Diabetics are more prone to developing clogged arteries that cause heart disease, but a new study suggests increasing their levels of vitamin D could greatly counteract that trend and boost longevity.
Researchers at Washington University School of Medicine in St. Louis found blood vessels are less like to clog in people with diabetes who get adequate vitamin D, through supplements or exposure to the sun. But in patients with insufficient vitamin D, immune cells bind to blood vessels near the heart, then trap cholesterol to block those blood vessels, which can lead to heart attack.
"About 26 million Americans now have type 2 diabetes," said Dr. Carlos Bernal-Mizrachi, who led the study, published in the Journal of Biological Chemistry. "And as obesity rates rise, we expect even more people will develop diabetes. Those patients are more likely to experience heart problems due to an increase in vascular inflammation, so we have been investigating why this occurs."
Prior research led by Bernal-Mizrachi, an assistant professor of medicine, found vitamin D may play a key role in heart disease. The new study determined when vitamin D levels are low, white blood cells are more likely to adhere to cells in artery walls.
For the study, researchers examined vitamin D levels in 43 people with type 2 diabetes and in 25 others who were similar in age, sex, and body weight but didn't have the blood sugar disorder.
They results showed diabetes patients with low vitamin D — less than 30 nanograms per milliliter of blood — were more likely to have clogged vessels that could block blood flow.
"We took everything into account," said Dr. Amy E. Riek, a co-researcher. "We looked at blood pressure, cholesterol, diabetes control, body weight and race. But only vitamin D levels correlated to whether these cells stuck to the blood vessel wall."
The research team could not say whether giving vitamin D supplements to people with diabetes will reverse their risk of developing clogged arteries, also known as atherosclerosis. The researchers are now are treating mice with vitamin D to see what impact it may have.
"In the future, we hope to generate medications, potentially even vitamin D itself, that help prevent the deposit of cholesterol in the blood vessels," Bernal-Mizrachi explained. "Previous studies have linked vitamin D deficiency in these patients to increases in cardiovascular disease and in mortality. Other work has suggested that vitamin D may improve insulin release from the pancreas and insulin sensitivity.
“Our ultimate goal is to intervene in people with diabetes and to see whether vitamin D might decrease inflammation, reduce blood pressure and lessen the likelihood that they will develop atherosclerosis or other vascular complications."
The study was funded, in part, by the National Heart, Lung and Blood Institute of the National Institutes of Health.