The Nutrient Data Laboratory (NDL), Beltsville Human Nutrition Research Center, USDA is working with the Office of Dietary Supplements and other federal agencies to plan and develop a Dietary Supplement Ingredient Database (DSID) to estimate the actual levels of ingredients in dietary supplement products. Agencies include:

• DHHS, NIH, Office of Dietary Supplements
• USDA, ARS, Food Composition Laboratory
• DHHS, Centers for Disease Control, National Center for Health Statistics
• DHHS, U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition
• DOC, National Institute of Standards and Technology

The DSID is being developed in parallel with NDL’s ongoing research effort, the National Food and Nutrient Analysis Program, in which high consumption food products are identified, sampled and analyzed. Accurate and complete information on the composition of dietary supplements is essential for determining their contribution to the nation’s dietary intake.

For dietary supplements, priority product categories and ingredients were identified based on prevalence reports from national surveys.  High priority categories include multivitamin/minerals, antacids, calcium, other single mineral supplements, multi-mineral supplements, vitamin E, vitamin C, B vitamins, and caffeine-containing products.  In addition, ingredients in dietary supplements were ranked based on exposure public health significance, research priorities, and the availability of reference materials and validated analytical methods of analysis.  Using this scheme, seven high priority (Tier 1) nutrients were identified for initial pilot study work:  folic acid, vitamin C, vitamin A (retinol and beta-carotene), vitamin E (alpha-tocopherol), calcium, and iron.

To aid in designing a research plan, pilot studies were conducted to review sample handling procedures and methods of analysis and to qualify laboratories for the analysis of dietary components in supplement products.  Selected representative multivitamin/mineral (MVM) products were then analytically tested to gather preliminary information about the levels of these nutrients in supplements. The study was conducted to test levels of 23 nutrients in MVM products and to assess nutrient variability between products labeled at common levels.  Tier 1 nutrients plus vitamins B-6, B-12, D, and K, niacin, riboflavin, thiamin, chromium, copper, iodine, magnesium, manganese, phosphorus, potassium, selenium, and zinc were analyzed. 

In a subsequent comprehensive study, commonly reported and lower market share adult MVM products were identified using market-share data verified with prevalence and frequency-of-intake information from two national surveys.   Representative samples were purchased in a geographically based national sampling plan and sent to qualified laboratories with appropriate quality control materials.  Results are being statistically evaluated and will be used to provide nutrient content and variability estimates for up to 20 nutrients in adult MVM products.  NDL’s next study will evaluate children’s MVM products using many of the same techniques identified for adult MVMs.  Data quality is monitored with validated laboratory methods, standard reference materials, and duplicate analyses. 

The major product of this research will be a publicly available dietary supplement ingredient database.  A preliminary release is scheduled for late 2008.  Research methodologies and results have been and will continue to be published in scientific journals and discussed at scientific conferences.  The DSID will be critical in assessing the total intake of nutrients and other components from foods and supplements for their impact on public health. The DSID will be maintained and made available on a public website and will be free of charge for users.

DSID Publications and Presentations