A new study could help explain how selenium reduces the risk of certain cancers.
Researchers reported in the Proceedings of the National Academy of Sciences Early Edition that the selenium component selenomethionine switches on a gene (p53) which prevents tumors from developing. P53, which is inactive in many cancers, apparently causes abnormal cells to die and stops them from replicating.
However, researchers noted that selenomethionine activated p53 only when another compound, Ref1, was present. When Ref1 was removed from cells, the p53 gene did not appear to be active.
The study was carried out on human lung cancer cells without p53 genes. The gene was introduced and some cells were treated with selenomethionine.
Selenium is found naturally in nuts, vegetables and wholegrains but few people consume the recommended daily levels.
The researchers noted that for cancer prevention selenium intake would have to be around 200 mcg daily.
They concluded that further studies on the molecular basis for antioxidant action could help to develop tumor suppression and cancer prevention.