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Protect the prostate with zinc

Over Exposure

Expose a prostate gland to enough cadmium and you’ve got trouble.

Cadmium is a toxic heavy metal that somehow finds its way to all of us. Smokers get a daily dose, as does anyone exposed to secondhand smoke. It’s also an environmental pollutant, pumped into the air by various industries and the burning of coal and household wastes. Once airborne, cadmium can travel long distances, eventually falling to ground or water. The result: When you eat fish (especially shellfish) or plants, you often pick up a little cadmium.

And it gets worse. According to the Department of Health and Human Resources, “Cadmium stays in the body a very long time and can build up from many years of exposure to low levels.”

Not a rosy picture – especially for men, because cadmium is believed to cause prostate cancer. But add a little zinc, and you might change everything.

Cadmium clues

To test the hypothesis that zinc may protect the prostate from cadmium-induced prostate cancer, researchers at the University of Rochester Medical Center collected records from the 2001-2002 National Health and Nutrition Examination Survey (NHANES).

More than 1,300 men over the age of 40 who participated in NHANES were tested to determine levels of prostate specific antigen (PSA), a marker that tends to be elevated when prostate cancer is present. (As we’ve seen in previous e-Alerts, PSA is not an entirely reliable marker for prostate cancer, but a consistently high PSA level is still a red flag.)

The Rochester team found NHANES records for 422 men who had been PSA tested and also met two additional criteria to be included in their study: 1) measurement of urinary cadmium concentrations, and 2) assessment of zinc intake based on dietary questionnaires.

Analysis revealed that PSA levels were significantly higher among subjects with higher than average cadmium levels and lower than average zinc intake.

Reporting their findings in The Prostate, the authors summed up their investigation with this conclusion: “These findings suggest a protective effect of zinc intake on cadmium- induced prostatic injury.”

A dozen on the half shell

You don’t have to have a prostate gland to reap the benefits of adequate zinc intake.

The lead author of the Rochester study, epidemiologist Edwin van Wijngaarden, told United Press International that zinc prompts the production of a protein that binds cadmium to help move the toxin out of the body.

In addition, zinc enhances your immune system, helps repair damaged tissues, inhibits the abnormal clotting that contributes to cardiovascular disease, assists in maintaining healthy vision, and is one of the key elements required for DNA reproduction and repair.

Dietary sources of zinc include cabbage, red meat, poultry, beans, nuts, whole grains, and dairy products. Ironically, the best dietary source of zinc – oysters – is also a source of cadmium. But you also get vitamin D and omega-3 fatty acids from oysters, so you probably come out on the plus side with a dozen on the half shell.

And you might further fortify yourself against cadmium and other heavy metals with two additional key nutrients: vitamin E and selenium.

Here’s what HSI Panelist Allan Spreen, M.D., had to say about this topic in the e-Alert “Mineral with Muscle” (12/18/02): “Both selenium and vitamin E are intimately associated with stimulation of the part of the immune system dealing with production of immunoglobulins. Antibody response in several animal studies was dependent on both selenium and vitamin E status. In addition, animal sensitivity to toxic heavy metals (mercury, lead, cadmium) was closely related to both substances. In fact, combined deficiencies in concert with heavy metals caused sudden death in animals, associated with pathological changes of the heart.”

Talk to your doctor before adding zinc, selenium, or vitamin E supplements to your daily regimen.

“Prostate-Specific Antigen Levels in Relations to Cadmium Exposure and Zinc Intake: Results from the 2001-2002 National Health and Nutrition Examination Survey” The Prostate, Vol. 68, No. 2, 11/28/07,
“Zinc, Prostate Cancer Link Examined” United Press International, 2/1/08,
“Doctor Accused of Leak to Drug Maker” Stephanie Saul, The New York Times, 1/30/08,