The Daily D Study: Impact of Vitamin D Supplementation on Cardiometabolic Risk in Schoolchildren

Vitamin D deficiency has been linked to the development of cardiovascular disease and it is estimated that six million children are currently vitamin D deficient. Vitamin D deficiency is even more common in northern latitudes, amongst some minority groups with darker skin pigmentation, and in those who are overweight or obese. In these groups, higher supplemental doses may be needed to maintain optimal serum levels and to prevent cardiovascular risk. As it is difficult for many children to consume the new recommended intake of 600 IU/d set forth by the Institute of Medicine, many have suggested that vitamin D supplementation is necessary. The overall objective of the proposed work is to determine the appropriate vitamin D supplementation requirements for children with various risk factors, living at northern latitudes (above 42°). We will also investigate for the first time in a randomized controlled trial what happens to serum 25(OH)D and cardiometabolic risk factors after supplementation is discontinued.

Fourth-eighth grade children from socioeconomically disadvantaged and racially diverse communities with high obesity rates in the northeastern U.S. will be randomized to 600 IU, 1000 IU, or 2000 IU/d for six months starting in the early winter. Adiposity, physical activity, dietary intake of vitamin D, and sun exposure will also be assessed. Results of this work will inform the development of evidence-based recommendations and guidelines regarding vitamin D supplementation to maintain optimal 25(OH)D levels and to reduce cardiometabolic risk. The Principal Investigator is Dr. Jennifer Sacheck of the John Hancock Research Center at Tufts University Friedman School of Nutrition Science and Policy. This study is funded by a grant from the National Institute of Health.

One current USDA Fellow will be studying Vitamin D serum levels and supplementation in relation to adiposity and skin pigmentation in overweight and obese children. This Fellow’s research will help us to better understand a number of interactions between childhood obesity and Vitamin D.