Effect of long-term exercise training on zinc status: A systematic review

Abstract

Background: Zinc is an essential trace element with many functions in the body, including energy metabolism, immunity and antioxidant activity. Regular exercise is a common recommendation for the prevention of chronic diseases, with irrefutable benefits. Zinc has a central role in exercise, however some groups of active individuals have suboptimal zinc status. Effects of short-term exercise on zinc status have been well documented, however effects of long-term exercise training on zinc status in the literature have been conflicting. Objective: To evaluate the effects of long-term exercise on zinc status, in trained compared to untrained groups. Design: We conducted a systematic review of peer-reviewed articles up to January 28, 2016 to identify studies that investigated effects of long-term exercise training on zinc status. Results: Six studies were included in the systematic review. Serum zinc did not display consistent results in the included studies in response to exercise training. There was a greater increase in urinary zinc excretion, erythrocyte zinc, dietary zinc intake and the activity of copper-zinc-superoxide dismutase in some groups undergoing exercise training, compared to the control group. Conclusion: The present review indicates that some zinc markers exemplify that there is a change in zinc homeostasis that occurs with exercise training. Further research is required to determine if these fluctuations warrant a change in dietary requirements for active individuals, and to allow dietitians to create best possible intervention plans for optimal health and/or physical performance.