A press release notes that the study did not show improvements in other markers of cardiovascular and metabolic health.
Kumaravel Rajakumar, MD, MS, Professor of Pediatrics at the University of Pittsburgh School of Medicine, and his team enrolled 225 healthy, but vitamin D-deficient, 10- to 18-year olds in Pittsburgh who were overweight or obese in the clinical trial. 211 of them were black; the release notes that people with darker skin have more melanin pigment, which acts as a natural sunscreen and inhibits vitamin D production, making them more likely than white people to be vitamin D-deficient.
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The children were split into three groups: One group received a 600 IU tablet, one group received a 1,000 IU tablet, and one group received a 2,000 IU tablet. The study was double-blind, and ran for six months.By the conclusion of the trial, none of the groups was considered vitamin D deficient. After six months, the children receiving the 1,000 IU tablets had lower blood pressure, and those receiving the 2,000 IU tablets had a reduced fasting blood glucose level and improved insulin sensitivity. There were no significant changes in measures of the health of the membrane that lines the blood vessels or in arterial stiffness, both of which are strong indicators of heart health and were the primary measures the researchers were seeking to influence.
Dr. Rajakumar said in the release: “There are many reasons we might not have seen changes in endothelial function or arterial stiffness. Maybe vitamin D simply doesn’t influence these, or perhaps we didn’t reach and maintain a level of vitamin D to cause an effect. It could also be that our trial didn’t run long enough. However, treatment of vitamin D deficiency with these higher daily doses can have a positive impact on cardiometabolic health of children, without negative side effects.”
