title: 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.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Physical Education and Sport Science, University of Thessaly, Trikala, Greece.
authors.forename: Anastasios A
authors.initials: AA
authors.lastname: Theodorou
authors.forename: Michalis G
authors.initials: MG
authors.lastname: Nikolaidis
authors.forename: Vassilis
authors.initials: V
authors.lastname: Paschalis
authors.forename: Stilianos
authors.initials: S
authors.lastname: Koutsias
authors.forename: George
authors.initials: G
authors.lastname: Panayiotou
authors.forename: Ioannis G
authors.initials: IG
authors.lastname: Fatouros
authors.forename: Yiannis
authors.initials: Y
authors.lastname: Koutedakis
authors.forename: Athanasios Z
authors.initials: AZ
authors.lastname: Jamurtas
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects*; D000328:Adult; D000975:Antioxidants / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000494:pharmacology*; D001663:Bilirubin / Q000097:blood; D015415:Biomarkers / Q000097:blood; D019587:Dietary Supplements; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects; D014810:Vitamin E / Q000494:pharmacology*; D055815:Young Adult
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D006454:Hemoglobins; D014810:Vitamin E; D001205:Ascorbic Acid; D001663:Bilirubin