Tuesday, September 6, 2011

Zinc and the Prostate-Cancer Link by Jerry Brainum

While all essential minerals are vital for health, zinc has emerged as one with particular relevance to those seeking more muscle and strength.

Like other minerals, zinc has multiple functions in the body, most prominently as an enzyme coactivator. Certain enzymes simply won’t function unless zinc is present. It’s involved in more than 200 enzyme reactions, including the synthesis and release of anabolic hormones like insulin, testosterone, growth hormone and insulinlike growth factor 1 (IGF-1).

Without zinc, enzymes that convert pro-hormones into testosterone won’t function. Without zinc you wouldn’t be able to digest protein. You couldn’t process lactic acid or carbon dioxide. Your cells couldn’t reproduce, since zinc is required for DNA activity. Rats deficient in zinc have an average of 40 percent fewer androgen receptors, with an equal number of upgraded estrogen receptors, a scenario that favors gynecomastia, or male breasts, and other signs of an estrogen/testosterone imbalance. You would likely get fat without zinc, since it’s needed to activate enzymes required for the production of active thyroid hormone, or T3.

Zinc concentrates in the prostate gland more than in any other tissue. Men with prostate cancer often show lower levels of zinc, and studies show that zinc protects against prostate cancer. On the other hand, zinc also enhances the activity of telomerase, an enzyme manufactured by tumor cells that allows them to become immortal, which would promote the spread of cancer. When prostate cancer spreads, it becomes deadly.

Newly published research using data obtained on 46,974 men participating in the Health Professionals Follow-up Study examines the role of zinc in prostate cancer.1 The study found an association between men who used 100 milligrams or more a day of supplemental zinc and increased incidence of prostate cancer. The longer that dose was taken, the higher the incidence. Some had taken large doses for more than 10 years.

Why would zinc, a nutrient often suggested for prostate health, be linked to prostate cancer? Note that risks occurred only with long-term daily doses of 100 milligrams or more. The daily suggested requirement of zinc for men is only 11 milligrams. Zinc works on a bell curve: Too much leads to effects that resemble a zinc deficiency. A potent stimulant to immune response, zinc in large doses cripples immunity. In normal amounts—i.e., less than 100 milligrams daily—zinc offers antioxidant protection through its role as a component of the body’s built-in enzyme system (superoxide dismutase). In larger doses it impairs oxidant defenses.

Other studies show that another mineral, selenium, is a potent protector against prostate cancer, yet too much zinc blocks selenium’s protective role. Zinc’s promotion of testosterone and IGF-1 is pushed to overkill when too much is taken in. Though they don’t cause prostate cancer, both of those hormones do promote it. The study found that zinc obtained from food sources had no effect on prostate cancer.

Zinc shows up in numerous food supplements. It’s often added to meal replacements, multiminerals, vitamin-and-mineral tablets and so on. So it’s not difficult to consume 100 milligrams a day. The newer zinc-magnesium-B6 supplements contain an average of 30 milligrams of zinc, not enough to cause any problems if taken alone but possibly having a cumulative effect if used with other zinc-laced supplements.

The moral: Simply be aware of how much zinc you’re getting from food and particularly supplements. If it adds up to 100 milligrams a day or more, cut back. Zinc offers many benefits, but, as the adage says, too much of anything isn’t good.

Another prudent technique for those concerned about preventing prostate cancer, which is the second leading cause of cancer death in men, is to take in other nutrients known to suppress it. Those include selenium, green tea, resveratrol (found in grapes and peanuts), vitamin D, lycopene, soy isoflavones, garlic and gamma-tocopherol, a form of vitamin E available as a supplement.

1 Leitzmann, M.F., et al. (2003). Zinc supplement use and risk of prostate cancer. J Nat Cancer Instit. 95:1004-07.

©,2013 Jerry Brainum. Any reprinting in any type of media, including electronic and foreign is expressly prohibited.

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The Applied Ergogenics blog is a collection of articles written and published by Jerry Brainum over the past 20 years. These articles have appeared in Muscle and Fitness, Ironman, and other magazines. Many of the posts on the blog are original articles, having appeared here for the first time. For Jerry’s most recent articles, which are far more in depth than anything that appears on this blog site, please subscribe to his Applied Metabolics Newsletter, at www.appliedmetabolics.com. This newsletter, which is more correctly referred to as a monthly e-book, since its average length is 35 to 40 pages, contains the latest findings about nutrition, exercise science, fat-loss, anti-aging, ergogenic aids, food supplements, and other topics. For 33 cents a day you get the benefit of Jerry’s 53 years of writing and intense study of all matters pertaining to fitness,health, bodybuilding, and disease prevention.


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