Effect of Selenium Supplementation on Glycemic Control in Patients With Type 2 Diabetes or Prediabetes

Although it has been suggested that selenium (Se) increases the risk of T2DM, most evidence comes from observational studies that cannot prove causality. A systematic review assessed randomized clinical trials and found that the risk of T2DM was not greater in those randomized to Se supplementation than in those randomized to placebo. Se is a toxic element in animals and humans, and overexposure to Se has also been linked to detrimental health effects in humans. Previous studies were mostly conducted in Se-sufficient areas. Moreover, the effectiveness of low-dose Se supplementation on participants with elevated glycemic status was unknown. This cross-over, double blinded, randomized controlled trail aimed to investigate the effectiveness of Se supplementation for glucose control among participants with diabetes or prediabetes. Moreover, we also aimed to examine whether selenoprotein P genotypes, Se-related gut microbiota and their related metabolite modified the effectiveness.