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GAZZETTA MEDICA ITALIANA ARCHIVIO PER LE SCIENZE MEDICHE
A Journal on Internal Medicine and Pharmacology
Indexed/Abstracted in: BIOSIS Previews, EMBASE, Scopus, Emerging Sources Citation Index
Gazzetta Medica Italiana Archivio per le Scienze Mediche 2009 February;168(1):23-30
Antioxidant vitamin supplementation and oxidative stress in triathletes
Schneider C. D. 1, Silveira M. M. 2, Moreira J. C. F. 2, Belló-Klein A. 3, Oliveira A. R. 4
1 Laboratório de Pesquisa do Exercício (LAPEX) Escola de Educação Física UFRGS, Porto Alegre, RS, Brazil
2 Centro de Estudo em Estresse Oxidativo Departamento de Bioquímica Instituto de Ciências Básicas da Saúde UFRGS, Porto Alegre, RS, Brazil
3 Laboratório de Espécies Ativas de Oxigênio Departamento de Fisiologia Instituto de Ciências Básicas da Saúde UFRGS, Porto Alegre, RS, Brazil
4 Laboratory of Exercise Research Federal University of Rio Grande fo Sul Porto Alegre, RS, Brazil
Aim. Triathletes taking part in the Ironman triathlon supply a unique model to study the effects of exercise-induced oxidative stress and the effects of prolonged training on physiological processes. These athletes represent a population potentially exposed to oxidative damage due to high oxygen consumption during training. As a consequence, the idea of using antioxidant supplementation in athletes has become popular. The aim of this study was to describe oxidative stress parameters after 8 weeks of antioxidant vitamin supplement, at nutritional doses, during Ironman training.
Methods. Twelve male amateur triathletes (mean±SD for age 31.8±5.6 yr; body mass 74.4±6.4 kg; height 1.76±5.2 m; fat mass 15.0±5.5%; V.O2max treadmill 57.9±6.8 ml·kg-1·min-1; cycle-ergometer V.O2max 59.2±6.4 ml·kg-1·min-1) participated in this study. All athletes trained 15.5±3.4 h·week-1, and took 900 mg retinol acetate, 15 mg a-tocopherol acetate, and 270 mg ascorbic acid capsules for 8 weeks. Blood samples, taken before and after 8 weeks, were analyzed for antioxidant enzyme activity, total antioxidant capacity, uric acid, sulfhydryl, carbonyl, and lipid peroxidation.
Results. Activity of erythrocyte antioxidant enzyme decreased after 8 weeks of supplementation period (p<0.05); so did plasmatic carbonyls (p=0.001). We did not find significant differences in total antioxidant capacity, lipid peroxidation, uric acid, sulfhydryl, and creatine quinase during the period of the study.
Conclusion. The effects of the antioxidant mixture were observed for doses that can be provided by a diversified and balanced diet. Whatever the mechanisms involved, the antioxidant mixture and/or training helped to preserve the endogenous antioxidant system after these 8 weeks.