Researchers show vitamin D supplementation may help African-Americans lower blood pressure

Brigham and Women's Hospital study could have widespread public health benefits

High blood pressure, a risk factor for heart attacks, heart failure and stroke, is 40 percent more common in African-Americans than in other American ethnic groups. In a new study from Brigham and Women's Hospital (BWH), along with the Dana-Farber Cancer Institute and Massachusetts General Hospital, researchers show that vitamin D supplementation may help African-Americans lower their blood pressure. The study publishes online in the March 13, 2013 edition of the American Heart Association journal Hypertension.

"This study may explain and help treat an important public health disparity," said the study's lead author, John Forman, MD, a physician in the Renal Division and Kidney Clinical Research Institute at BWH. "More research is needed, but these data may indicate that vitamin D supplementation lowers blood pressure in African-Americans."

To conduct the study, 250 African-American adult voluntary research participants were divided into four groups. Three of the groups received a three-month regimen of daily vitamin D supplementation at various doses that ranged between 1,000 and 4,000 units. The fourth group received a placebo. Participants in the placebo group saw their systolic blood pressure rise, but participants in the supplementation group had their systolic blood pressure decrease by one to four points, with those who received the highest dose benefiting the most. Systolic blood pressure is the top number in a blood pressure reading; it measures the pressure in the arteries when the heart beats.

"The gains were modest, but significant," said Forman. "If further research supports our finding, widespread use of vitamin D supplementation in African-Americans could have significant public health benefits."