NIH panel says little benefit to be gained by taking multivitamin supplements

May 21 2006

According to a National Institutes of Health panel there is little evidence to support that taking multivitamin supplements is of any benefit to healthy adults.

The panel, after reviewing evidence on the safety and effectiveness of multivitamin/minerals (MVMs), concluded that more rigorous scientific research is needed before strong recommendations can be made regarding their use in preventing chronic diseases.

The panel's findings apply to the generally healthy population, and do not include pregnant women, children, or those with diseases.

Panel chairman J. Michael McGinnis, M.D., M.P.P., a senior Scholar with the Institute of Medicine of the National Academy of Sciences, says 50% of American adults are taking MVMs in the belief that they will help prevent heart disease, cancer and other chronic diseases and in fact it is unclear whether they offer any benefit at all.

He says there is also a concern that some people may be getting too much of certain nutrients.

It seems Americans spend as much as $23 billion annually on such supplements.

McGinnis says for example that it is believed that Vitamin E can prevent prostate cancer, but there is no evidence supporting such a claim.

The panel apparently could only find only three credited examples where vitamins have a significant benefit; taking folic acid during pregnancy which prevents birth defects of the brain and spine in babies, vitamins C and E, beta carotene and the minerals zinc and copper may reduce the risk of age-related macular degeneration,and calcium and Vitamin D supplements were found to lower the risk of fracture in post-menopausal women.

The panel says that the very fact that MVM use is highest among those who engage in other positive health behaviors such as regular exercise and eating a healthier diet, makes it difficult to determine whether the MVM alone is truly responsible for any observed improvement in health.

The majority of the general public harbours the illusion that MVM supplements are safe, because many of the ingredients are found in everyday foods and the products are available over-the-counter.

But the panel identified several possible risks associated with MVM consumption, and among them is the potential for over consumption of certain nutrients, with the resulting possibility of adverse effects.

The panel advise that changes are needed in the regulation of dietary supplements including MVMs, by the Food and Drug Administration (FDA).

The panel suggests that it should be mandatory for manufacturers to disclose adverse events, to ensure quality production, and to encourage the reporting of adverse events by consumers and record such information on dietary supplement labels.

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.

The full text of the panel's draft state-of-the-science statement is available on http://consensus.nih.gov.