In “Cholesterol Buildup in Diabetes Patients Deficient in Vitamin D,” ElementsForHealth.com writes:
Researchers believe they have found out why low levels of vitamin D are known to nearly double the risk of cardiovascular disease in patients with diabetes.
They found that diabetes patients deficient in vitamin D can’t process cholesterol normally, so it builds up in their blood vessels, increasing the risk of heart attack and stroke. The research has identified a mechanism linking low vitamin D levels to heart disease risk and may lead to ways to fix the problem, simply by increasing levels of vitamin D.
“Vitamin D inhibits the uptake of cholesterol by cells called macrophages,” says principal investigator Carlos Bernal-Mizrachi. “When people are deficient in vitamin D, the macrophage cells eat more cholesterol, and they can’t get rid of it. The macrophages get clogged with cholesterol and become what scientists call foam cells, which are one of the earliest markers of atherosclerosis.”
Macrophages are dispatched by the immune system in response to inflammation and often are activated by diseases such as diabetes. The researchers believe that in diabetes patients with inadequate vitamin D, macrophages become loaded with cholesterol and eventually stiffen blood vessels and block blood flow.
Bernal-Mizrachi studied macrophage cells taken from people with and without diabetes and with and without vitamin D deficiency. His research team exposed the cells to cholesterol and to high or low vitamin D levels. When vitamin D levels were low in the culture dish, macrophages from diabetes patients were much more likely to become foam cells. Vitamin D regulates signaling pathways linked both to uptake and to clearance of cholesterol in macrophages.
1. Oh J, Weng S, Felton SK, Bhandare S, Riek A, Butler B, Proctor BM, Petty M, Chen Z, Schechtman KB, Bernal-Mizrach L, Bernal-Mizrachi C. 1,25 (OH) vitamin D inhibits foam cell formation and suppresses macrophage cholesterol uptake in patients with type 2 diabetes mellitus. Circulation, vol. 120(8);pp. 687-698. Aug. 25. 2009. doi:10.1161/CIRCULATIONAHA.109.856070