NIH Panel Finds Limited Evidence to Support Public's Multivitamin Use

WASHINGTON--An independent panel assembled by the National Institutes of Health (NIH) Office of Medical Applications of Research and the Office of Dietary Supplements (ODS) to assess the available evidence on the safety and effectiveness of multivitamin/minerals (MVMs) concluded more rigorous scientific research is needed before strong recommendations can be made regarding MVM use to prevent chronic diseases. The panel convened for two days of expert presentations, public discussion and panel deliberations, after which they made recommendations regarding certain specific supplements.

Among their findings, the panel recommended combined calcium and vitamin D supplementation to protect bones in postmenopausal women; daily folate for women of childbearing age take to prevent infant neural tube defects; and antioxidant and zinc supplementation in non-smoking adults with early-stage, age-related macular degeneration (AMD). On the other hand, the panel found no evidence to recommend beta-carotene supplements for the general population, and cautioned smokers against taking them, citing strong evidence linking beta-carotene to an increase in lung cancer among smokers who took the vitamin regularly.

Half of American adults are taking MVMs and the bottom line is that we dont know for sure that theyre benefiting from them," said J. Michael McGinnis, M.D., M.P.P., senior scholar with the Institute of Medicine (IOM) of the National Academy of Sciences and chair of the NIH panel "In fact, were concerned that some people may be getting too much of certain nutrients."

Based on these safety concerns and the limitations of the available evidence, the panel advocated changes in the regulation of dietary supplements, including MVMs, by the Food and Drug Administration (FDA). Specifically, the panel recommended Congress expand FDAs authority and resources to require manufacturers to disclose adverse events, to ensure quality production, and to facilitate consumer reporting of adverse events by including reporting information on dietary supplement labels.

Steven M. Mister, Esq., president and chief executive officer (CEO) of the Council for Responsible Nutrition (CRN), noted for millions of Americans who struggle with diet and nutrition, a daily MVM provides a safe, affordable and reliable means of filling nutrition gaps and promoting overall good health. "FDA already regulates dietary supplements including multivitamins and has indicated on numerous occasions that it has the appropriate regulatory authority necessary to protect the public," he said, noting CRN supports mandatory reporting of serious adverse events by supplement companies to FDA. "CRN agrees that more research examining the effects of multivitamins on the prevention of chronic diseases could provide valuable insights for consumers. However, consideration should also be given as to whether the drug model for clinical research is the appropriate way to assess the preventive benefits of nutrients. In the meantime, consumers should be encouraged to eat a well-balanced diet, get plenty of exercise, and take a multivitamin every day."

Regarding future research on MVM and other dietary supplements, the panel called for rigorous randomized, controlled trials of the impact of individual supplements to test their efficacy and safety in prevention of chronic disease, using well-validated measures. They further suggested the creation of new MVM databases detailing the exact composition of supplements, which would be available to the research community and updated regularly. Additional concern was expressed in support of a better understanding of possible interactions between MVMs and prescribed or over-the-counter (OTC) medications.

The 13-member panel included experts in the fields of food science and human nutrition, biostatistics, biochemistry, toxicology, geriatric medicine, family medicine, pediatrics and pediatric endocrinology, cancer prevention, epidemiology, disease prevention and health promotion, and consumer protection. Their findings pertain to the generally healthy population, and do not include pregnant women, children, or those with disease. Full text of the panels draft state-of-the-science statement is available at http://consensus.nih.gov. The final version will be available at the same Web site in four to six weeks.

In addition to the material presented at the conference by speakers and the comments and concerns of conference participants presented during discussion periods, the panel considered pertinent research from the published literature and the results of a systematic review of the literature commissioned by the NIH Office of Medical Applications of Research (OMAR). The systematic review was prepared through the Agency for Healthcare Research and Quality (AHRQ) Evidence-based Practice Center (EPC) program, by the Johns Hopkins University Evidence-based Practice Center. The EPCs develop evidence reports and technology assessments based on rigorous, comprehensive syntheses and analyses of the scientific literature, emphasizing explicit and detailed documentation of methods, rationale, and assumptions. The evidence report on Multivitamin/Mineral Supplements and Prevention of Chronic Diseases is available at http://www.ahrq.gov/clinic/tp/multivittp.htm.