Use of zinc supplements tied to possible increase in risk of prostate cancer

Consumption of supplemental zinc is associated with an increased risk of advanced prostate cancer, according to an analysis of data from the Health Professionals Follow-up Study.

The prostate has higher concentrations of zinc than do other soft tissues, Dr. Michael F. Leitzmann, of the National Cancer Institute in Bethesda, Maryland, and colleagues point out in the Journal of the National Cancer Institute for July 2. However, studies of the effect of zinc on prostate cancer risk have been inconclusive.Among more than 46,000 men followed in the health professionals study, there were 2901 documented cases of prostate cancer during 14 years of follow-up, including 434 cases that were advanced at diagnosis.The relative risk of advanced prostate cancer increased by a factor of 2.29 among men who took more than 100 mg of zinc per day, after adjusting for supplemental calcium and vitamin E as well as age, body mass index at age 21, height, smoking, and family history (p = 0.003 for trend).Adjustment for the same variables also showed a 2.37-fold increased relative risk of advanced prostate cancer for men who used zinc supplements for 10 years or more (p < 0.001).Despite the lack of a robust explanation for the described association, "our findings suggest that the role of chronic oversupply of zinc in prostate carcinogenesis requires further investigation," Dr. Leitzmann and his associates conclude.(Source: J Natl Cancer Inst 2003;95:1004-1007: Reuters Health: July 1, 2003: Oncolink)