Greater zinc intake associated with a lower risk of death from prostate cancer

An article published online on January 12, 2011 in the American Journal of Clinical Nutrition reveals a protective effect for a higher dietary intake of zinc against mortality from cancer of the prostate gland. Swedish and Harvard University researchers evaluated data from 525 men under the age of 80 enrolled in a case-control study in Sweden. Participants were diagnosed with prostate cancer between January, 1989 and July, 1994. Responses to dietary questionnaires administered upon enrollment were analyzed for the intake of calories, and iron and zinc from food sources. The subjects were followed through February, 2009, during which time the causes of any deaths were confirmed. Over the 6.4 year average follow-up period there were 475 deaths, of which 218 were attributed to prostate cancer. Men whose intake of zinc was among the highest 25 percent of participants at greater than 15.6 milligrams per day had a 36 percent lower adjusted risk of dying from prostate cancer compared with those whose intake was among the lowest fourth. For those whose tumors were localized, there was a 76 percent lower risk among those whose intake was highest compared to men whose intake was least. Iron intake was not significantly associated with prostate cancer mortality and zinc was not associated with death from other causes. The authors of the report note that the results of previous research concerning a protective effect for zinc in the prevention of prostate cancer have been inconsistent, and suggest that zinc could play a greater role in determining outcome of the disease rather than in its development. They remark that zinc is involved in a number of cellular functions, including maintenance of the immune system and DNA repair. "These results suggest that high dietary intake of zinc is associated with lower prostate cancer–specific mortality after diagnosis, particularly in men with localized disease," Mara M. Epstein and her colleagues write. "These findings should encourage future studies of zinc and prostate cancer to include survival endpoints in an attempt to confirm our conclusions."