Vitamin D may reduce diabetes risk

Increased blood levels of vitamin D may reduce the risk of developing type 2 diabetes, says a new Spanish study.

In the observational study, serum vitamin D concentration measurement and diabetes diagnosis (oral glucose tolerance test) were performed in 961 adults at the beginning, during, and at the end of the nine-year study (1). The study results showed that incidence of diabetes was less than 5% in people with 25-hydroxyvitamin D levels greater than 18.5 ng/mL, compared with an incidence of 12.4% in people with blood levels lower than this. In addition, the risk of developing diabetes was significantly lower in people with the higher vitamin D levels, with no diabetes recorded in people with blood levels of 25-hydroxyvitamin D higher than 30 ng/mL.

The researchers commented that although the results show correlation and not causation, it is biologically plausible that vitamin D may reduce the incidence of diabetes, including influencing the function of beta-cells in the pancreas that control insulin production. The vitamin may also affect sensitivity to insulin. In addition, an anti-inflammatory role of vitamin D may also affect diabetes risk. Already, US researchers have recently reported on the vitamin’s potential anti- diabetic activity: a daily 2,000 international units ( IU) dose of vitamin D3 boosted the functioning of beta cells by 25% (2).

1. González-Molero I. et al. Vitamin D and incidence of diabetes: A prospective cohort study Vitamin D and diabetes incidence. Clinical Nutrition. Published online January 2012.
   
   
2. Mitri J. et al. Effects of vitamin D and calcium supplementation on pancreatic ? cell function, insulin sensitivity, and glycemia in adults at high risk of diabetes: the Calcium and Vitamin D for Diabetes Mellitus (CaDDM) randomized controlled trial. American Journal of Clinical Nutrition. 2011; 94(2):486–494.