Low vitamin D raises diabetic heart risk

ST. LOUIS, Aug. 24 (UPI) -- Diabetics deficient in vitamin D can't process cholesterol so it builds in blood vessels, increasing heart attack and stroke risk, U.S. researchers said.

Principal investigator Dr. Carlos Bernal-Mizrachi, a Washington University endocrinologist at Barnes-Jewish Hospital in St. Louis, said when people are deficient in vitamin D the macrophage cells -- dispatched by the immune system in response to inflammation -- eat more cholesterol, which they can't get rid of.

"Vitamin D inhibits the uptake of cholesterol by cells called macrophages," Bernal-Mizrachi said in a statement. "The macrophages get clogged with cholesterol and become what scientists call foam cells, which are one of the earliest markers of atherosclerosis."

The researchers studied macrophage cells taken from people with and without diabetes, and with and without vitamin D deficiency. When vitamin D levels were low in the culture dish, macrophages from diabetic patients were much more likely to become foam cells.

The study, published in the journal Circulation, found vitamin D regulates signaling pathways linked both to uptake and to clearance of cholesterol in macrophages.