Selenium Offers No Benefit for Diabetes

Supplemental dietary selenium provides no diabetes-prevention benefit—in fact, it may actually increase the risk of diabetes, according to recent research.

Some research with animals has indicated that the antioxidant selenium may help glucose control. To test the theory in humans, researchers examined the incidence of diabetes in 1,202 people being treated with selenium for an unrelated dermatologic condition at seven clinics in the eastern U.S.

Half of the participants were randomized to receive a 200 μg daily dose of selenium as a dietary supplement. The other half received placebo. Participants were followed up for an average of 7.7 years.

During the follow-up, 58 people in the selenium group developed diabetes, equal to 12.6 cases per 1,000 person-years, compared with 39 people in the placebo group, equal to 8.4 cases per 1,000 person-years, so people who took selenium were 55% more likely to develop diabetes than those on placebo in this study. In addition, the researchers found an exposure-response relationship between plasma selenium levels and diabetes: People with the highest levels of plasma selenium were 2.7 times more likely to develop diabetes than those with the lowest levels.

“Selenium supplementation does not seem to prevent type 2 diabetes, and it may increase risk for the disease,” the researchers conclude.