Effects of selenium supplementation on glucose homeostasis and free androgen index in women with polycystic ovary syndrome: A randomized, double blinded, placebo controlled clinical trial.

Background/objectives: Insulin resistance (IR) is a main pathophysiologic feature in polycystic ovary syndrome (PCOS) patients which is triggered by elevated oxidative stress in these patients. Selenium, an essential micronutrient, is a major constituent of antioxidant enzymes such as glutathione peroxidase. Recently, decreased plasma selenium concentrations were reported in PCOS patients. So, the present study was carried out in order to assess whether selenium consumption can improve the metabolic response to insulin and reduce the insulin resistance in these women.

Subjects/methods: A total of 53 PCOS patients (diagnosed by Rotterdam criteria), 18-42 years old, participated in this randomized, double-blind and placebo controlled trial for 12 weeks (selenium, n=26; placebo, n=27). The effects of daily administration of 200 μg selenium or placebo on serum glucose, total testosterone (tT), sex hormone binding globulin (SHBG) and free androgen index (FAI) in fasting state were evaluated.

Results: At the end of the study, insulin resistance was significantly increased in selenium recipients when compared with the placebo group (2.05 ± 0.39 when compared with 1.81 ± 0.25, p=0.017). Also, selenium supplementation resulted in marginally significant increase (p=0.056) in insulin level when compared with the placebo group. There were no statistically significant changes in other study endpoints, when comparing the two groups.

Conclusion: This study showed that selenium supplementation in PCOS patients may worsen insulin resistance in them. Until the results of larger studies become available, indiscriminate consumption of selenium supplements in PCOS patients will warrant caution.