An independent panel convened this week by the NIH Office of Medical Applications of Research and the Office of Dietary Supplements assessed the available evidence on the safety and effectiveness of multivitamin/minerals (MVMs). Following two days of expert presentations, public discussion, and panel deliberations, the panel made recommendations regarding certain specific supplements but ultimately concluded that more rigorous scientific research is needed before strong recommendations can be made regarding MVM use to prevent chronic diseases.

The panel released a draft statement of its findings this morning, at the close of the conference. The panel's findings pertain to the generally healthy population, and do not include pregnant women, children, or those with disease. Full text of the panel's draft state-of-the-science statement will be available late today at http://consensus.nih.gov. The final version will be available at the same Web site in four to six weeks.

"More than half of American adults are taking dietary supplements, the majority of which are MVMs, and the bottom line is that we don't know for sure that they're benefiting from them. In fact, we're concerned that some people may be getting too much of certain nutrients," said J. Michael McGinnis, M.D., M.P.P., Senior Scholar with the Institute of Medicine of the National Academy of Sciences, who chaired the panel.

The panel recommended the combined use of calcium and vitamin D supplementation for postmenopausal women to protect bone health. The panel also advocated that anti-oxidants and zinc be considered for use by non-smoking adults with early-stage, age-related macular degeneration, an eye condition that can cause blindness. The panel supports previous recommendations by the CDC that women of childbearing age take daily folate to prevent neural tube defects (birth defects of the brain and spinal cord) in infants. Conversely, it found no evidence to recommend beta carotene supplements, a form of vitamin A, for the general population, and strong evidence to caution smokers against taking them. Specifically, beta-carotene was linked to an increase in lung cancer among smokers who took the vitamin regularly.

In looking specifically at MVMs for chronic disease prevention, however, the panel found that the available data are insufficient to make a firm recommendation for or against their use in the general population.

Of note, rates of MVM use are highest among those who engage in other positive health behaviors such as regular exercise and eating a healthier diet, making it difficult to determine whether the MVM alone is truly responsible for any observed improvement in health.

Most of the public assumes that the components of MVM supplements are safe, because many of the ingredients are found in everyday foods and the products are available over-the-counter. The panel identified several possible risks associated with MVM consumption, however. Among these is the potential for overconsumption of certain nutrients, with the resulting possibility of adverse effects. Though health-conscious individuals are likely to be focused on ensuring that they meet the recommendations for essential nutrients, the combined effects of eating fortified foods, taking MVMs, and consuming single vitamins or minerals in large doses, may lead them to unwittingly exceed the Upper Levels (ULs) of nutrients, which can be harmful.