Dietary supplement
Dietary supplements can also contain substances that have not been confirmed as being essential to life, and so are not nutrients per se, but are marketed as having a beneficial biological effect, such as plant pigments or polyphenols.
The essential nutrient minerals for humans, listed in order by weight needed to be at the Recommended Dietary Allowance or Adequate Intake are potassium, chlorine, sodium, calcium, phosphorus, magnesium, iron, zinc, manganese, copper, iodine, chromium, molybdenum, selenium and cobalt (the last as a component of vitamin B12).
[16] In the same year, the European Food Safety Authority also approved a dietary supplement health claim for calcium and vitamin D and the reduction of the risk of osteoporotic fractures by reducing bone loss.
A meta-analysis found a moderate degree of evidence in favor of whey protein supplements use as a safe and effective adjunct to an athlete's training and recovery, including benefits for endurance, average power, muscle mass, and reduced perceived exercise intensity.
[37] The non-essential amino acid arginine, consumed in sufficient amounts, is thought to act as a donor for the synthesis of nitric oxide, a vasodilator.
[50] Dietary supplements can be manufactured using intact sources or extracts from plants, animals, algae, fungi or lichens, including such examples as ginkgo biloba, curcumin, cranberry, St. John's wort, ginseng, resveratrol, glucosamine and collagen.
[51][52][53] Products bearing promotional claims of health benefits are sold without requiring a prescription in pharmacies, supermarkets, specialist shops, military commissaries, buyers clubs, direct selling organizations, and the internet.
[52] While most of these products have a long history of use in herbalism and various forms of traditional medicine, concerns exist about their actual efficacy, safety and consistency of quality.
[54][55][56] Canada has published a manufacturer and consumer guide describing quality, licensing, standards, identities, and common contaminants of natural products.
[66] A meta-analysis provided preliminary evidence that men treated with supplements containing selenium, zinc, omega-3 fatty acids, coenzyme Q10 or carnitines reported improvements in total sperm count, concentration, motility, and morphology.
[68] A 2021 review also supported selenium, zinc, omega-3 fatty acids, coenzyme Q10 or carnitines, but warned that "excessive use of antioxidants may be detrimental to the spermatic function and many of the over-the-counter supplements are not scientifically proven to improve fertility.
[70] A review provided evidence that taking dehydroepiandrosterone before starting an in vitro fertilization series may increase pregnancy rates and decrease miscarriage likelihood.
[71] Prenatal vitamins are dietary supplements commonly given to pregnant women to supply nutrients that may reduce health complications for the mother and fetus.
[73] In 2006, the World Health Organization endorsed the recommendation for women of child-bearing age to consume 400 micrograms of folate through the diet daily if planning a pregnancy.
[75] A 2013 review found folic acid supplementation during pregnancy did not affect the mother's health other than a risk reduction on low pre-delivery serum folate and megaloblastic anemia.
[77][78] Evidence does not support the routine use of vitamin E supplementation during pregnancy to prevent adverse events, such as preterm birth, fetal or neonatal death, or maternal hypertensive disorders.
[87] Using undercover staff, the GAO also found that supplement retailers intentionally engaged in "unequivocal deception" to sell products advertised with baseless health claims, particularly to elderly consumers.
Muscle building supplements were contaminated with anabolic steroids that can lead to health complications affecting the kidney, the heart, and cause gynecomastia.
Dietary supplements are regulated by the FDA as food products subject to compliance with current Good Manufacturing Practices (CGMP) and labeling with science-based ingredient descriptions and advertising.
[95][96] When finding CGMP or advertising violations, FDA warning letters are used to notify manufacturers of impending enforcement action, including search and seizure, injunction, and financial penalties.
[86] The potential for adverse effects also occurs when individuals consume more than the necessary daily amount of vitamins or minerals that are needed to maintain normal body processes and functions.
[112][113] As a result of the lack of good data for supplementation and the strong data for dietary pattern, public health recommendations for healthy eating urge people to eat a plant-based diet of whole foods, minimizing ultra-processed food, salt and sugar and to get exercise daily, and to abandon Western pattern diets and a sedentary lifestyle.
The FDA can visit manufacturing facilities, send Warning Letters[99] if not in compliance with GMPs, stop production, and if there is a health risk, require that the company conduct a recall.
ANH, however, interpreted the ban as applying only to synthetically produced supplements, and not to vitamins and minerals normally found in or consumed as part of the diet.
[124] Nevertheless, the European judges acknowledged the Advocate General's concerns, stating that there must be clear procedures to allow substances to be added to the permitted list based on scientific evidence.
[126][127] By August 2020, the FDA and FTC had issued warning letters to dozens of companies advertising scam products, which were purported "to be drugs, medical devices or vaccines.
[136][140] High-dose products have received research attention,[130][141] especially for emergency situations such as vitamin A deficiency in malnutrition of children,[142] and for women taking folate supplements to reduce the risk of breast cancer.
[143] In the United States, the National Health and Nutrition Examination Survey (NHANES) has investigated habits of using dietary supplements in context of total nutrient intakes from the diet in adults and children.
Examples: A 2017 academic review indicated a rising incidence of liver injury from use of herbal and dietary supplements, particularly those with steroids, green tea extract, or multiple ingredients.
[106] The potential benefit of using essential nutrient dietary supplements to lower the risk of diseases has been refuted by findings of no effect or weak evidence in numerous clinical reviews, such as for HIV,[154] or tuberculosis.
