Increased vitamin D intakes may benefit heart health of diabetics

A new study from Israel suggests that regular intakes of supplements with vitamin D may improve cardiovascular health for diabetic patients, with implications for recommended doses.

In the randomized controlled trial, 47 type-2 diabetic patients received either a daily dose of vitamin D (1,000 IU/ day) or placebo for one year (1). The study results showed that the central aortic augmentation index, a predictor of adverse cardiovascular events, significantly decreased in the vitamin D group compared with the placebo group. In addition, levels of adiponectin – a collagen-like protein specifically expressed in human adipose cells, which plays an important role in insulin sensitivity, inflammation and atherosclerosis – increased in participants of the vitamin D group. No changes were seen in other measures, such as maintai-ning a healthy blood sugar level (glucose homeostasis).

The researchers commented that these findings may have clinical implications for the usual recommended daily allowance for vitamin D for diabetic patients. Since the levels of vitamin D are extremely low in this population, more appropriate daily supplementation doses above 1,000 IU/day might be recommended to achieve optimal levels of vitamin D. Since the study included a small number of patients, the scientists called for larger studies to establish the benefits of vitamin D supplementation on vascular health as well as its clinical impact on cardiovascular outcomes in type-2 diabetics.

An earlier study associated optimal blood vitamin D levels (at least 75 nmol/L) of people with metabolic syndrome with a 66% reduction in the risk of cardiovascular disease related mortality compared with people with severe vitamin D deficiency (2).

1. Breslavsky A. et al. Effect of high doses of vitamin D on arterial properties, adiponectin, leptin and glucose homeostasis in type 2 diabetic patients. Clinical Nutrition. Published online March 2003.
2. Thomas G. N. et al. Vitamin D levels predict all-cause and cardiovascular disease mortality in subjects with the metabolic syndrome: the Ludwigshafen Risk and Cardiovascular Health (LURIC) Study. Diabetes Care. 2012; 35(5):1158–1164.