By: Mark A Moyad, MD, MPH, Stanley A Brosman, MD, Edward David Kim, MD, FACS
Updated: Oct 11, 2019
Answer
Zinc is commonly used as a dietary supplement. Healthy individuals with a balanced diet consume about 11 mg of zinc daily. Zinc is found in meat and nuts and in vegetables such as chickpeas and beans. Many individuals consume large amounts of supplemental zinc because of the possible health benefits that have been promoted by commercial interests.
The findings that zinc levels are decreased in men with prostate cancer and that zinc suppresses prostate cancer cell growth and invasion have led to the hypothesis that zinc may play a protective role. However, the Health Professionals Follow-Up Study showed an increased risk of prostate cancer in men who consumed more than 100 mg daily. [89] High-dose zinc has been shown to promote prostate cancer development. Studies of persons taking large amounts of zinc have also reported adverse effects on the urinary tract.
In a study of the relationship between zinc intake in black men and risk of prostate cancer by Mahmoud et al, prostate cancer patients had lower zinc intake, with a mean of 11 mg/day versus 14 mg/day, but comparison of tertiles of zinc intake showed a non-significant, non-linear increase in prostate cancer. A dose-response meta-analysis of 17 studies by these authors showed a non-linear trend in the relationship between zinc intake and prostate cancer. [90] Thus, there is no compelling reason to supplement with zinc for prostate health; the amount contained in the diet, with or without a multivitamin (usually the recommended daily allowance), is normally sufficient.
