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1 From the Office of Dietary Supplements, National Institutes of Health, Bethesda, MD
2 Presented at the conference "Multivitamin/Mineral Supplements and Chronic Disease Prevention," held at the National Institutes of Health, Bethesda, MD, May 15–17, 2006. 3 Address reprint requests to AL Thurn, Office of Dietary Supplements, Office of the Director, NIH, 6100 Executive Boulevard, Room 3B01 MSC 7517, Bethesda, MD 20892-7517. E-mail: thurna{at}od.nih.gov.
The purpose of this conference—Multivitamin/Mineral Supplements and Chronic Disease Prevention—was to evaluate the state-of-the-science regarding several key questions about the role of multivitamin and multimineral supplements (MVMs) in health promotion and in reducing the risk of chronic diseases such as cancer and cardiovascular disease, among others. The state-of-the-science conference process provides an opportunity for the National Institutes of Health (NIH) to pose questions to an independent panel, the answers to which delineate the research gaps that exist in our knowledge and provide guidance about how the NIH can fill those gaps.
In addition to helping the NIH Office of Dietary Supplements (ODS) foster research, the outcomes of this conference will help the ODS with other aspects of its mission. These were detailed in the ODS strategic plan:
In particular, the goals of expanding the evaluation of dietary supplements in disease prevention by commissioning evidence reports to assess the current scientific literature and helping the ODS better inform and educate the public, health care providers, and scientists about the benefits and risks of dietary supplements will be furthered by this activity.
According to the Nutrition Business Journal, Americans spent more than $20 billion in 2005 on a variety of dietary supplements, from vitamins and minerals to glucosamine and chondroitin to echinacea and ginkgo (1). Their goals in purchasing these products are wide-ranging and include reasons such as to compensate for nutritional inadequacies; promote and maintain their health; provide some protection against the functional declines seen with aging; reduce their risk of developing chronic diseases such as cancer, heart disease, and the like; and manage or treat diseases.
Current estimates of the $20 billion annual investment in supplements by American consumers suggest that roughly one-third of that is spent on vitamins and minerals—approximately $7 billion in 2005 (1). Of this amount, it is estimated that half or more is spent on MVM combinations, so that this segment of the market accounted for about $3.5 billion in sales in the United States last year.
The use of MVMs by the American public has increased significantly since 1994 when the Dietary Supplement Health and Education Act was passed by Congress and signed into law. The conference covered in this supplement explored patterns of MVM use and evaluated the evidence that has accumulated regarding the efficacy of these products in the prevention of chronic disease.
An NIH State-of-the-Science Conference format was deemed the best strategy for considering the issues before us today. On the one hand, MVM use has been associated with better health outcomes in observational studies; on the other hand, few data are available from randomized prospective controlled trials to provide more definitive evidence for the efficacy of MVMs. In addition, opinions are wide-ranging on the strength of the scientific evidence required to make informed decisions regarding the use of MVMs. Videocasts of all presentations are available (2). The results of this meeting will help us to determine, independently and objectively, the state of the current science on this topic and, at least as important, where best to focus future research efforts.
The conference focused specifically on vitamins and minerals and did not evaluate issues related to botanicals or other dietary supplements. It also did not address the treatment of vitamin or mineral deficiencies. Except for considerations of safety, the conference did not review issues of primary relevance to pregnant women or children.
Specifically, the conference explored the following key questions:
An impartial, independent panel was charged with reviewing the available published literature, including a systematic literature review commissioned through the Agency for Healthcare Research and Quality. The first day and a half of the conference consisted of presentations by expert researchers and practitioners as well as open public discussions. This format allowed the presentation of a wide range of information and points of view on the subject, some of which might not otherwise have been included in a scientific workshop. On the last day of the conference, the panel presented a statement of its collective assessment of the evidence to answer each of the questions given above. The panel also held a press conference to address questions from the media.
In answer to the key questions, the panel reached the following conclusions:
In summary, the panel concluded that the present evidence is insufficient to recommend either for or against the use of MVMs by the American public to prevent chronic disease. It stated that the resolution of this important issue will require advances in research and improved communication and collaboration among scientists, health care providers, patients, industry, consumers, and the public.
ACKNOWLEDGMENTS
We thank Barnett Kramer, Susan Rossi, Elsa Bray, and Kelli Marciel from the NIH Office of Medical Applications of Research for their hard work, skill, and advice in organizing and running this important meeting; Judith Dickson for her excellent editing of the manuscripts and for her work with the authors and guest editors to see that all aspects of the project were completed on time; and Claudia Faigen for her help in coordinating communications among the authors, editors, and ODS staff.
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