Research by the American Journal on Zinc

Researchers from the Linus Pauling Institute at Oregon State University, Children’s Hospital Oakland Research Institute, and the University of California, Davis report in the August, 2009 issue of the American Journal of Clinical Nutrition that lowering dietary zinc intake is associated with increased breakage of peripheral blood cell DNA strands, while restoring zinc to normal levels reduces breakage. Zinc deficiency is estimated to affect 2 billion people worldwide, and is believed to elevate the risk of several chronic diseases, including cancer. The ability of zinc to increase DNA repair, in addition to its role as an antioxidant, may be responsible for its protective effect.
For the first 13 days of the current study, nine healthy men received a diet that contained 11 milligrams zinc per day to ensure adequate zinc status. The subjects then underwent a period of zinc depletion during which they received liquid diets containing 0.6 milligrams zinc for seven days, followed by a diet containing 4 milligrams zinc for 35 days. During the first 21 days of the low zinc diet, participants received 1.3 grams per day of phytate, which inhibits zinc absorption. On the 56th day of the study, the participants were switched back to the zinc replete diet provided at the beginning of the study, and continued on this diet for 18 days with the addition of supplemental zinc for the first 7 days of this period. Fasting blood samples drawn at the beginning and end of the study and at several intermediate points were analyzed for DNA damage, plasma zinc levels, and antioxidant status.