A single dose of 60,000 IU of vitamin D every 4 weeks for 16 weeks was associated with significantly improved health and function of endothelial cells – the cells lining the blood vessels, according to new data from Georgia Health Sciences University in Augusta.
According to Ryan Harris, PhD, the associate professor presenting the data, this is equivalent to about 2,000 IU per day, given the time it takes the body to clear vitamin D.
"This points to a beneficial effect of Vitamin D supplementation on endothelial cell function," said Dr Harris. "If you're deficient in Vitamin D and you take supplements, you have a good probability of increasing endothelial function and therefore decreasing the risk of cardiovascular disease."
The study involved 45 overweight African-American adults divided into two groups: One group received 60,000 IU vitamin D dose once every 4 weeks for 16 weeks, while the second group received placebo.
"We could have used daily dosing, but we knew compliance would be better with monthly dosing. One dose a month is easier than taking two pills a day," explained Dr Harris.
While the dosages used were associated with vascular benefits, the researchers notes that the mechanism is not clear. "Vitamin D interacts with a lot of different systems in the body. It may decrease inflammation, which is better for endothelial function,” he added.