This major review analyzed 10 high-quality studies with over 27,000 people taking selenium supplements or placebos. The result: selenium supplements did not reduce cancer risk. In fact, the data showed essentially no difference between people taking selenium and those taking placebo (risk ratio of 1.01, meaning virtually identical outcomes).

Researchers systematically reviewed decades of clinical trials and observational studies about selenium and cancer prevention, focusing on the most rigorous studies (randomized controlled trials) to reach their conclusions.

Funding not disclosed in abstract