Higher intake of vitamin D could reduce the risk of incidence of heart disease in black teens, a new study conducted by researchers in the United States has found.

Researchers from the Medical College of Georgia (MCG) Georgia Prevention Institute said the black youths could ward off heart diseases by taking daily vitamin D supplementation at levels that are five times the current recommendations as it helps increase in the flexibility of blood vessels while alleviating arterial stiffness.

Currently, the recommended dose for vitamin D consumption is set at 400 IUs per day, with 2,000 IUs per day considered to be the upper limit for safety, says study author Dr. Yanbin Dong, a geneticist and cardiologist at the Georgia Prevention Institute, and co-director of the MCG Diabetes and Obesity Discovery Institute.

To find the association between vitamin D and reduced heart risk in black youths, the researchers studied the vitamin consumption among 44 vitamin D-deficient black teens living in Augusta, Georgia, a region with a great deal of sunlight.

They supplied the participants with either 400 IUs or 2,000 IUs over a four-month period. During the study period, the researchers monitored the blood levels of the vitamin D in the teens on a regular basis. An analysis of the data revealed that even though there was some increase in vitamin D blood levels, none of the teens who took just 400 IUs reached vitamin D sufficiency.

Children taking 2,000 IUs per day did not show any side effect from vitamin D overdose, but actually appeared to be benefiting from it given that those with the highest vitamin D levels developed the most flexible blood vessels, the researchers said.

Increased flexibility of the blood vessels can diminish the risk for high blood pressure and narrowing of the arteries. The findings were published online in advance of publication in an upcoming print issue of the Journal of Clinical Endocrinology & Metabolism.

Vitamin D has several different forms including ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Vitamin D2 is synthesized by plants. Vitamin D3 is synthesized by humans in the skin when it is exposed to ultraviolet-B (UVB) rays from sunlight.

Vitamin D is found in many dietary sources such as fish, eggs, fortified milk, and cod liver oil. The sun also contributes significantly to the daily production of vitamin D, and as little as 10 minutes of exposure is thought to be enough to prevent deficiencies. Its deficiency can lead to depressed mood and energy levels, weakened bones and cardiovascular complications.

Blacks generally face a higher risk for serious heart disease, while also facing difficulties in absorbing vitamin D from sun exposure due to dark skin pigmentation, the authors noted.