Vitamin D has many benefits, and a new study finds that it can help African-Americans lower their blood pressure.

High blood pressure is 40 percent common in African-Americans than in other American ethnic groups, and is a major risk factor in cardiovascular disease, heart attacks, and stroke.

African-Americans are also known to have a higher rate of Vitamin D deficiency than the general American population. Skin pigmentation reduces Vitamin D production in the skin, and dietary Vitamin D tends to be lower than the recommended intake among African-Americans. As a result, many black Americans have lower circulating levels of Vitamin D (also known as 25-hydoxyvitamin D, or cholecalciferol).

Previous research indicated that Vitamin D supplements can help any patients with hypertension lower their blood pressure. The new study, published in the American Heart Association journal Hypertension on March 13, highlights Vitamin D's benefits for African-Americans in particular.

"This study may explain and help treat an important public health disparity," said the lead investigator, Dr. John Forman, of Brigham and Women's Hospital (BWH) in Boston, in a statement.

"More research is needed, but these data may indicate that vitamin D supplementation lowers blood pressure in African-Americans."

Researchers from BWH, in collaboration with the Dana-Farber Cancer Institute and Massachusetts General Hospital, conducted their study on 250 African-American adult volunteers who were separated into four groups.

Three of the groups were assigned a daily Vitamin D supplement regimen that lasted three months, with doses of 1000, 2000, or 4000 international units per day. The fourth group was given a placebo containing no Vitamin D.

Researchers monitored all participants' blood pressures at regular intervals, using systolic blood pressure- the higher number in a blood pressure reading, which measures arterial pressure as the heart beats- as a baseline indicator.

The results shows that participants who took Vitamin D supplements saw their systolic blood pressure decrease, and the higher their Vitamin D dosage was, the more their blood pressure decreased.

The participants taking 4000 IU decreased their blood pressure by an average of 4.0 mm Hg, while the 1000 IU group decreased by 0.7 mm Hg on average. Participants in the placebo group, on the other hand, saw a blood pressure increase of 1.7 mm Hg.

Forman concluded that the gains were modest but still significant, and hopes that further research will confirm the findings.

If so, Vitamin D supplements could be recommended to African-Americans in order to help prevent high blood pressure.