Dogs fed a diet supplemented with selenium show a lower level of DNA damage in their prostates compared with dogs fed a normal (unsupplemented) diet, report researchers.
The study, published in this week's Journal of the National Cancer Institute, suggests that taking selenium supplements decreases the cellular changes that may lead to prostate cancer.
David J. Waters, of Purdue University in West Lafayette, Indiana, and his colleagues randomly assigned 49 elderly male dogs to a normal diet or one of four diets supplemented with different amounts of selenium.
After seven months, the prostates of dogs fed diets supplemented with selenium had less DNA damage than the prostates of dogs fed the normal diet. Also, compared with those on the normal diet, dogs fed the supplemented diet had twice the number of prostate cells that had undergone apoptosis, a mechanism that can remove damaged cells.
The authors conclude that "selenium may benefit the aging prostate by decreasing the accumulation of DNA damage in epithelial cells even before these cells show cytotoxic changes suggestive of malignancy."
The authors did not relate the study to developments in humans, but the trace mineral, present naturally in nuts, vegetables and wholegrains, has been shown to inhibit cancer development in a variety of experimental animal models. In a recent study on former smokers, selenium was associated with a lower risk of bladder cancer. Research is continuing to understand the way in which the mineral acts to prevent cancer.