Vitamin D May Reduce Risk for Type 2

A Boston-based study has found that vitamin D supplements can reduce the risk of developing type 2 diabetes in people with prediabetes by improving their beta cell functioning.

Researchers at Tufts University Medical Center tracked the effects of vitamin D3 supplements on 92 subjects who were considered to have prediabetes by virtue of being overweight and having higher-than-normal blood sugar levels. (In prediabetes, blood sugar levels are high, but do not yet reach the levels found in full-blown diabetes.)

The subjects were divided into four study groups, with one group receiving the vitamin D supplements, a second group receiving vitamin D and calcium, a third group receiving calcium only, and a fourth group receiving a placebo.

Researchers tracked participants’ blood sugar levels using the A1C test and monitored their pancreatic beta cell function, including how much insulin the cells were producing and the patients’ sensitivity to the hormone.  

The four-month study showed that the vitamin D groups enjoyed slightly lower A1C levels and a 15 percent to 30 percent improvement in beta cell function. The other groups showed no similar gains.

The study scientists were careful to point out that the results do not show that vitamin D can prevent the onset of type 2, only that it may be one element in a series of steps that people with prediabetes can take to avoid developing the disease. Maintaining insulin sensitivity and control of blood sugar levels are mainstays in diabetes prevention.

An abstract of the study is available online at the American Journal of Clinical Nutrition.