Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/20/2008
Publication Date: 6/7/2009
Citation: Holden, J.M., Roseland, J.M., Andrews, K., Zhao, C., Feinberg, M., Middleton, A., Dwyer, J., Picciano, M., Saldanha, L. 2009. Assessing vitamin D levels in dietary supplements. International Conference on Diet and Activity Methods, June 5-7, 2009, Washington, D.C.
Technical Abstract: Vitamin D is a nutrient of public health concern, particularly in the elderly, and is naturally present in some foods, added to others, and available as a dietary supplement. It is essential for bone growth and bone remodeling and recent research indicates it has other roles in human health, including modulation of neuromuscular and immune function and reduction of inflammation. To assess current levels of intake, data for vitamin D content in foods and dietary supplements are urgently needed. The Nutrient Data Laboratory (NDL) has been conducting research to select and analyze important dietary contributors to vitamin D intake. Since over 50% of American adults report consuming a dietary supplement, the contribution of vitamin D from supplements to dietary intake must be captured. Data from the National Health and Nutrition Examination Survey (NHANES) 2003-04 indicates that 69% of reported adult multivitamin/mineral (MVM) supplements contained vitamin D. Labeled vitamin D levels for those products ranged from 10 to 816 IU/serving, although over 90% (calculated from weighted frequency) of these were labeled at 400 IU, the level which is 100% of the Daily Value. NDL, in collaboration with the Office of Dietary Supplements (ODS), recently conducted a study based upon chemical analysis to obtain nationally representative estimates for 18 nutrients in adult MVM products, and to assess variability in specific products. NDL developed a statistical sampling plan for purchasing over 100 representative adult MVM products in specific market channels in 6 geographic regions. Nutrient contents in these products were measured with validated laboratory methods and monitored for quality control. Statistical analysis using regression techniques identified nutrient-based patterns of variance. These results were released as Dietary Supplement Ingredient Database, Release 1 (DSID-1). As part of this study, preliminary results for vitamin D in up to 6 lots of 35 commonly reported adult MVMs showed mean analytical levels close to labeled amounts, but high variability between and within products. NDL continues to work with analytical experts to optimize laboratory methodology for vitamin D in supplements. Final data for analytical estimates of vitamin D in representative adult MVMs will be included in a future release of the DSID. These data will be critical for developing estimates for intake of vitamin D in dietary supplements reported in the NHANES: What We Eat In America and other dietary surveys. The estimates for supplements will complement vitamin D values for foods reported in these surveys.