Antioxidant supplementation and tapering exercise improve exercise-induced antioxidant response.
OBJECTIVE
The present controlled-training, double-blind study (supplemented, n = 7; placebo, n = 9) investigated whether taper training (TT) and antioxidant supplementation, i.e., 150 micro g of selenium, 2000 IU of retinol, 120 mg of ascorbic acid and 30 IU of alpha-tocopherol, modulates antioxidant potential, redox status and oxidative damage occurrence both at rest and in response to exercise. Two weeks of TT followed four weeks of overloaded training. Dietary intakes were recorded. Before and after TT, triathletes did a duathlon consisting of 5-km run, 20-km bike and 5-km run. Biological studies were conducted at rest and after exercise.


RESULTS
Whatever the nutritional status, TT induced a decrease in resting blood reduced glutathione (GSH) concentration (p < 0.001), erythrocyte superoxide dismutase (SOD) activity (p < 0.0001) and plasma total antioxidant status (TAS) (p < 0.05). Only in the supplemented group (Su) with TT, did plasma glutathione peroxidase (GSH-Px) activity decrease (p < 0.05) and CD4(+) cell concentration increase (p < 0.05). However, antioxidant supplementation increased plasma TAS increase in response to exercise and TT (p < 0.05). After exercise, TT also induced a lower decrease in blood reduced and oxidized (GSSG) glutathione (p < 0.01) in both groups, but TT had no effect on lipoperoxidation as estimated by plasma thiobarbituric reactive substances or on muscular damage occurrence estimated by plasma creatine kinase isoenzyme MB mass.


CONCLUSIONS
During TT, antioxidant supplementation at nutritional doses reinforces antioxidant status response to exercise, with an effect on exercise-induced oxidative stress, and no effect on oxidative damage.
Margaritis
Irène
I
Laboratoire de Physiologie Cellulaire et Moléculaire des Systèmes Intégrés, CNRS UMR 6548, Faculté des Sciences du Sport, Université de Nice-Sophia-Antipolis, 261 Route de Grenoble, BP 3259, 06205 Nice Cedex 3, France. margarit@unice.fr
Palazzetti
Stéphane
S
Rousseau
Anne-Sophie
AS
Richard
Marie-Jeanne
MJ
Favier
Alain
A
D000328:Adult; D000975:Antioxidants / Q000008:administration & dosage* / Q000378:metabolism; D019587:Dietary Supplements; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology*; D005978:Glutathione / Q000097:blood*; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects*; D010101:Oxygen Consumption; D010807:Physical Endurance / Q000502:physiology*; D013482:Superoxide Dismutase / Q000097:blood; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis
D000975:Antioxidants; D017392:Thiobarbituric Acid Reactive Substances; D013482:Superoxide Dismutase; D005978:Glutathione