Effect of Vitamin A administration on free radicals and lactate levels in individuals exercised to exhaustion

This study was performed to explore the effect of Vitamin A administration on Free Radicals production and antioxidant system activity and lactate levels in individuals exercised to exhaustion The study registered 10 healthy sedentary males their mean age was 22,85±0,26 years. The subjects were orally administrated with 300 mg Vitamin A (retinol) for 4 weeks and engaged in strenuous exercise (using the Bruce protocol) once a week. Blood samples were collected from the subjects at four different times, before and after the supplementation and before and after exercise to analyze Malondialdehyde (MDA), Nitric oxide (NO), Glutathione (GSH), Glutathione peroxidase (GSH-Px), Catalase (CAT), Superoxide dismutase (SOD) levels using colorimetric ELISA test kits and plasma lactate levels using an autoanalyzer. Exhaustion exercise leaded to an increase in both MDA, NO, and lactate, and GSH, GSH-Px, CAT and SOD levels compared to resting levels both before and after supplementation (p<0.05). Increased NO levels found in pre-supplementation exhaustion showed a significant decrease after the supplementation of Vitamin A (p<0.05), but the other parameters were not changed after Vitamin A administration. The results of our study demonstrate that the increase caused by 4-week strenuous exercise in the levels of the free radical NO was offset by Vitamin A supplementation. It can be suggested that supplementation of Vitamin A at physiological doses has a limited effect on lipid peroxidation caused by strenuous exercise.