Dr. Pierce's Tip of the Week - Archive

Zinc in Musculoskeletal Metabolism
April 14, 2004

Exerpted from Dr. Steve Haltiwangers E-Book "Anabolic Nutrition and Musculoskeletal Repair"

Zinc is involved with tissue repair, bone formation and maintenance of testosterone levels in men and estrogen levels in women. Zinc is a necessary mineral for normal osteoblastic activity, for the production of collagen, chondroitin sulfate, and for the activity of the zinc dependent enzyme alkaline phosphatase (Calhoun et al., 1974). Alkaline phosphatase is an enzyme secreted by osteoblasts when they are actively depositing calcium salts. Adequate dietary zinc is also required by the body in order to secrete Insulin-like growth factor-1 (IGF-1), which is a critical anabolic regulator of muscle protein synthesis, bone formation, remodeling, and calcium homeostasis. IGF-1 levels and other critical growth factors decrease when zinc levels are low (Canalis et al., 1992; Devine et al., 1998). Zinc supplementation may also play an additional role in maintaining bone density in exercise related bone injuries, since zinc may help reduce excessive osteoclastic bone resorption (Moonga and Dempster, 1995).

Clinical studies have found that zinc levels in both blood and bone to be low in people with osteoporosis (Sahap, 1995) and loss of zinc in the urine has been reported to be high (Relea et al., 1995). A clinical study done in 1993 compared a zinc restricted diet of men consuming only 10 mg of zinc per day to men using over 20 mg per day. The men who were zinc restricted had almost twice the risk of osteoporotic fractures compared with those men who ate the diet with higher levels of zinc (Elmstahl et al., 1998).

Nutritional studies of athletes have shown that many athletes consume diets inadequate in zinc or develop zinc depletion as a result of training programs (Dressendorfer and Sockolov, 1980; Haralambie, 1981; Deuster et al., 1986; Couzy et al., 1990). Earlier sections of this paper have documented that body stores of zinc are depleted during stress and prolonged physical exertion due to increased loss of zinc in sweat and urine. It is also recognized that the development of zinc depletion can reduce testosterone levels in men and estrogen levels in women, which impairs anabolic metabolism. Zinc is involved in the production, storage, and secretion of many of the bodys hormones as well as maintaining cell membrane integrity and cell receptor responsiveness to circulation hormones.

Although there is ample evidence demonstrating that athletes do not have adequate zinc status, few studies have examined the effects of zinc supplementation on bone density. Zinc supplementation may play multiple roles in the maintenance of lean muscle mass and bone density during physical training programs including the support of testosterone levels in men and estrogen levels in women.

Check out our members section to hear this weeks audio interview with Charles Poliquin and Dr. Haltiwanger, as they discuss the importance of minerals and anabolism.

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