The effect of zinc supplementation on the urinary excretion of elements in female athletes

Abstract

This study was carried out to find out how oral zinc supplementation to elite athletes affects the element changes in the urine. The study registered 10 female athletes who were on the women’s volleyball team of Gazi University Sports Club and whose mean age, weight, and height were 14.2±0.42 years, 59.8±7.79kg and 173.6±6.15 cm. The study protocol was approved by the local ethics committee. The athletes who continued their daily routine training sessions (6 days/week) were supplemented with 220mg/day oral zinc sulfate for 4 weeks. In order to induce exhaustion, the subjects were put to a 20-meter shuttle run test before and after supplementation. A total, 7 times urine samples were collected follows as pre and post exercise before the start of the experiment and at the end (4 times), at the end of first, second and third week (3 times). Urinary levels of magnesium, phosphorus, and calcium (mg/dl), as well as zinc, copper, and selenium (µg/dl) were analyzed in the atomic emission device (ICP-MS). Arithmetic means and standard errors of the data were calculated. Kruskal Wallis test was used to determine differences between weeks. Values for which p<0,05 were considered significant. When compared to resting values, urinary excretion of copper and selenium decreased in exercise (p<0,05), but increased with zinc supplementation (p<0,05). Pre- and post-supplementation exercise resulted in reduced urinary zinc excretion (p<0,05). Zinc supplementation increased urinary zinc excretion in one-week intervals over the course of 4 weeks (p<0,05), and reduced selenium levels (p<0,05). When zinc is supplemented to athletes, the relation between the duration and dose of supplementation is important. The results of the study indicated that zinc does not have any negative effect on the urinary excretion of the concerned elements. It can thus be concluded that athletes may benefit from zinc support.