By Isagenix Nutritional SciencesVitamin D has once again established itself as fundamental for a healthier heart—this time in a study on overweight African American adults who supplemented with vitamin D in the amount of 60,000 IU monthly, which is the equivalent of taking 2,000 IU daily.
Researchers from Georgia Health Sciences University in Augusta found supplementating the subjects improved vascular function of endothelial cells. Vascular endothelial cells line the inside of blood vessels and serve to dilate or constrict blood vessels in response to changes in blood flow. When endothelial cells are dysfunctional, the heart must pump harder to improve blood flow through the blood vessels.
By using an inflatable cuff to increase blood pressure in the arteries of participants’ arms, the researchers were able to measure arterial flow-mediated dilation using ultrasound. After 16 weeks of supplementation, the participants blood flow improved significantly.
The findings were presented by Ryan A. Harris, Ph.D., assistant professor, on April 11 at Experimental Biology in Washington DC. “This points to a beneficial effect of vitamin D supplementation on endothelial cell function,” says Dr. Harris. “If you’re deficient in vitamin D and you take supplements, you have a good probability of increasing endothelial function.”
The results of the study are noteworthy, explained Dr. Harris in his presentation, because African-Americans are at greater risk of cardiometabolic factors that include higher blood pressure, increased waist circumference, elevated plasma glucose, and dyslipidemia.
African Americans also have a greater risk of having low circulating vitamin D levels. The greater amount of pigmentation in darker skin offers rewards such as natural protection against ultraviolet light that would otherwise burn skin and increase risk of skin cancer, but it also decreases the skin’s ability to activate vitamin D’s precursor (pre-vitamin D) into the full-fledged hormone-like vitamin.
Living at Northern latitudes, staying indoors or otherwise avoiding exposure to sunlight, combined with diets containing little vitamin D can compound risk of vitamin D insufficiency or deficiency.
Supplementation provides a safe and effective way to bring vitamin D levels back to normal ranges. As in previous studies, this new study reported no side effects in participants.
How vitamin D acts on endothelial cells to help to improve vascular function remains unclear, Dr. Harris explains. The results of this study, however, suggest the need for greater awareness of the impact of vitamin D on African Americans’ heart health.