5-HTP by Finest Nutrition

POSSIBLY EFFECTIVE

• Depression. Oral 5-HTP seems to improve symptoms of depression. Details: A meta-analysis of preliminary clinical research shows that taking 5-HTP for up to 8 weeks might improve symptoms of depression in some patients. The pooled remission rate across 13 studies was 65%, and the pooled effect size across 7 studies assessing the change in depressive symptom scores from baseline was large (102854). In most studies, the dose of 5-HTP administered ranged from 150-800 mg daily, although doses as high as 3 grams daily have been used (903,30000,30125,30138,102854). Some research has compared 5-HTP to conventional antidepressants. In one clinical trial of adults experiencing a first episode of depression, taking 5-HTP orally, titrated up to a daily dose of 400 mg, decreased depression symptoms similarly to fluoxetine titrated up to 40 mg daily (30112). Limited research also suggests that taking 5-HTP 300-800 mg daily seems to work similarly to fluvoxamine 50 mg (2203) or imipramine 150 mg daily (30125). Adding 5-HTP 300 mg orally daily to clomipramine 50 mg daily for 28 days has also been shown to reduce depressive symptoms when compared with clomipramine alone (6245).

POSSIBLY INEFFECTIVE

• Down syndrome. Oral 5-HTP does not seem to improve muscle tone or cognitive skills in patients with this condition. Details: Although early reports suggested that 5-HTP might improve muscle tone and activity levels in infants with Down syndrome (88172), other research has shown no benefit. One small clinical study suggests that taking 5-HTP 0.5-5 mg/kg daily orally from early infancy until 3-4 years of age does not improve muscle tone or developmental ability scores in children with Down syndrome when compared with a control group (88173). Also, a prospective, double-blind study shows that taking 5-HTP 1-2 mg/kg daily orally, alone or with pyridoxine 5-10 mg/kg daily orally, beginning at birth and continuing until 3 years of age, does not improve muscle tone or development of cognitive, social, or language skills when compared with placebo (30153).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Alcohol use disorder. Oral 5-HTP has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that taking a food supplement containing 5-HTP 5 mg, phenylalanine 300 mg, and glutamine 150 mg daily for 40 days during alcohol detoxification therapy reduces withdrawal symptoms when compared with alcohol detoxification therapy alone (30100). However, taking a combination of 5-HTP 25-100 mg with carbidopa 25 mg four times daily for one year does not seem to improve alcohol abstinence rates when compared with placebo (30007). The effect of 5-HTP alone is unclear.
• Alzheimer disease. Although there has been interest in using oral 5-HTP for Alzheimer disease, there is insufficient reliable information about the clinical effects of 5-HTP for this condition.
• Anxiety. It is unclear if oral 5-HTP is beneficial in patients with anxiety disorders. Details: A small clinical study in people with anxiety disorders shows that taking 5-HTP 25-150 mg daily with carbidopa 150 mg daily for 8 weeks reduces anxiety when compared with baseline, but not when compared with clomipramine 25-150 mg daily (30124).
• Attention deficit-hyperactivity disorder (ADHD). Although there is interest in using oral 5-HTP for ADHD, there is insufficient reliable information about the clinical effects of 5-HTP for this condition.
• Cerebellar ataxia. It is unclear if oral 5-HTP reduces cerebellar ataxia symptoms. Details: One small clinical trial in people with cerebellar ataxia of various etiologies shows taking 5-HTP orally 10 mg/kg daily for 4 months improve quantitative ataxia scores when compared with placebo. Further improvement was noted in subjects continuing treatment for another 8 months (916). However, in a subsequent trial in this population, taking 5-HTP orally 1 gram daily for 10 months did not improve symptom scores when compared with placebo (30164). Also, a small clinical study in people with Friedreich's ataxia shows that taking 5-HTP 200-300 mg daily for 1 month, then 600-900 mg daily for 5 months (depending on body weight), does not improve symptoms when compared with placebo (30165).
• Fibromyalgia. Small clinical studies suggest that oral 5-HTP may improve symptoms of primary fibromyalgia syndrome. Details: Small clinical studies in people with primary fibromyalgia syndrome suggest that taking 5-HTP 100 mg orally three times daily for 30-90 days might improve pain, tenderness, sleep, anxiety, fatigue, and morning stiffness when compared with baseline or placebo (913,10286).
• Inflammatory bowel disease (IBD). It is unclear if oral 5-HTP is beneficial for IBD. Details: Preliminary clinical research in adults with stable IBD and fatigue shows that taking a specific 5-HTP (Levotonine, Panpharma) 100 mg orally twice daily for 8 weeks does not improve fatigue scores when compared with placebo. However, the validity of this study is limited by high patient drop-out (111311).
• Menopausal symptoms. It is unclear if oral 5-HTP is beneficial for symptoms of menopause. Details: A small clinical study in postmenopausal patients shows that taking 5-HTP orally 50 mg three times daily for 4 weeks does not reduce hot flash frequency when compared with placebo (30061).
• Migraine headache. It is unclear if oral 5-HTP reduces frequency of migraines. Details: Preliminary clinical research shows that taking 5-HTP 600 mg daily decreases migraine attack frequency similarly to methysergide 3 mg daily (30129). However, other small clinical studies show that taking 5-HTP 400 mg daily does not reduce the frequency or severity of migraine attacks when compared with placebo (30130,30184). Also, in children 6-12 years of age, one very small clinical study shows that taking 5-HTP 5 mg/kg daily in 3 divided doses for 12 weeks does not reduce the frequency or severity of migraine attacks when compared with placebo (30128).
• Obesity. It is unclear if oral 5-HTP is beneficial in for weight loss. Details: Some very small clinical studies show that taking 5-HTP orally, 300 mg three times daily 30 minutes before meals for 2-12 weeks, improves early satiety and decreases daily caloric intake in females with obesity when compared with placebo (914,30018). 5-HTP was also associated with a mean weight loss of 1.7 kg over 6 weeks when caloric intake was not restricted, and a mean weight loss of 3.3 kg over 6 weeks when caloric intake was restricted to about 1200 calories daily (914,30114). In moderately overweight adults with type 2 diabetes, taking 5-HTP 250 mg three times daily 30 minutes before meals for 2 weeks reduces caloric intake by about 22% and decreases body weight by about 2 kg when compared to baseline (30175).
• Obsessive-compulsive disorder (OCD). It is unclear if oral 5-HTP is beneficial in patients with OCD. Details: A small clinical study in patients with moderate to severe OCD shows that adding 5-HTP 200 mg orally daily to fluoxetine, titrated up to 60 mg daily, for 12 weeks reduces symptom severity when compared with placebo and fluoxetine. A complete response, defined as greater than or equal to 35% improvement in overall Yale-Brown Obsessive Compulsive Scale (Y-BOCS) score, was seen in 54% of those taking 5-HTP at week 12, compared with only 12% of those taking placebo (104250). These results were not observed until week 12, which indicates that a longer treatment period may be needed to see the full effects of the intervention.
• Opioid withdrawal. Oral 5-HTP has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in Chinese males undergoing detoxification for heroin addiction shows that taking 5-HTP 200 mg orally daily for 6 days, in combination with tyrosine, phosphatidylcholine, and L-glutamine, might reduce insomnia and withdrawal symptoms and improve mood when compared with a control group (88178).
• Panic disorder. It is unclear if intravenous 5-HTP is beneficial for reducing anxiety in panic disorder. Details: A small clinical trial in females with panic disorders shows that receiving an intravenous (IV) infusion of 5-HTP, 60 mg over 30 minutes after premedication with carbidopa 100 mg orally, does not appear to reduce anxiety when compared with control (30093).
• Parkinson disease. It is unclear if oral 5-HTP is beneficial for improving Parkinson disease symptoms. Details: Two preliminary clinical trials show that taking 5-HTP 50 mg daily for 1 month seems to improve levodopa-induced dyskinesia and symptoms of depression, but not motor functioning or apathy, when compared with placebo in patients with Parkinson disease (102853,104251). Both studies used a crossover design to correct for the small sample size, but may still have been inadequately powered to detect small changes in these outcomes. However, in another study, taking larger doses of 5-HTP, 275-1500 mg orally daily along with carbidopa 150-1000 mg daily for up to 38 days, worsened rigidity, bradykinesia, and functional disability (30140). Other research has evaluated 5-HTP in patients with Parkinson disease and REM sleep behavior disorder (RBD). A small crossover study in these patients shows taking oral 5-HTP 50 mg daily for 4 weeks does not improve the percentage of REM sleep without atonia or the frequency of RBD events when compared with baseline or placebo. Patients taking 5-HTP report modest improvements in part II (motor function; e.g. swallowing, walking, and dressing) of the Unified Parkinson Disease Rating Scale (UPDRS), but not other parts of the UPDRS, when compared with placebo (107793). This study may have been inadequately powered to detect a difference between groups.
• Premenstrual syndrome (PMS). Although there is interest in using oral 5-HTP for PMS, there is insufficient reliable information about the clinical effects of 5-HTP for this condition.
• Seizures. Although there is interest in using oral 5-HTP for seizures, there is insufficient reliable information about the clinical effects of 5-HTP for this condition.
• Tension headache. It is unclear if oral 5-HTP reduces tension headache severity. Details: A small clinical study in adults with a history of chronic tension headaches suggests that taking 5-HTP 100 mg three times daily for 8 weeks does not reduce pain intensity or the number of days with headache when compared with placebo (2204).
• Tinnitus. Oral 5-HTP has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Research has evaluated a specific capsule formulation (Tinnitan Duo; Laboratorios Salvat) containing 5-HTP, ginkgo extract, magnesium, melatonin, pantothenic acid, vitamin B6, and zinc at undeclared doses. A small clinical trial in patients with subjective tinnitus shows taking this product as one capsule twice daily for 3 months improves Tinnitus Handicap Inventory (THI) total score and THI emotional subscale score at 3 months when compared with baseline. Patients also report improvement in tinnitus-related distress (107792). The validity of this study is limited by the lack of randomization and placebo-control; additionally, it is unclear if any effects are due to 5-HTP, other ingredients, or the combination. More evidence is needed to rate 5-HTP for these uses.

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EFFECTIVE

• 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).

LIKELY EFFECTIVE

• 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.

POSSIBLY EFFECTIVE

• 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 in adults with or without hypertension. However, it is unclear if this reduction is clinically significant. Details: Many clinical trials and observational studies, including a meta-analysis of 18 high-quality clinical trials, show that intake of calcium supplements or dietary calcium modestly reduces systolic 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 those who are salt-sensitive or have low baseline dietary calcium intake (945,972,974,976,984,1818,1819,1820,1821,6852)(13138,14406,38803,39063,39094,39221,113920,113925). 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 supplemental 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). Research evaluating the effect of calcium supplementation during pregnancy on the child's blood pressure has yielded conflicting findings. A systematic review of 2 clinical studies and 3 observational studies found that calcium intake during pregnancy is associated with a 1-2 mmHg reduction in the systolic blood pressure of the offspring between the ages of 1-7 years (38852). However, a separate meta-analysis of 3 clinical studies shows that calcium intake during pregnancy does not reduce systolic or diastolic blood pressure in the offspring (113923).
• 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, especially in high-risk individuals and those with low baseline dietary calcium intake. Details: Although there is some conflicting evidence (971,38756), most clinical research shows that taking calcium orally 1-2 grams daily reduces the risk of pre-eclampsia (973,1833,8828,39043,39319,39426,97348,113919). A large clinical trial of 11,000 pregnant individuals in India and Tanzania shows that supplementation with 500 mg daily is similarly effective to 1500 mg daily (113908). Multiple meta-analyses which include 16-30 clinical studies have found that varying doses of calcium supplementation reduce the relative risk of pre-eclampsia by 46% to 51% when compared with placebo (97348,113909,113919). One of these meta-analyses found that for every 19 females treated with calcium, one episode of pre-eclampsia would be avoided (97348). Additionally, one of these meta-analyses found that calcium reduces the relative risk of pre-eclampsia by 51%, regardless of whether it is taken at a dose above or below 1000 mg daily (113919). Some research suggests that calcium supplementation may have a greater effect in individuals at high risk of pre-eclampsia or with low baseline dietary calcium intake, and when taken at greater than or equal to 20 weeks of gestation (15029,38497,97348,99714,113919). However, another meta-analysis of 30 clinical studies found a similar benefit of calcium in both high- and low-risk individuals (113919). A separate meta-analysis of 6 clinical studies conducted in China evaluated the benefits of calcium carbonate 500-600 mg daily taken in conjunction with aspirin 50-75 mg daily during pregnancy. This combination was associated with an 80% lower relative risk of pre-eclampsia and an 83% lower relative risk of pre-eclampsia with gestational hypertension when compared with routine care (113913). 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 (102366). 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 1.5-2 grams daily during pregnancies at high risk of pre-eclampsia if dietary calcium intakes are low (97347).
• Pregnancy-induced hypertension. Oral calcium may reduce the risk of pregnancy-induced hypertension. Details: A meta-analysis of 17 clinical studies shows that calcium supplementation during pregnancy may reduce the relative risk of pregnancy-induced hypertension by 30% when compared with control (113909). A separate meta-analysis of 6 clinical studies conducted in China, which evaluated the benefits of calcium carbonate 500-600 mg daily taken in conjunction with aspirin 50-75 mg daily during pregnancy, shows that this combination reduces the relative risk of pregnancy-induced hypertension by 85% when compared with routine care (113913).
• 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).

POSSIBLY INEFFECTIVE

• Breast cancer. Oral calcium, via supplementation or as part of the diet, does not seem to be beneficial for breast cancer prevention. Details: Although some studies disagree (15631,39041,95811,107237,113917), most population research suggests that increased calcium intake is not associated with overall breast cancer risk (15631,16715,98895,107236,107237,113917). However, one meta-analysis of observational studies shows that although higher total calcium intake is not associated with breast cancer risk, higher dietary calcium intake, specifically, may be associated with a slightly reduced risk (113917). Also, some analyses suggest that calcium intake may be associated with the risk for certain breast cancer sub-types. Some subgroup analyses suggest that calcium intake may reduce the risk of breast cancer in postmenopausal, but not pre-menopausal, adults (15631,107237) and that dietary calcium intake may reduce estrogen receptor(ER)-negative breast cancer, but not ER-positive breast cancer (107236). However, most 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: Robust meta-analyses of mostly large, high-quality clinical studies show that calcium supplementation 500-1600 mg daily for 0.5-7 years with or without vitamin D does not reduce total fractures, hip fractures, vertebral fractures, or non-vertebral fractures in older adults without osteoporosis (95822,112486). A large-scale study in postmenopausal females aged 50-79 years who were enrolled in the Women's Health Initiative (WHI) suggests that 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 WHI study found that, in older females with the lowest genetic susceptibility to low 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 in adults or children with overweight or obesity. 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 (12128,15397,14438,98905,113918), most clinical research has found that increased calcium intake does not increase weight loss (12052,13138,15396,15399,38985,39004,97356). A 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 (93533,97308,113584).

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)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• 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).
• Brain tumor. It is unclear if dietary calcium intake is associated with risk of brain tumor. Details: A meta-analysis of 4 case-control studies has found that higher dietary calcium intake is associated with a lower odds of brain tumor when compared with lower dietary intake (113922). The validity of this finding is limited by the exploratory nature of the included studies, which analyzed all dietary ingredients for any potential associations.
• 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 dietary calcium intake is associated with type 2 diabetes risk. Details: Some population research has found that a higher intake of calcium from the 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 (14265,16713,96473,113929). One meta-analysis of cohort and cross-sectional studies found that the highest level of dietary calcium intake is associated with an 18% relative reduction in risk of type 2 diabetes when compared with the lowest level of intake. A dose-response analysis suggests that each 300, 600, and 1000 mg per day increase in dietary calcium intake is associated with a 7%, 14%, and 23% reduced risk of type 2 diabetes, respectively (113929). However, population research is often limited by confounding variables. For example, one analysis suggests that any beneficial effect might be influenced by concomitant magnesium intake (96473,113929), while another suggests that any benefit from increased intake may be more pronounced in females, adults aged 50 years or older, and Asian populations (113929). 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 (95815).
• Dyslipidemia. It is unclear if oral calcium is beneficial for dyslipidemia. Details: One clinical study in adults with mild to moderate hypercholesterolemia shows that adding calcium carbonate 400 mg three times daily to a low-fat diet (American Heart Association Step 1) for 6 weeks reduces low-density lipoprotein (LDL) cholesterol levels by 4% and increases high-density lipoprotein (HDL) cholesterol levels by 4% when compared with the low-fat diet and placebo (2557). In contrast, a clinical study in females with dyslipidemia shows that taking calcium 800 mg daily for 2 years INCREASES total cholesterol levels and carotid intima-media thickness in postmenopausal, but not premenopausal, females when compared with placebo (97350). Calcium supplementation has also been evaluated in combination with vitamin D. A meta-analysis of randomized controlled trials including adults with normolipidemia and 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 most beneficial in patients with dyslipidemia at baseline (107227). The relationship between dietary calcium intake and serum lipid levels has also been evaluated in observational research. A meta-analysis of 7-11 observational studies found that dietary calcium intake is not associated with total cholesterol levels, although small differences in individual lipid parameters were identified. Additionally, a meta-analysis of 4-9 observational studies suggests that calcium intake is not associated with the risk of developing hypertriglyceridemia, hypercholesterolemia, or low HDL. A subgroup analysis found that higher calcium intake may be associated with lower triglyceride levels in Asian populations (113927). Overall, these findings are limited by significant heterogeneity and the cross-sectional nature of the included studies.
• 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).
• Exercise-induced muscle damage. It is unclear if oral calcium is beneficial for reducing exercise-induced muscle damage. Details: A very small clinical study in resistance-trained adults shows that taking calcium carbonate 500 mg 4 times daily for 3 weeks does not attenuate exercise-induced muscle damage from bench presses when compared with placebo (113933). This study may have been inadequately powered to detect a difference between groups.
• 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).
• 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).
• Prematurity. It is unclear if supplemental calcium is beneficial for the growth and development of preterm infants. Details: A small clinical study in preterm infants consuming human milk shows that supplementation with calcium 45 mg/kg daily and phosphorus 25 mg/kg daily does not affect infant weight, length, head circumference, or risk of osteopenia after 6 weeks when compared with human milk alone (113924). However, the duration and size of this study may have been too limited to detect any difference between groups.
• Preterm labor. It is unclear if oral calcium reduces the risk of preterm labor. Details: A meta-analysis of 10 clinical studies shows that taking calcium supplements during pregnancy does not reduce the risk of preterm labor when compared with placebo (113909). A separate meta-analysis of 7 clinical studies conducted in China, which evaluated the benefits of calcium carbonate 500-600 mg daily taken in conjunction with aspirin 50-75 mg daily during pregnancy, shows that this combination reduces the relative risk of preterm labor by 74% when compared with routine care (113913).
• 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.

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POSSIBLY SAFE ...when used orally and appropriately. 5-HTP has been used safely in doses up to 400 mg daily for up to one year (913,30007,30130). Doses up to 1.2 grams daily have been used with apparent safety for up to 10 months (914,30018,30125,30164,30165). Doses of 3 grams daily have been used safely for 3 weeks (30138). There is some controversy about the safety of 5-HTP due to concerns for eosinophilia myalgia syndrome (EMS) (902,919,7067,10084,30178). There is speculation that only certain, contaminated 5-HTP products may cause this serious adverse effect (88174). So far, there is not enough evidence to know if EMS is caused by 5-HTP, contaminants, or other unknown factors (919,7067,10084).

POSSIBLY UNSAFE ...when used orally in large doses. Doses of 6-10 grams daily have been associated with severe gastrointestinal effects and hyperkinesis (30139,30183). The risk may be reduced if the dose is increased gradually.

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

CHILDREN: POSSIBLY SAFE
when used orally and appropriately. Doses of 5-HTP up to 5 mg/kg daily have been used safely for up to 3 years in infants and children up to 12 years old (30128,30153,88173). There is some controversy about the safety of 5-HTP due to concerns for eosinophilia myalgia syndrome (EMS) (902,919,7067,10084,30178). There is speculation that only certain, contaminated 5-HTP products may cause this serious adverse effect (88174). So far, there is not enough evidence to know if EMS is caused by 5-HTP, contaminants, or other unknown factors (919,7067,10084).

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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). Other clinical studies suggest that, when combined with vitamin D supplementation, calcium supplementation is not associated with an increased risk of CVD, CHD, or MI (93533,107231). 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, to consider total calcium intake from both dietary and supplemental sources (17484), and to combine calcium supplementation with vitamin D supplementation (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). Other clinical studies suggest that, when combined with vitamin D supplementation, calcium supplementation is not associated with an increased risk of CVD, CHD, or MI (93533,107231). 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, to consider total calcium intake from both dietary and supplemental sources (17484), and to combine calcium supplementation with vitamin D supplementation (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).

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CARBIDOPA (Lodosyn) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Combining 5-HTP and carbidopa can increase the risk of serotonergic side effects.  Details Carbidopa is sometimes used with 5-HTP to minimize peripheral 5-HTP metabolism and boost the amount that reaches the brain. However, this combination might also increase the risk of some side effects including hypomania, restlessness, rapid speech, anxiety, insomnia, and aggressiveness (30076,30132,30158). Combining carbidopa and 5-HTP might also increase the risk of scleroderma-like skin changes due to elevated serotonin levels (1403).

CNS DEPRESSANTS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use of 5-HTP with medications that cause sedation might have additive effects.  Details In clinical trials, 5-HTP has been associated with drowsiness and somnolence (914,30093,30129,30130).

SEROTONERGIC DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Combining serotonergic drugs with 5-HTP might cause additive serotonergic effects.  Details 5-HTP can increase serotonin levels and cause serotonergic effects (901). Theoretically, combining serotonergic drugs with 5-HTP might increase the risk of serotonergic side effects, including serotonin syndrome and cerebral vasoconstrictive disorders (8056). However, serotonin syndrome with 5-HTP has not yet been reported in humans (104941). Monitor patients for signs of serotonin syndrome and other serotonergic side effects if using 5-HTP with serotonergic drugs.

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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.

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General ...Orally, 5-HTP is generally well tolerated, short-term.
Most Common Adverse Effects:
Orally: Abdominal pain, anorexia, dizziness, diarrhea, drowsiness, fatigue, headache, insomnia, nausea, and vomiting. Severity appears to be dose-dependent.
Serious Adverse Effects (Rare):
Orally: Aggression, hallucinations, mania, severe gastrointestinal complaints.

Cardiovascular ...Orally, palpitations have been reported with 5-HTP (30076,30130,30167). Conversely, bradycardia has been reported in patients taking 5-HTP 0.4-2 grams daily in combination with carbidopa 100-300 mg daily (30132). In patients with schizophrenia, a combination of 5-HTP in doses up to 6 grams daily and carbidopa 150 mg daily was associated with diaphoresis and mild diastolic hypotension, especially when doses were increased at a rate faster than 200 mg per day (30183).

Dermatologic ...Orally, 5-HTP has been reported to cause urticaria, other allergic-type skin reactions, and flushing (2204,30000,30140). A scleroderma-like illness was reported in a 70-year-old man who had been taking 5-HTP 1400 mg daily and carbidopa 150 mg daily for 20 months. Elevated serotonin levels may be linked to this condition (1403).

Gastrointestinal ...Orally, 5-HTP has been reported to cause gastrointestinal side effects such as nausea, vomiting, abdominal or epigastric pain, heartburn, constipation, diarrhea, flatulence, anorexia, and taste alteration at any dose (2203,2204,30000,30112,30114,30125,30132,30139,30140)(30165,30183,104250). Severity may be dose-dependent and also related to how quickly doses are increased (30183). Some data suggests that these effects may diminish or disappear with continued use of 5-HTP (30132).

Hematologic ...Symptoms suggestive of eosinophilia myalgia syndrome (EMS) have been reported in some patients using 5-HTP (902,10084,30178,88174,90927). In one case, a woman was exposed to 5-HTP, tetrahydrobiopterin, carbidopa, and levodopa while administering them to her children for 2 years (90927). Her diagnosis was not confirmed, and the validity of the tests performed on the 5-HTP product has been questioned (88174). Other cases of eosinophilia or EMS in patients taking 5-HTP have been attributed to impurities that resemble previously identified contaminants found in L-tryptophan products (902,919,7067,10084). The L-tryptophan contaminants associated with EMS were linked to a specific manufacturer's production method that is not used in the preparation of 5-HTP (88174). Although 5-HTP supplements have been associated with EMS, it seems that this adverse effect is likely due to the presence of contaminants in the 5-HTP products, not 5-HTP itself.

Musculoskeletal ...Orally, rhabdomyolysis was noted in one patient with progressive myoclonus epilepsy who was treated with 5-HTP 300 mg daily for 21 days (30162).

Neurologic/CNS ...Orally, 5-HTP has been reported to cause drowsiness, dizziness, insomnia, fatigue, and headache (30076,30112,30132).

Psychiatric ...Orally, 5-HTP has been associated with euphoria, hypomania and mania, anxiety, insomnia, and aggressiveness (30076,30132,30158,88179). In patients with schizophrenia, a combination of high-dose 5-HTP, up to 6 grams daily, and carbidopa 150 mg daily was associated with transient increases in hallucinations, delusions, marked confusion, looseness of associations, flight of ideas, and a hyperkinetic syndrome consisting of restlessness, hand wringing, pacing, and an inability to sit quietly in a chair (30183).

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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).

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