The goal of MEET is to review whether the current dietary supplement regulations are sufficiently informative and protective for American consumers about potential negative health risks associated with use of some supplements. The regulatory aspects of the dietary supplement industry provide a backdrop to several areas of public health concern, including consumer behaviors regarding usage, safety, and effectiveness, as well as studies that address health effects from regular supplementation. In the U.S., the FDA regulates supplement safety, but legal limitations have prevented FDA from effectively regulating supplements (e.g. This has increased risks for public health, which has led to multiple calls for reform. Dietary supplements, which include vitamins, minerals, plant and animal extracts, hormones, and amino acids ingested orally, are used extensively in the US, with four out of five adults reporting having taken one. The dietary supplement market has grown exponentially in the past 25 years–from a $4 billion industry with 4,000 products in 1994 to one of over $40 billion today, with up to 8,00 products2–but consumer safety regulations have failed to keep up.
Dietary supplement use has grown, despite a lack of evidence to show a clear health benefit for most, and concerns about increased health risks for some. Multivitamins are the most frequently used dietary supplements, with over 60% of women in IWHS reporting use. However, the 2010 Dietary Guidelines for Americans found no evidence recommending the use of multivitamins for chronic disease prevention. An Iowa study found a link between the standard multivitamin use and increased risk for death; additionally, data are available that indicate supplementation increases the risk for developing cancer. The use of multivitamin supplements in older American food programs is of concern, as they may be used by food programs as an alternative to diets following the American Dietary Guidelines. Vitamin and mineral supplements are the most widely used food additives among populations around the world. The amounts of trace minerals that they provide vary from lower than recommended intakes to far higher, making them an important contribution to overall intake.
In some cases, excess vitamin and mineral intake can be detrimental or produce undesirable side effects; thus, maximal levels are needed to assure safe supplementation with foods. Federal guidelines, such as the U.S. Dietary Guidelines for Americans 2010, issued by the U.S. Departments of Agriculture and Health and Human Services, recommend meeting nutritional needs primarily by eating foods, with vitamin and mineral use restricted. The guidelines advocate use of supplements for pregnant and lactating women (e.g., iron), women of childbearing years (e.g., folate), and individuals aged 50 years or older (e.g., vitamin B 12). In the United States, reasons for supplement use cited by the National Health and Nutrition Examination Survey are related to prevention/prevention and diet-containment (references Bailey, Gahche, & Miller6).
In the USA, the National Health and Nutrition Examination Survey reasons for supplement use relate to disease prevention/treatment and supplementing the diet (Reference Bailey, Gahche and Miller6 ). The Nutritional Supplementation Trial of the Cancer Prevention Studies (CPS)-II cohort found that supplemented calcium at >=1000 mg/day was associated with increased all-cause mortality risk for men, while higher levels of dietary calcium were associated with no harm. In U.S. adults, proper food-based intakes, without supplementation, were associated with lower all-cause mortality. The benefits of dietary nutrient intakes might reflect synergistic interactions between several nutrients and other bioactive substances in foods. Higher rates of supplement use were associated with women, Whites, older age (age 51-74 years, as opposed to 18-50 years), higher income, higher education levels, and higher food nutrient intake. Compared to lighter and moderate users of food supplements, heavier and very heavy users were more likely to shop at health food stores, purchase supplements by mail, read health-related specialty literature, believe that they personally control their health, exercise daily, avoid having their physicians participate in supplement decisions, and perceive specific health benefits rather than overall benefits of supplementation.
Other nutritional supplements, such as vitamins B 6, vitamin A, multivitamins, antioxidants, and iron, and dietary interventions, such as reductions in dietary fat, had no significant effects on mortality or cardiovascular outcome (very low-to-moderate-certainty evidence). For example, more than 80 percent of children aged 1 to 3 years taking dietary supplements consumed levels of vitamin A and niacin that exceeded upper limits. In the United States, excessive intakes were noted for vitamin A (97 percent) and zinc (68 percent) among infants given dietary supplements. High-quality evidence is lacking regarding long-term adverse effects of excessive intakes for multiple nutrients, and therefore, it is not clear if it is cause for concern.
Patients may not disclose to healthcare providers the use of dietary supplements and herbal medicines, and therefore, the risks for interactions or substitutes of prescribed medicines or treatments. Although supplement products cannot be marketed as treatments for or preventions of diseases–claims may describe how only one specific nutrient or food component may affect body structure or function–manufacturers are not required to submit to an agency the evidence supporting claims made for their products. Even if they were required to do so, the evidence supporting use of dietary supplements is mixed. Dietary supplements may include generic health claims, nutrient-content claims, or structural-function claims. Some scientific validations are required to be submitted to FDA for health claims alone, establishing the direct connection between use of the supplement and reduced disease risk. Dietary supplements–and their sometimes questionable claims about health effects–are regulated by The Food and Drug Administration (FDA) in a different way from regular foods or medications. These views are at odds with the guidelines on public health in those countries, which generally do not see any role for adult supplementation except for disease/special conditions, and, most recently, vitamin D supplementation for high-risk groups in the United Kingdom.