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POSSIBLY EFFECTIVE

• Athletic performance. Oral beet may improve athletic performance associated with aerobic activities. However, it is not clear who is most likely to benefit, for which type of competition it is most useful, or what dose or duration of use is most appropriate. Details: Several small clinical trials, most of which enrolled elite athletes, recreational athletes, and sedentary males, as well as meta-analyses of some of these and other studies, show that beet improves various measures of athletic performance, including ability, muscular endurance, power output, sprinting, and strength (93844,94464,94468,94469,100143,100150,100152,105761,113422). Clinical research also shows that drinking beetroot juice improves the use of oxygen during exercise testing in recreationally-trained athletes, especially with severe exercise testing (94460,94463,94467,100147,105762). Also, in obese adolescents, taking beetroot juice daily for 6 days increases the time to exhaustion from severe exercise, but does not improve moderate exercise (100145). Not all research shows that beet supplementation benefits athletic performance. Another meta-analysis of several small clinical studies, including some of the studies above, shows that taking beetroot does not improve performance in high-intensity or sprint interval training (111159). Additionally, the majority of research in elite athletes does not support the use of beetroot juice to decrease the time needed to complete a task, aid in some sort of graded exercise test, or improve the use of oxygen during exercise testing (94455,94458,94460,94461,94464,94465,94466,94469,94473,100142,100153,105763). The supposed lack of effect of beetroot juice in elite athletes might be related to the natural production of nitrates and nitrites in the body or the increased ability to use oxygen that comes from extensive training (94458,94463). Alternatively, any changes might be very small (<1%) and not identified with statistical comparisons, although even very small changes might be beneficial in competition (94464). The most commonly used doses in all studies, regardless of effect, have included an acute dose of beetroot juice 70-500 mL up to 3 hours prior to exercise (93844,94463,94464,94466,94467,94473,97726,100142,100143,105761)(105762,111159,113422) or chronic dosing of up to 500 mL daily for 3-6 days (94459,94464,94469,100145,100147,100153,111159,113422). Less commonly, beetroot juice 70-140 mL daily, betalain-rich concentrate 100 mg daily, or a beetroot-based nutritional gel 100 grams daily, have been taken for longer dosing schedules of 7-15 days (97720,100144,100148,100152,105763,113422). Benefits in elite athletes, most often related to time trials, are usually limited to studies using chronic dosing of 7-15 days, which is longer than the duration of 6 days used in the majority of studies (94473,97720,100144,100148). Brands of juice used in clinical trials have included Beet It Sport (James White Drinks Ltd.) (94455,94458,94465,100142,100143,100144,100148,105761,105763), Beet It Stamina Shot (James White Drinks Ltd.) (93844), Beet It (James White Drinks Ltd) (94457,94459,94460,94467,94469,97726,100145,100153,105762,111159), and Love Beets Beetroot Juice (Gs Fresh Ltd.) (94461,94462). Although plasma levels have not been analyzed in all studies, the majority of studies suggest that these doses are adequate to increase levels of nitrates or nitrites, which is thought to be essential for increasing athletic potential (93844,94455,94458,94459,94460,94465,94467,94469,94466,94473,97726). The evidence also suggests benefit in both normoxic and hypoxic environments (94465,100148,105763).
• Exercise-induced muscle soreness. Drinking beetroot juice 7-8 times over 48 hours after strenuous exercise may reduce exercise-induced muscle soreness, but evidence is conflicting. Details: Some clinical research shows drinking beetroot juice (Love Beets Beetroot Juice, Gs Fresh Ltd.) 125 mL or 250 mL seven times over 48 hours after strenuous box jumps improves muscle soreness when compared with placebo and sodium nitrite (96964,97722). Other small clinical studies show that drinking beetroot juice 50-250 mL as eight separate doses over 48 hours after strenuous exerciseimproves muscle soreness and reduces tissue edema when compared with placebo (94461,113424). However, drinking beetroot juice 250 mL as seven separate doses over 48 hours after running a marathon does not appear to reduce muscle soreness when compared with placebo (94462). A meta-analysis of 4 small studies, mostly in healthy or physically active males, shows that drinking beetroot juice improves the pressure pain threshold, which is a measure of muscle soreness, at 48- and 72-hours post-exercise when compared with a fruit-flavored drink. However, beetroot juice does not improve subjective muscle soreness scores (111160). The validity of the findings from this meta-analysis is limited by the heterogeneity of the beetroot juice regimens among the included studies. Further, these results should not be generalized to elite athletes.

POSSIBLY INEFFECTIVE

• Chronic obstructive pulmonary disease (COPD). Drinking beetroot juice for up to 14 days may not improve exercise capacity in patients with COPD. Details: A meta-analysis of eight small clinical trials in patients with COPD shows that taking nitrate-rich beetroot juice does not improve most measures of exercise capacity, including the 6-minute walk test, cycling ergometry endurance time, and maximum rate of oxygen consumption (VO2 max), when compared with placebo. Additionally, beetroot juice did not reduce blood pressure or heart rate. However, the analysis did show a significant improvement in scores on the Borg Rating of Perceived Exhaustion scale with beetroot juice over placebo. Nitrate-rich beetroot juice doses ranged from 70-140 mL daily for up to 14 days (104200).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Cognitive function. It is unclear if drinking beetroot juice is beneficial for cognitive function. Details: A small clinical study in adults with overweight or obesity on a calorie-restricted diet shows that drinking 70 mL of concentrated beetroot juice daily for 14 days improves the time to complete part B of the trail making test, which is a test of cognitive function, but not part A, when compared with controls (111158). However, the duration and size of this study limits its validity. Further, it is unclear whether any improvement is clinically significant. The effect of acute beet administration on cognitive function has also been studied. A very small clinical study in healthy adults shows that taking beet extract (RedNite, Enovate Biolife) chewable tablets 3 grams 90 minutes prior to neuropsychological testing improves immediate and delayed memory capacity, frontal lobe function, and lexical flexibility but does not improve working memory, information processing speed, or subjective reports of memory performance when compared with placebo (113427).
• Coronary heart disease (CHD). It is unclear if oral beetroot extract is beneficial in patients with CHD. Details: A small clinical trial in patients with CHD shows that taking red beetroot extract 500 mg, containing around 25 mg betalains, twice daily for 2 weeks reduces total cholesterol and low-density lipoprotein (LDL) cholesterol by 15 mg/dL and reduces triglycerides by 8 mg/dL when compared to baseline. Slight improvements in blood pressure and blood glucose were also reported, but these changes were not clinically significant (103883). The validity of these findings is limited by the lack of a comparator group. Also, it is unclear whether beetroot can reduce the risk of cardiovascular events in patients with CHD.
• Dyslipidemia. It is unclear if oral beetroot is beneficial in patients with dyslipidemia. Details: A meta-analysis of small clinical studies in healthy individuals or patients with dyslipidemia, cardiovascular disease, or overweight or obesity, shows that consuming beetroot juice or leaves does not improve levels of triglycerides or total, low-density lipoprotein, or high-density lipoprotein cholesterol when compared with controls (111163). However, the validity of the findings from this meta-analysis is limited by the heterogeneity of the enrolled patients and beetroot regimens.
• Exercise-induced muscle damage. It is unclear if oral beetroot juice improves recovery from muscle damage after exercise. Details: A meta-analysis of 4 small clinical studies in healthy or physically active individuals, most of which enrolled males only, shows that drinking beetroot juice improves measures of muscle recovery at 72 hours post-exercise when compared with a fruit-flavored drink. However, beetroot juice does not consistently improve recovery at earlier time points post-exercise, nor does it reduce levels of creatine kinase or markers of inflammation (i.e., interleukin-6, interleukin-8, c-reactive protein, or tumor necrosis factor-alpha) (111160). However, the validity of the findings from this meta-analysis is limited by the heterogeneity of the beetroot juice regimens among the included studies, which usually varied from 210-250 mg of nitrate in 7-11 servings over 3-7 days. Further, these results should not be generalized to elite athletes. Another very small clinical study in semi-professional female athletes shows that ingesting beetroot juice 50 mL 8 times over 48 hours after exercise-induced muscle damage enhances the recovery of some functional parameters such as muscle endurance but not others such as flexibility and vertical jump performance when compared with placebo (113424).
• Hypertension. Oral beet may slightly reduce blood pressure in healthy individuals, but it is unclear if it is beneficial in patients with hypertension. Details: Meta-analyses of small studies show the potential for a minor reduction in systolic blood pressure (SBP) and diastolic blood pressure (DBP) in healthy adults taking beetroot juice (94470,97718,97728). The average reduction in SBP and DBP with beetroot juice consumption is about 4 mmHg and 1 mmHg, respectively, which is greater than the effect seen with consuming blackcurrant juice or nitrate-depleted beetroot juice. The most benefit is seen when beetroot juice is taken for at least 2 weeks or at doses of 500 mL daily (97728). The effect of acute beet supplementation on blood pressure is conflicting. A small clinical study in healthy adults shows that drinking beet juice (Beet It, James White Company) 140 mL two hours prior to cardiovascular measurements reduces resting SBP by about 4 mmHg but does not improve resting or post-exercise DBP, central blood pressure, or arterial stiffness nor does it improve post-exercise SBP when compared with placebo. Subgroup analysis suggests that the reductions in resting SBP were only observed in males, not females (113423). Another small clinical study shows that consuming beet 100 grams baked into bread modestly decreases DBP over a 6-hour period when compared with white bread (97725). It is possible that genetics might play a role in the magnitude of effect seen with beetroot consumption. Adults with a specific gene polymorphism, eNOS Glu298Asp, experienced a greater reduction in DBP after consuming beet-containing bread (97724). Despite positive findings in studies of healthy individuals, research on the use of beetroot juice in patients with hypertension is unclear. A small clinical study in adults with hypertension who were taking antihypertensive medications shows that drinking nitrate-rich beetroot juice (Beet it; James White Drinks Ltd.) 70 mL twice daily for one week does not lower blood pressure when compared with nitrate-depleted beetroot juice (94457). Also, in patients with mild to moderate hypertension, clinical research shows that taking a combination of beetroot powder (Sensient) 300 mg, olive leaf extract 1000 mg, and green coffee bean extract 200 mg daily for 6 weeks does not lower blood pressure when compared with placebo (97723). However, some evidence suggests that at least part of the blood pressure lowering effects of beet might be independent of nitrate (97728). Furthermore, some research suggests that identifying effects on blood pressure might be dependent on the method of measurement, including clinic resting measurements, 24-hour monitoring, or morning/evening home resting measurements (97729).
• Hypertriglyceridemia. It is unclear if oral beet is beneficial in patients with hypertriglyceridemia. Details: A small clinical study in overweight or obese individuals with dyslipidemia shows that taking freeze-dried beet leaf 2.8 grams daily for 4 weeks in addition to nutritional guidance does not lower triglyceride levels when compared with nutritional guidance alone (100146). Beet has also been evaluated in combination with other ingredients. A small clinical trial in patients at risk for heart disease shows that a specific combination of beet and hawthorn berry (Neo40-Daily, Neogenis Labs), taken twice daily for 30 days, can modestly reduce blood triglyceride levels when compared to baseline (18222). It is unclear if these findings are due to beet, hawthorn berry, or the combination.
• Liver disease. Although there has been interest in using oral beet for liver disease, there is insufficient reliable information about the clinical effects of beet for this purpose.
• Muscle strength. It is unclear if oral beetroot juice is beneficial for muscle strength. Details: A meta-analysis of 18 clinical studies in healthy males shows that taking beetroot juice or beetroot gel 2-3 hours before exercise improves muscular strength when compared with placebo. Subgroup analysis suggests that beetroot-based supplements improve muscular strength in a fatigued but not resting state (113422). A small clinical study in adults with overweight or obesity on a calorie-restricted diet shows that drinking 70 mL of concentrated beetroot juice daily for 14 days improves handgrip strength by approximately 18% compared with 4% in controls (111158). However, it is unclear whether any improvement is clinically significant.
• Obesity. It is unclear if oral beet leaf or beetroot juice is beneficial for weight loss. Details: A small clinical study in patients with overweight or obesity and dyslipidemia shows that taking freeze-dried beet leaf 2.8 grams daily for 4 weeks in addition to nutritional guidance does not reduce body weight or body mass index (BMI) when compared with nutritional guidance alone (100146). Similarly, a small clinical study in adults with overweight or obesity on a calorie-restricted diet shows that drinking 70 mL of concentrated beetroot juice daily for 14 days does not improve weight loss when compared with controls (111158). However, the size and duration of this study may have been inadequate to detect differences between groups.
• Pregnancy-induced hypertension. It is unclear if oral beetroot juice is beneficial in patients with pregnancy-induced hypertension. Details: A small clinical trial in pregnant patients with hypertension who are at approximately 22-35 weeks gestation shows that taking beetroot juice (James White Drinks Ltd) 70 mL daily for 8 days does not reduce blood pressure when compared with a nitrate-depleted beetroot juice (100151). However, the study was small and designed to investigate the feasibility of using beetroot juice in this population.
• Pulmonary hypertension. It is unclear if oral beetroot juice is beneficial in patients with pulmonary hypertension. Details: A small clinical study shows that taking beetroot juice (Beet-It Sport; James White Drinks Ltd) 70 mL twice daily for 7 days does not improve right ventricular systolic function when compared with nitrate-depleted beetroot juice in patients with pulmonary hypertension (100149). However, this study was small and not adequately powered to detect differences between groups.
• Raynaud syndrome. It is unclear if oral beetroot juice is beneficial in patients with Raynaud syndrome. Details: A small clinical study in patients with Raynaud syndrome undergoing cold sensitivity tests shows that drinking beetroot juice (Beet-It, James White Drinks Ltd) 70 mL daily for 13 days, followed by 140 mL prior to testing, does not reduce pain in the hands or feet, but might improve thermal comfort in the feet, when compared to baseline (103884). The validity of this finding is limited by the lack of a comparator group. More evidence is needed to rate beet for these uses.

(Read more about BEET)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Angina. It is unclear if oral hawthorn is beneficial in patients with angina. Details: Preliminary clinical research in patients with angina taking chronic beta-adrenergic receptor blockers or ACE inhibitor therapy shows that taking a hawthorn (Crataegus pinnatifada) extract 100 mg orally three times daily for four weeks improves angina and electrocardiogram (ECG) findings and reduces nitroglycerin intake when compared with placebo (19242). Other preliminary clinical research in patients with unstable angina shows that taking hawthorn 10 grams and hu zang 15 grams orally daily for 4 weeks does not reduce the frequency of angina pectoris attacks when compared with control. However, taking hawthorn and hu zang improved some subjective symptom scores and quality of life scores (109610).
• Anxiety. Oral hawthorn has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A clinical study in adults with mild to moderate generalized anxiety shows that taking a specific product (Sympathyl, not available in the US) containing hawthorn, magnesium, and California poppy for 90 days modestly improves anxiety scores when compared with placebo (12583). Also, a clinical study in adults with adjustment disorder and anxious mood shows that hawthorn, in combination with black horehound, passion flower, valerian, kola nut, and guarana, modestly improves anxiety scores when compared with placebo (6250). It is unclear if these effects are due to hawthorn, other ingredients, or the combination. Another small clinical study in healthy adults shows that taking a combination of herbal extracts containing hawthorn, passionflower, ballota, and valerian root daily for 14 days reduces subjective anxiety and objective sympathetic and autonomic nervous system activation in response to a psychosocial stressor when compared with placebo (111222). It is unclear if these effects are due to hawthorn, other ingredients, or the combination.
• Arrhythmia. Although there has been interest in using oral hawthorn for arrhythmia, there is insufficient reliable information about the clinical effects of arrhythmia for this condition.
• Atherosclerosis. Although there has been interest in using oral hawthorn for atherosclerosis, there is insufficient reliable information about the clinical effects of arrhythmia for this condition.
• Cardiovascular disease (CVD). Although there has been interest in using oral hawthorn for CVD, there is insufficient reliable information about the clinical effects of arrhythmia for this condition.
• Cognitive function. Oral hawthorn has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: In a preliminary clinical trial, a single dose of 25 drops of a combination product of D-camphor and hawthorn berry extract (Korodin) was superior to placebo for increasing cognitive performance in elderly female patients as measured by visuomotor speed and information processing capacity. The active treatment group showed an improvement in attentional and mental performance (19240,91504).
• Congestive heart failure (CHF). The evidence on the effects of oral hawthorn in patients with CHF is conflicting. Although some older research suggests it may be beneficial, more recent, larger studies suggest it may actually increase the risk for complications. Details: There is contradictory evidence about the effects of hawthorn extract in heart failure patients. Several clinical studies show that taking specific hawthorn leaf and flower extracts (LI 132, Faros 300, Lichtwer Pharma; WS 1442, Crataegutt forte, Dr. Willmar Schwabe Pharmaceuticals; or HeartCare, Nature's Way) 240-600 mg daily improves ejection fraction and exercise tolerance, reduces subjective symptoms, and decreases the risk of death in patients with New York Heart Association (NYHA) stage II heart failure. In these studies, the maximum effect was usually seen after 6-12 weeks of treatment (8279,8280,11449,19221,19223,19225,19226,19227,19228). Another clinical trial shows that hawthorn extract (WS 1442, Crataegutt forte, Dr. Willmar Schwabe Pharmaceuticals or HeartCare, Nature's Way) 1800 mg daily, combined with diuretic therapy, improves exercise tolerance and reduces subjective symptoms in NYHA stage III heart failure. In this study, maximum effect was usually seen after 16 weeks of treatment (8281). In another trial, patients with NYHA II heart failure taking either hawthorn (LI 132, Faros) 300 mg three times daily or captopril 12.5 mg three times daily experienced similar improvements in cardiac performance and symptoms (19230). However, other clinical research suggests no benefit and possible harm with hawthorn. A large-scale clinical trial (SPICE) in patients with NYHA stage II or III heart failure shows that taking specific hawthorn extracts (WS 1442, Crataegutt forte, Dr. Willmar Schwabe Pharmaceuticals; HeartCare, Nature's Way) 900 mg daily for 24 months, in combination with conventional treatment, does not decrease hospitalization due to progressive heart failure, non-fatal myocardial infarction, or cardiac death (17203). Another clinical trial in patients with NYHA stage II or III heart failure shows that taking these same specific hawthorn extracts at the same dose for up to 6 months does not slow the progression of heart failure when compared with placebo (19222). In a retrospective analysis of this study, it was shown that heart failure progression was significantly increased in patients taking hawthorn when compared with placebo. The rate of death was also increased by 1.7% over placebo, and heart failure-related hospitalizations increased by 8% over placebo in patients treated with hawthorn (16824).
• Hyperlipidemia. Although there has been interest in using oral hawthorn for hyperlipidemia, there is insufficient reliable information about the clinical effects of arrhythmia for this condition.
• Hypertension. It is unclear if oral hawthorn is beneficial for lowering blood pressure. Details: One preliminary clinical trial showed that taking hawthorn standardized extract 1,000-2,500 mg daily for three days does not significantly reduce blood pressure in hypertensive or prehypertensive patients when compared with placebo (19244). However, another study in patients with diabetes and hypertension shows that taking a specific hawthorn extract (LI 132) 1,200mg daily for 16 weeks significantly decreased diastolic, but not systolic, blood pressure when compared with placebo (19245).
• Obesity. Although there has been interest in using oral hawthorn for obesity, there is insufficient reliable information about the clinical effects of hawthorn for this condition.
• Orthostatic hypotension. Oral hawthorn has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in older adults with orthostatic hypotension shows that taking a specific combination product containing hawthorn and camphor (Korodin Herz-Kreislauf-Tropfen) 25 drops orally three times daily for 7 days attenuates the blood pressure reduction upon standing when compared with placebo. Signs and symptoms of orthostatic hypotension such as dizziness, blurry vision, and falls also seem to be reduced when compared with baseline (39614,39617). A meta-analysis of 4 studies shows that giving single doses of 20-25 drops of the same combination product increases systolic and diastolic blood pressure when compared with placebo (103620). However, the studies have methodologic problems and, while 2 were conducted in females with orthostatic hypotension, the others involved health young adults or normotensive elderly subjects. The effect of hawthorn alone for treatment of orthostatic hypotension has not been determined. The combination product used in these studies is not available in the US. More evidence is needed to rate hawthorn for these uses.

(Read more about HAWTHORN)

POSSIBLY EFFECTIVE

• Athletic performance. Small studies show that taking a single oral dose of L-citrulline before anaerobic resistance exercise might reduce exhaustion and improve some performance measures. It is unclear if L-citrulline improves aerobic exercise performance; results are conflicting. Details: A meta-analysis of small clinical trials in healthy trained and untrained adults shows that taking L-citrulline prior to mostly anaerobic exercise marginally reduces perceived exhaustion and muscle soreness when compared with placebo (105965). Another meta-analysis including some of the same clinical studies shows that taking L-citrulline malate before exercise modestly increases performance on resistance exercises by an average of 6% when compared with placebo (105968). Individual studies show mixed benefit and mostly use a single dose of L-citrulline malate 8 grams 1 hour before exercise; other studies used L-citrulline 3.3-6 grams mixed in watermelon juice or sucrose water or L-citrulline malate 12 grams given 1-2 hours before exercise (94966,94957,97395,105965). L-citrulline has also been evaluated for use with aerobic exercise. A small study in healthy young adults taking L-citrulline 9 grams in 3 divided doses over 24 hours or as a single dose of 3 grams 3 hours before a treadmill test does not improve performance, but might reduce time to exhaustion, when compared with placebo (16473). Another small clinical study in healthy adults shows that taking about 6.8 grams (100 mg/kg) of L-citrulline daily for 5 days prior to a cycling trial does not improve time to exhaustion, oxygen uptake, or lactate levels when compared with taking 3 grams of glucose as placebo (105964). However, two small clinical trials in healthy males show that taking L-citrulline 2.4-6 grams daily for 7 days prior to a cycling test improves peak power by 9%, total work by 7%, and cycling time trial performance by 1.5% when compared with placebo (94954,94965). Differences in methods of testing athletic performance, the form and dose of L-citrulline used, and/or the duration of supplementation may explain the mixed results. L-citrulline has also been evaluated in combination with L-arginine. Research in male soccer players shows that taking L-citrulline 1.2 grams and L-arginine 1.2 grams daily for 7 days increases total power output over a 10-minute cycling test and improves subjective perceptions of exertion when compared with placebo (100956).

POSSIBLY INEFFECTIVE

• Sarcopenia. Oral L-citrulline does not seem beneficial for muscle strength in older adults when added to structured exercise. Details: Two small clinical studies in older adults show that taking L-citrulline in conjunction with structured exercise does not improve measures of strength, endurance, speed, or balance when compared with placebo and structured exercise (110146,110148). One study evaluated otherwise healthy adults aged 60-73 years taking L-citrulline 3 grams daily for 6 weeks (110146). The other study evaluated older adults with obesity and an average age of 68.5 years taking a specific L-citrulline product (Citrage) 10 grams daily for 12 weeks (110148).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Cardiovascular disease (CVD). Although there is interest in using oral L-citrulline for CVD, there is insufficient reliable information about the clinical effects of L-citrulline for this condition.
• Dementia. Although there is interest in using oral L-citrulline for dementia, there is insufficient reliable information about the clinical effects of L-citrulline for this condition.
• Diabetes. It is unclear if oral L-citrulline is beneficial in patients with diabetes. Details: A small clinical study in adults with diabetes who are taking metformin and sulfonylureas shows that adding L-citrulline (Bulk Supplements Co., Ltd.) 3 grams daily before breakfast for 8 weeks reduces average fasting blood glucose levels by 22 mg/dL and glycated hemoglobin by 0.7%, but does not affect lipid levels, when compared with taking a microcrystalline cellulose placebo (105963).
• Erectile dysfunction (ED). It is unclear if oral L-citrulline is beneficial in patients with ED. Details: A small non-randomized crossover study in adults with mild ED shows that taking L-citrulline 1.5 grams daily for one month improves erection hardness from "mild dysfunction" to "normal function" in 50% of patients, compared with only 8% of patients taking placebo (94956). L-citrulline has also been evaluated in combination with other ingredients. A clinical study in middle-aged males with ED shows that taking a specific combination product (Revactin, MD Concepts LLC) containing L-citrulline, muira puama, ginger root, and guarana twice daily for 3 months improves scores related to erectile function and intercourse satisfaction, but does not improve sexual desire or orgasmic function scores, when compared to baseline (103224). The validity of this study is limited by the lack of a placebo control, the use of per-protocol analysis, and a high dropout rate. In fact, 44% of patients withdrew in order to resume use of phosphodiesterase type 5 (PDE5) inhibitors. Another small clinical study in adults with ED living in Japan and using PDE5 inhibitors as needed shows that taking an adjunct 50 mL drink containing L-citrulline 800 mg, a specific fenugreek extract (Testofen) 600 mg, resveratrol 300 mg, and caffeine 40 mg daily for 14 days modestly improves erectile function and satisfaction with intercourse and orgasm when compared with a placebo drink (105966). The validity of this finding may be confounded by the "as needed" use of PDE5 inhibitors, which was not reported throughout the study. Further, in both combination studies, it is unclear if these effects are due to L-citrulline, other supplement ingredients, or the combination.
• Heart failure. Small clinical studies suggest that oral L-citrulline might be beneficial in patients with heart failure. Details: A very small clinical study in patients with heart failure with preserved ejection fraction (HFpEF) shows that taking L-citrulline malate 3 grams daily for 2 months decreases systolic pulmonary arterial pressure by 16% and improves the right ventricular ejection fraction after a stress test by 27% when compared to baseline (94962). The validity of this finding is limited by the lack of a control group. Another small open-label clinical study in patients with heart failure with reduced ejection fraction (HFrEF) shows that taking L-citrulline 3 grams daily for 4 months increases left ventricular ejection fraction by about 20% at rest and 13% during the stress test, and increases the right ventricular ejection fraction by about 15%, both at rest and with the stress test, when compared with no supplementation. This improved the heart failure functional class in 35% of patients (94955).
• Hypertension. It is unclear if oral L-citrulline is beneficial for lowering blood pressure. Details: A small clinical trial in adults with prehypertension shows that taking L-citrulline 2 grams with grape and cranberry polyphenols 548 mg daily for 6 weeks does not reduce mean ambulatory blood pressure when compared with a cellulose placebo (105969). A small crossover study in postmenopausal females with hypertension shows that taking L-citrulline 6 grams as a single dose does not improve systolic or diastolic blood pressure at rest or during 5 minutes of plantar flexion exercise when compared with placebo (110147). The effects of using L-citrulline regularly or in other patients with diagnosed hypertension is unclear.
• Lysinuric protein intolerance. Although there is interest in using oral L-citrulline for lysinuric protein intolerance, there is insufficient reliable information about the clinical effects of L-citrulline for this condition.
• Muscle strength. It is unclear if oral L-citrulline can improve muscle strength when used in conjunction with resistance training. Details: A clinical study in healthy resistance-trained adults shows that taking L-citrulline malate 2 grams daily for 8 weeks in conjunction with resistance training does not further increase lean mass or muscle strength, measured by leg and bench presses, when compared with a cellulose placebo and resistance training (97394).
• Muscular dystrophy. It is unclear if oral L-citrulline is beneficial in patients with Duchenne muscular dystrophy. Details: A small clinical study in adults with Becker muscular dystrophy, a milder form of Duchenne muscular dystrophy (DMD), shows that taking L-citrulline 5 grams with or without metformin 500 mg three times daily for 6 weeks improves 6-minute walking distance and decreases markers of muscle necrosis when compared to baseline (100975). A small clinical study in males aged 6.5-10 years with DMD shows that taking L-citrulline 2.5 grams with metformin 250 mg three times daily for 26 weeks does not appear to slow decline in motor function when compared with placebo. However, this combination seems to slow decline in children with more stable disease, defined as those who can walk at least 350 meters in 6 minutes (100976). The reasons for these disparate results are unclear, but they may be due to the different patient populations, disease severities, doses, and durations of therapy being studied.
• Postoperative pulmonary hypertension. It is unclear if oral citrulline prevents postoperative hypertension in children undergoing heart surgery. Details: A small clinical study in children 6 years of age and younger undergoing congenital heart surgery shows that higher blood levels of L-citrulline might protect against the incidence of postoperative hypertension. L-citrulline blood levels of at least 37 micromol/L immediately after surgery, and at 12, 24, and 36 hours postoperatively, protects against its development. However, supplementation with 1.9 grams/m2 during induction of anesthesia is not necessarily protective (16467).
• Post-polio syndrome. It is unclear if oral L-citrulline is beneficial for patients with this condition. Details: A small clinical study in adults with post-polio syndrome shows that taking L-citrulline 5 grams three times daily for 24 weeks does not improve 6-minute walking distance, motor function scores, muscle strength, or quality of life when compared with placebo (110149).
• Pulmonary hypertension. It is unclear if oral L-citrulline is beneficial in patients with pulmonary hypertension. Details: A very small clinical study in patients with idiopathic arterial pulmonary hypertension or pulmonary hypertension due to Eisenmenger syndrome shows that taking L-citrulline malate 1 gram three times daily for 2 weeks increases 6-minute walking distance by 44 meters and reduces mean pulmonary arterial pressure by 5% when compared with baseline (94963). The validity of these findings is limited by the small study size and the lack of a comparator group.
• Reye syndrome. Although there is interest in using oral L-citrulline for Reye syndrome, there is insufficient reliable information about the clinical effects of L-citrulline for this condition.
• Sickle cell disease. It is unclear if oral L-citrulline is beneficial in patients with sickle cell disease. Details: A small clinical study in children ages 10-18 years shows that taking L-citrulline 90-130 mg/kg daily in 2 divided doses for up to 9 months might reduce neutrophilia and other symptoms when compared with baseline (16463). The validity of these findings is limited by the small study size and the lack of a comparator group. More evidence is needed to rate L-citrulline for these uses.

(Read more about L-CITRULLINE)

LIKELY SAFE ...when used in amounts commonly found in foods.

POSSIBLY SAFE ...when used orally and appropriately for medicinal purposes, short term. Beetroot juice has been safely used in clinical trials in doses of up to 500 mL daily for up to 7 days and a beetroot-based nutritional gel has been used safely in doses of up to 100 grams daily for 8 days (94461,94462,94464,100149,100152,100153).

PREGNANCY AND LACTATION:
There is insufficient reliable information available about the safety of beets used medicinally during pregnancy and breast-feeding.

(Read more about BEET)

POSSIBLY SAFE ...when used orally and appropriately, short-term. Hawthorn preparations in doses of up to 1800 mg daily seem to be safe when used for up to 16 weeks. Although hawthorn might be safe for long-term use, current studies have not evaluated safety past 16 weeks (8279,8280,8281,10144,17203,104689). There is insufficient reliable information available about the safety of hawthorn when used topically.

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

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POSSIBLY SAFE ...when used orally and appropriately. In clinical trials, L-citrulline has been used with apparent safety for up to 2 months at doses of 1.5-6 grams daily (94954,94956,94961,94962,100974). Doses of up to 15 grams have also been used as single doses or within a 24 hour period (16470,16473).

CHILDREN: POSSIBLY SAFE
when used orally and appropriately. L-citrulline has been used with apparent safety in infants at a dose of 0.17 grams/kg daily (16472). It has also been used in children 6.5-10 years of age at a dose of 7.5 grams daily for 26 weeks (100976). ...when used intravenously and appropriately. An intravenous bolus dose of L-citrulline 150 mg/kg followed by 9 mg/kg/hour for 48 hours has been used safely in children under 6 years of age (16469).

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

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CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, beet might decrease the levels and clinical effects of CYP1A2 substrates.  Details In vitro research suggests that beet induces CYP1A2 enzymes (111404).

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, beet might increase the levels of CYP3A4 substrates.  Details In vitro research suggests that betanin, the major pigment in beet, competitively inhibits CYP3A4 in a dose-dependent manner similarly to strong CYP3A4 inhibitor ketoconazole (113425).

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ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, hawthorn may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.  Details In vitro and animal research shows that hawthorn can inhibit platelet aggregation (95528,95529,95530,95531). However, its effect in humans is unclear. One observational study shows that patients taking hawthorn shortly before undergoing coronary artery bypass graft (CABG) surgery or valve replacement surgery have a 10% incidence of postoperative bleeding, compared with 1% in those who never consumed hawthorn extract (95527). However, clinical research shows that taking a specific preparation of dried hawthorn leaves and flowers (Crataesor, Soria Natural Lab) 800 mg three times daily for 15 days does not affect platelet aggregation or levels of thromboxane B2, the metabolite of thromboxane A2, in healthy humans (54664).

BETA-BLOCKERS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use might cause additive effects on blood pressure and heart rate.  Details Some evidence shows that hawthorn might lower blood pressure and heart rate (12595,19245,113112,113113).

CALCIUM CHANNEL BLOCKERS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use might cause additive coronary vasodilation and hypotensive effects.  Details Some evidence shows that hawthorn might lower blood pressure due to vasodilatory effects (12595,19245).

DIGOXIN (Lanoxin) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, hawthorn might potentiate the effects and adverse effects of digoxin.  Details Hawthorn appears to improve cardiac output (12595); however, hawthorn does not appear to affect digoxin pharmacokinetics (19249). Case reports suggest that at least one species of hawthorn root extract (Crataegus mexicana) may produce adverse effects similar to digoxin and can cross-react with digoxin assays, leading to falsely elevated plasma digoxin levels (113112,113113).

NITRATES Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = D Theoretically, concomitant use might cause additive coronary vasodilatory effects.  Details Some evidence shows that hawthorn might lower blood pressure due to vasodilatory effects (12595,19245).

PHOSPHODIESTERASE-5 INHIBITORS Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = D Theoretically, concomitant use might result in additive vasodilation and hypotension.  Details Hawthorn might inhibit PDE-5 and cause vasodilation (12595).

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ANTIHYPERTENSIVE DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, concomitant use of L-citrulline with antihypertensive drugs might have additive effects and increase the chance of hypotension.  Details L-citrulline is converted to L-arginine, which can increase nitric oxide and cause vasodilation (7822,16460,16461). However, a meta-analysis of 5 small clinical studies suggests that taking L-citrulline 3-6 grams daily for 1-8 weeks does not lower blood pressure when compared with control (100974).

PHOSPHODIESTERASE-5 INHIBITORS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, concurrent use of phosphodiesterase-5 (PDE-5) inhibitors and L-citrulline might result in additive vasodilation.  Details L-citrulline is converted to L-arginine, which can increase nitric oxide and cause vasodilation (7822,16460,16461). Theoretically, taking L-arginine with PDE-5 inhibitors might have additive vasodilatory and hypotensive effects. However, in studies evaluating the combined use of L-arginine and sildenafil for erectile dysfunction, hypotension was not reported (105065).

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General ...Orally, beet seems to be well tolerated when used for medicinal purposes, short term.
Most Common Adverse Effects:
Orally: Red stools and red urine.
Serious Adverse Effects (Rare):
Orally: Hypocalcemia and kidney damage when ingested in large amounts.

Endocrine ...Theoretically, ingestion of large quantities of beets could lead to hypocalcemia because of the oxaluric acid content (18).

Gastrointestinal ...Orally, beet juice may cause red stools (94470,97726,100142,100145,105762). This red coloring of the stools is not harmful. Additionally, beet supplementation has been reported to cause black stools. In one case, a 79-year-old male on apixaban and clopidogrel presented with black stools, nausea, and vomiting after taking beet pills 2-3 days prior. The likelihood of upper gastrointestinal bleed was determined to be low based on factors such as normal vital signs and lack of severe anemia. The patient was diagnosed with beet-induced pseudo-hematochezia which was successfully treated with fluids and discontinuation of the beet supplement (113426).
Other less common gastrointestinal side effects include loose stools, constipation, and nausea (100149).

Genitourinary ...Orally, beet is known to produce red or pink urine (beeturia) in some people (32569,34134,94464,94470,97725,97726,100142,100145,100152,105762,113422). However, this red coloring of the urine is not harmful and dissipates after about 12 hours (113422).

Neurologic/CNS ...Orally, vivid dreams and worsening headaches have each occurred in one person in a clinical trial, although it is not clear if this is due to beet (97723).

Renal ...Theoretically, ingestion of large quantities of beets could lead to kidney damage due to its oxaluric acid content (18).

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General ...Orally, hawthorn seems to be well tolerated when used appropriately. Topically, no adverse effects have been reported, although a thorough evaluation of safety outcomes has not been conducted.
Serious Adverse Effects (Rare):
Orally: Multiorgan hypersensitivity reactions resulting in acute renal failure have been reported rarely.

Cardiovascular ...Orally, tachycardia (with facial pains) of uncertain relationship to hawthorn was reported in a multicenter clinical trial (54640). Palpitations (19244) were reported in three patients in a large surveillance trial of 3,664 patients with cardiac failure (54692) and in 11 patients with congestive heart failure (CHF) in a literature review of 5,577 patients (19247). Circulation failure has been reported in two patients with CHF in a literature review of 5,577 patients (19247). Incidences of hospitalization, hospitalization due to CHF, worsening of CHF, angina, and atrial fibrillation have also been reported with the use of hawthorn extract WS 1442 (Crataegutt forte), although it is unclear if these events are related to hawthorn supplementation or existing CHF (19222). In clinical trials, chest pain (8281), short-term increases in blood pressure (19240), and other non-specific heart problems (17203) have also been reported following the use of various hawthorn preparations (e.g. WS 1442, Korodin).
Orally, severe bradycardia, bradypnea, and Mobitz type 1 second degree heart block have been reported in a 16-year-old female who consumed Hawthorn root extract. Blood tests indicated plasma digoxin levels in the therapeutic range, despite no history of digoxin use. Medical treatment for digoxin cardiotoxicity did not improve symptoms. Symptoms gradually normalized over 3 days after discontinuation of the product (113112). Similarly, a 40-year-old female presented with bradycardia and elevated plasma digoxin levels after taking hawthorn root extract 196 mg daily for 2 days with no history of digoxin use. Symptoms resolved within 24 hours (113113).

Dermatologic ...Orally, erythematous rash has been reported in patients with CHF in a literature review of 5,577 patients (19247). Non-specific rashes and itching (19222,19243) as well as toxiderma from the fruits of hawthorn (54670) have also been reported.

Gastrointestinal ...Orally, rare abdominal discomfort of uncertain relationship to hawthorn has been reported in a large clinical trial, surveillance study, case reports, and a literature review (19247,54640,54692,113112). Digestive intolerance (19241), diarrhea (19243,113112), flatulence (8281), gastroenteritis (8281), increased bowel movements (19243), obstipation (8281), mild and rare nausea (10144,19247,19244), vomiting (113112), nutritional and metabolic problems (17203), and other non-specific gastrointestinal effects (19222), have also been reported. Furthermore, gastrointestinal hemorrhage has been reported in two patients with CHF in a literature review of 5,577 patients (19247).

Musculoskeletal ...In clinical trials, arthritis (8281), back pain (8281), weakness (19243), and other non-specific musculoskeletal effects (19222) have been reported following the use of various hawthorn preparations g. WS 1442, CKBM-A01). Additionally, in a case report, myalgia has been reported following use of hawthorn root extract (113113).

Neurologic/CNS ...Orally, headache and dizziness/vertigo were reported in 2 patients in a large surveillance trial of 3,664 patients with cardiac failure (54692), in 15 patients with CHF as reported in a literature review of 5,577 patients (19247), in a varying number of clinical trial participants (8281,19222,19244), and in case reports (113112,113113). Incidences of fainting (19222), fever (17203), and infrequent, mild and transient sleepiness have also been reported (19221,54692).

Psychiatric ...Orally, agitation was reported in a large surveillance trial of 3,664 patients with cardiac failure (54692).

Pulmonary/Respiratory ...Orally, bronchitis has been reported following the use of hawthorn extract WS 1442 (8281), and bradypnea has been reported following the use of hawthorn root extract (113112).

Renal ...A case of multiorgan hypersensitivity reaction and acute renal failure following the consumption of C. orientalis has been reported (54654).

Other ...Flu-like syndrome (8281) and other non-specific infections have been reported following the use of the hawthorn extract WS 1442 (17203,19222). Hawthorn has also been reported to cause nosebleeds (8281,10144).

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General ...Orally, L-citrulline seems to be generally well tolerated.
Most Common Adverse Effects:
Orally: Gastrointestinal discomfort, heartburn.

Gastrointestinal ...Orally, gastrointestinal intolerance, stomach discomfort, and heartburn have been reported with L-citrulline use (94955,94963,94966).

Genitourinary ...Orally, 2 of 25 patients with pulmonary hypertension reported increased urinary frequency and edema while taking 1 gram of powdered L-citrulline in water daily (94963).

Pulmonary/Respiratory ...Orally, 2 of 25 patients with pulmonary hypertension reported cough while taking 1 gram of powdered L-citrulline in water daily (94963).

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