 hours (85915). Other small studies have not found benefit, but it is unclear if they were adequately powered. One small clinical study in healthy untrained males shows that taking whey protein 36.6 grams daily, starting 7 days before and continuing until 4 days after arm exercise, does not prevent muscle soreness over 5 days or attenuate reductions in strength (96024). Another small study in untrained healthy males shows that taking whey protein isolate (biPro, Eden Prairie) 0.3 grams/kg three times daily for 5 days does not reduce self-reported delayed onset muscle soreness, but may reduce creatine kinase, a biomarker of muscle damage, when compared with water (104758). Whey protein may not be beneficial for recovery from exercise in trained athletes. Small clinical studies show that consuming a whey protein beverage before or after exercise does not improve muscle recovery for trained adult and adolescent athletes when compared with a carbohydrate or non-caloric control (86303,91799,105592).
Hepatitis. It is unclear if oral whey protein is beneficial for hepatitis. Details: A small clinical study in patients with chronic hepatitis B shows that taking a specific type of whey protein (Immunocal) 12 grams twice daily for 12 weeks can reduce liver transaminase levels and can increase glutathione (GSH) levels when compared with baseline. However, whey protein supplementation does not seem to improve liver function in patients with chronic hepatitis C (85687). The validity of these findings is limited by the lack of a comparator group.
HIV/AIDS. It is unclear if oral whey protein is beneficial for improving immune function in children with HIV/AIDS. Details: One small clinical study in children with rapidly progressive HIV infection shows that taking whey protein at levels corresponding to 20% to 50% of total required protein for 4 months does not affect CD4 or CD8 cell count or the ratio of CD4+/CD8+ when compared with baseline. However, the occurrence of acute co-infections might be reduced with whey protein supplementation when compared with control (85781).
HIV/AIDS-related wasting. Although oral whey is an adequate source of protein, it is unclear if it is better than other protein sources for reducing HIV/AIDs-related wasting. Details: A small open-label clinical study in malnourished patients with HIV shows that taking whey protein (dose unspecified) daily for 14 weeks increases muscle and fat mass when compared with baseline (85693). The validity of these findings is limited by the lack of a comparator group. Another small study in patients with HIV, stable weight, and a history of unintentional weight loss shows that taking whey protein 40 grams daily for 12 weeks does not affect weight or muscle mass when compared with taking an isocaloric control (85921). These study findings are limited because they cannot be generalized to patients with active weight loss or wasting. Another limitation is the higher dropout rate in the whey protein group due to gastrointestinal adverse events.
Hyperlipidemia. It is unclear if oral whey protein is beneficial for lowering cholesterol levels. Details: A very small clinical study in overweight males with hyperlipidemia shows that taking whey protein 26.6 grams daily while participating in a resistance training program for 12 weeks reduces total cholesterol levels when compared with baseline but not when compared with placebo (85941). A meta-analysis of small heterogeneous clinical studies in healthy adults, as well as those with obesity and/or mild hypertension, shows that consuming whey protein alone or with other interventions seems to reduce lipid levels when compared with control (105586). However, most included studies were in patients without hyperlipidemia; it is unclear if whey protein is beneficial in patients with hyperlipidemia. Furthermore, these findings are limited by the variability in whey protein dosing, study duration, and patient population.
Hypertension. It is unclear if oral whey protein reduces blood pressure. Details: Preliminary clinical research shows that drinking a beverage containing whey protein 2.6 grams daily for 12 weeks does not lower blood pressure in patients with mild hypertension when compared with placebo (85835). Also, taking whey protein 28 grams twice daily in water for 8 weeks reduces 24-hour systolic and diastolic blood pressure by 2.9 mm Hg and 2 mmHg, respectively, when compared with maltodextrin or casein in adults with mild hypertension and prehypertension. There were also improvements in endothelial function (96019).
Mitochondrial myopathies. It is unclear if oral whey protein improves symptoms in patients with mitochondrial myopathies. Details: A small clinical study in individuals with mitochondrial diseases shows that taking a whey protein supplement 10 grams daily for one month does not improve muscle strength or quality of life when compared with placebo (85984).
Nonalcoholic steatohepatitis (NASH). It is unclear if oral whey protein improves NASH. Details: A small clinical study in patients with untreated NASH shows that taking whey protein 20 grams daily for 12 weeks can reduce liver function tests, including alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and reduce hepatic macrovesicular steatosis when compared with baseline (85961). The validity of these findings is limited by the lack of a comparator group.
Obesity. It is unclear if oral whey protein is beneficial for weight loss when used without dietary modifications. Adding whey protein to a calorie-restricted diet or an exercise regimen does not seem to improve weight loss. Details: Most research in overweight and obese individuals shows that taking whey protein along with a low-calorie diet and/or in addition to an exercise program does not further increase weight loss when compared with the low-calorie diet or exercise alone (85897,86069,86130,91794,91798,91802,96027,102172). However, a small clinical study in patients who have regained weight after bariatric surgery shows that following a low-calorie diet and taking whey protein 0.5 grams/kg daily for 16 weeks reduces body weight by about 2 kg and fat mass by about 3 kg when compared with following a low-calorie diet alone (96022). When whey protein is taken without diet modifications, studies have yielded conflicting results. One small clinical study in overweight and obese adults shows that taking whey protein isolate 27 grams twice daily for 12 weeks does not reduce body weight when compared with a glucose control (86011). However, another small clinical study in overweight and obese adults shows that taking whey protein concentrate 52 grams daily for 23 weeks reduces weight by 1.8 kg and fat by 2.4 kg when compared with a carbohydrate control, but is no better than taking soy protein isolate 52 grams (86077). In contrast, a small clinical study in overweight males shows that taking whey protein concentrate 65 grams before lunch daily for 12 weeks decreases calorie intake and reduces weight by about 1 kg when compared with taking soy protein isolate 60 grams (91801). In contrast to adults, supplementation with whey protein might increase weight in adolescents. A clinical study in overweight adolescents shows that consuming 1 liter of a milk-based whey protein drink daily for 12 weeks increases weight and body mass index when compared with a water control (86144).
Parkinson disease. It is unclear if oral whey protein improves symptoms of Parkinson disease. Details: Clinical research in a small group of patients shows that taking a specific type of whey protein isolate (HMS 90/Immunocal) 10 grams twice daily for 6 months does not improve symptoms of Parkinson disease when compared with placebo (96026). However, this study may have been inadequately powered to detect a difference between groups.
Polycystic ovary syndrome (PCOS). It is unclear if oral whey protein improves symptoms and metabolic effects of PCOS. Details: One small clinical study in patients with PCOS shows that taking 240 kcal as a nutritional supplement containing pure whey protein 96% daily, in addition to a calorie-restricted diet for 2 months, reduces body weight, fat mass, and cholesterol and apolipoprotein B levels when compared with a simple sugar control supplement. However, the whey protein supplement does not improve glucose or insulin levels, and seems to decrease high-density lipoprotein (HDL) cholesterol levels (85912). The validity of this study is limited by its small size and a significant dropout rate.
Polymyalgia rheumatica. It is unclear if oral whey protein improves muscle function in patients with polymyalgia rheumatica. Details: A small clinical study in patients with polymyalgia rheumatica shows that taking a whey protein-enriched dairy product twice daily for 8 weeks does not improve lower limb muscle function, walking speed, chair stand test performance, peak jump power, or peak jump force when compared with a regular dairy product (Play, Valio Ltd.) (86075).
Psoriasis. It is unclear if oral whey protein improves psoriasis. Details: A small clinical study in patients with stable psoriasis shows that taking a specific whey protein extract product (Dermylex, Advitech, Inc.) 5 grams daily for 8 weeks modestly decreases symptom severity when compared with placebo (85885).
Sarcopenia. Research on the use of oral whey protein in older adults with sarcopenia is conflicting. Details: Small clinical studies in trained older females show that consuming whey protein 35 grams three times weekly for 12 weeks, either before or after resistance training, modestly increases skeletal muscle mass, strength, and functional capacity when compared with resistance training and insufficient protein intake (98887,98890). Research on the use of whey supplementation without exercise is conflicting. A small clinical study in older adults with low muscle mass living in China shows that taking whey, or a whey-soy protein blend, 16 grams daily for 6 months slightly attenuates muscle loss when compared with no intervention (105603). However, a clinical study in healthy, active older adults living in Denmark shows that taking whey protein hydrolysate 20 grams twice daily does not increase muscle size or strength when compared with a carbohydrate control (105593). This finding may not be generalizable to frail adults or those with existing sarcopenia. Whey protein with or without exercise has shown benefit when used in combination with other nutrients. Specifically, whey protein 60 grams has been used with creatine 5 grams, calcium 800 mg, vitamin D 1000 IU, and omega-3 fatty acids 3 grams (Infinit Nutrition) for 6 weeks (96016). A beverage with leucine-enriched whey protein 20 grams has been used in combination with vitamin D 800 IU (Nutricia Advanced Medical Nutrition) daily for 6 weeks (96017). Another beverage containing whey protein 20 grams and vitamin D 800 IU has been used daily for 6 months (98882).
Sepsis. It is unclear if oral whey protein is beneficial in children with sepsis. Details: A very small clinical study in long-term intensive care pediatric patients shows that taking a specific whey protein supplement (Beneprotein) 0.3 grams/kg daily for up to 28 days has a similar effect on the time to onset and the rate of hospital-acquired infection or sepsis when compared with taking a combination of zinc, selenium, glutamine, and metoclopramide. It is not clear how these results compare to patients receiving no supplementation (86095). More evidence is needed to rate whey protein for these uses.

Safety view details

Below is general information about the safety of the known ingredients contained in the product W+ 100% Whey Isolate Protein Energy. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.

CAFFEINE

LIKELY SAFE ...when used orally, parenterally, or rectally and appropriately. Caffeine has Generally Recognized As Safe (GRAS) status in the US (4912,98806). Caffeine is also an FDA-approved product and a component of several over-the-counter and prescription products (4912,11832). According to a review by Health Canada, and a subsequent large meta-analysis conducted in the US, doses of caffeine up to 400 mg daily are not associated with significant adverse cardiovascular, bone, behavioral, or reproductive effects in healthy adults (11733,98806). The US Dietary Guidelines Advisory Committee states that there is strong and consistent evidence that consumption of caffeine 400 mg daily is not associated with increased risk of major chronic diseases, such as cardiovascular disease or cancer, in healthy adults (98806). This amount of caffeine is similar to the amount of caffeine found in approximately 4 cups of coffee. Keep in mind that only the amount of ADDED caffeine must be stated on product labels. The amount of caffeine from caffeine-containing natural ingredients such as coffee or green tea does not need to be provided. This can make it difficult to determine the total amount of caffeine in a given product.

POSSIBLY UNSAFE ...when used orally, long-term or in high doses (91063). Chronic use, especially in large amounts, can produce tolerance, habituation, psychological dependence, and other adverse effects (3719). Acute use of high doses, typically above 400 mg daily, has been associated with significant adverse effects such as tachyarrhythmia and sleep disturbances (11832). Keep in mind that only the amount of ADDED caffeine must be stated on product labels. The amount of caffeine from caffeine-containing natural ingredients such as coffee or green tea does not need to be provided. This can make it difficult to determine the total amount of caffeine in a given product.

LIKELY UNSAFE ...when used orally in very high doses. The fatal acute oral dose of caffeine is estimated to be 10-14 grams (150-200 mg/kg). Serious toxicity can occur at lower doses depending on variables in caffeine sensitivity such as smoking, age, or prior caffeine use (11832,95700,97454,104573). Caffeine products sold to consumers in highly concentrated or pure formulations are considered to a serious health concern because these products have a risk of being used in very high doses. Concentrated liquid caffeine can contain about 2 grams of caffeine in a half cup. Powdered pure caffeine can contain about 3.2 grams of caffeine in one teaspoon. Powdered pure caffeine can be fatal in adults when used in doses of 2 tablespoons or less. As of 2018, these products are considered by the FDA to be unlawful when sold to consumers in bulk quantities (95700).

CHILDREN: POSSIBLY SAFE
when used orally or intravenously and appropriately in neonates under the guidance of a healthcare professional (6371,38340,38344,91084,91087,97452). ...when used orally in amounts commonly found in foods and beverages in children and adolescents (4912,11833,36555). Daily intake of caffeine in doses of less than 2.5 mg/kg daily are not associated with significant adverse effects in children and adolescents (11733,98806). Keep in mind that only the amount of ADDED caffeine must be stated on product labels. The amount of caffeine from caffeine-containing natural ingredients such as coffee or green tea does not need to be provided. This can make it difficult to determine the total amount of caffeine in a given product.

PREGNANCY: POSSIBLY SAFE
when used orally in amounts commonly found in foods. Intakes of caffeine should be monitored during pregnancy. Caffeine crosses the human placenta, but is not considered a teratogen (38048,38252,91032). Fetal blood and tissue levels are similar to maternal concentrations (4260). The use of caffeine during pregnancy is controversial; however, moderate consumption has not been associated with clinically important adverse fetal effects (2708,2709,2710,2711,9606,16014,16015,98806,108814). In some studies consuming amounts over 200 mg daily is associated with a significantly increased risk of miscarriage (16014,37960). This increased risk seems to occur in those with genotypes that confer a slow rate of caffeine metabolism (98806). According to a review by Health Canada, and a subsequent large meta-analysis conducted in the US, up to 300 mg daily can be consumed during pregnancy without an increased risk of spontaneous abortion, stillbirth, preterm birth, fetal growth retardation, or congenital malformations (11733,98806). However, observational research in a Norwegian cohort found that caffeine consumption is associated with a 16% increased odds of the baby being born small for gestational age when compared with no consumption (100369,103707). The same Norwegian cohort found that low to moderate caffeine consumption during pregnancy is not associated with changes in neurodevelopment in children up to 8 years of age (103699). Advise patients to keep caffeine consumption below 300 mg daily during pregnancy. This is similar to the amount of caffeine in about 3 cups of coffee or tea.

PREGNANCY: POSSIBLY UNSAFE
when used orally in amounts over 300 mg daily. Caffeine crosses the placenta, producing fetal blood concentrations similar to maternal levels (4260,98806). Consumption of caffeine in amounts over 300 mg daily is associated with a significantly increased risk of miscarriage in some studies (16014,98806). Advise patients to keep caffeine consumption below 300 mg daily during pregnancy. This is similar to the amount of caffeine in about 3 cups of coffee or tea. Additionally, high doses of caffeine throughout pregnancy have resulted in symptoms of caffeine withdrawal in newborn infants (9891). High doses of caffeine have also been associated with spontaneous abortion, premature delivery, and low birth weight (2709,2711,91033,91048,95949). In a cohort of mother/infant pairs with a median maternal plasma caffeine level of 168.5 ng/mL (range 29.5-650.5 ng/mL) during pregnancy, birth weights and lengths were lower in the 4th quartile of caffeine intake compared with the 1st. By age 7, heights and weights were lower by 1.5 cm and 1.1 kg respectively. In another cohort of mother/infant pairs with higher maternal pregnancy plasma caffeine levels, median 625.5 ng/mL (range 86.2 to 1994.7 ng/mL), heights at age 8 were 2.2 cm lower, but there was no difference in weights (109846).

LACTATION: POSSIBLY SAFE
when used orally in amounts commonly found in foods. Caffeine intake should be closely monitored while breast-feeding. During lactation, breast milk concentrations of caffeine are thought to be approximately 50% of serum concentrations and caffeine peaks in breastmilk approximately 1-2 hours after consumption (23590).

LACTATION: POSSIBLY UNSAFE
when used orally in large amounts. Caffeine is excreted slowly in infants and may accumulate. Caffeine can cause sleep disturbances, irritability, and increased bowel activity in breast-fed infants exposed to caffeine (2708,6026).

CALCIUM

LIKELY SAFE ...when used orally or intravenously and appropriately. Calcium is safe when used in appropriate doses (7555,12928,12946,95817). However, excessive doses should be avoided. The Institute of Medicine sets the daily tolerable upper intake level (UL) for calcium according to age as follows: Age 0-6 months, 1000 mg; 6-12 months, 1500 mg; 1-8 years, 2500 mg; 9-18 years, 3000 mg; 19-50 years, 2500 mg; 51+ years, 2000 mg (17506). Doses over these levels can increase the risk of side effects such as kidney stone, hypercalciuria, hypercalcemia, and milk-alkali syndrome. There has also been concern that calcium intake may be associated with an increased risk of cardiovascular disease (CVD) and coronary heart disease (CHD), including myocardial infarction (MI). Some clinical research suggests that calcium intake, often in amounts over the recommended daily intake level of 1000-1300 mg daily for adults, is associated with an increased risk of CVD, CHD, and MI (16118,17482,91350,107233). However, these studies, particularly meta-analyses, have been criticized for excluding trials in which calcium was administered with vitamin D (94137). Many of these trials also only included postmenopausal females. Other analyses report conflicting results, and have not shown that calcium intake affects the risk of CVD, CHD, or MI (92994,93533,97308,107231). Advise patients not to consume more than the recommended daily intake of 1000-1200 mg per day and to consider total calcium intake from both dietary and supplemental sources (17484). Also, advise patients taking calcium supplements to take calcium along with vitamin D (93533).

POSSIBLY UNSAFE ...when used orally in excessive doses. The National Academy of Medicine sets the daily tolerable upper intake level (UL) for calcium according to age as follows: 19-50 years, 2500 mg; 51 years and older, 2000 mg (17506). Doses over these levels can increase the risk of side effects such as kidney stones, hypercalciuria, hypercalcemia, and milk-alkali syndrome. There has also been concern that calcium intake may be associated with an increased risk of cardiovascular disease (CVD) and coronary heart disease (CHD), including myocardial infarction (MI). Some clinical research suggests that calcium intake, often in amounts over the recommended daily intake level of 1000-1300 mg daily for adults, is associated with an increased risk of CVD, CHD, and MI (16118,17482,91350,107233). However, these studies, particularly meta-analyses, have been criticized for excluding trials in which calcium was administered with vitamin D (94137). Many of these trials also only included postmenopausal females. Other analyses report conflicting results, and have not shown that calcium intake affects the risk of CVD, CHD, or MI (92994,93533,97308,107231). Advise patients to not consume more than the recommended daily intake of 1000-1200 mg per day and to consider total calcium intake from both dietary and supplemental sources (17484). Also, advise patients taking calcium supplements to take calcium along with vitamin D (93533).

CHILDREN: LIKELY SAFE
when used orally and appropriately. Calcium is safe when used in appropriate doses (17506).

CHILDREN: POSSIBLY UNSAFE
when used orally in excessive doses. The Institute of Medicine sets the daily tolerable upper intake level (UL) for calcium according to age as follows: 0-6 months, 1000 mg; 6-12 months, 1500 mg; 1-8 years, 2500 mg; 9-18 years, 3000 mg (17506). Doses over these levels can increase the risk of side effects such as kidney stones, hypercalciuria, hypercalcemia, and milk-alkali syndrome.

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally and appropriately (945,1586,3263,3264,17506). The World Health Organization (WHO) recommends prescribing oral calcium supplementation 1.5-2 grams daily during pregnancy to those with low dietary calcium intake to prevent pre-eclampsia (97347).

PREGNANCY AND LACTATION: POSSIBLY UNSAFE
when used orally in excessive doses. The Institute of Medicine sets the same daily tolerable upper intake level (UL) for calcium according to age independent of pregnancy status: 9-18 years, 3000 mg; 19-50 years, 2500 mg (17506). Doses over these amounts might increase the risk of neonatal hypocalcemia-induced seizures possibly caused by transient neonatal hypoparathyroidism in the setting of excessive calcium supplementation during pregnancy, especially during the third trimester. Neonatal hypocalcemia is a risk factor for neonatal seizures (97345).

COFFEE (natural Coffee bean extract powder, Coffeeberry organic Coffee (fruit) extract)

LIKELY SAFE ...when used orally and appropriately. Drinking decaffeinated coffee or coffee containing caffeine in low to moderate amounts is safe (15,98806). According to a review by Health Canada, and a subsequent large meta-analysis conducted in the US, drinking up to 4 cups of coffee daily providing caffeine 400 mg daily is not associated with significant adverse cardiovascular, bone, behavioral, or reproductive effects in healthy adults (11733,98806). The US Dietary Guidelines Advisory Committee states that there is strong and consistent evidence that consumption of beverages such as coffee that contain caffeine 400 mg daily is not associated with increased risk of major chronic diseases, such as cardiovascular disease or cancer, in healthy adults (98806).

POSSIBLY UNSAFE ...when used orally in excessive amounts. Acute use of high doses of caffeine (more than 400 mg per day), which is found in more than 4 cups of caffeinated coffee, has been associated with significant adverse effects such as tachyarrhythmia and sleep disturbances (11832). Drinking caffeinated coffee in amounts greater than 6 cups per day (about 600 mg caffeine) short-term or long-term can also cause caffeinism, with symptoms of anxiety possibly progressing to delirium and agitation. Chronic use of caffeine, especially in large amounts, can sometimes produce tolerance, habituation, and psychological dependence (3719). Abrupt discontinuance of caffeine can cause physical withdrawal symptoms (11733). Keep in mind that only the amount of ADDED caffeine must be stated on product labels. The amount of caffeine found in ingredients such as coffee, which naturally contains caffeine, does not need to be provided. This can make it difficult to determine the total amount of caffeine in a given product. ...when used rectally as an enema. Coffee enemas have been linked to cases of severe electrolyte abnormalities and septicemia leading to severe side effects including death (3026,3347,3349,6652).

CHILDREN: POSSIBLY SAFE
when coffee containing caffeine is consumed orally in moderate amounts. Oral intake of caffeine in doses of less than 2.5 mg/kg daily is not associated with significant adverse effects in children and adolescents (11733,98806). However, higher doses should be avoided. The adverse effects typically associated with caffeine-containing coffee are usually more severe in children than adults (11733).

PREGNANCY: POSSIBLY SAFE
when used orally in moderate amounts. Intake of caffeine from coffee and other sources should be monitored during pregnancy. Caffeine crosses the human placenta, but is not considered a teratogen. Fetal blood and tissue levels are similar to maternal concentrations (4260). The use of caffeine during pregnancy is controversial; however, moderate consumption has not been associated with clinically important adverse fetal effects (2708,2709,2710,2711,9606,11733,16014,16015). However, some research has also found that intrauterine exposure to even modest amounts of caffeine, based on maternal blood levels during the first trimester, is associated with a shorter stature in children ages 4-8 years (109846). In some studies, consuming amounts over 200 mg daily has been associated with a significantly increased risk of miscarriage (16014). This increased risk may be most likely to occur in people with genotypes that confer a slow rate of caffeine metabolism (98806). According to a review by Health Canada, and a subsequent large meta-analysis conducted in the US, most healthy pregnant patients can safely consume caffeine in doses up to 300 mg daily without an increased risk of spontaneous abortion, stillbirth, preterm birth, fetal growth retardation, or congenital malformations (11733,98806). Advise patients to keep caffeine consumption below 300 mg daily during pregnancy. This is similar to the amount of caffeine in about 3 cups of coffee. Keep in mind that only the amount of ADDED caffeine must be stated on product labels. The amount of caffeine found in ingredients such as coffee, which naturally contains caffeine, does not need to be provided. This can make it difficult to determine the total amount of caffeine in a given product.

PREGNANCY: POSSIBLY UNSAFE
when caffeinated coffee providing more than 300 mg of caffeine daily is consumed orally. Caffeine from coffee crosses the placenta, producing fetal blood concentrations similar to maternal levels (4260). Consumption of caffeine in amounts over 300 mg daily is associated with a significantly increased risk of miscarriage in some studies (16014,98806). Advise patients to keep caffeine consumption from all sources below 300 mg daily during pregnancy. This is similar to the amount of caffeine in about 3 cups of coffee. High doses of caffeine throughout pregnancy have resulted in symptoms of caffeine withdrawal in newborn infants (9891). High doses of caffeine have also been associated with spontaneous abortion, premature delivery, and low birth weight (2709,2711). Drinking more than 6 cups of coffee daily increases the risk of spontaneous abortion (2709). Drinking 8 or more cups of coffee daily doubles the risk of stillbirth when compared with those who do not drink coffee during pregnancy (10621).

LACTATION: POSSIBLY SAFE
when used orally. Drinking one or two caffeine-containing beverages daily during lactation is not associated with unacceptable levels of caffeine in human milk (11734).

LACTATION: POSSIBLY UNSAFE
when used orally in large amounts. Caffeine from coffee can cause wakefulness or irritability in breast-fed infants. Caffeine can also cause feeding intolerance and gastrointestinal irritation in infants (6026).

MAGNESIUM

LIKELY SAFE ...when used orally and appropriately. Oral magnesium is safe when used in doses below the tolerable upper intake level (UL) of 350 mg daily (7555). ...when used parenterally and appropriately. Parenteral magnesium sulfate is an FDA-approved prescription product (96484).

POSSIBLY UNSAFE ...when used orally in excessive doses. Doses greater than the tolerable upper intake level (UL) of 350 mg daily frequently cause loose stools and diarrhea (7555).

CHILDREN: LIKELY SAFE
when used orally and appropriately. Magnesium is safe when used in doses below the tolerable upper intake level (UL) of 65 mg daily for children 1 to 3 years, 110 mg daily for children 4 to 8 years, and 350 mg daily for children older than 8 years (7555,89396). ...when used parenterally and appropriately (96483).

CHILDREN: LIKELY UNSAFE
when used orally in excessive doses. Tell patients not to use doses above the tolerable upper intake level (UL). Higher doses can cause diarrhea and symptomatic hypermagnesemia including hypotension, nausea, vomiting, and bradycardia (7555,8095).

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally and appropriately. Magnesium is safe for those pregnant and breast-feeding when used in doses below the tolerable upper intake level (UL) of 350 mg daily (7555).

PREGNANCY AND LACTATION: POSSIBLY SAFE
when prescription magnesium sulfate is given intramuscularly and intravenously prior to delivery for up to 5 days (12592,89397,99354,99355). However, due to potential adverse effects associated with intravenous and intramuscular magnesium, use during pregnancy is limited to patients with specific conditions such as severe pre-eclampsia or eclampsia. There is some evidence that intravenous magnesium can increase fetal mortality and adversely affect neurological and skeletal development (12590,12593,60818,99354,99355). However, a more recent analysis of clinical research shows that increased risk of fetal mortality seems to occur only in the studies where antenatal magnesium is used for tocolysis and not for fetal neuroprotection or pre-eclampsia/eclampsia (102457). Furthermore, antenatal magnesium does not seem to be associated with increased risk of necrotizing enterocolitis in preterm infants (104396). There is also concern that magnesium increases the risk of maternal adverse events. A meta-analysis of clinical research shows that magnesium sulfate might increase the risk of maternal adverse events, especially in Hispanic mothers compared to other racial and ethnic groups (60971,99319).

PREGNANCY AND LACTATION: POSSIBLY UNSAFE
when used orally in excessive doses. Tell patients to avoid exceeding the tolerable upper intake level (UL) of 350 mg daily. Taking magnesium orally in higher doses can cause diarrhea (7555). ...when prescription magnesium sulfate is given intramuscularly and intravenously prior to delivery for longer than 5 days (12592,89397,99354,99355). Maternal exposure to magnesium for longer than 5-7 days is associated with an increase in neonatal bone abnormalities such as osteopenia and fractures. The U.S. Food and Drug Administration (FDA) recommends that magnesium injection not be given for longer than 5-7 days (12590,12593,60818,99354,99355).

LIKELY SAFE ...when used orally and appropriately short-term (15). ...when sodium phosphate is used rectally and appropriately, no more than once every 24 hours, short-term (104471). Long-term use or high doses used orally or rectally require monitoring of serum electrolytes (2494,2495,2496,2497,2498,3092,112922). ...when used intravenously. Potassium phosphate is an FDA-approved prescription drug (15).

POSSIBLY UNSAFE ...when phosphate (expressed as phosphorus) intake exceeds the tolerable upper intake level (UL) of 4 grams daily for adults under 70 years and 3 grams daily for adults older than 70. Hyperphosphatemia, resulting in electrolyte disturbances, alterations in calcium homeostasis, and calcification of nonskeletal tissues, may occur (7555). ...when used rectally more frequently than once every 24 hours, in excessive doses, with longer retention enema time, or in older patients with comorbidity or renal impairment (112922). The US Food and Drug Administration (FDA) warns that this may increase the risk of hyperphosphatemia, dehydration, and electrolyte imbalances leading to kidney and heart damage (104471).

CHILDREN: LIKELY SAFE
when used orally and appropriately at recommended dietary allowances (RDAs). The daily RDAs are: children 1-3 years, 460 mg; children 4-8 years, 500 mg; males and females 9-18 years, 1250 mg (7555). ...when sodium phosphate is used rectally and appropriately, no more than once every 24 hours, short-term in children 2 years and older (104471). ...when used intravenously. Intravenous potassium phosphate is an FDA-approved prescription drug (15).

CHILDREN: POSSIBLY UNSAFE
when phosphate (expressed as phosphorus) intake exceeds the tolerable upper intake level (UL) of 3 grams daily for children 1-8 years of age and 4 grams daily for children 9 years and older. Hyperphosphatemia, resulting in electrolyte disturbances, alterations in calcium homeostasis, and calcification of nonskeletal tissues, may occur (7555). ...when sodium phosphate is used rectally more frequently than once every 24 hours, or in children under 2 years of age or with Hirchsprung disease (112922). The US Food and Drug Administration (FDA) warns that these uses may increase the risk of hyperphosphatemia, dehydration, and electrolyte imbalances leading to kidney and heart damage (104471).

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally and appropriately at the recommended dietary allowance (RDA) of 1250 mg daily for individuals 14-18 years of age and 700 mg daily for those over 18 years of age (7555). ...when sodium phosphate is used rectally and appropriately short-term (15). ...when used intravenously. Intravenous potassium phosphate is an FDA-approved prescription drug (15).

PREGNANCY AND LACTATION: POSSIBLY UNSAFE
when phosphate (expressed as phosphorus) intake exceeds the tolerable upper intake level (UL). Hyperphosphatemia, resulting in electrolyte disturbances, alterations in calcium homeostasis, and calcification of nonskeletal tissues, may occur. The UL during pregnancy is 3.5 grams daily. During lactation, the UL is 4 grams daily (7555).

POTASSIUM

LIKELY SAFE ...when used orally in doses up to 100 mEq total potassium daily, not to exceed 200 mEq in a 24-hour period (95010,107989). Oral potassium chloride and potassium citrate are FDA-approved prescription products (95010,107989). Larger doses increase the risk of hyperkalemia (15). ...when administered intravenously (IV) at appropriate infusion rates (95011). Parenteral potassium is an FDA-approved prescription product (15,95011). A tolerable upper intake level (UL) for potassium has not been established; however, potassium levels should be monitored in individuals at increased risk for hyperkalemia, such as those with kidney disease, heart failure, and adrenal insufficiency (100310,107966).

CHILDREN: LIKELY SAFE
when used orally and appropriately in dietary amounts. A tolerable upper intake level (UL) has not been established for healthy individuals (6243,100310).

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally in dietary amounts of 40-80 mEq daily (15). A tolerable upper intake level (UL) has not been established for healthy individuals (100310).

SODIUM

LIKELY SAFE ...when used orally and appropriately. Sodium is safe in amounts that do not exceed the Chronic Disease Risk Reduction (CDRR) intake level of 2.3 grams daily (100310). Higher doses can be safely used therapeutically with appropriate medical monitoring (26226,26227).

POSSIBLY UNSAFE ...when used orally in high doses. Tell patients to avoid exceeding the CDRR intake level of 2.3 grams daily (100310). Higher intake can cause hypertension and increase the risk of cardiovascular disease (26229,98176,98177,98178,98181,98183,98184,100310,109395,109396,109398,109399). There is insufficient reliable information available about the safety of sodium when used topically.

CHILDREN: LIKELY SAFE
when used orally and appropriately (26229,100310). Sodium is safe in amounts that do not exceed the CDRR intake level of 1.2 grams daily for children 1 to 3 years, 1.5 grams daily for children 4 to 8 years, 1.8 grams daily for children 9 to 13 years, and 2.3 grams daily for adolescents (100310).

CHILDREN: POSSIBLY UNSAFE
when used orally in high doses. Tell patients to avoid prolonged use of doses exceeding the CDRR intake level of 1.2 grams daily for children 1 to 3 years, 1.5 grams daily for children 4 to 8 years, 1.8 grams daily for children 9 to 13 years, and 2.3 grams daily for adolescents (100310). Higher intake can cause hypertension (26229).

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally and appropriately. Sodium is safe in amounts that do not exceed the CDRR intake level of 2.3 grams daily (100310).

PREGNANCY AND LACTATION: POSSIBLY UNSAFE
when used orally in higher doses. Higher intake can cause hypertension (100310). Also, both the highest and the lowest pre-pregnancy sodium quintile intakes are associated with an increased risk of hypertensive disorders of pregnancy, including gestational hypertension and pre-eclampsia, and the delivery of small for gestational age (SGA) infants when compared to the middle intake quintile (106264).

LIKELY SAFE ...when used orally and appropriately. Whey protein up to 30 grams has been safely used in clinical trials for up to 6 months (4930,16728,16729,105587).

CHILDREN: LIKELY SAFE
when used orally and appropriately as a dietary protein in food or infant formula. Hydrolyzed whey protein-based formula has been safely used in infants for up to 6 months in clinical trials (4927,105585,105594).

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.

Interactions with Drugs view details

Below is general information about the interactions of the known ingredients contained in the product W+ 100% Whey Isolate Protein Energy. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.

CAFFEINE

ADENOSINE (Adenocard)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = B

Theoretically, caffeine might decrease the vasodilatory effects of adenosine and interfere with its use prior to stress testing.

Details

Some evidence shows that caffeine is a competitive inhibitor of adenosine and can reduce the vasodilatory effects of adenosine in humans (38172). However, other research shows that caffeine does not seem to affect supplemental adenosine because high interstitial levels of adenosine overcome the antagonistic effects of caffeine (11771). It is recommended that methylxanthines and methylxanthine-containing products be stopped 24 hours prior to pharmacological stress tests (11770). However, methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing (11771).

ALCOHOL (Ethanol)

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = D

Theoretically, concomitant use might increase levels and adverse effects of caffeine.

Details

Alcohol reduces caffeine metabolism. Concomitant use of alcohol can increase caffeine serum concentrations and the risk of caffeine adverse effects (6370).

ANTICOAGULANT/ANTIPLATELET DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

Theoretically, caffeine may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.

Details

Caffeine is reported to have antiplatelet activity. Theoretically, it might increase the risk of bleeding when used concomitantly with these agents (8028,8029); however, this interaction has not been reported in humans.

ANTIDIABETES DRUGS

Interaction Rating = Minor Be watchful with this combination.

Severity = Moderate • Occurrence = Unlikely • Level of Evidence = B

Theoretically, taking caffeine with antidiabetes drugs might interfere with blood glucose control.

Details

Data are conflicting. Reports claim that caffeine might increase or decrease blood sugar (6024,8646,114662).

BETA-ADRENERGIC AGONISTS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Mild • Occurrence = Probable • Level of Evidence = D

Theoretically, large amounts of caffeine might increase the cardiac inotropic effects of beta-agonists (15).

CARBAMAZEPINE (Tegretol)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, caffeine might reduce the effects of carbamazepine and increase the risk for convulsions.

Details

Animal research suggests that taking caffeine can lower the anticonvulsant effects of carbamazepine and can induce seizures when taken in doses above 400 mg/kg (23559,23561). Human research has shown that taking caffeine 300 mg in three divided doses along with carbamazepine 200 mg reduces the bioavailability of carbamazepine by 32% and prolongs the plasma half-life of carbamazepine 2-fold in healthy individuals (23562).

CIMETIDINE (Tagamet)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Mild • Occurrence = Likely • Level of Evidence = B

Theoretically, cimetidine might increase the levels and adverse effects of caffeine.

Details

Cimetidine decreases the rate of caffeine clearance by 31% to 42% (11736).

CLOZAPINE (Clozaril)

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = B

Caffeine might increase the levels and adverse effects of clozapine and acutely exacerbate psychotic symptoms.

Details

Caffeine might increase the effects and toxicity of clozapine. Caffeine doses of 400-1000 mg per day inhibit clozapine metabolism (5051). Clozapine is metabolized by cytochrome P450 1A2 (CYP1A2). Although researchers speculate that caffeine might inhibit CYP1A2, there is no reliable evidence that caffeine affects CYP1A2. There is also speculation that genetic factors might make some patients more sensitive to an interaction between clozapine and caffeine (13741). In one case report, severe, life-threatening clozapine toxicity and multiorgan system failure occurred in a patient with schizophrenia stabilized on clozapine who consumed caffeine 600 mg daily (108817).

CONTRACEPTIVE DRUGS

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = B

Theoretically, contraceptive drugs might increase the levels and adverse effects of caffeine.

Details

Oral contraceptives decrease the rate of caffeine clearance by 40-65% (2714,11737).

CYTOCHROME P450 1A2 (CYP1A2) INHIBITORS

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = D

Theoretically, concomitant use might increase the levels and adverse effects of caffeine.

Details

Caffeine is metabolized by CYP1A2. Theoretically, drugs that inhibit CYP1A2 may decrease the rate of caffeine clearance and increase caffeine levels (5051,11741).

DIPYRIDAMOLE (Persantine)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = B

Theoretically, caffeine might decrease the vasodilatory effects of dipyridamole and interfere with its use prior to stress testing.

Details

Caffeine inhibits dipyridamole-induced vasodilation (11770,11772). It is recommended that methylxanthines and methylxanthine-containing products be stopped 24 hours prior to pharmacological stress tests (11770). Methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing (11771).

DISULFIRAM (Antabuse)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Mild • Occurrence = Probable • Level of Evidence = B

Theoretically, disulfiram use might increase the levels and adverse effects of caffeine.

Details

Disulfiram decreases the rate of caffeine clearance (11840).

DIURETIC DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, using caffeine with diuretic drugs might increase the risk of hypokalemia.

Details

Caffeine, especially in excessive amounts, can reduce potassium levels due to stimulation of the sodium-potassium pump (23579,37905,37953,38003,38034). Diuretics can also cause lower potassium levels.

EPHEDRINE

Interaction Rating = Major Do not take this combination.

Severity = High • Occurrence = Probable • Level of Evidence = D

Theoretically, concomitant use might increase the risk for stimulant adverse effects.

Details

Use of ephedrine with caffeine can increase the risk of stimulatory adverse effects. There is evidence that using ephedrine with caffeine might increase the risk of serious life-threatening or debilitating adverse effects such as hypertension, myocardial infarction, stroke, seizures, and death (1275,6486,10307).

ESTROGENS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Mild • Occurrence = Probable • Level of Evidence = B

Theoretically, estrogens might increase the levels and adverse effects of caffeine.

Details

Estrogen inhibits caffeine metabolism (2714,23570).

ETHOSUXIMIDE (Zarontin)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, caffeine might reduce the effects of ethosuximide and increase the risk for convulsions.

Details

Animal research suggests that caffeine 92.4 mg/kg can decrease the anticonvulsant activity of ethosuximide (23560). However, this effect has not been reported in humans.

FELBAMATE (Felbatol)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, caffeine might reduce the effects of felbamate and increase the risk for convulsions.

Details

Animal research suggests that a high dose of caffeine 161.7 mg/kg can decreases the anticonvulsant activity of felbamate (23563). However, this effect has not been reported in humans.

FLUCONAZOLE (Diflucan)

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = B

Theoretically, fluconazole might increase the levels and adverse effects of caffeine.

Details

Fluconazole decreases caffeine clearance by approximately 25% (11022).

FLUTAMIDE (Eulexin)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = D

Theoretically, caffeine might increase the levels and adverse effects of flutamide.

Details

In vitro evidence suggests that caffeine can inhibit the metabolism of flutamide (23553). However, this effect has not been reported in humans.

FLUVOXAMINE (Luvox)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Mild • Occurrence = Probable • Level of Evidence = D

Theoretically, fluvoxamine might increase the levels and adverse effects of caffeine.

Details

Fluvoxamine reduces caffeine metabolism (6370).

LITHIUM

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = D

Abrupt caffeine withdrawal might increase the levels and adverse effects of lithium.

Details

Caffeine has diuretic activity. When abruptly discontinued, caffeine may alter the clearance of lithium (609). There are two case reports of lithium tremor that worsened upon abrupt coffee withdrawal (610) and 6 case reports of elevated serum lithium levels after reducing or eliminating caffeine intake (114665). In one case, a male with schizoaffective disorder stabilized on lithium had an elevated lithium level after reducing his caffeine intake by 87%. At a later date, he increased his caffeine intake by 6-fold, resulting in a subtherapeutic lithium level and a recurrence of psychiatric symptoms (114665).

METFORMIN (Glucophage)

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = D

Theoretically, metformin might increase the levels and adverse effects of caffeine.

Details

Animal research suggests that metformin can reduce caffeine metabolism (23571). However, this effect has not been reported in humans.

METHOXSALEN (Oxsoralen)

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = B

Theoretically, methoxsalen might increase the levels and adverse effects of caffeine.

Details

Methoxsalen reduces caffeine metabolism (23572).

MEXILETINE (Mexitil)

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = B

Theoretically, mexiletine might increase the levels and adverse effects of caffeine.

Details

Mexiletine reduces caffeine metabolism (1260,11741).

MONOAMINE OXIDASE INHIBITORS (MAOIs)

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

Theoretically, concomitant use might increase the risk of a hypertensive crisis.

Details

Caffeine has been shown to inhibit monoamine oxidase (MAO) A and B in laboratory studies (37724,37877,37912,38108). Concomitant intake of large amounts of caffeine with MAOIs might precipitate a hypertensive crisis (15). In a case report, a patient that consumed 10-12 cups of caffeinated coffee and took the MAOI tranylcypromine presented with severe hypertension (91086). Hypertension was resolved after the patient switched to drinking decaffeinated coffee.

NICOTINE

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = B

Theoretically, concomitant use might increase the risk of hypertension.

Details

Concomitant use of caffeine and nicotine has been shown to have additive cardiovascular effects, including increased heart rate and blood pressure. Blood pressure was increased by 10.8/12.4 mmHg when the agents were used concomitantly (36549).

PENTOBARBITAL (Nembutal)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = B

Theoretically, caffeine might decrease the effects of pentobarbital.

Details

Caffeine might negate the hypnotic effects of pentobarbital (13742).

PHENOBARBITAL (Luminal)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, caffeine might reduce the effects of phenobarbital and increase the risk for convulsions.

Details

Animal research suggests that caffeine can decrease the anticonvulsant activity of phenobarbital (23558,23559,23561). However, the exact mechanism of this interaction is unclear.

PHENOTHIAZINES

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = D

Theoretically, phenothiazines might increase the levels and adverse effects of caffeine.

Details

Phenothiazines, including perazine, chlorpromazine, levomepromazine, and thioridazine, can reduce the metabolism of caffeine by inhibiting cytochrome P450 1A2 (CYP1A2) (23573,23574).

PHENYLPROPANOLAMINE

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = B

Theoretically, phenylpropanolamine might increase the risk of hypertension, as well as the levels and adverse effects of caffeine.

Details

Concomitant use of phenylpropanolamine and caffeine might cause an additive increase in blood pressure (11738). Phenylpropanolamine also seems to increase caffeine serum levels (13743).

PHENYTOIN (Dilantin)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, caffeine might reduce the effects of phenytoin and increase the risk for convulsions.

Details

Animal research suggests that caffeine can decrease the anticonvulsant activity of phenytoin (23559,23561). The effect does not seem to be related to the seizure threshold-lowering effects of caffeine. However, the exact mechanism of this interaction is unclear.

PIOGLITAZONE (Actos)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, caffeine might increase the levels and clinical effects of pioglitazone.

Details

Animal research suggests that caffeine can modestly increase the maximum concentration, area under the curve, and half-life of pioglitazone, and also reduce its clearance. This increased the antidiabetic effects of pioglitazone (108812). However, the exact mechanism of this interaction is unclear.

QUINOLONE ANTIBIOTICS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Mild • Occurrence = Probable • Level of Evidence = B

Theoretically, quinolone antibiotics might increase the levels and adverse effects of caffeine.

Details

Quinolones (also called fluoroquinolones) can decrease caffeine clearance by inhibiting cytochrome P450 1A2 (CYP1A2) enzyme (606,607,608,23554,23555,23556).

RILUZOLE (Rilutek)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, concomitant use might increase the levels and adverse effects of both caffeine and riluzole.

Details

Caffeine and riluzole are both metabolized by cytochrome P450 1A2 (CYP1A2), and concomitant use might reduce the metabolism of one or both agents (11739).

STIMULANT DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = C

Theoretically, concomitant use might increase stimulant adverse effects.

Details

Due to the central nervous system (CNS) stimulant effects of caffeine, concomitant use with stimulant drugs can increase the risk of adverse effects (11832).

TERBINAFINE (Lamisil)

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = B

Theoretically, terbinafine might increase the levels and adverse effects of caffeine.

Details

Terbinafine decreases the clearance of intravenous caffeine by 19% (11740).

THEOPHYLLINE

Interaction Rating = Moderate Be cautious with this combination.

Severity = Mild • Occurrence = Probable • Level of Evidence = C

Theoretically, caffeine might increase the levels and adverse effects of theophylline.

Details

Large amounts of caffeine might inhibit theophylline metabolism (11741).

TIAGABINE (Gabitril)

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = D

Theoretically, caffeine might increase the levels and adverse effects of tiagabine.

Details

Animal research suggests that chronic caffeine administration can increase the serum concentrations of tiagabine. However, concomitant use does not seem to reduce the antiepileptic effects of tiagabine (23561).

TICLOPIDINE (Ticlid)

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = D

Theoretically, ticlopidine might increase the levels and adverse effects of caffeine.

Details

In vitro evidence suggests that ticlopidine can inhibit caffeine metabolism (23557). However, this effect has not been reported in humans.

VALPROATE

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, caffeine might reduce the effects of valproate and increase the risk for convulsions.

Details

Animal research suggests that caffeine can decrease the anticonvulsant activity of valproate (23558,23559,23561,37882). However, the exact mechanism of this interaction is unclear.

VERAPAMIL (Calan, others)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, verapamil might increase the levels and adverse effects of caffeine.

Details

Verapamil increases plasma caffeine concentrations by 25% (11741).

CALCIUM

ALUMINUM

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = B

Calcium citrate might increase aluminum absorption and toxicity. Other types of calcium do not increase aluminum absorption.

Details

Calcium citrate can increase the absorption of aluminum when taken with aluminum hydroxide. The increase in aluminum levels may become toxic, particularly in individuals with kidney disease (21631). However, the effect of calcium citrate on aluminum absorption is due to the citrate anion rather than calcium cation. Calcium acetate does not appear to increase aluminum absorption (93006).

BISPHOSPHONATES

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = C

Calcium reduces the absorption of bisphosphonates.

Details

Advise patients to take bisphosphonates at least 30 minutes before calcium, but preferably at a different time of day. Calcium supplements decrease absorption of bisphosphonates (12937).

CALCIPOTRIENE (Dovonex)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = B

Taking calcipotriene with calcium might increase the risk for hypercalcemia.

Details

Calcipotriene is a vitamin D analog used topically for psoriasis. It can be absorbed in sufficient amounts to cause systemic effects, including hypercalcemia (12938). Theoretically, combining calcipotriene with calcium supplements might increase the risk of hypercalcemia.

CALCIUM CHANNEL BLOCKERS

Interaction Rating = Minor Be watchful with this combination.

Severity = Moderate • Occurrence = Unlikely • Level of Evidence = D

Intravenous calcium may decrease the effects of calcium channel blockers; oral calcium is unlikely to have this effect.

Details

Intravenous calcium is used to decrease the effects of calcium channel blockers in the management of overdose. Intravenous calcium gluconate has been used before intravenous verapamil (Isoptin) to prevent or reduce the hypotensive effects without affecting the antiarrhythmic effects (6124). But there is no evidence that dietary or supplemental calcium when taken orally interacts with calcium channel blockers (12939,12947).

CEFTRIAXONE (Rocephin)

Interaction Rating = Major Do not take this combination.

Severity = High • Occurrence = Probable • Level of Evidence = D

Co-administration of intravenous calcium and ceftriaxone can result in precipitation of a ceftriaxone-calcium salt in the lungs and kidneys.

Details

Avoid administering intravenous calcium in any form, such as parenteral nutrition or Lactated Ringers, within 48 hours of intravenous ceftriaxone. Case reports in neonates show that administering intravenous ceftriaxone and calcium can result in precipitation of a ceftriaxone-calcium salt in the lungs and kidneys. In several cases, neonates have died as a result of this interaction (15794,21632). So far there are no reports in adults; however, there is still concern that this interaction might occur in adults.

DIGOXIN (Lanoxin)

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = B

Using intravenous calcium with digoxin might increase the risk of fatal cardiac arrhythmias.

Details

Hypercalcemia increases the risk of fatal cardiac arrhythmias with digoxin (12940). However, one retrospective analysis of clinical data suggests that intravenous calcium does not increase the risk of dysrhythmias or mortality in patients receiving digoxin (38960).

DILTIAZEM (Cardizem, others)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = D

Theoretically, calcium may reduce the therapeutic effects of diltiazem.

Details

Hypercalcemia can reduce the effectiveness of verapamil in atrial fibrillation (10574). Theoretically, calcium might increase this risk of hypercalcemia and reduce the effectiveness of diltiazem.

DOLUTEGRAVIR (Tivicay)

Interaction Rating = Major Do not take this combination.

Severity = High • Occurrence = Probable • Level of Evidence = B

Calcium seems to reduce levels of dolutegravir.

Details

Advise patients to take dolutegravir either 2 hours before or 6 hours after taking calcium supplements. Pharmacokinetic research suggests that taking calcium carbonate 1200 mg concomitantly with dolutegravir 50 mg reduces plasma levels of dolutegravir by almost 40%. Calcium appears to decrease levels of dolutegravir through chelation (93578).

ELVITEGRAVIR (Vitekta)

Interaction Rating = Major Do not take this combination.

Severity = High • Occurrence = Probable • Level of Evidence = B

Calcium seems to reduce levels of elvitegravir.

Details

Advise patients to take elvitegravir either 2 hours before or 2 hours after taking calcium supplements. Pharmacokinetic research suggests that taking calcium along with elvitegravir can reduce blood levels of elvitegravir through chelation (94166).

LEVOTHYROXINE (Synthroid, others)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = B

Calcium seems to reduce the absorption and effectiveness of levothyroxine.

Details

Advise patients to take levothyroxine and calcium supplements at least 4 hours apart. Calcium reduces levothyroxine absorption, probably by forming insoluble complexes (5082). Calcium carbonate supplements reduce effectiveness of levothyroxine in patients with hypothyroidism (5081,5082,6137).

LITHIUM

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = B

Theoretically, concomitant use of calcium and lithium may increase this risk of hypercalcemia.

Details

Clinical research suggests that long-term use of lithium may cause hypercalcemia in 10% to 60% of patients (38953). Theoretically, concomitant use of lithium and calcium supplements may further increase this risk.

QUINOLONE ANTIBIOTICS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = B

Calcium seems to reduce the absorption of quinolone antibiotics.

Details

Advise patients to take oral quinolones at least 2 hours before or 4-6 hours after calcium supplements or calcium-fortified foods. Taking calcium at the same time as oral quinolones can reduce quinolone absorption. Calcium binds to quinolones in the gut (4412,10339,21638,38570).

RALTEGRAVIR (Isentress)

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = B

Calcium may reduce levels of raltegravir.

Details

Pharmacokinetic research shows that taking a single dose of calcium carbonate 3000 mg along with raltegravir 400 mg twice daily modestly decreases the mean area under the curve of raltegravir, but the decrease does not necessitate a dose adjustment of raltegravir (94164). However, a case of elevated HIV-1 RNA levels and documented resistance to raltegravir has been reported for a patient taking calcium carbonate 1 gram three times daily plus vitamin D3 (cholecalciferol) 400 IU three times daily in combination with raltegravir 400 mg twice daily for 11 months. It is thought that calcium reduced raltegravir levels by chelation, leading to treatment failure (94165).

SOTALOL (Betapace)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = B

Calcium seems to reduce the absorption of sotalol.

Details

Advise patients to separate doses by at least 2 hours before or 4-6 hours after calcium. Calcium appears to reduce the absorption of sotalol, probably by forming insoluble complexes (10018).

TETRACYCLINE ANTIBIOTICS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = C

Calcium seems to reduce the absorption of tetracycline antibiotics.

Details

Advise patients to take oral tetracyclines at least 2 hours before, or 4-6 hours after calcium supplements. Taking calcium at the same time as oral tetracyclines can reduce tetracycline absorption. Calcium binds to tetracyclines in the gut (1843).

THIAZIDE DIURETICS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = C

Taking calcium along with thiazides might increase the risk of hypercalcemia and renal failure.

Details

Thiazides reduce calcium excretion by the kidneys (1902). Using thiazides along with moderately large amounts of calcium carbonate increases the risk of milk-alkali syndrome (hypercalcemia, metabolic alkalosis, renal failure). Patients may need to have their serum calcium levels and/or parathyroid function monitored regularly.

VERAPAMIL (Calan, others)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = D

Theoretically, calcium may reduce the therapeutic effects of verapamil.

Details

Hypercalcemia can reduce the effectiveness of verapamil in atrial fibrillation (10574). Theoretically, use of calcium supplements may increase this risk of hypercalcemia and reduce the effectiveness of verapamil.

COFFEE (natural Coffee bean extract powder, Coffeeberry organic Coffee (fruit) extract)

ADENOSINE (Adenocard)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = B

Theoretically, coffee might decrease the vasodilatory effects of adenosine and interfere with its use prior to stress testing.

Details

Coffee contains caffeine. Caffeine is a competitive inhibitor of adenosine at the cellular level (38172). However, caffeine does not seem to affect supplemental adenosine because high interstitial levels of adenosine overcome the antagonistic effects of caffeine (11771). It is recommended that methylxanthines such as caffeine, as well as methylxanthine-containing products, be stopped 24 hours prior to pharmacological stress tests (11770). However, methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing (11771).

ALCOHOL (Ethanol)

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = D

Theoretically, alcohol might increase the levels and adverse effects of caffeine.

Details

Coffee contains caffeine. Concomitant use of alcohol and caffeine can increase caffeine serum concentrations and the risk of caffeine adverse effects. Alcohol reduces caffeine metabolism (6370,24693).

ALENDRONATE (Fosamax)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = B

Coffee reduces alendronate bioavailability.

Details

Separate coffee ingestion and alendronate administration by two hours. Coffee reduces alendronate bioavailability by 60% (11735).

ANTICOAGULANT/ANTIPLATELET DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Unlikely • Level of Evidence = D

Theoretically, coffee may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.

Details

Coffee contains caffeine. Caffeine is reported to have antiplatelet activity (8028,8029). Theoretically, the caffeine in coffee might increase the risk of bleeding when used concomitantly with these agents. However, this interaction has not been reported in humans. There is some evidence that caffeinated coffee might increase the fibrinolytic activity in blood (8030).

ANTIDIABETES DRUGS

Interaction Rating = Minor Be watchful with this combination.

Severity = Moderate • Occurrence = Unlikely • Level of Evidence = B

Theoretically, concomitant use of coffee and antidiabetes drugs might interfere with blood glucose control.

Details

Coffee contains caffeine. Reports claim that caffeine might increase or decrease blood sugar levels (6024,8646).

BETA-ADRENERGIC AGONISTS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Mild • Occurrence = Probable • Level of Evidence = D

Theoretically, concomitant use of large amounts of coffee might increase cardiac inotropic effects of beta-agonists.

Details

Coffee contains caffeine. Caffeine can increase cardiac inotropic effects of beta-agonists (15).

CIMETIDINE (Tagamet)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Mild • Occurrence = Likely • Level of Evidence = B

Theoretically, cimetidine might increase the effects and adverse effects of caffeine in coffee.

Details

Coffee contains caffeine. Cimetidine can reduce caffeine clearance by 31% to 42% (11736,24700).

CLOZAPINE (Clozaril)

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = B

Theoretically, coffee might increase the levels and adverse effects of clozapine and acutely exacerbate psychotic symptoms.

Details

Coffee contains caffeine. Caffeine can increase the effects and toxicity of clozapine. Caffeine doses of 400-1000 mg daily inhibit clozapine metabolism (5051). Clozapine is metabolized by cytochrome P450 1A2 (CYP1A2). Researchers speculate that caffeine might inhibit CYP1A2. However, there is no reliable evidence that caffeine affects CYP1A2. There is also speculation that genetic factors might make some patients be more sensitive to the interaction between clozapine and caffeine (13741).

CONTRACEPTIVE DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Mild • Occurrence = Probable • Level of Evidence = B

Theoretically, concomitant use might increase the effects and adverse effects of caffeine found in coffee.

Details

Coffee contains caffeine. Oral contraceptive drugs can decrease caffeine clearance by 40% to 65% (2714,11737).

DIPYRIDAMOLE (Persantine)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = B

Theoretically, coffee might decrease the vasodilatory effects of dipyridamole and interfere with its use prior to stress testing.

Details

Coffee contains caffeine. Caffeine is a methylxyanthine that may inhibit dipyridamole-induced vasodilation (11770,11772,24974,37985,53795). It is recommended that methylxanthines such as caffeine, as well as methylxanthine-containing products such as coffee, be stopped 24 hours prior to pharmacological stress tests (11770). Methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing (11771).

DISULFIRAM (Antabuse)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Mild • Occurrence = Probable • Level of Evidence = B

Theoretically, disulfiram might increase the risk of adverse effects from caffeine.

Details

Coffee contains caffeine. In human research, disulfiram decreases the clearance and increases the half-life of caffeine (11840).

DIURETIC DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, concomitant use might increase the risk of hypokalemia.

Details

Coffee contains caffeine. Caffeine, especially in excessive amounts, can reduce potassium levels due to stimulation of the sodium-potassium pump (23579,37905,37953,38003,38034). Diuretics can also cause lower potassium levels.

EPHEDRINE

Interaction Rating = Major Do not take this combination.

Severity = High • Occurrence = Probable • Level of Evidence = D

Theoretically, concomitant use might increase the risk of stimulant adverse effects.

Details

Coffee contains caffeine. There is evidence that using ephedrine with caffeine might increase the risk of serious life-threatening or debilitating adverse effects such as hypertension, myocardial infarction, stroke, seizures, and death (1275,6486,9740,10307). Tell patients to avoid taking caffeine with ephedrine and other stimulants.

ESTROGENS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Mild • Occurrence = Probable • Level of Evidence = B

Theoretically, estrogens might increase the levels and adverse effects of caffeine.

Details

Coffee contains caffeine. Estrogen inhibits caffeine metabolism (2714).

FLUCONAZOLE (Diflucan)

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = B

Theoretically, fluconazole might increase the levels and adverse effects of caffeine.

Details

Coffee contains caffeine. Fluconazole decreases caffeine clearance by approximately 25% (11022,24978).

FLUVOXAMINE (Luvox)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Mild • Occurrence = Probable • Level of Evidence = B

Theoretically, fluvoxamine might increase the levels and adverse effects of caffeine.

Details

Coffee contains caffeine. Fluvoxamine reduces caffeine metabolism (6370,38287).

LAMOTRIGINE (Lamictal)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = B

Coffee consumption can decrease the levels and clinical effects of lamotrigine.

Details

A pharmacokinetic study in patients taking lamotrigine shows that consumption of coffee, both caffeinated and decaffeinated, can decrease the area under the concentration-time curve (AUC) and the peak plasma level (Cmax) of lamotrigine. Each additional cup of coffee reduced the AUC and Cmax by 4% and 3%, respectively. It is unclear whether this interaction is due to induction of lamotrigine metabolism or inhibition of lamotrigine absorption (107837).

LEVOTHYROXINE (Synthroid, others)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = B

Coffee can reduce the absorption of levothyroxine.

Details

In some patients, coffee can reduce levothyroxine absorption, possibly through the formation of non-absorbable complexes. A pharmacokinetic study in these patients found that 25-30 mL of espresso coffee consumed with levothyroxine tablets delayed the time to peak plasma levels by 38-43 minutes, reduced the peak plasma level (Cmax) by 19% to 36%, and reduced the area under the curve (AUC) by 27% to 36%. Coffee consumed one hour after levothyroxine did not affect absorption (16401). It is not known whether this interaction occurs with other types of coffee. Tell patients to avoid drinking coffee at the same time that they take their levothyroxine, and for up to an hour afterwards.

LITHIUM

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = D

Theoretically, abrupt coffee withdrawal might increase the levels and adverse effects of lithium.

Details

Coffee contains caffeine. Abrupt caffeine withdrawal can increase serum lithium levels (609). Two cases of lithium tremor that worsened with abrupt coffee withdrawal have been reported (609,610). There is also one case of a 2.8-fold increase in blood lithium levels after a patient taking lithium reduced his coffee consumption from 13-20 cups daily to 10 cups daily (97369).

MEXILETINE (Mexitil)

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = B

Theoretically, mexiletine might increase the levels and adverse effects of caffeine.

Details

Coffee contains caffeine. Mexiletine can decrease caffeine elimination by 50% (1260,11741,24981).

MONOAMINE OXIDASE INHIBITORS (MAOIs)

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

Theoretically, concomitant use might increase the risk of a hypertensive crisis.

Details

Coffee contains caffeine. Caffeine has been shown to inhibit monoamine oxidase (MAO) A and B in laboratory studies (37724,37877,37912,38108). Concomitant intake of large amounts of caffeine with MAOIs might precipitate a hypertensive crisis (15). In a case report, a patient that consumed 10-12 cups of caffeinated coffee and took the MAOI tranylcypromine presented with severe hypertension (91086). Hypertension was resolved after the patient switched to drinking decaffeinated coffee.

NICOTINE

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = B

Theoretically, concomitant use might increase the risk of hypertension.

Details

Coffee contains caffeine. Concomitant use of caffeine and nicotine has been shown to have additive cardiovascular effects, including increased heart rate and blood pressure. Blood pressure was increased by 10.8/12.4 mmHg when the agents were used concomitantly (36549).

PENTOBARBITAL (Nembutal)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = B

Theoretically, coffee might reduce the effects of pentobarbital.

Details

Coffee contains caffeine. Theoretically, caffeine might negate the hypnotic effects of pentobarbital (13742).

PHENOTHIAZINES

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = D

Theoretically, phenothiazines might increase the levels and adverse effects of caffeine. Also, coffee may bind to phenothiazines and reduce their absorption.

Details

Coffee contains caffeine. Phenothiazines can reduce the metabolism of caffeine by inhibiting cytochrome P450 1A2 (CYP1A2) (23573,23574). Additionally, the tannins in coffee may bind to phenothiazines in the gastrointestinal tract and reduce their absorption (626,627).

PHENYLPROPANOLAMINE

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = B

Theoretically, phenylpropanolamine might increase the risk of hypertension, as well as the levels and adverse effects of caffeine.

Details

Coffee contains caffeine. Concomitant use of phenylpropanolamine and caffeine might cause an additive increase in blood pressure (11738). Phenylpropanolamine also seems to increase caffeine serum levels (13743).

PIOGLITAZONE (Actos)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, coffee might increase the levels and clinical effects of pioglitazone.

Details

Coffee contains caffeine. Animal research suggests that caffeine can modestly increase the maximum concentration, area under the curve, and half-life of pioglitazone, and also reduce its clearance. This increased the antidiabetic effects of pioglitazone (108812). However, the exact mechanism of this interaction is unclear.

QUINOLONE ANTIBIOTICS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Mild • Occurrence = Probable • Level of Evidence = B

Theoretically, quinolone antibiotics might increase the levels and adverse effects of caffeine.

Details

Coffee contains caffeine. Concomitant use of caffeine and quinolones can decrease caffeine clearance and increase effects and risk of adverse effects (606,607,608,23555,24695,24696,24697).

RILUZOLE (Rilutek)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, concomitant use might increase the levels and adverse effects of both caffeine and riluzole.

Details

Coffee contains caffeine. Caffeine and riluzole are both metabolized by cytochrome P450 1A2 (CYP1A2), and concomitant use might reduce metabolism of one or both agents (11739).

STIMULANT DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = C

Theoretically, concomitant use might increase stimulant adverse effects.

Details

Coffee contains caffeine. Due to the central nervous system (CNS) stimulant effects of caffeine, concomitant use with stimulant drugs can increase the risk of adverse effects (11832).

TERBINAFINE (Lamisil)

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = B

Theoretically, terbinafine might increase the levels and adverse effects of caffeine.

Details

Coffee contains caffeine. Terbinafine decreases the clearance of intravenous caffeine by 19% (11740).

THEOPHYLLINE

Interaction Rating = Moderate Be cautious with this combination.

Severity = Mild • Occurrence = Probable • Level of Evidence = B

Theoretically, coffee might increase the levels and adverse effects of theophylline.

Details

Coffee contains caffeine, which can increase theophylline levels (11741,11862,24984).

TRICYCLIC ANTIDEPRESSANTS (TCAs)

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = D

Theoretically, TCAs might bind with coffee constituents when taken at the same time.

Details

In vitro research suggests that the tannins in coffee might cause precipitation of TCAs (626,627). However, this effect has not been reported in humans.

VERAPAMIL (Calan, others)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, concomitant use might increase the levels and adverse effects of caffeine.

Details

Coffee contains caffeine. Verapamil increases plasma caffeine concentrations by 25% (11741).

MAGNESIUM

AMINOGLYCOSIDE ANTIBIOTICS

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

Concomitant use of aminoglycoside antibiotics and magnesium can increase the risk for neuromuscular weakness.

Details

Both aminoglycosides and magnesium reduce presynaptic acetylcholine release, which can lead to neuromuscular blockade and possible paralysis. This is most likely to occur with high doses of magnesium given intravenously (13362).

ANTACIDS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Use of acid reducers may reduce the laxative effect of magnesium oxide.

Details

A retrospective analysis shows that, in the presence of H2 receptor antagonists (H2RAs) or proton pump inhibitors (PPIs), a higher dose of magnesium oxide is needed for a laxative effect (90033). This may also occur with antacids. Under acidic conditions, magnesium oxide is converted to magnesium chloride and then to magnesium bicarbonate, which has an osmotic laxative effect. By reducing acidity, antacids may reduce the conversion of magnesium oxide to the active bicarbonate salt.

ANTICOAGULANT/ANTIPLATELET DRUGS

Interaction Rating = Minor Be watchful with this combination.

Severity = Moderate • Occurrence = Unlikely • Level of Evidence = B

Theoretically, magnesium may have antiplatelet effects, but the evidence is conflicting.

Details

In vitro evidence shows that magnesium sulfate inhibits platelet aggregation, even at low concentrations (20304,20305). Some preliminary clinical evidence shows that infusion of magnesium sulfate increases bleeding time by 48% and reduces platelet activity (20306). However, other clinical research shows that magnesium does not affect platelet aggregation, although inhibition of platelet-dependent thrombosis can occur (60759).

BISPHOSPHONATES

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = B

Magnesium can decrease absorption of bisphosphonates.

Details

Cations, including magnesium, can decrease bisphosphonate absorption. Advise patients to separate doses of magnesium and these drugs by at least 2 hours (13363).

CALCIUM CHANNEL BLOCKERS

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

Magnesium can have additive effects with calcium channel blockers, although evidence is conflicting.

Details

Magnesium inhibits calcium entry into smooth muscle cells and may therefore have additive effects with calcium channel blockers. Severe hypotension and neuromuscular blockades may occur when nifedipine is used with intravenous magnesium (3046,20264,20265,20266), although some contradictory evidence suggests that concurrent use of magnesium with nifedipine does not increase the risk of neuromuscular weakness (60831). High doses of magnesium could theoretically have additive effects with other calcium channel blockers.

DIGOXIN

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = B

Magnesium salts may reduce absorption of digoxin.

Details

Clinical evidence suggests that treatment with oral magnesium hydroxide or magnesium trisilicate reduces absorption of digoxin from the intestines (198,20268,20270). This may reduce the blood levels of digoxin and decrease its therapeutic effects.

GABAPENTIN (Neurontin)

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Unlikely • Level of Evidence = B

Gabapentin absorption can be decreased by magnesium.

Details

Clinical research shows that giving magnesium oxide orally along with gabapentin decreases the maximum plasma concentration of gabapentin by 33%, time to maximum concentration by 36%, and area under the curve by 43% (90032). Advise patients to take gabapentin at least 2 hours before, or 4 to 6 hours after, magnesium supplements.

KETAMINE (Ketalar)

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

Magnesium might precipitate ketamine toxicity.

Details

In one case report, a 62-year-old hospice patient with terminal cancer who had been stabilized on sublingual ketamine 150 mg four times daily experienced severe ketamine toxicity lasting for 2 hours after taking a maintenance dose of ketamine following an infusion of magnesium sulfate 2 grams (105078). Since both magnesium and ketamine block the NMDA receptor, magnesium is thought to have potentiated the effects of ketamine.

LEVODOPA/CARBIDOPA (Sinemet)

Interaction Rating = Major Do not take this combination.

Severity = High • Occurrence = Probable • Level of Evidence = B

Magnesium can reduce the bioavailability of levodopa/carbidopa.

Details

Clinical research in healthy volunteers shows that taking magnesium oxide 1000 mg with levodopa 100 mg/carbidopa 10 mg reduces the area under the curve (AUC) of levodopa by 35% and of carbidopa by 81%. In vitro and animal research shows that magnesium produces an alkaline environment in the digestive tract, which might lead to degradation and reduced bioavailability of levodopa/carbidopa (100265).

POTASSIUM-SPARING DIURETICS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = D

Potassium-sparing diuretics decrease excretion of magnesium, possibly increasing magnesium levels.

Details

Potassium-sparing diuretics also have magnesium-sparing properties, which can counteract the magnesium losses associated with loop and thiazide diuretics (9613,9614,9622). Theoretically, increased magnesium levels could result from concomitant use of potassium-sparing diuretics and magnesium supplements.

QUINOLONE ANTIBIOTICS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = D

Magnesium decreases absorption of quinolones.

Details

Magnesium can form insoluble complexes with quinolones and decrease their absorption (3046). Advise patients to take these drugs at least 2 hours before, or 4 to 6 hours after, magnesium supplements.

SEVELAMER (Renagel, Renvela)

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = B

Sevelamer may increase serum magnesium levels.

Details

In patients on hemodialysis, sevelamer use was associated with a 0.28 mg/dL increase in serum magnesium. The mechanism of this interaction remains unclear (96486).

SKELETAL MUSCLE RELAXANTS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = A

Parenteral magnesium alters the pharmacokinetics of skeletal muscle relaxants, increasing their effects and accelerating the onset of effect.

Details

Parenteral magnesium shortens the time to onset of skeletal muscle relaxants by about 1 minute and prolongs the duration of action by about 2 minutes. Magnesium potentiates the effects of skeletal muscle relaxants by decreasing calcium-mediated release of acetylcholine from presynaptic nerve terminals, reducing postsynaptic sensitivity to acetylcholine, and having a direct effect on the membrane potential of myocytes (3046,97492,107364). Magnesium also has vasodilatory actions and increases cardiac output, allowing a greater amount of muscle relaxant to reach the motor end plate (107364). A clinical study found that low-dose rocuronium (0.45 mg/kg), when given after administration of magnesium 30 mg/kg over 10 minutes, has an accelerated onset of effect, which matches the onset of effect seen with a full-dose rocuronium regimen (0.6 mg/kg) (96485). In another clinical study, onset times for rocuronium doses of 0.3, 0.6, and 1.2 mg/kg were 86, 76, and 50 seconds, respectively, when given alone, but were reduced to 66, 44, and 38 seconds, respectively, when the doses were given after a 15-minute infusion of magnesium sulfate 60 mg/kg (107364). Giving intraoperative intravenous magnesium sulfate, 50 mg/kg loading dose followed by 15 mg/kg/hour, reduces the onset time of rocuronium, enhances its clinical effects, reduces the dose of intraoperative opiates, and prolongs the spontaneous recovery time (112781,112782). It does not affect the activity of subsequently administered neostigmine (112782).

SULFONYLUREAS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Mild • Occurrence = Probable • Level of Evidence = B

Magnesium increases the systemic absorption of sulfonylureas, increasing their effects and side effects.

Details

Clinical research shows that administration of magnesium hydroxide with glyburide increases glyburide absorption, increases maximal insulin response by 35-fold, and increases the risk of hypoglycemia, when compared with glyburide alone (20307). A similar interaction occurs between magnesium hydroxide and glipizide (20308). The mechanism of this effect appears to be related to the elevation of gastrointestinal pH by magnesium-based antacids, increasing solubility and enhancing absorption of sulfonylureas (22364).

TETRACYCLINE ANTIBIOTICS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = D

Magnesium decreases absorption of tetracyclines.

Details

Magnesium can form insoluble complexes with tetracyclines in the gut and decrease their absorption and antibacterial activity (12586). Advise patients to take these drugs 1 hour before or 2 hours after magnesium supplements.

BISPHOSPHONATES

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

Theoretically, taking phosphate salts with bisphosphonates might increase the risk of hypocalcemia.

Details

Combining bisphosphonates and phosphate can cause hypocalcemia. In one report, hypocalcemic tetany developed in a patient taking alendronate (Fosamax) who received a large dose of phosphate salts as a pre-operative laxative (14589).

ERDAFITINIB (Balversa)

Interaction Rating = Major Do not take this combination.

Severity = High • Occurrence = Probable • Level of Evidence = A

Taking erdafitinib with phosphate salts increases the risk of hyperphosphatemia.

Details

Erdafitinib increases phosphate levels. It is recommended that patients taking erdafitinib restrict phosphate intake to no more than 600-800 mg daily (104470).

FUTIBATINIB (Lytgobi)

Interaction Rating = Major Do not take this combination.

Severity = High • Occurrence = Likely • Level of Evidence = A

Taking futibatinib with phosphate salts increases the risk of hyperphosphatemia.

Details

Futibatinib can cause hyperphosphatemia, as reported in 88% of patients in clinical studies. In addition, 77% of patients in clinical studies required use of a phosphate binder to manage hyperphosphatemia. Phosphate salts should generally be avoided by people taking this medication (112912).

POTASSIUM

ACE INHIBITORS (ACEIs)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Mild • Occurrence = Likely • Level of Evidence = C

Using ACEIs with high doses of potassium increases the risk of hyperkalemia.

Details

ACEIs block the actions of the renin-angiotensin-aldosterone system and reduce potassium excretion (95628). Concomitant use of these drugs with potassium supplements increases the risk of hyperkalemia (15,23207). However, concomitant use of these drugs with moderate dietary potassium intake (about 3775-5200 mg daily) does not increase serum potassium levels (95628).

ANGIOTENSIN RECEPTOR BLOCKERS (ARBs)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Mild • Occurrence = Likely • Level of Evidence = C

Using ARBs with high doses of potassium increases the risk of hyperkalemia.

Details

ARBs block the actions of the renin-angiotensin-aldosterone system and reduce potassium excretion (95628). Concomitant use of these drugs with potassium supplements increases the risk of hyperkalemia (15,23207). However, concomitant use of these drugs with moderate dietary potassium intake (about 3775-5200 mg daily) does not increase serum potassium levels (95628).

POTASSIUM-SPARING DIURETICS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Mild • Occurrence = Likely • Level of Evidence = C

Concomitant use increases the risk of hyperkalemia.

Details

Using potassium-sparing diuretics with potassium supplements increases the risk of hyperkalemia (15).

SODIUM

ANTIHYPERTENSIVE DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = A

Theoretically, a high intake of dietary sodium might reduce the effectiveness of antihypertensive drugs.

Details

High intake of dietary sodium can increase systolic and diastolic blood pressure (26222). Also, high intake of sodium may necessitate increased use of antihypertensive medications to achieve blood pressure control in some patients, such as those with chronic kidney disease (26223).

CORTICOSTEROIDS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Concomitant use of mineralocorticoids and some glucocorticoids with sodium supplements might increase the risk of hypernatremia.

Details

Mineralocorticoids and some glucocorticoids (corticosteroids) cause sodium retention. This effect is dose-related and depends on mineralocorticoid potency. It is most common with hydrocortisone, cortisone, and fludrocortisone, followed by prednisone and prednisolone (4425).

LITHIUM

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = B

Altering dietary intake of sodium might alter the levels and clinical effects of lithium.

Details

High sodium intake can reduce plasma concentrations of lithium by increasing lithium excretion (26225). Reducing sodium intake can significantly increase plasma concentrations of lithium and cause lithium toxicity in patients being treated with lithium carbonate (26224,26225). Stabilizing sodium intake is shown to reduce the percentage of patients with lithium level fluctuations above 0.8 mEq/L (112909). Patients taking lithium should avoid significant alterations in their dietary intake of sodium.

SODIUM-CONTAINING DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Concomitant use of sodium-containing drugs with additional sodium from dietary or supplemental sources may increase the risk of hypernatremia and long-term sodium-related complications.

Details

The Chronic Disease Risk Reduction (CDRR) intake level of 2.3 grams of sodium daily indicates the intake at which it is believed that chronic disease risk increases for the apparently healthy population (100310). Some medications contain high quantities of sodium. When used in conjunction with sodium supplements or high-sodium diets, the CDRR may be exceeded. Additionally, concomitant use may increase the risk for hypernatremia; this risk is highest in the elderly and people with other risk factors for electrolyte disturbances.

TOLVAPTAN (Samsca)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = C

Theoretically, concomitant use of tolvaptan with sodium might increase the risk of hypernatremia.

Details

Tolvaptan is a vasopressin receptor 2 antagonist that is used to increase sodium levels in patients with hyponatremia (29406). Patients taking tolvaptan should use caution with the use of sodium salts such as sodium chloride.

BISPHOSPHONATES

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = D

Theoretically, whey protein might reduce the absorption of bisphosphonates.

Details

Whey protein contains minerals such as calcium that bind bisphosphonates in the gut (9,12937). Advise patients to take bisphosphonates at least 30 minutes before whey protein, but preferably at a different time of day.

LEVODOPA

Interaction Rating = Major Do not take this combination.

Severity = High • Occurrence = Probable • Level of Evidence = D

Theoretically, whey protein might decrease levodopa absorption.

Details

Small clinical studies show that concomitant ingestion of protein or high doses of leucine or isoleucine (100 mg/kg) and levodopa can exacerbate tremor, rigidity, and the "on-off" syndrome in patients with Parkinson disease (3291,3292,3293,3294,4944).

QUINOLONE ANTIBIOTICS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = D

Theoretically, whey protein might decrease quinolone absorption.

Details

Whey protein contains minerals, such as calcium, that can bind to quinolones in the gut (9,10339). To avoid this interaction, advise patients to take oral quinolones at least 2 hours before or 4-6 hours after whey protein.

TETRACYCLINE ANTIBIOTICS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = D

Theoretically, whey protein might decrease tetracycline absorption.

Details

Whey protein contains minerals, such as calcium, that bind to tetracyclines in the gut (9,1843). To avoid this interaction, advise patients to take oral tetracyclines at least 2 hours before or 4-6 hours after whey protein.

Report an Adverse Reaction to W+ 100% Whey Isolate Protein Energy

Adverse Effects view details

Below is general information about the adverse effects of the known ingredients contained in the product W+ 100% Whey Isolate Protein Energy. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.

CAFFEINE

General ...Caffeine in moderate doses is typically well tolerated.
Most Common Adverse Effects:
Orally: Anxiety, dependence with chronic use, diarrhea, diuresis, gastric irritation, headache, insomnia, muscular tremors, nausea, and restlessness.
Serious Adverse Effects (Rare):
Orally: Stroke has been reported rarely.

Cardiovascular ...Caffeine can temporarily increase blood pressure. Usually, blood pressure increases 30 minutes after ingestion, peaks in 1-2 hours, and remains elevated for over 4 hours (36539,37732,37989,38000,38300).
Although acute administration of caffeine can cause increased blood pressure, regular consumption does not seem to increase either blood pressure or pulse, even in mildly hypertensive patients (1451,1452,2722,38335). However, the form of caffeine may play a role in blood pressure increase after a more sustained caffeine use. In a pooled analysis of clinical trials, coffee intake was not associated with an increase in blood pressure, while ingesting caffeine 410 mg daily for at least 7 days modestly increased blood pressure by an average of 4.16/2.41 mmHg (37657). Another meta-analysis of clinical research shows that taking caffeine increases systolic and diastolic blood pressure by approximately 2 mmHg when compared with control. Preliminary subgroup analyses suggest that caffeine may increase blood pressure more in males or at doses over 400 mg (112738).
When used prior to intensive exercise, caffeine can increase systolic blood pressure by 7-8 mmHg (38308). The blood pressure-raising effects of caffeine are greater during stress (36479,38334) and after caffeine-abstinence of at least 24 hours (38241).
Epidemiological research suggests there is no association of caffeine consumption with incidence of hypertension (38190). Habitual coffee consumption also doesn't seem to be related to hypertension, but habitual consumption of sugared or diet cola is associated with development of hypertension (13739).
Epidemiological research has found that regular caffeine intake of up to 400 mg daily is not associated with increased incidence of atrial fibrillation (38018,38076,91028,91034,97451,97453,103708), atherosclerosis (38033), cardiac ectopy (91127), stroke (37804), ventricular arrhythmia (95948,97453), and cardiovascular disease in general (37805,98806). One clinical trial shows that in adults with diagnosed heart failure, consumption of 500 mg of coffee does not result in an increased risk for arrhythmia during exercise (95950). However, caffeine intake may pose a greater cardiovascular risk to subjects that are not regular users of caffeine. For example, in one population study, caffeinated coffee consumption was associated with an increased risk of ischemic stroke in subjects that don't regularly drink coffee (38102). In a population study in Japanese subjects, caffeine-containing medication use was modestly associated with hemorrhagic stroke in adults that do not consume caffeine regularly (91059).
The most common side effect of caffeine in neonates receiving caffeine for apnea is tachycardia (98807,114658).

Dermatologic ...There are several case reports of urticaria after caffeine ingestion (36546,36448,36475).

Endocrine ...Some evidence shows caffeine is associated with fibrocystic breast disease or breast cancer in females; however, this is controversial since findings are conflicting (8043,108806). Restricting caffeine in females with fibrocystic breast conditions doesn't seem to affect breast nodularity, swelling, or pain (8996). A population analysis of the Women's Health Initiative observational study has found no association between consumption of caffeine-containing beverages and the incidence of invasive breast cancer in models adjusted for demographic, lifestyle, and reproductive factors (108806). Also, a dose-response analysis of 2 low-quality observational studies has found that high consumption of caffeine is not associated with an increased risk of breast cancer (108807).
Clinical research in healthy adults shows that an increase consumption of caffeine results in increased insulin resistance (91023).

Gastrointestinal ...Gastrointestinal upset, nausea, diarrhea, abdominal pain, and fecal incontinence may occur with caffeine intake (36466,37755,37806,37789,37830,38138,38136,38223,95956,95963). Also, caffeine may cause feeding intolerance and gastrointestinal irritation in infants (6023). Perioperative caffeine during cardiopulmonary bypass surgery seems to increase the rate of postoperative nausea and vomiting (97451). Caffeine and coffee consumption have been associated with an increase in the incidence of heartburn (37545,37575,38251,38259,38267) and gastrointestinal esophageal reflux disease (GERD) (38329,37633,37631,37603).

Genitourinary ...Caffeine, a known diuretic, may increase voiding, give a sense of urgency, and irritate the bladder (37874,37961,104580). In men with lower urinary tract symptoms, caffeine intake increased the risk of interstitial cystitis/painful bladder syndrome (38115). Excessive caffeine consumption may worsen premenstrual syndrome. Consumption of up to 10 cups of caffeinated drinks daily was associated with increased severity of premenstrual syndrome (38177). Finally, population research shows that exposure to caffeine was not associated with an increased risk of endometriosis (91035).

Immunologic ...Caffeine can cause anaphylaxis in sensitive individuals, although true IgE-mediated caffeine allergy seems to be relatively rare (11315).

Musculoskeletal ...Caffeine can induce or exacerbate muscular tremors (38136,37673,38161). There has also been a report of severe rhabdomyolysis in a healthy 40-year-old patient who consumed an energy drink containing 400 mg of caffeine (4 mg/kg) and then participated in strenuous weightlifting exercise (108818).
Epidemiological evidence regarding the relationship between caffeine use and the risk for osteoporosis is contradictory. Caffeine can release calcium from storage sites and increase its urinary excretion (2669,10202,11317,111489). Females with a genetic variant of the vitamin D receptor appear to be at an increased risk for the detrimental effect of caffeine on bone mass (2669). However, moderate caffeine intake, less than 300 mg daily, does not seem to significantly increase osteoporosis risk in most postmenopausal adults with normal calcium intake (2669,6025,10202,11317). Premature infants treated with intravenous caffeine for apnea of prematurity, have a lower bone mineral content compared with infants who are not treated with caffeine, especially when treatment extends beyond 14 days (111489).

Neurologic/CNS ...Caffeine can cause headaches, anxiety, jitteriness, restlessness, and nervousness (36466,37694,37755,37806,37865,37830,37889,38223,95952). In adolescents, there is an inverse correlation between the consumption of caffeine and various measurements of cognitive function (104579). Insomnia is a frequent adverse effect in children (10755). Caffeine may result in insomnia and sleep disturbances in adults as well (36445,36483,36512,36531,37598,37795,37819,37862,37864,37890)(37968,37971,38091,38242,91022,92952). Additionally, caffeine may exacerbate sleep disturbances in patients with acquired immunodeficiency syndrome (AIDS) (10204). Combining ephedra with caffeine can increase the risk of adverse effects. Jitteriness, hypertension, seizures, temporary loss of consciousness, and hospitalization requiring life support has been associated with the combined use of ephedra and caffeine (2729). Finally, epidemiological research suggests that consuming more than 190 mg of caffeine daily is associated with an earlier onset of Huntington disease by 3.6 years (91078).

Ocular/Otic ...In individuals with glaucoma, coffee consumption and caffeine intake has been found to increase intraocular pressure (8540,36464,36465,37670). The magnitude of this effect seems to depend on individual tolerance to caffeine. Some research in healthy young adults shows that caffeine increases intraocular pressure to a greater degree in low-consumers of caffeine (i.e., 1 cup of coffee or less daily) when compared to high-consumers (i.e., those consuming 2 cups of coffee or more daily) (100371). The peak increase of intraocular pressure seems to occur at about 1.5 hours after caffeine ingestion, and there is no notable effect 4 hours after ingestion (36462,100371).

Oncologic ...Most human studies which have examined caffeine or methylxanthine intake have found that they do not play a role in the development of various cancers, including breast, ovarian, brain, colon, rectal, or bladder cancer (37641,37737,37775,37900,38050,38169,38220,91054,91076,108806).

Psychiatric ...Caffeine may lead to habituation and physical dependence (36355,36453,36512,36599), with amounts as low as 100 mg daily (36355,36453). An estimated 9% to 30% of caffeine consumers could be considered addicted to caffeine (36355). Higher doses of caffeine have caused nervousness, agitation, anxiety, irritability, delirium, depression, sleep disturbances, impaired attention, manic behavior, psychosis and panic attacks (36505,37717,37818,37839,37857,37982,38004,38017,38028,38072)(38079,38138,38306,38325,38331,38332,97464). Similar symptoms have been reported in a caffeine-naïve individual experiencing fatigue and dehydration after a dose of only 200 mg, with resolution of symptoms occurring within 2 hours (95952).
Withdrawal: The existence or clinical importance of caffeine withdrawal is controversial. Some researchers think that if it exists, it appears to be of little clinical significance (11839). Headache is the most common symptom, due to cerebral vasodilation and increased blood flow (37769,37991,37998). Other researchers suggest symptoms such as tiredness and fatigue, decreased energy, alertness and attentiveness, drowsiness, decreased contentedness, depressed mood, difficulty concentration, irritability, and lack of clear-headedness are typical of caffeine withdrawal (13738). Withdrawal symptoms typically occur 12-24 hours after the last dose of caffeine and peak around 48 hours (37769,36600). Symptoms may persist for 2-9 days. Withdrawal symptoms such as delirium, nausea, vomiting, rhinorrhea, nervousness, restlessness, anxiety, muscle tension, muscle pains, and flushed face have been described. However, these symptoms may be from nonpharmacological factors related to knowledge and expectation of effects. Clinically significant symptoms caused by caffeine withdrawal may be uncommon (2723,11839). In a case report, caffeine consumption of 560 mg daily was associated with increased suicidality (91082).

Renal ...Data on the relationship between caffeine intake and kidney stones are conflicting. Some clinical research shows that caffeine consumption may increase the risk of stone formation (37634,111498), while other research shows a reduced risk with increasing caffeine intakes (111498). A meta-analysis of 7 studies found that overall, there is an inverse relationship, with a 32% decrease in the risk of kidney stones between the lowest and highest daily intakes of caffeine (111498).

Other ...People with voice disorders, singers, and other voice professionals are often advised against the use of caffeine; however, this recommendation has been based on anecdotal evidence. One small exploratory study suggests that caffeine ingestion may adversely affect subjective voice quality, although there appears to be significant intra-individual variability. Further study is necessary to confirm these preliminary findings (2724).

CALCIUM

General ...Orally and intravenously, calcium is well-tolerated when used appropriately.
Most Common Adverse Effects:
Orally: Belching, constipation, diarrhea, flatulence, and stomach upset.
Serious Adverse Effects (Rare):
Orally: Case reports have raised concerns about calciphylaxis and kidney stones.

Cardiovascular ...There has been concern that calcium intake may be associated with an increased risk of cardiovascular disease (CVD) and coronary heart disease (CHD), including myocardial infarction (MI). Some clinical research suggests that calcium intake, often in amounts over the recommended daily intake level of 1000-1300 mg daily for adults, is associated with an increased risk of CVD, CHD, and MI (16118,17482,91350,107233). However, these results, particularly meta-analyses, have been criticized for excluding trials in which calcium was administered with vitamin D (94137). Many of these trials also only included postmenopausal females. Other analyses report conflicting results, and have not shown that calcium intake affects the risk of CVD, CHD, or MI (92994,93533,97308,107231). Reasons for these discrepancies are not entirely clear. It may relate to whether calcium is taken as monotherapy or in combination with vitamin D. When taken with vitamin D, which is commonly recommended, calcium supplementation does not appear to be associated with an increased risk of CVD, CHD, or MI (93533,107231). Also, the association between calcium supplementation and CVD, CHD, or MI risk may be influenced by the amount of calcium consumed as part of the diet. Supplementation with calcium may be associated with an increased risk of MI in people with dietary calcium intake above 805 mg daily, but not in those with dietary calcium intake below 805 mg daily (17482). To minimize the possible risk of CVD, CHD, or MI, advise patients not to consume more than the recommended daily intake of 1000-1200 mg and to consider total calcium intake from both dietary and supplemental sources (17484). While dietary intake of calcium is preferred over supplemental intake, advise patients who require calcium supplements to take calcium along with vitamin D, as this combination does not appear to be associated with an increased risk of MI (93533).
Rarely, calcium intake can increase the risk of calciphylaxis, which usually occurs in patients with kidney failure. Calciphylaxis is the deposition of calcium phosphate in arterioles, which causes skin ulcers and skin necrosis. In a case report, a 64-year-old female with a history of neck fracture, sepsis, and ischemic colitis presented with painful leg ulcers due to calciphylaxis. She discontinued calcium and vitamin D supplementation and was treated with sodium thiosulfate and supportive care (95816).

Gastrointestinal ...Orally, calcium can cause belching, flatulence, nausea, gastrointestinal discomfort, and diarrhea (1824,1843,12950,38803). Although constipation is frequently cited as an adverse effect of calcium, there is no scientific substantiation of this side effect (1824,1843,1844,1845,12950,38978). Calcium carbonate has been reported to cause acid rebound, but this is controversial (12935,12936).

Oncologic ...There is some concern that very high doses of calcium might increase the risk of prostate cancer. Some epidemiological evidence suggests that consuming over 2000 mg/day of dietary calcium might increase the risk for prostate cancer (4825,12949). Additional research suggests that calcium intake over 1500 mg/day might increase the risk of advanced prostate cancer and prostate cancer mortality (14132). Consumption of dairy products has also been weakly linked to a small increase in prostate cancer risk (98894). However, contradictory research suggests no association between dietary intake of calcium and overall prostate cancer risk (14131,14132,104630). More evidence is needed to determine the effect of calcium, if any, on prostate cancer risk.

Renal ...Kidney stones have been reported in individuals taking calcium carbonate 1500 mg daily in combination with vitamin D 2000 IU daily for 4 years (93943).

COFFEE (natural Coffee bean extract powder, Coffeeberry organic Coffee (fruit) extract)

General ...Orally, caffeinated or decaffeinated coffee is well tolerated in moderate amounts.
Most Common Adverse Effects:
Orally: Drinking coffee containing caffeine can cause agitation, anxiety, chest pain, diuresis, gastric distress, headache, insomnia, nervousness, premature heart rate, ringing in the ears, and vomiting. These effects are more likely with increasing intake of caffeine and in certain populations (e.g., children, elderly). With chronic caffeine use, especially in large amounts, habituation, tolerance, and psychological dependence can occur.
Abrupt discontinuation of caffeine may result in physical withdrawal symptoms, including anxiety, decreased physical energy, depressed mood, difficulty concentrating, drowsiness, fatigue, headache, irritability, reduced alertness, and rhinorrhea.
Rectally: Coffee enemas have been linked to proctocolitis, severe electrolyte abnormalities, and septicemia leading to death.

Cardiovascular ...Orally, coffee containing caffeine can cause chest pain and premature heartbeat (8042,111045). These effects are more likely with increasing intake of caffeine and in certain populations (e.g., children, elderly) (8042). Excessive doses of caffeine can cause massive catecholamine release and subsequent sinus tachycardia (11832,11838,13734,13735).
Although acute administration of caffeine can cause increased blood pressure, regular consumption does not seem to increase either blood pressure or pulse, even in hypertensive patients (1451,1452,2722,13739,105312). Drinking one or more cups of caffeinated coffee daily also doesn't seem to increase the risk of developing hypertension in habitual coffee drinkers (8033,13739,111037).
Epidemiological research has found that regular caffeine intake of up to 400 mg daily, or approximately 4 cups of caffeinated coffee, is not associated with an increased incidence of atrial fibrillation (38018,38076,91028,91034,97451,97453,105310), atherosclerosis (38033), cardiac ectopy (91127), stroke (37804), ventricular arrhythmia (95948,97453,105310), or cardiovascular disease (CVD) in general (37805,98806,104882). However, some observational research suggests that drinking at least 1 cup of coffee per week is associated with a 40% increased risk of atrial fibrillation, with the highest incidence of atrial fibrillation occurring in adults consuming at least 6 cups daily (111042). Also, one large, observational study found a J-shaped association between regular coffee consumption and the risk of developing acute coronary syndromes. Moderate consumption of less than 300 mL daily (about 1.3 cups) was associated with a lower risk of developing acute coronary syndromes, whereas regular consumption of 300 mL daily or more was associated with an increased risk (11318). In contrast, other observational research in people without a history of CVD has found that drinking more than 6 cups of coffee daily does not appear to be associated with an increased risk of developing coronary heart disease (14343). Also, in people with a history of CVD, population research has found that coffee consumption is associated with a reduction in CVD-related mortality (97373,97374,103997,103998,104594,104595,104882,105308,105311,105313,105314); however not all research agrees (112735). However, in current smokers with a history of acute coronary syndrome, consuming more than 3 cups of coffee daily is associated with more than a two-fold increased risk of overall mortality (105313). Also, population research in patients with severe hypertension, but not mild hypertension, suggests that drinking at least two cups of coffee daily is associated with a 2-fold increase in CVD mortality compared with non-coffee drinkers (111027).
Caffeine intake may pose a greater cardiovascular risk to subjects who are not regular caffeine users. Population research suggests that drinking caffeinated coffee might trigger a myocardial infarction (MI) in some people. People who drink one or fewer cups of coffee daily and are sedentary and have multiple risk factors for heart disease have a significantly increased risk of MI within an hour after drinking coffee. However, this risk appears diminished in people who routinely consume greater amounts of coffee on a daily basis (14497). In another population study, caffeinated coffee consumption was associated with an increased risk of ischemic stroke in subjects who didn't regularly drink coffee (38102).
Boiled coffee that is prepared without a filter appears to increase serum cholesterol and triglyceride levels (1353,4200,8036,8539). Drinking one liter of strong, unfiltered coffee daily for two weeks can raise serum cholesterol by 10% and serum triglycerides by 36% (1353). Tell patients to use coffee filters since these effects do not seem to occur with filtered coffee (4200,8036,8539).
Coffee can adversely affect homocysteine levels. Higher homocysteine levels have been associated with CVD. One liter of unfiltered strong coffee daily for two weeks can increase plasma homocysteine levels by 10% (1353). The same amount of filtered strong coffee appears to raise plasma homocysteine levels by 20%, although there have been no head-to-head comparisons of filtered versus unfiltered coffee (3344).

Dermatologic ...Some researchers suggest symptoms such as flushed face occur during caffeine withdrawal. However, withdrawal symptoms may be due to nonpharmacological factors related to knowledge and expectation of effects. Clinically significant symptoms caused by caffeine withdrawal may be uncommon (2723,11839).

Endocrine ...Orally, excessive doses of caffeine can cause massive catecholamine release and subsequent metabolic acidosis, hyperglycemia, and ketosis (13734). Other symptoms include hypokalemia and respiratory alkalosis (11832,11838,13735).
Some evidence shows that caffeine, a constituent of coffee, is associated with fibrocystic breast disease, breast cancer, and endometriosis in females; however, this is controversial since findings are conflicting (8043). Restricting caffeine intake in patients with fibrocystic breast conditions doesn't seem to affect breast nodularity, swelling, or pain (8996). Population research suggests that exposure to caffeine is not associated with an increased risk of endometriosis (91035).
A population analysis of the Women's Health Initiative observational study has found no association between consumption of caffeine-containing beverages, such as coffee, and the incidence of invasive breast cancer in models adjusted for demographic, lifestyle, and reproductive factors (108806). Also, a dose-response analysis of 2 low-quality observational studies has found that high consumption of caffeine is not associated with an increased risk of breast cancer (108807).

Gastrointestinal ...Orally, coffee containing caffeine can cause gastric distress and vomiting. These effects are more likely with increasing intake of caffeine and in certain populations (e.g., children, elderly) (8042,13734). There is also some evidence that consumption of three or more cups of caffeinated coffee might increase the risk of Helicobacter pylori infection (8034).
Caffeine withdrawal symptoms such as nausea and vomiting have been described. However, these symptoms may be due to nonpharmacological factors related to knowledge and expectation of effects. Clinically significant symptoms caused by caffeine withdrawal may be uncommon (2723,11839).
Rectally, at least 5 cases of proctocolitis related to the use of coffee enemas have been reported (96868,103273).

Genitourinary ...The caffeine found in coffee is a known diuretic and may increase voiding, give a sense of urgency, and irritate the bladder (37874,37961,104580). In males with lower urinary tract symptoms, caffeine intake increased the risk of interstitial cystitis/painful bladder syndrome (38115). Excessive caffeine consumption may worsen premenstrual syndrome. Consumption of up to 10 cups of caffeinated drinks daily has been associated with increased severity of premenstrual syndrome (38177).

Hematologic ...There is evidence that coffee containing caffeine shortens whole blood fibrinolysis time (8030).
Rectally, coffee enemas have been linked to severe electrolyte abnormalities leading to death (3026,3347,3349,6652)

Hepatic ...Boiled coffee that is prepared without a filter appears to increase liver aminotransferase enzymes. Tell patients to use coffee filters since these effects do not seem to occur with filtered coffee (8539).

Immunologic ...Caffeine can cause anaphylaxis in sensitive individuals, although true IgE-mediated caffeine allergy seems to be relatively rare (11315).
Rectally, coffee enemas have been linked to septicemia leading to death (3026,3347,3349,6652).

Musculoskeletal ...Orally, there is preliminary evidence that use of greater than four cups of coffee daily can increase the risk of rheumatoid factor positive rheumatoid arthritis, but this association has not been confirmed (6482).
Epidemiological evidence regarding the relationship between caffeine use and the risk for osteoporosis is contradictory. Caffeine can increase urinary excretion of calcium (2669,10202,11317). Females identified with a genetic variant of the vitamin D receptor appear to be at an increased risk for the detrimental effect of caffeine on bone mass (2669). However, moderate caffeine intake of less than 400 mg daily does not seem to significantly increase osteoporosis risk in most postmenopausal adults with normal calcium intake (2669,6025,10202,11317,98806).
Caffeine withdrawal symptoms, such as muscle tension and muscle pains, have been described. However, these symptoms may be due to nonpharmacological factors related to knowledge and expectation of effects. Clinically significant symptoms caused by caffeine withdrawal may be uncommon (2723,11839).

Neurologic/CNS ...Orally, coffee containing caffeine can cause agitation, headache, insomnia, and nervousness, . These effects are more likely with increasing intake of caffeine and in certain populations (e.g., children, elderly) (8042,11832,11838,13734,13735).
Combining ephedra with coffee can increase the risk of adverse effects, due to the caffeine contained in coffee. Jitteriness, seizures, and temporary loss of consciousness have been associated with the combined use of ephedra and caffeine (2729).
Some researchers suggest that symptoms such as headache; tiredness and fatigue; decreased energy, alertness, and attentiveness; drowsiness; decreased contentedness; difficulty concentrating; irritability; and lack of clear-headedness are typical of caffeine withdrawal (13738). Withdrawal symptoms such as delirium, nervousness, and restlessness have also been described. However, these symptoms may be due to nonpharmacological factors related to knowledge and expectation of effects. Clinically significant symptoms caused by caffeine withdrawal may be uncommon (2723,11839).

Ocular/Otic ...Orally, coffee containing caffeine can cause ringing in the ears. This is more likely with increasing intake of caffeine and in certain populations (e.g., children, elderly) (8042,13734). Coffee containing caffeine also increases intraocular pressure, starting about 30 minutes after consumption and persisting for at least 90 minutes. Decaffeinated coffee does not appear to affect intraocular pressure (8540).

Oncologic ...The association between consumption of coffee and pancreatic cancer is controversial. Coffee may increase the incidence of some types of pancreatic cancers, but it may decrease other types (8535,8536,8537). Some studies do not support this association, especially in patients that have never smoked (8038,8040,93878,103999). Patients who are at risk of pancreatic cancer (pancreatitis) should limit their consumption of coffee.
People who consume 2-4 or more cups of caffeinated coffee dail might have a significantly increased risk of developing lung cancer (13191,90177). But drinking decaffeinated coffee seems to be associated with a decreased risk of lung cancer (13191).
Coffee consumption has also been associated at various times with an increased risk of breast cancer, bladder cancer, colon cancer, and other types of cancers, but there's no good evidence that coffee consumption increases cancer risk (8039,8040,8041). Most human studies that have examined caffeine or coffee intake have found that they do not play a role in the development of various cancers, including breast or most gastric cancers (91054,91076,98806). However, drinking caffeinated coffee might increase the risk of gastric cardia cancer (91076).

Psychiatric ...Orally, coffee containing caffeine can cause anxiety. This is more likely with increasing intake of caffeine and in certain populations (e.g., children, elderly) (8042,13734). With chronic use, especially in large amounts, habituation, tolerance, and psychological dependence can occur (3719). Other researchers suggest symptoms such as depressed mood are typical of caffeine withdrawal (13738). However, withdrawal symptoms may be due to nonpharmacological factors related to knowledge and expectation of effects. Clinically significant symptoms caused by caffeine withdrawal may be uncommon (2723,11839).

Pulmonary/Respiratory ...Caffeine withdrawal symptoms such as rhinorrhea have been described. However, these symptoms may be due to nonpharmacological factors related to knowledge and expectation of effects. Clinically significant symptoms caused by caffeine withdrawal may be uncommon (2723,11839).

Renal ...Orally, coffee containing caffeine can cause diuresis. This is more likely with increasing intake of caffeine and in certain populations (e.g., children, elderly) (8042,13734).

MAGNESIUM

General ...Magnesium is generally well tolerated. Some clinical research shows no differences in adverse effects between placebo and magnesium groups.
Most Common Adverse Effects:
Orally: Diarrhea, gastrointestinal irritation, nausea, and vomiting.
Intravenously: Bradycardia, dizziness, flushing sensation, hypotension, and localized pain and irritation. In pregnancy, may cause blurry vision, dizziness, lethargy, nausea, nystagmus, and perception of warmth.
Serious Adverse Effects (Rare):
All ROAs: With toxic doses, loss of reflexes and respiratory depression can occur. High doses in pregnancy can increase risk of neonatal mortality and neurological defects.

Cardiovascular ...Intravenously, magnesium can cause bradycardia, tachycardia, and hypotension (13356,60795,60838,60872,60960,60973,60982,61001,61031,114681). Inhaled magnesium administered by nebulizer may also cause hypotension (113466). Magnesium sulfate may cause rapid heartbeat when administered antenatally (60915,114681).
In one case report, a 99-year-old male who took oral magnesium oxide 3000 mg daily for chronic constipation was hospitalized with hypermagnesemia, hypotension, bradycardia, heart failure, cardiomegaly, second-degree sinoatrial block, and complete bundle branch block. The patient recovered after discontinuing the magnesium oxide (108966).

Dermatologic ...Intravenously, magnesium may cause flushing, sweating, and problems at the injection site (including burning pain) (60960,60982,111696,114681). In a case study, two patients who received intravenous magnesium sulfate for suppression of preterm labor developed a rapid and sudden onset of an urticarial eruption (a skin eruption of itching welts). The eruption cleared when magnesium sulfate was discontinued (61045). Orally, magnesium oxide may cause allergic skin rash, but this is rare. In one case report, a patient developed a rash after taking 600 mg magnesium oxide (Maglax) (98291).

Gastrointestinal ...Orally, magnesium can cause gastrointestinal irritation, nausea, vomiting, and diarrhea (1194,4891,10661,10663,18111,60951,61016,98290). In rare cases, taking magnesium orally might cause a bezoar, an indigestible mass of material which gets lodged in the gastrointestinal tract. In a case report, a 75-year-old female with advanced rectal cancer taking magnesium 1500 mg daily presented with nausea and anorexia from magnesium oxide bezoars in her stomach (99314). Magnesium can cause nausea, vomiting, or dry mouth when administered intravenously or by nebulization (60818,60960,60982,104400,113466,114681). Antenatal magnesium sulfate may also cause nausea and vomiting (60915,114681). Two case reports suggest that giving magnesium 50 grams orally for bowel preparation for colonoscopy in patients with colorectal cancer may lead to intestinal perforation and possibly death (90006).
Delayed meconium passage and obstruction have been reported rarely in neonates after intravenous magnesium sulfate was given to the mother during pregnancy (60818). In a retrospective study of 200 neonates born prematurely before 32 weeks of gestation, administration of prenatal IV magnesium sulfate, as a 4-gram loading dose and then 1-2 grams hourly, was not associated with the rate of meconium bowel obstruction when compared with neonates whose mothers had not received magnesium sulfate (108728).

Genitourinary ...Intravenously, magnesium sulfate may cause renal toxicity or acute urinary retention, although these events are rare (60818,61012). A case of slowed cervical dilation at delivery has been reported for a patient administered intravenous magnesium sulfate for eclampsia (12592). Intravenous magnesium might also cause solute diuresis. In a case report, a pregnant patient experienced polyuria and diuresis after having received intravenous magnesium sulfate in Ringer's lactate solution for preterm uterine contractions (98284).

Hematologic ...Intravenously, magnesium may cause increased blood loss at delivery when administered for eclampsia or pre-eclampsia (12592). However, research on the effect of intravenous magnesium on postpartum hemorrhage is mixed. Some research shows that it does not affect risk of postpartum hemorrhage (60982), while other research shows that intrapartum magnesium administration is associated with increased odds of postpartum hemorrhage, increased odds of uterine atony (a condition that increases the risk for postpartum hemorrhage) and increased need for red blood cell transfusions (97489).

Musculoskeletal ...Intravenously, magnesium may cause decreased skeletal muscle tone, muscle weakness, or hypocalcemic tetany (60818,60960,60973).
Although magnesium is important for normal bone structure and maintenance (272), there is concern that very high doses of magnesium may be detrimental. In a case series of 9 patients receiving long-term tocolysis for 11-97 days, resulting in cumulative magnesium sulfate doses of 168-3756 grams, a lower bone mass was noted in 4 cases receiving doses above 1000 grams. There was one case of pregnancy- and lactation-associated osteoporosis and one fracture (108731). The validity and clinical significance of this data is unclear.

Neurologic/CNS ...Intravenously, magnesium may cause slurred speech, dizziness, drowsiness, confusion, or headaches (60818,60960,114681). With toxic doses, loss of reflexes, neurological defects, drowsiness, confusion, and coma can occur (8095,12589,12590).
A case report describes cerebral cortical and subcortical edema consistent with posterior reversible encephalopathy syndrome (PRES), eclampsia, somnolence, seizures, absent deep tendon reflexes, hard to control hypertension, acute renal failure and hypermagnesemia (serum level 11.5 mg/dL), after treatment with intravenous magnesium sulfate for preeclampsia in a 24-year-old primigravida at 39 weeks gestation with a previously uncomplicated pregnancy. The symptoms resolved after 4 days of symptomatic treatment in an intensive care unit, and emergency cesarian delivery of a healthy infant (112785).

Ocular/Otic ...Intravenously, magnesium may cause blurred vision (114681). Additionally, cases of visual impairment or nystagmus have been reported following magnesium supplementation, but these events are rare (18111,60818).

Psychiatric ...A case of delirium due to hypermagnesemia has been reported for a patient receiving intravenous magnesium sulfate for pre-eclampsia (60780).

Pulmonary/Respiratory ...Intravenously, magnesium may cause respiratory depression and tachypnea when used in toxic doses (12589,61028,61180).

Other ...Hypothermia from magnesium used as a tocolytic has been reported (60818).

General ...Orally, intravenously, and rectally, phosphate salts are generally well tolerated when used appropriately and/or as prescribed.
Most Common Adverse Effects:
Orally: Abdominal pain, anal irritation, bloating, diarrhea, headache, gastrointestinal irritation, hyperphosphatemia, hypocalcemia, malaise, nausea, sleep disturbance, and vomiting.
Rectally: Hyperphosphatemia and hypocalcemia.
Serious Adverse Effects (Rare):
Orally: Extraskeletal calcification.

Cardiovascular ...Orally, a case of allergic acute coronary syndrome e., Kounis syndrome) is reported in a 43-year-old female after ingesting a specific sodium phosphate laxative product (Travad oral). She presented with maculopapular rash that progressed to anaphylaxis and a non-ST elevation acute coronary syndrome. The patient recovered after hospitalization for 3 days with medical management (112894).

Gastrointestinal ...Orally, phosphate salts can cause gastrointestinal irritation, nausea, abdominal pain, bloating, anal irritation, and vomiting (15,2494,2495,2496,2497,93846,93848,93850,93851,93853,107008). Sodium and potassium phosphates can cause diarrhea (15). Aluminum phosphate can cause constipation (15). A large comparative study shows that, when taken orally as a bowel preparation for colonoscopy, sodium phosphate is associated with gastric mucosal lesions in about 4% of patients (93868).

Neurologic/CNS ...Orally, phosphate salts can commonly cause malaise (93846). Headaches and sleep disturbance may also occur (93848,93851).

Renal ...Orally, use of sodium phosphate for bowel cleansing has been associated with an increased risk of acute kidney injury in some patients (93863). However, a pooled analysis of clinical research suggests that results are not consistent for all patients (93864). Some evidence suggests that female gender, probably due to lower body weight, iron-deficiency anemia, dehydration, and chronic kidney disease are all associated with an increased risk of sodium phosphate-induced kidney dysfunction (93865).

Other ...Orally, phosphate salts can cause fluid and electrolyte disturbances including hyperphosphatemia and hypocalcemia, and extraskeletal calcification. Potassium phosphates can cause hyperkalemia. Sodium phosphates can cause hypernatremia and hypokalemia (15,2494,2495,2496,2497,107008).
Rectally, phosphate salts can cause fluid and electrolyte disturbances including hyperphosphatemia and hypocalcemia (15,112922).
Deaths related to intake of oral or rectal phosphate salts are rare and most have occurred in infants and are related to overdose (93866). However, death has also been reported in elderly patients using sodium phosphate enemas, mainly at standard doses of 250 mL (93867).

POTASSIUM

General ...Orally or intravenously, potassium is generally well-tolerated.
Most Common Adverse Effects:
Orally: Abdominal pain, belching, diarrhea, flatulence, nausea, and vomiting.
Serious Adverse Effects (Rare):
All ROAs: High potassium levels can cause arrhythmia, heart block, hypotension, and mental confusion.

Cardiovascular ...Orally or intravenously, high potassium levels can cause hypotension, cardiac arrhythmias, heart block, or cardiac arrest (15,16,3385,95011,95626,95630).

Gastrointestinal ...Orally or intravenously, high doses of potassium can cause, nausea, vomiting, abdominal pain, diarrhea, and flatulence (95010,95011). Bleeding duodenal ulcers have also been associated with ingestion of slow-release potassium tablets (69625,69672).

Neurologic/CNS ...Orally or intravenously, high potassium levels can cause paresthesia, generalized weakness, flaccid paralysis, listlessness, vertigo, or mental confusion (15,16,3385,95011).

SODIUM

General ...Orally, sodium is well tolerated when used in moderation at intakes up to the Chronic Disease Risk Reduction (CDRR) intake level. Topically, a thorough evaluation of safety outcomes has not been conducted.
Serious Adverse Effects (Rare):
Orally: Worsened cardiovascular disease, hypertension, kidney disease.

Cardiovascular ...Orally, intake of sodium above the CDRR intake level can exacerbate hypertension and hypertension-related cardiovascular disease (CVD) (26229,98176,100310,106263). A meta-analysis of observational research has found a linear association between increased sodium intake and increased hypertension risk (109398). Observational research has also found an association between increased sodium salt intake and increased risk of CVD, mortality, and cardiovascular mortality (98177,98178,98181,98183,98184,109395,109396,109399). However, the existing research is unable to confirm a causal relationship between sodium intake and increased cardiovascular morbidity and mortality; high-quality, prospective research is needed to clarify this relationship (100312). As there is no known benefit with increased salt intake that would outweigh the potential increased risk of CVD, advise patients to limit salt intake to no more than the CDRR intake level (100310).
A reduction in sodium intake can lower systolic blood pressure by a small amount in most individuals, and diastolic blood pressure in patients with hypertension (100310,100311,106261). However, post hoc analysis of a small crossover clinical study in White patients suggests that 24-hour blood pressure variability is not affected by high-salt intake compared with low-salt intake (112910). Additionally, the available research is insufficient to confirm that a further reduction in sodium intake below the CDRR intake level will lower the risk for chronic disease (100310,100311). A meta-analysis of clinical research shows that reducing sodium intake increases levels of total cholesterol and triglycerides, but not low-density lipoprotein (LDL) cholesterol, by a small amount (106261).
It is unclear whether there are safety concerns when sodium is consumed in amounts lower than the adequate intake (AI) levels. Some observational research has found that the lowest levels of sodium intake might be associated with increased risk of death and cardiovascular events (98181,98183). However, this finding has been criticized because some of the studies used inaccurate measures of sodium intake, such as the Kawasaki formula (98177,98178,101259). Some observational research has found that sodium intake based on a single 24-hour urinary measurement is inversely correlated with all-cause mortality (106260). The National Academies Consensus Study Report states that there is insufficient evidence from observational studies to conclude that there are harmful effects from low sodium intake (100310).

Endocrine ...Orally, a meta-analysis of observational research has found that higher sodium intake is associated with an average increase in body mass index (BMI) of 1. 24 kg/m2 and an approximate 5 cm increase in waist circumference (98182). It has been hypothesized that the increase in BMI is related to an increased thirst, resulting in an increased intake of sugary beverages and/or consumption of foods that are high in salt and also high in fat and energy (98182). One large observational study has found that the highest sodium intake is not associated with overweight or obesity when compared to the lowest intake in adolescents aged 12-19 years when intake of energy and sugar-sweetened beverages are considered (106265). However, in children aged 6-11 years, usual sodium intake is positively associated with increased weight and central obesity independently of the intake of energy and/or sugar-sweetened beverages (106265).

Gastrointestinal ...In one case report, severe gastritis and a deep antral ulcer occurred in a patient who consumed 16 grams of sodium chloride in one sitting (25759). Chronic use of high to moderately high amounts of sodium chloride has been associated with an increased risk of gastric cancer (29405).

Musculoskeletal ...Observational research has found that low sodium levels can increase the risk for osteoporosis. One study has found that low plasma sodium levels are associated with an increased risk for osteoporosis. Low levels, which are typically caused by certain disease states or chronic medications, are associated with a more than 2-fold increased odds for osteoporosis and bone fractures (101260).
Conversely, in healthy males on forced bed rest, a high intake of sodium chloride (7.7 mEq/kg daily) seems to exacerbate disuse-induced bone and muscle loss (25760,25761).

Oncologic ...Population research has found that high or moderately high intake of sodium chloride is associated with an increased risk of gastric cancer when compared with low sodium chloride intake (29405). Other population research in patients with gastric cancer has found that a high intake of sodium is associated with an approximate 65% increased risk of gastric cancer mortality when compared with a low intake. When zinc intake is taken into consideration, the increased risk of mortality only occurred in those with low zinc intake, but the risk was increased to approximately 2-fold in this sub-population (109400).

Pulmonary/Respiratory ...In patients with hypertension, population research has found that sodium excretion is modestly and positively associated with having moderate or severe obstructive sleep apnea. This association was not found in normotensive patients (106262).

Renal ...Increased sodium intake has been associated with impaired kidney function in healthy adults. This effect seems to be independent of blood pressure. Observational research has found that a high salt intake over approximately 5 years is associated with a 29% increased risk of developing impaired kidney function when compared with a lower salt intake. In this study, high salt intake was about 2-fold higher than low salt intake (101261).

General ...Orally, whey protein is generally well tolerated.
Most Common Adverse Effects:
Orally: Acne, bloating, cramps, diarrhea, fatigue, headache, nausea, reflux, reduced appetite, and thirst. Most adverse effects are dose-related.

Cardiovascular ...In one case report, use of an unclear quantity of whey protein over one month was thought to be probably responsible for the development of coronary embolism in three coronary arteries in a 33-year-old male with no history of atherosclerosis risk factors. The patient required treatment with intravenous glycoprotein IIb/IIIa inhibitor and heparin (96023).

Dermatologic ...Orally, whey protein has been reported to trigger the onset or worsening of acne. Multiple case reports in teenagers and young adults have associated intake of whey protein with the development of acne or the worsening of existing acneiform lesions. In these reports, the discontinuation of whey protein was typically associated with the clearance of acne lesions. In some cases, patients who were unresponsive to acne treatments while using whey protein became responsive after whey protein discontinuation (103965,103970,103971). Cow's milk, which is comprised of 20% whey protein, is also thought to exacerbate acne. It is theorized that this effect may be due to the growth factor and alpha-lactalbumin content of whey protein (103971,103982).

Gastrointestinal ...Orally, whey protein, especially in higher doses of 2. 3-6.5 grams/kg daily, may cause increased bowel movements, nausea, thirst, bloating, esophageal reflux, cramps, and reduced appetite (2640,85961,85702,86043,86074,86075,86084,86089,86095).

Hepatic ...In two case reports, acute cholestatic liver injury occurred after consumption of the combination of whey protein and creatine supplements (46701,90319).

Musculoskeletal ...In one case report, a 26-year-old male experienced fasciitis, or swelling of the forearms, hands, and legs, after consuming the supplement Pure Whey (85895).

Neurologic/CNS ...Orally, high doses of whey protein may cause tiredness or fatigue and headache (2640). Mild drowsiness has also been reported (86089,86092,86124).

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