title: Does quercetin and vitamin C improve exercise performance, muscle damage, and body composition in male athletes?
abstract: BACKGROUND
  Quercetin is a bioflavonoid occurs in many food items. Some previous studies on quercetin showed the inconsistent results on exercise performance and muscle damage in athletes. The aim of this study was to determine the effects of 8 weeks of quercetin supplementation on exercise performance and muscle damage indices in student athletes.
  
  
  METHODS
  This placebo-controlled, double-blind clinical trial was conducted on 60 male students for 8 weeks. The subjects were randomly assigned to one of the four groups: a) quercetin (500 mg/day quercetin + 200 mg/day placebo), b) quercetin+ vitamin C (500 mg/day quercetin + 200 mg/day vitamin C), vitamin C (500 mg/day placebo + 200 mg/day vitamin C), and placebo (500 mg/day placebo + 200 mg/day placebo). Time to exhaustion (TTE) for measuring performance, aspartate transaminase (AST), and creatine kinase (CK) for measuring muscle damage and body fat percent (BFP) were measured before and after intervention.
  
  
  RESULTS
  CK levels reduced in group 1 significantly (P=0.045) and BFP reduced in group 1, 3, and 4, significantly, too (P=0.018, P=0.013, and P=0.043, respectively). Whereas statistically significant changes between groups were not observed for TTE, AST, CK, and BFP after 8 weeks of intervention.
  
  
  CONCLUSIONS
  Supplementation with quercetin and vitamin C for 8 weeks did not improve exercise performance but reduced muscle damage and body fat percent in healthy subjects.
authors.affiliation: Food Security Research Center, Isfahan, Iran.
authors.forename: Gholamreza
authors.initials: G
authors.lastname: Askari
authors.forename: Reza
authors.initials: R
authors.lastname: Ghiasvand
authors.forename: Jahangir
authors.initials: J
authors.lastname: Karimian
authors.forename: Awat
authors.initials: A
authors.lastname: Feizi
authors.forename: Zamzam
authors.initials: Z
authors.lastname: Paknahad
authors.forename: Gholamreza
authors.initials: G
authors.lastname: Sharifirad
authors.forename: Maryam
authors.initials: M
authors.lastname: Hajishafiei