title: The effects of an antioxidant-supplemented beverage on exercise-induced oxidative stress: results from a placebo-controlled double-blind study in cyclists.
abstract: The objective of this study was to test the effects of an antioxidant-supplemented beverage on exercise-induced oxidative stress in moderately trained cyclists. A double-blind study was conducted in moderately trained cyclists. They were randomly allocated to receive either an antioxidant (13 subjects) or a placebo (13 subjects) 15 min pre-exercise (30 ml.kg(-1)) and during a 90 min constant-load test (30 ml.kg(-1).15 min(-1)) on a bicycle ergometer at 70% VO2max The supplemented beverage contained black grape (81 g/l), raspberry (93 g/l) and red currant (39 g/l) concentrates, and its total antioxidant capacity, measured by the ABTS(.+) technique, was 0.41 mM Trolox. No significant difference from basal to post-exercise period was detected for plasma TBARS in either the placebo group or the group receiving the antioxidant supplemented beverage. Post-exercise carbonyls decreased by 29% in the group receiving antioxidants, and the pattern of change was significantly different between antioxidant and placebo conditions. The urinary excretion of 8-OHdG increased significantly by 21% in the placebo group. Again differences in the pre- to post-exercise change were significant between both conditions These results suggest that in moderately trained cyclists, antioxidant supplementation counters oxidative stress induced by a 90 min exercise at 70% VO2max.
authors.affiliation: Department of Physiology, Catholic University of Murcia, Murcia, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Morillas-Ruiz
authors.forename: P
authors.initials: P
authors.lastname: Zafrilla
authors.forename: M
authors.initials: M
authors.lastname: Almar
authors.forename: M J
authors.initials: MJ
authors.lastname: Cuevas
authors.forename: F J
authors.initials: FJ
authors.lastname: López
authors.forename: P
authors.initials: P
authors.lastname: Abellán
authors.forename: J A
authors.initials: JA
authors.lastname: Villegas
authors.forename: J
authors.initials: J
authors.lastname: González-Gallego
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000328:Adult; D000975:Antioxidants / Q000008:administration & dosage*; D001628:Beverages; D003402:Creatine Kinase / Q000097:blood; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000652:urine; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology*; D005638:Fruit; D006801:Humans; D008297:Male; D018384:Oxidative Stress / Q000502:physiology*; D050050:Protein Carbonylation / Q000502:physiology; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
chemical_list: D000975:Antioxidants; D017392:Thiobarbituric Acid Reactive Substances; D000080242:8-Hydroxy-2'-Deoxyguanosine; D003402:Creatine Kinase; D003849:Deoxyguanosine