This study aims to examine the effect of zinc supplementation on free-radical 
formation and antioxidant system in individuals who are actively engaged in 
wrestling as a sport. The study registered a total of 40 male subjects, of whom 
20 were wrestlers and 20 were sedentary individuals. The subjects were equally 
allocated to four groups: group 1, zinc-supplemented sportsmen group; group 2, 
sportsmen group without supplementation; group 3, zinc-supplemented sedentary 
group; group 4, sedentary group without supplementation. Blood samples were 
collected from all subjects twice, once at the beginning of the study and once 
again at the end of 8-week procedures. The blood samples collected were analyzed 
to determine the levels of malondialdehyde (MDA), serum glutathione (GSH), serum 
glutathione peroxidase (GPx) activity, serum superoxide dismutase (SOD) activity 
(ELISA colorimetric method) and zinc (colorimetric method). No difference was 
found between MDA levels of the study groups in the beginning of the study. The 
highest MDA value at the end of the study was obtained in group 4 (p < 0.01). 
MDA levels in group 2 were established to be significantly higher than those in 
groups 1 and 3 (p < 0.01). GSH level, GPx, and SOD activities and zinc level 
measured in the beginning of the study were not different between groups. 
Measurements performed at the end of the study showed that groups 1 and 3 
(zinc-supplemented groups) had the highest GSH level, GPx, and SOD activities 
and zinc level (p < 0.01). These parameters were not different in the groups 
without supplementation (groups 2 and 4). Results obtained at the end of the 
study indicate that zinc supplementation prevents production of free radicals by 
activating the antioxidant system. In conclusion, physiologic doses of zinc 
supplementation to athletes may beneficially contribute to their health and 
performance.