title: Assessing vitamin D contents in foods and supplements: challenges and needs.
abstract: Scientists need specific data on the amounts of vitamin D in foods and dietary supplements to facilitate the assessment of vitamin D dietary intake. This vitamin is available in foods both naturally and from fortification. The Nutrient Data Laboratory of the US Department of Agriculture (USDA) is collaborating with vitamin D experts to review and develop methods for analyzing the vitamin D content of foods and to use these methods to analyze the vitamin D content of certain foods and dietary supplements. In this article, we review existing sources of vitamin D data on foods and dietary supplements, describe the USDA's Dietary Supplements Ingredients Database, and discuss the development of the USDA's vitamin D database for foods. In addition, we define the challenges and needs related to providing updated data on the vitamin D content of foods and supplements. After we analyze the vitamin D content of these food samples, we will disseminate the current values in the National Nutrient Database for Standard Reference (Internet: http://www.ars.usda.gov/nutrientdata).
authors.affiliation: Nutrient Data Laboratory, Beltsville Human Nutrition Research Center, US Department of Agriculture, Beltsville, MD, USA. joanne.holden@ars.usda.gov
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Holden
authors.forename: Linda E
authors.initials: LE
authors.lastname: Lemar
mesh_terms: D016208:Databases, Factual / Q000592:standards*; D019587:Dietary Supplements / Q000032:analysis*; D005504:Food Analysis; D005527:Food, Fortified / Q000032:analysis*; D006801:Humans; D011786:Quality Control; D012015:Reference Standards; D012016:Reference Values; D014481:United States; D016885:United States Department of Agriculture; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000032:analysis*
chemical_list: D014807:Vitamin D