Selenium for Preventing Cancer

The review concluded that well-designed randomized controlled trials (RCTs) showed no beneficial effect of selenium supplements in reducing cancer risk, with high certainty of evidence. Some RCTs indicated increased risks of high-grade prostate cancer and type 2 diabetes with selenium supplementation. Observational studies suggested an inverse association between selenium exposure and some cancer types, but these studies had significant limitations, such as exposure misclassification and unmeasured confounding. Overall, there was no evidence to support that increasing selenium intake prevents cancer in humans. Further research was needed to explore potential genetic or nutritional factors that might influence selenium's effect on cancer risk.