Selenium Supplementation May Increase Diabetes Risk

Risk increased if dietary intake is already adequate

THURSDAY, July 12 (HealthDay News) -- Selenium supplementation in cases of already adequate dietary selenium intake increases the risk of developing type 2 diabetes, according to a study published online July 10 in the Annals of Internal Medicine.

Saverio Stranges, M.D., Ph.D., from Warwick Medical School in Coventry, United Kingdom, and colleagues examined the incidence of type 2 diabetes in 1,202 patients seen in dermatology clinics in the United States who were randomized to placebo or 200 micrograms per day of selenium.

During an average follow-up of 7.7 years, the researchers found that 58 selenium recipients and 39 placebo recipients developed diabetes (hazard ratio 1.55). The effect of selenium persisted even after grouping patients by age, sex, body mass index and smoking status. Those who were in the highest tertile of plasma selenium level at baseline (greater than 121.6 nanograms per milliliter) also had a significantly increased risk of diabetes (hazard ratio 2.70).

"The balance of the potential benefits and harms of selenium supplementation depends on the dietary selenium intake in different countries," Joachim Bleys, M.D., and colleagues from Johns Hopkins University in Baltimore, write in an accompanying editorial. "By taking selenium supplements on top of an adequate dietary intake, people may increase their risk for diabetes."

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