Low vitamin D levels raise cardiovascular risk: study

Last Updated: Tuesday, January 8, 2008 | 12:23 PM ET

CBC News

Many recent studies have made connections between a lack of Vitamin D and increased risk of cancer.

Now a new study finds that a vitamin D deficiency can increase one's risk of cardiovascular problems, particularly if a person has high blood pressure.

The research is to be published in the Jan. 29 issue of Circulation, the journal of the American Heart Association.

The study of 1,739 white people participating in a heart study between 1996 and 2001 found that those individuals with levels of vitamin D below 15 nanograms per millilitre had a 62-per-cent higher risk of developing cardiovascular problems such as a heart attack, heart failure or stroke in the five years following than those with higher blood levels of the vitamin.

"We found that people with low vitamin D levels had a higher rate of cardiovascular events over the five-year follow-up period," said Thomas Wang, assistant professor of medicine at Boston's Harvard Medical School in a release. "These results are intriguing and suggestive but need to be followed up with further study."

Researchers isolated 688 study participants that had high blood pressure from the rest of the study group. They found that in this group, the risk of cardiovascular problems was two times higher than the other participants.

Levels of vitamin D in the participants were generally low. Twenty-eight per cent had levels of vitamin D below 15 ng/mL and nine per cent had levels below 10 ng/mL. The ideal levels of vitamin D concentration in blood are 30 ng/mL, according to the study's authors; only 10 per cent of the study participants had this amount in their bloodstream.

The researchers believe the presence of vitamin D reduces inflammation and the formation of blood clots — two factors linked to cardiovascular diseases. They note that in smaller clinical trials, vitamin D has shown to reduce blood pressure, the breakdown of heart tissue and reduce inflammatory processes in the body.

To prevent cardiovascular problems, the authors suggest dietary changes. "These data raise the possibility that treatment of vitamin D deficiency, via supplementation or lifestyle measures, could reduce cardiovascular risk," reads the study.

But we get most of our vitamin D from sunlight on our skin.

Good food sources of vitamin D are oily fish and eggs. Other sources include fortified foods such as margarine, breakfast cereals and powdered milk.