special subjects
Overview of Dietary Supplements
Safety and Effectiveness
Because dietary supplements are not regulated as drugs by the FDA, their manufacturers are not required to prove that supplements are safe and effective (although they must have a history of safety). Consequently, few supplements have been studied rigorously for safety and effectiveness. Furthermore, because the need to evaluate supplements in humans has been recognized only recently, much of the available information has not been gathered systematically or scientifically and so is difficult to evaluate. Manufacturers must now report serious adverse events to the FDA through the FDA MedWatch system. However, a few supplements (for example, Fish Oil , Manufacturers are not required to prove that dietary supplements are safe and effective. In contrast, both prescription and nonprescription (over-the-counter) drugs have been extensively and systematically studied by researchers and reviewed for Drug Effectiveness and Safety by the FDA. These include studies in animals to detect the development of cancer and organ damage and studies in humans to detect any signs of toxicity. The amount and quality of evidence supporting the effectiveness of supplements vary greatly. For some supplements, evidence supporting their effectiveness is convincing. However, for most, scientific studies have not been designed well enough to provide clear, reliable answers. For some supplements, the only evidence suggesting effectiveness is reports about small numbers of people or studies conducted in animals. Evidence about the safety and effectiveness of dietary supplements is increasing rapidly as more and more clinical studies are being done. Information about such studies is available from the National Institutes of Health's National Center for Complementary and Integrative Health(NCCIH). 