Dietary supplement use in women: Current status and future directions - Introduction and conference summary

Abstract

In many respects, the presentations and deliberations of the panels echoed the conclusions reached at the previously held conference on dietary supplement use in children - that is, substantial gaps exist in our knowledge about who is using dietary supplements, what particular dietary supplements are being used and why they are being used. In terms of surveillance, as with children, those responsible for the design and conduct of the national surveillance system to determine what the American population consumes continue to struggle with a myriad of issues related to the ability to determine both the quality and quantity of supplements consumed by women in the United States. Accurate data on quantity and quality of supplement ingredients, identity of active ingredients in herbal and botanical supplements and the evidence base to document efficacy and subsequent label claims continue to be inadequate. As recently documented in the papers summarizing the conference, "What We Eat in America Survey: Future Directions" (4-7), there is an increasing recognition by all of the agencies within the federal nutrition science policy community of a need to focus our efforts on better methods for determining the extent and effect of dietary supplement use across all segments of the U.S. population. From a research perspective, a need exists for greater understanding about the social, cultural and behavioral factors that predict a woman's decision to use dietary supplements. Research efforts in this area must distinguish among factors influencing uses of different classes of dietary supplements (e.g., vitamin and mineral supplements and herbal supplements) to determine whether there is a common mindset regardless of the supplement used or whether differences exist in the orientation, knowledge base or sources of information for these groups. Questions exist about the safety, efficacy and indications for use of the full array of dietary supplements currently on the market. Specific research questions include the effect of supplement use on fetal health, birth outcomes and reproductive endocrinology and the potential for drug-supplement or supplement-drug interactions. Gaps also were identified in the potential interactions between supplements, whether nutrient and botanically derived. The effect of physiological state on the bioavailability of dietary supplements was also identified as a research priority. Although much has been learned from our experiences with such well-characterized public policies as food fortification and recommendations to increase the intake of specific nutrients, the effect of such policies has been difficult to track. As with the general issue of monitoring supplement use, the ability to track changes in nutrient intakes and the potential public health effect subsequent to the initiation of such policies as fortification of foods with folic acid or health claims based on specific diet-disease relationships (e.g., calcium and osteoporosis) has been slow to develop. Moreover, our understanding of the public's responsiveness to these policies has also been difficult to characterize. A more effective interface between the public agencies charged with the responsibility of monitoring these changes and the private sector responsible for providing these products was identified as a high priority area for enhancement. Special acknowledgments are extended to Drs. Duane Alexander and Yvonne Maddox, Director and Deputy Director, NICHD, for their leadership and support in both the planning and conduct of this workshop. The organizers also thank the members of the consortium providing support for this conference. Sponsors of the conference included NICHD and ODS. Cosponsors included Centers for Disease Control and Prevention, Food and Drug Administration Office of Women's Health, National Institutes of Health Office of Research on Women's Health, National Institute of Diabetes and Digestive and Kidney Diseases Division of Nutrition Research Coordination, U.S. Department of Health and Human Services, National Center for Complementary Medicine, U.S. Department of Agriculture Agricultural Research Service, International Life Sciences Institute North America, March of Dimes, and Whitehall Robbins Healthcare. The organizers also express their gratitude to members of the NIH community who provided valuable insights and feedback during the planning of the meeting. Finally, the organizers wish to acknowledge the valuable input of the faculty and session chairs, (Drs. Johanna Dwyer, Anne Looker and Mark Conner) without whom this conference could not have succeeded in achieving its goals. The following papers reflect both the quality and insight of the plenary presentations.