May 11, 2011
Taking Additional Selenium Will Not Reduce Cancer Risk
Although some people believe that taking selenium can reduce a person's risk of cancer, a Cochrane Systematic Review of randomised controlled clinical trials found no protective effect against non-melanoma skin cancer or prostate cancer. In addition, there is some indication that taking selenium over a long period of time could have toxic effects.
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. The researchers located 49 prospective observational studies and six randomised controlled trials.
When the team of researchers looked at the more carefully conducted randomised controlled trials, any sign of benefit disappeared. "In fact, the results of the Nutritional Prevention of Cancer Trial and the Selenium and Vitamin E Cancer Prevention Trial raised concerns about possible harmful effects from long-term use of selenium supplements," says Dennert.
The researchers believe that there is a need for more research looking at selenium's effect on liver cancer and think that it would be worth investigating the possible gender differences that appear to be present in the uncontrolled studies.
"However, we could find no evidence to recommend regular intake of selenium supplements for cancer prevention in people whether or not they already have enough selenium," says Dennert.
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