Vitamin D may inhibit the build-up of cholesterol in blood vessels improving heart health of diabetics, says in vitro study.
Researchers found that diabetics – a population group at higher risk of heart disease – with low vitamin D levels displayed difficulties in processing cholesterol, putting them at an increased risk of heart attack and stroke (1).
Cholesterol is transported through the blood attached to lipoproteins such as LDL, the 'bad' cholesterol. As it is stimulated by free radicals in the vessel wall, LDL becomes oxidated, and cells called macrophages eat it uncontrollably. LDL cholesterol then clogs the macrophages, leading to stiffening of blood vessels and blocking of blood flow (atherosclerosis).
Vitamin D inhibits the uptake of cholesterol macrophages. When people are deficient in vitamin D, the macrophage cells eat more cholesterol, and are unable to 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. Macrophage activation is higher in people with disease such as diabetes.
The scientists said that the problem may be solved by simply ensuring adequate vitamin D status via supplements, as there is debate about whether any amount of sun exposure is safe.
The next stage in the research is to look at vitamin D-deficient diabetics who also have high blood pressure, and to learn whether replacing vitamin D will lower blood pressure and improve blood flow.