NIH and USDA funding of dietary supplement research, 1999-2007.

Over one-half of U.S. adults use dietary supplements, so federally supported research into the safety and effectiveness of these compounds is important for the health of many Americans. Data collected in the Computer Access to Research on Dietary Supplements database, which compiles federally sponsored dietary supplement-related research, are useful to scientists in determining the type of dietary supplement research that federal agencies are currently funding and where research gaps exist. This article describes the dietary supplement-related research funded by the NIH and the USDA. Between fiscal years 1999 and 2007, the number of research projects and funding for dietary supplement research more than doubled. During that period, NIH funded 6748 dietary supplement-related projects at a cost of $1.9 billion and the USDA funded 2258 projects at a cost of $347 million. The top funded dietary supplement ingredient categories were vitamins and minerals, botanicals, phytochemicals, and fatty acids. Cancer was by far the most frequent health outcome in dietary supplement research funding, nearly double the next closest health outcome category. Other health outcomes with the greatest funding were cellular and molecular mechanisms, cardiovascular health, women's reproductive health, and immune function. The greatest number of dietary supplement research projects are funded by the NIH National Cancer Institute, the NIH National Center for Complementary and Alternative Medicine, the NIH Office of Dietary Supplements, and the USDA Agricultural Research Service.