title: The Effect of Green Tea and Sour Tea (Hibiscus sabdariffa L.) Supplementation on Oxidative Stress and Muscle Damage in Athletes.
abstract: OBJECTIVE
  Additional oxygen consumption during intense exercises may lead to oxidative stress and contribute to muscular fatigue. Green tea and sour tea (Hibiscus sabdariffa L.), which contain various flavonoids and polyphenols, have many healthful properties such as anticarcinogenic, anti-inflammatory, and heart protecting effects. The aim of the present study was to assess the effects of green tea and sour tea supplementation on oxidative stress and muscle damage in soccer athletes.
  
  
  METHODS
  This randomized, double-blind control trial was conducted on 54 male soccer players. Participants were randomly assigned to three groups to receive: 450 mg/d green tea extract (GTE) in the first group (n = 18), 450 mg/d sour tea extract (STE) in the second group (n = 18) and 450 mg/d maltodextrin in the control group (n = 18). Fasting whole blood samples were taken under resting conditions at the beginning and the end of the study to quantify the serum levels of muscle damage indices, aspartate aminotransferase (AST), creatine kinase (CK), lactate dehydrogenase (LDH), and oxidative stress biomarkers, malondialdehyde (MDA), and total antioxidant capacity (TAC).
  
  
  RESULTS
  After six weeks intervention, athletes who received GTE and STE supplements compared with the placebo had a significantly decreased MDA level (P = 0.008). Furthermore, STE supplementation resulted in a significant increase in TAC level compared with GTE and placebo groups (P = 0.01). However, supplementation with GTE and STE had no significant effects on muscle damage indices.
  
  
  CONCLUSIONS
  GTE and STE supplementation have beneficial effects on oxidative stress status in male athletes. However, both kinds of tea extract did not affect muscle damage status.
authors.affiliation: a Food Security and Nutrition Research Center, Department of Clinical Nutrition, School of Nutrition and Food Sciences, Isfahan University of Medical Sciences , Isfahan , Iran.
authors.forename: Amir
authors.initials: A
authors.lastname: Hadi
authors.affiliation: a Food Security and Nutrition Research Center, Department of Clinical Nutrition, School of Nutrition and Food Sciences, Isfahan University of Medical Sciences , Isfahan , Iran.
authors.forename: Makan
authors.initials: M
authors.lastname: Pourmasoumi
authors.affiliation: a Food Security and Nutrition Research Center, Department of Clinical Nutrition, School of Nutrition and Food Sciences, Isfahan University of Medical Sciences , Isfahan , Iran.
authors.forename: Marzieh
authors.initials: M
authors.lastname: Kafeshani
authors.affiliation: b Department of Physical Education and Sports Science , School of Management and Medical Information, Isfahan University of Medical Sciences , Isfahan , Iran.
authors.forename: Jahangir
authors.initials: J
authors.lastname: Karimian
authors.affiliation: c Department of Epidemiology , School of Health, Isfahan University of Medical Sciences , Isfahan , Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Maracy
authors.affiliation: a Food Security and Nutrition Research Center, Department of Clinical Nutrition, School of Nutrition and Food Sciences, Isfahan University of Medical Sciences , Isfahan , Iran.
authors.forename: Mohammad Hasan
authors.initials: MH
authors.lastname: Entezari
mesh_terms: D000293:Adolescent; D000328:Adult; D001219:Aspartate Aminotransferases / Q000097:blood; D056352:Athletes; D015415:Biomarkers / Q000097:blood; D028241:Camellia sinensis / Q000737:chemistry*; D003402:Creatine Kinase / Q000097:blood; D019587:Dietary Supplements; D004311:Double-Blind Method; D031584:Hibiscus / Q000737:chemistry*; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000097:blood; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D018482:Muscle, Skeletal / Q000187:drug effects*; D018384:Oxidative Stress / Q000187:drug effects*; D010936:Plant Extracts / Q000494:pharmacology*; D012146:Rest; D012916:Soccer; D055815:Young Adult
chemical_list: D015415:Biomarkers; D010936:Plant Extracts; D008315:Malondialdehyde; D007770:L-Lactate Dehydrogenase; D001219:Aspartate Aminotransferases; D003402:Creatine Kinase
keywords: athletes; green tea; muscle damage; oxidative stress; sour tea; supplementation