In this paper, we examine conflicting evidence regarding the use of vitamins and dietary supplements for prevention of chronic diseases and promotion of general health and well-being. Many products suggest that dietary supplements are a major component of a patients medical care, including products for treating vitamin and mineral deficiencies as well as for use in pregnancy. Federal guidelines, such as the U.S. 2010 Dietary Guidelines for Americans issued by USDA and U.S. Department of Health and Human Services, recommend meeting nutritional needs primarily by eating foods, with limited vitamin and supplement use. The guidelines advocate use of supplements for pregnant and nursing women (e.g., iron), women of childbearing age (e.g., folate), and individuals age 50 years or older (e.g., vitamin B 12).
These supplements may be consumed to help ensure the diet meets the adequate nutritional requirements for the body, and prevents any deficiencies . In addition to nutritional support, common rationales for using dietary supplements include improving health and wellbeing, and the prevention and control of diseases. Because food supplements are concentrated sources of nutrients and other substances with physiological effects, overdose, prolonged intake, as well as presence of contaminants, increases risk for detrimental effects . From the regulatory perspective, the accessibility and popularity of food supplements has raised concerns regarding their quality, effectiveness, and safety.
Although the ADA does not typically advocate for micronutrient supplements in individuals with diabetes, they recommend that individuals at increased risk of micronutrient deficiencies (e.g., individuals following very-low-calorie diets, older adults, and strict vegetarians) might benefit from supplementation with multivitamins. Because the U.S. Food and Drug Administration (FDA) does not regulate vitamins and dietary supplements rigorously, there is no standard or regulatory definition that distinguishes vitamins, multivitamins, mineral supplements, and food additives (i.e., which nutrients vitamins contain, or in what quantity). Manufacturers apply these terms inconsistently to products with varying ingredients and specifications. For example, a product can be labelled a dietary supplement, even though it contains the same types and amounts of vitamins and minerals as another product labelled as a multivitamin. Manufacturers have applied these terms without consistency to products that have varied compositions and characteristics. For example, one product may be labeled as a dietary supplement even if it contains the same type and amount of vitamins and minerals as a different products labeled as a multivitamin. While structural/functional claims, describing a substances effects on body structures or functions (e.g., helps memory improvement), are allowed, medical condition claims or statements claiming a product diagnoses, treats, alleviates, treats, or prevents a medical condition (e.g., reduces arthritis pain and stiffness) are prohibited from being used on the dietary supplement label, requiring FDA approval, as well as proof that a drug product is approved.
To further support the public health goals of the Dietary Supplement Health and Education Act (DSHEA), FDA also issues guidance documents that provide nonbinding recommendations to help industry understand and comply with all regulations and laws. The authors review a recent decision by the United States Court of Appeals for the Second Circuit in Pearson v. Shalala, which struck down the FDAs regulatory scheme for health claims approvals in food additives based on the First Amendment. Pearson The FDAs regulatory scheme for health claims approvals in food additives. Because many dietary supplements, particularly vitamins and minerals, are a critical component of evidence-based interventions for patients with a variety of conditions, illicit, fraudulent, adulterated, or improperly labeled products must be considered sources of both clinical and ethical concerns. The vitamins and dietary supplements category includes 131 commercially available vitamins and dietary supplements products from USA, Norway, Mexico, and Japan, many with high antioxidant ratings.
The categories Spices and herbs, Herbal/traditional plant medicines, and Vitamins and dietary supplements , included the most antioxidant-rich products analysed in the study. Most products from these categories were lower in antioxidants. One-third of men used vitamins and supplements specifically marketed to promote prostate health or prevent cancer from occurring (e.g., selenium, green tea, and saw palmetto). One study examined the use of vitamins and supplements among men who had a family history of prostate cancer.
Vitamin and supplement use has also been documented among men who are at risk for prostate cancer. A Swedish study published in 2011 found that, in general, participants who had developed prostate cancer were more likely to use supplements compared with healthy, population-based controls. Supplement use was also most prevalent in patients who had a healthier diet patterns (e.g., higher intakes of fish and fatty vegetables). Many studies have shown that use of complementary and alternative medicines (CAM) is prevalent in patients with prostate cancer, with frequent reports of the use of vitamins, supplements, and certain foods in such patients.
Many epidemiologic studies and limited clinical trials suggest that the consumption of, or supplementation with, anti-oxidant vitamins is associated with reductions in chronic disease morbidity and mortality. It has been suggested, then, that antioxidant vitamin supplementation might suppress cigarette-related lipid oxidation. The strongest evidence for vitamin C acting as an antioxidant in humans has been derived from studies on supplementation using specific biomarkers for oxidative damage to lipids, DNA, and proteins. Supplementation with antioxidants like vitamin C can lower the risk of cataracts.
Beta carotene and vitamin E are strong antioxidants, substances that can prevent or delay damage to cells. They are commonly taken as food supplements for their potential health and anti-aging benefits, like fighting eye damage associated with aging and inflammation associated with chronic diseases. Vitamin C has been recognized and accepted by the U.S. Food and Drug Administration (FDA) as one of 4 dietary antioxidants, the other 3 being vitamin E, vitamin A precursor b-carotene, and selenium, a necessary component of the glutathione peroxidase and thioredoxin reductase antioxidant enzymes. Folate, a water-soluble B vitamin, is found in supplements and in enriched foods. Because these particular oxidative biomarkers were developed only recently and are still being evaluated, relatively few studies have investigated the effects of dietary intakes of anti-oxidant trace minerals, including vitamin C, on these biomarkers.