High intake of zinc may increase risk of prostate cancer




Journal of the National Cancer Institute

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The prostate is a walnut-sized gland in men that lies just below the bladder, surrounding the urethra. The function of the prostate is to enhance the movement of sperm cells by secreting a thin, lubricating fluid into the urethra.

Prostate cancer is the most common form of cancer, excluding skin cancer, in men in the United States. It is primarily diagnosed in men over 65, although it may begin much earlier. Some cancers of the prostate are very slow growing, while others behave aggressively. Prostate cancer often metastasizes to other tissue, including the brain, lungs, lymph nodes, and bones. Early detection is critical in order to increase the chances for survival. The cancer can be felt upon digital rectal examination (DRE). These examinations are recommended routinely for all men over the age of 50 and high-risk men should commence at age 40.

Prostate cancer, like BPH, may initially have no symptoms. Eventually there will be an increased number of trips to the restroom for urination, which are hurried and necessary. An increase in the number of trips to the restroom at night, difficulty in starting the urine stream and a decrease in the force of the urine stream will be experienced. Cancer differs from BPH in that the individual will experience fatigue, nausea, weakness, back pain, hip pain, and swollen lymph nodes. There will likely be discomfort in the area between the scrotum and the anus and eventual weight loss. Blood may be present in the urine.

A recent study published in the Journal of the National Cancer Institute stated that there are high levels of zinc in the prostate. Researchers investigated the link between zinc supplements and prostate cancer risk in over 46,000 men. During the 14 year follow-up period, 2,901 men developed the disease. Although zinc supplements up to 100 mg a day were not associated with prostate cancer, the results showed that when compared to those who did not take supplements, the men taking the supplements had an increased risk of advanced prostate cancer. The authors concluded that “chronic zinc oversupply may play a role in prostate carcinogenesis, warrant further investigation.”1


1. Leitzmann MF, et al. Zinc Supplement Use and Risk of Prostate Cancer. JNCI. July 2003;95(13):1004-07.