title: Green tea extract supplementation gives protection against exercise-induced oxidative damage in healthy men.
abstract: The purpose of this study was to evaluate the effects of a long-term (4-week) green tea extract (GTE) supplementation in combination with strength training on selected blood markers of oxidative stress and muscular damage after a short-term exercise in previously untrained men. We hypothesized that GTE supplementation would elevate antioxidant potential and attenuate exercise-induced oxidative stress and muscular damage. Thirty-five male students were exposed to 4 weeks of strength training and received (in a randomized, double-blind design) GTE (n = 17; 640 mg polyphenols/d) or placebo (P; n = 18). Before (term I) and after 4 weeks of strength training and supplementation (term II), students performed a short-term muscular endurance test. Blood samples were collected at rest, 5 minutes after the muscular endurance test, and after 24 hours of recovery. Supplementation with GTE enhanced plasma total polyphenols at rest and 5 minutes after the muscular endurance test. Supplementation also contributed to the rise of resting total antioxidant status in plasma. Throughout the experiment (terms I and II), a reduction in plasma lipid hydroxyperoxides was observed 24 hours after the muscular endurance test. Four weeks of strength training resulted in an increase in plasma lipid hydroxyperoxides at rest, but only in the P group. In term I, the muscular endurance test induced an increase in activity of creatine kinase in plasma after 24 hours of recovery in both the P and GTE groups. In term II, plasma creatine kinase activity after 24 hours of recovery was elevated only in the P group. In conclusion, in previously untrained men, dietary supplementation with GTE (in combination with strength training) enhances the antioxidant defense system in plasma at rest and, in turn, may give protection against oxidative damage induced by both short-term muscular endurance test and long-term strength training.
authors: Department of Biochemistry, Faculty of Physical Education and Sport in Biala Podlaska, Jozef Pilsudski University of Physical Education in Warsaw, Akademicka 2, 21-500 Biala Podlaska, Poland. ewa.jowko@awf-bp.edu.pl
authors: Ewa
authors: E
authors: Jówko
authors: Jaroslaw
authors: J
authors: Sacharuk
authors: Bozena
authors: B
authors: Balasińska
authors: Piotr
authors: P
authors: Ostaszewski
authors: Malgorzata
authors: M
authors: Charmas
authors: Robert
authors: R
authors: Charmas
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000032:analysis; D028241:Camellia sinensis / Q000737:chemistry*; D003402:Creatine Kinase / Q000097:blood; D019587:Dietary Supplements; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology*; D006801:Humans; D015227:Lipid Peroxidation; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects*; D010919:Placebos; D010936:Plant Extracts / Q000008:administration & dosage*; D055070:Resistance Training
chemical_list: D000975:Antioxidants; D010919:Placebos; D010936:Plant Extracts; D003402:Creatine Kinase