Zinc is a mineral that is found in large concentrations in the prostate gland, suggesting it is important for prostate health. In addition to its role in proper sexual development and reproduction, zinc helps keep the immune system strong, memory intact, cholesterol and blood sugar in line, and blood pressure and heart beat regulated.
It is believed that a deficiency of zinc may result in an increase in infections and prostatitis, or it may make a male susceptible to prostate cancer because the mineral is also a key player in the body’s DNA-damage repair process. Although zinc sulfate is the most frequently used zinc supplement (and also the most inexpensive), it is not easily absorbed. Therefore the preferred form is zinc citrate, which is more bioavailable, at a dose of 15 mg daily.
Zinc and Prostate Cancer
In a University of Washington Cancer Prevention Program study, researchers analyzed the relationship between dietary and supplemental zinc and prostate cancer using the VITamins And Lifestyle (VITAL) cohort. Of 35,242 men who completed the dietary and supplemental questionnaire, 832 men developed invasive prostate cancer over a four-year period. The investigators did not observe a reduced risk of prostate cancer associated with a ten-year average intake of supplemental zinc greater than 15 mg per day, but they did see a decreased risk of advanced prostate cancer with a greater intake of supplemental zinc (greater than 15 mg daily vs no zinc supplement). No association between dietary zinc and prostate cancer risk was seen. (Gonzalez 2009)
A study conducted in Venezuela set out to determine zinc concentrations in the prostatic fluid of men who had prostate problems (30 subjects) compared with healthy controls (10). The researchers found that zinc concentrations in men who had prostatitis and prostate cancer—but not BPH–were lower than those in the controls. This finding led them to “consider the possibility of recommending zinc supplements as a coadjuvant therapy in patients with prostatitis,” and to use zinc levels as a diagnostic tool to distinguish BPH from prostate cancer. (Gomez 2007)
Zinc and Laboratory Studies
Researchers at the University of Maryland (Baltimore) showed that exposing human prostate cancer and BPH cells to zinc induced cell suicide, and they identified the specific genes involved. Thus this study provided an extensive database on zinc-related prostate cancer research, and the results suggested zinc regulation of gene expression is cell-type specific; that is, the genes Fos, Akt1, Jak3, and PI3K showed themselves to be highly regulated by zinc. (Lin 2009)
In a similar vein, Oregon State University was the setting for a study that evaluated the antiproliferative effects of zinc in both prostate cancer cells and benign prostatic hyperplasia cells. Based on the knowledge that zinc concentrations in the prostate are “uniquely high” but significantly low in the presence of prostate cancer, the study’s authors set out to evaluate the antiproliferative effects of zinc in prostate cancer cells and BPH cells, with the goal of identifying possible mechanisms. Both prostate cancer and BPH cells were treated with zinc for 24 and 48 hours, and cell viability and growth were observed. BPH cells were more sensitive than were prostate cancer cells to zinc’s antiproliferative effects. The authors concluded that the differential response to zinc in the prostate cancer and BPH cells “suggests that zinc may serve an important role in regulating cell growth and apoptosis in prostate cancer and hyperplasia cells.” (Yan 2010)
Foods that contain a good level of zinc include oysters (extremely high levels), beef, poultry, seafood, fortified cereals, calf’s liver, sesame seeds, pumpkin seeds, crimini mushrooms, and low-fat yogurt. The RDA for zinc is 11 mg for adult males.
Gomez Y et al. Zinc levels in prostatic fluid of patients with prostate pathologies. Invest Clin 2007 Sep; 48(3): 287-94
Gonzalez A et al. Zinc intake from supplements and diet and prostate cancer. Nutr Cancer 2009; 61(2):206-215.
Lin SF et al. Profiling of zinc-altered gene expression in human prostate normal vs cancer cells: a time course study. J Nutr Biochem 2009 Dec; 20(12): 1000-12
Yan M et al. Differential response to zinc-induced apoptosis in benign prostate hyperplasia and prostate cancer cells. J Nutr Biochem 2010 Aug; 21(8): 687-94