Selenium is a powerful antioxidant supplement that could help shield the body from innumerable diseases. In the vitamin/mineral world, it is one of the natural supplements most frequently studied. It is also the subject of health news here, which addressed its overall effects on cancer. As it turns out, the news isn’t so positive.
Many believe that taking selenium could reduce a person’s risk of cancer. But a large study that reviewed a big swath of evidence found that the mineral has no protective effect against skin or prostate cancer. Also, taking too much selenium over time may lead to toxic effects in the body.
These conclusions were reached after researchers scanned the medical literature, looking for trials that studied the effects of taking selenium supplements and observational studies on selenium intake. They identified 49 prospective observational studies and six randomized controlled trials.
In the observational studies (where you look at a huge chunk of the population to arrive at conclusions), there was some indication that people may be marginally protected from cancer if they had a higher selenium intake. And that this effect was slightly greater for men than women. This data came from a wide variety of trials, so coming up with a summary is tricky.
Randomized controlled trials are done carefully and specifically address a treatment’s ability to help patients. When researchers looked at these studies, there was no hint of selenium having a protective effect on cancer. They also found that there are possible harmful effects from long-term use of selenium supplements.
Still, the investigators believe there is a need for more research looking at selenium’s effect on liver cancer in particular. Selenium remains a powerful mineral and its antioxidant abilities have been proven by scores of medical studies. The question here is whether it has specific effects on cancer.
From the evidence, one cannot recommend regular intake of selenium supplements for cancer prevention in people. Sometimes the best health advice is to be as knowledgeable as possible about all the available modes of prevention, both conventional and alternative.