Myths vs facts: Selen and blood sugar

Myths vs facts: Selenium and blood sugar. Selenium is an essential trace element incorporated into selenoproteins (e.g., glutathione peroxidases) that protect against oxidative stress. Some observational studies suggest a U-shaped relationship: both low and high selenium levels may increase type 2 diabetes risk. The SELECT trial (2009) reported a modest but significant increase in diabetes incidence among men taking 200 µg selenium daily. Mechanistically, selenium can modulate insulin signaling via selenoproteins like GPX1 and selenoprotein P, but effects are context-dependent. A common GPX1 variant (rs1050450) reduces enzyme efficiency, yet its impact on blood glucose is not clinically actionable. Fact: In selenium-replete populations, supplementation does not improve glycemic control and may be harmful. Myth: Selenium supplements are a safe way to lower blood sugar. Evidence is mixed (human-moderate) and does not support routine supplementation for diabetes prevention or management. Consumers should be cautious of direct-to-consumer tests that overclaim selenium's role in blood sugar regulation.