Low zinc intake may influence exercise performance

In a recent study published in the May 2005 American Journal of Clinical Nutrition, researchers analyzed the effect of restricted dietary zinc on metabolic responses during exercise. Certain zinc-containing enzymes are believed to regulate energy expenditure, but there is limited data on the role of zinc in promoting physiologic function during exercise.

Male study participants received a low-zinc diet (3.8 mg/day) for 9 weeks and after a 6 week wash-out period, the same diet supplemented with 15 mg of zinc for an additional 9 weeks. Using two types of stationary exercise bike tests, researchers tested the subjects' cardiovascular fitness during the second and ninth week of each diet period.

Low dietary zinc resulted in a significant decline in work capacity and performance in the subjects when compared to results during the supplemented period. Blood tests confirmed that the low-zinc regimen resulted in reduced blood zinc concentration and retention, and lowered the activity of specific zinc-dependent enzymes. The lowered activity of these enzymes impacts exercise performance by compromising the body's ability to regulate the increase in blood carbon dioxide that is produced during exercise. These results suggest that adequate zinc is necessary for peak performance and metabolic response during exercise.