Location: Nutrient Data LaboratoryTitle: The emerging issue of 25-hydroxyvitamin D in foods
|Taylor, Christine - National Institutes Of Health (NIH)|
|Coates, Paul - National Institutes Of Health (NIH)|
Submitted to: Journal of Nutrition
Publication Type: Abstract Only
Publication Acceptance Date: 4/5/2016
Publication Date: 4/5/2016
Citation: Taylor, C.L., Roseland, J.M., Coates, P.M., Pehrsson, P.R. 2016. The emerging issue of 25-hydroxyvitamin D in foods. Journal of Nutrition. 64:3167-3175.
Interpretive Summary: Scientists at the U.S. Department of Agriculture’s (USDA) Agricultural Research Service and the National Institutes of Health’s Office of Dietary Supplements (ODS) write to express concerns and needs regarding measurement of 25-hydroxyvitamin D (25(OH)D), the metabolized form of vitamin D. We are informing readers that research from several studies has resulted in better laboratory measurement of 25(OH)D in serum as an indicator of vitamin D status in humans. USDA and ODS scientists have also shown the importance of including the content of 25(OH)D in animal-based foods, when estimating total vitamin D intake. These scientists have determined in a recent study that amounts of 25(OH)D in foods were in agreement as measured by different labs. These results, along with reference materials developed from the study, can support continued work in determining 25(OH)D content in foods.
Technical Abstract: Scientists at the U.S. Department of Agriculture’s (USDA) Agricultural Research Service and the National Institutes of Health’s Office of Dietary Supplements (ODS) write to notify the nutrition community of concerns and needs regarding measurement of vitamin D’s metabolized form, 25-hydroxyvitamin D (25(OH)D). Differences in quantitative measures of 25(OH)D in human serum, as the measure of vitamin D status, has impeded comparing research outcomes and caused differences in clinical determinations and interventions. Fortunately, collaborations have recently occurred to promote standardized laboratory measures of serum 25(OH)D. In addition, discrepancies between recommended and reported vitamin D intakes based on national surveys have caused public health concern about the need to increase vitamin D fortification of foods. However, U.S. food composition tables currently report only the non-metabolized forms of vitamin D, and not the metabolized forms. When 25(OH)D in animal-derived foods is not measured, this may explain, in part, the discrepancy between reported population-based intakes of vitamin D and the measures of serum 25(OH)D. The latter is much higher than expected given intake estimates. Only some of the difference can be attributed to the contribution of sunlight. USDA and ODS demonstrated that meaningful underestimates of vitamin D intake can exist when 25(OH)D in foods is ignored. Using the only available U.S. data, which were preliminary and limited, we concluded that vitamin D intake estimates would be increased by 15-30% of the average requirement if dietary 25(OH)D were included. Similar to the challenges of measuring serum 25(OH)D, the determination of 25(OH)D in foods requires standardization of laboratory methodologies. Up to now, the lack of well-characterized reference materials, as well the lack of validated methodologies, has presented analytical challenges. Recently, USDA and ODS have studied consistency among analytical laboratories in assaying 25(OH)D in various food materials. The results suggest likely agreement among laboratories and has yielded potential standard reference materials for 25(OH)D in foods. Such work needs to continue so that vitamin D intake can be more accurately assessed and used to model the impact of modifying the food supply. Such modeling is an essential task before dietary interventions can be determined. Targeted efforts are needed, to raise 25(OH)D measurement in foods to a higher priority within nutrition research.