Vitamin D in foods: development of the US Department of Agriculture database.

Specific data on vitamin D2 and vitamin D3 are needed to enable the assessment of vitamin D dietary intake. These forms of the vitamin can occur in foods, both naturally or from fortification. The Nutrient Data Laboratory at the Beltsville Human Nutrition Research Center, Agricultural Research Service, US Department of Agriculture collaborated with vitamin D experts in an analytic project with 2 major goals: 1) to review and develop methods for analyzing a variety of food items for vitamin D content and 2) to sample and analyze foods considered to be major contributors of vitamin D. During 2007, analysts from up to 6 laboratories compared methods, made modifications in some cases, and validated results with quality-control samples of similar food types in preparation for the analysis of sampled foods. The Nutrient Data Laboratory has prioritized foods for analysis and has identified the following as important contributors of vitamin D: finfish and shellfish, naturally occurring sources, and fortified foods such as milk, calcium-fortified orange juice, breakfast cereals, American cheese, margarines, and yogurt. A nationwide multistage sampling plan was designed and conducted to select and procure representative sample units of all such foods. After analysis of these food samples and review of the results, acceptable values for vitamin D2 and D3 will be disseminated in the National Nutrient Database for Standard Reference (Internet: http://www.ars.usda.gov/nutrientdata).