title: Creatine ingestion effects on oxidative stress in a steady-state test at 75% VO(2max).
abstract: OBJECTIVE
  The present study was carried out with the aim to analyze the role of creatine on oxidative stress during exercise, i.e. whether creatine is a pro-oxidative or an antioxidant substance.
  
  
  METHODS
  In a randomized double-blind study involving 30 adult males, we examined plasma lactate, oxidative stress markers (malondialdehyde, MDA) and glutathione redox ratio (GSSG·GSH-1), antioxidative systems (vitamins A, E, C), and ergospirometric responses (respiratory quotient and relative oxygen uptake) before and after 30 min steady-state tests 75% VO2max (placebo and creatine).
  
  
  RESULTS
  Ergospirometric tests, hematocrit values, blood lactate as well as vitamins A, E and C concentrations did not show significant differences between creatine and placebo testing. Conversely, oxidative stress markers MDA and GSSG·GSH-1 increased during placebo trials much more than in creatine trials.
  
  
  CONCLUSIONS
  This is the first report documenting that a creatine loading, i.e., a 0.3 g/kg/die of creatine ingestion for 5 consecutive days, could reduce the oxidative stress, whereas its consumption may not have a clear metabolic advantage in certain aerobic activities.
authors.affiliation: Department of Bio-Medical Sciences, University of Catania, Catania, Italy. marinella.coco@unict.it
authors.forename: M
authors.initials: M
authors.lastname: Coco
authors.forename: V
authors.initials: V
authors.lastname: Perciavalle
mesh_terms: D000293:Adolescent; D000328:Adult; D001205:Ascorbic Acid / Q000097:blood; D003401:Creatine / Q000008:administration & dosage / Q000494:pharmacology*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005978:Glutathione / Q000097:blood; D019803:Glutathione Disulfide / Q000097:blood; D006400:Hematocrit; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D018384:Oxidative Stress / Q000187:drug effects*; D010101:Oxygen Consumption; D005082:Physical Exertion; D013147:Spirometry; D014801:Vitamin A / Q000097:blood; D014810:Vitamin E / Q000097:blood; D055815:Young Adult
chemical_list: D014801:Vitamin A; D014810:Vitamin E; D019344:Lactic Acid; D008315:Malondialdehyde; D005978:Glutathione; D003401:Creatine; D001205:Ascorbic Acid; D019803:Glutathione Disulfide