No effect of antioxidant supplementation on muscle performance and blood redox status adaptations to eccentric training

Abstract

Background: It was recently reported that antioxidant supplementation decreases training efficiency and prevents cellular adaptations to chronic exercise. Objective: This study aimed to investigate the effects of vitamin C and vitamin E supplementation on muscle performance, blood and muscle redox status biomarkers, and hemolysis in trained and untrained men after acute and chronic exercise. A specific type of exercise was applied (eccentric) to produce long-lasting and extensive changes in redox status biomarkers and to examine more easily the potential effects of antioxidant supplementation. Design: In a double-blinded fashion, men received either a daily oral supplement of vitamin C and vitamin E (n = 14) or placebo (n = 14) for 11 wk (started 4 wk before the pretraining exercise testing and continued until the posttraining exercise testing). After baseline testing, the subjects performed an eccentric exercise session 2 times/ wk for 4 wk. Before and after the chronic eccentric exercise, the subjects underwent one session of acute eccentric exercise, physiologic measurements were performed, and blood samples and muscle biopsy samples (from 4 men) were collected. Results: The results failed to support any effect of antioxidant supplementation. Eccentric exercise similarly modified muscle damage and performance, blood redox status biomarkers, and hemolysis in both the supplemented and nonsupplemented groups. This occurred despite the fact that eccentric exercise induced marked changes in muscle damage and performance and in redox status after exercise. Conclusion: The complete lack of any effect on the physiologic and biochemical outcome measures used raises questions about the validity of using oral antioxidant supplementation as a redox modulator of muscle and redox status in healthy humans.

Role of antioxidant vitamins administration on the oxidative stress

“…The duration of vitamins C and E administration was one week, shorter compared to previous reports with supplementation period with over three weeks [10,[12][13][14][15]18], however, proved that one week antioxidant vitamin administration could increase the plasma concentration of vitamin C. Plasma SOD was significantly decreased while GPx activity increased, resulting in an increase in the GPx/ SOD activity ratio. Although the indices of protein carbonyl and TBARS contents showed slight decreases, the differences were not significant.…”

“…Vitamins C and/or E, despite protection against oxidative stress interfere with the adaptive responses to endurance exercise training [10]. Most of the studies have reported that vitamins C and/or E supplementation does not affect redox status [12][13][14], less have reported attenuation of oxidant stress [10,15], and there are reports indicating a pro-oxidant effect [14]. These differences between responses and adaptation to exercise possible indicate the complexity of redox biochemistry [16].…”

Ascorbic Acid and Performance: A Review

“…The results did not support any effect of antioxidant supplementation. The complete lack of any effect on measures of physiological and biochemical results used, raises questions about the validity of the use of oral antioxidant supplementation as a redox muscle modulator and redox status in healthy humans [26].…”

Delayed Onset Muscle Soreness and Mechanisms: Relation with Oxidative Stress: Review

“…78 Benzer şekilde Theodorou ve ark., E ve C vitamini takviyesinin kas hasarı, performans ve oksidatif strese etkisinin olmadı-ğını belirtmişlerdir. 79 Üç haftalık E vitamini takviyesinin direnç antrenmanlarının neden olduğu kas ağrısı, performans ve MDA seviyesine etkisinin olmadığı rapor edilmiştir.…”