People with diabetes are known to have an increased risk of heart disease. New research published in BioMed Central's open access journal BMC Medicine shows that regular consumption of a vitamin D-fortified yoghurt drink improves cholesterol levels and biomarkers of endothelial dysfunction, a precursor of heart disease, in diabetics.

Not having enough vitamin D affects the inner lining of blood vessels (endothelial cells) eventually leading to atherosclerosis and cardiovascular disease. Endothelial dysfunction can be measured by the increased levels of a set of biomarkers, such as serum endothelin-1, E-Selectin and MMP-9. In a double-blind trial, researchers from Tehran investigated the effect of vitamin D on the glycemic status, cholesterol levels and endothelial biomarkers of diabetics. Patients were given either a plain yoghurt drink (Doogh) or the same drink fortified with vitamin D twice a day for 12 weeks.

Researchers from the National Research Institute and Faculty of Nutrition and Food Technology had previously shown that a vitamin D-fortified yoghurt drink could improve the glycemic status of people with type 2 diabetes. In collaboration with Tehran University of Medical Sciences their new trial showed that vitamin D improved the fasting glucose, insulin, QUICK1 (a measure of insulin resistance), and found some improvement in long term HbA1c.

Dr Neyestani explained, "The patients who had taken the vitamin D yoghurt also had improved cholesterol levels with lower total cholesterol and LDL levels and an increase in HDL. All the improvements in cholesterol seemed to be due to the reduction in insulin resistance. The biomarkers of endothelial dysfunction, serum endothelin-1, E-Selectin and MMP-9, levels were also lower for the patients taking vitamin D."

Prof Djazayery continued, "Most of our patients were deficient in vitamin D at the start of the trial but the fortified yoghurt drink elevated most of their levels to normal. However, even amongst those who took the vitamin D supplement, some people (about 5%) remained deficient at the end of the 12 weeks. These people did not show the same improvements. Nevertheless for most diabetics with vitamin D deficiency this is an easy way to improve their outcome."