Zinc is an essential trace element, meaning that very little is needed in the human body. Zinc is found in high concentrations in the male prostate gland. The prostate, a walnut-shaped gland, produces fluid for semen. Prostate cancer is the third most common cause of cancer death in men in the United States according to MedlinePlus. The role of zinc in causing, preventing or treating prostate cancer is controversial and still under study. Cadmium, another metal, has similar properties to zinc; the two often occur together. Cadmium may increase cancer risks.
Risks
Although cadmium is a known carcinogen, researchers from the National Cancer Institute report in the October 2003 issue of "The Journal of the National Cancer Institute" that it has not been specifically linked to prostate cancer. However, they also state that the role of zinc cadmium supplements needs further investigation. When taken in doses of more than 100 mg per day, zinc itself may also increase rather than decrease the risk of developing prostate cancer, researchers from the National Cancer Institute reported in the July 2003 "Journal of the National Cancer Institute." While doses up to 100 mg per day did not increase the risk of prostate cancer, higher doses, especially if taken for more than 10 years, more than doubled the risk.
Dosing
Many men in the United States take zinc supplements to improve sexual performance, to prevent prostate cancer or to increase semen output, despite the lack of clinical evidence that zinc has any of these benefits. Around 10 percent of men taking zinc supplements take double or triple the recommended dose of 11 mg per day, author and radio personality Gabe Mirkin, M.D. reports. The maximum upper intake established by the U.S. Institute of Medicine is 40 mg. If you do take zinc supplements, look for zinc-gluconate supplements rather than zinc cadmium supplements, since cadmium may increase the risk of developing kidney disease. The levels of cadmium in zinc supplements can vary as much as 37-fold, MedlinePlus warns. Multi-mineral supplements rather than zinc-only supplements may also contain higher amounts of cadmium, due to higher levels of impurities, National Cancer Institute researchers theorize.
Preventing Prostate Cancer
Zinc may reduce cadmium toxicity and have a protective effect on the prostate, researchers from the University of Rochester School of Medicine and Dentistry reported in the February 2008 issue of "The Prostate." Men who consumed less than 12.67 mg per day of zinc and who had higher than average cadmium levels had a 35 percent increase in prostate-specific antigen, or PSA levels, associated with prostate cancer development.
Considerations
Getting enough zinc from dietary sources appears to benefit the prostate, which contains more zinc than any other soft tissue in the body. Taking supplements, especially supplements that contain large amounts of cadmium, may negate the benefits of extra zinc. Do not exceed the maximum 40 mg per day dose if you do take zinc supplements. Ask your doctor before taking zinc to treat any prostate conditions, including cancer.
References
- "The Journal of the National Cancer Institute;" RESPONSE: Re: Zinc Supplement Use and Risk of Prostate Cancer; Michael F. Leitzmann, M.D., et al.; October 2003
- MedlinePlus: Zinc; February 2011
- "The Journal of the National Cancer Institute;" Zinc Supplement Use and Risk of Prostate Cancer; M. Leitzmann, et al.; July 2003
- Urosource: Diet Rich in Zinc Linked to Higher Prostate Cancer Survival; April 2010
- Dr. Mirkin.com: Zinc Causes Prostate Cancer?; Gabe Mirkin, M.D.; September 2005
- "The Prosate;" Prostate-Specific Antigen Levels in Relation to Cadmium Exposure and Zinc Intake; Evan Wijngaarden , et al.; February 2008
