In April of 2015, researchers in Turin Italy completed a five-year-long randomized double-blind placebo controlled study detailing the effects of a supplement containing green tea cachetins, lycopene, and selenium on prostate health. Men with precancerous prostate conditions and men with healthy prostates were given either a placebo or the supplement. The results were quite surprising, with those taking the supplement ending up with a higher risk of prostate cancer. (Source)
The scientists were unable to isolate the exact compound that caused the higher risk. While preliminary reports have shown green tea catchetins to have the potential to support prostate health, when a randomized placebo-controlled study was done, no benefit was found. (Source) Selenium has also been shown to be helpful for prostate health in some studies, but when a phase III trial was done, serum levels of selenium were found not to have a beneficial effect on prostate health. (Source) Other studies have backed up the controversial nature of selenium supplementation. (Source)
These findings are in line with other studies that have found that while antioxidants are known to be beneficial, some antioxidant supplements can be harmful. (Source)
The best thing to do for your prostate? Eat a high-fiber, vegetable-loaded diet rich in natural antioxidants and phytonutrients.