Micronutrients and antioxidant capacity in sedentary adolescents and runners

Objective The aim of this study was to compare body composition, biochemical indices of antioxidant micronutrients, intake and nutritional status and antioxidant capacity in post-puberty sedentary adolescents (n=15) and runners (n=18). Methods Skin-fold measurements, total body mass and height were used for anthropometric evaluation and a food frequency questionnaire for assessment of micronutrient intake. Biochemical indices measured after an overnight fast included: blood hemoglobin and hematocrit; plasma testosterone, a-tocopherol, copper zinc and ceruloplasmin; and in erythrocytes, osmotic fragility zinc, Cu-Zn superoxide dismutase and metallothionein. Results Indices of antioxidant capacity dietary intake, and body composition were not different between the groups, except for the sum of skin-folds that was lower in runners (p<0.05). Most adolescents had vitamin E intakes lower than nutritional recommendations. Plasma levels of copper and zinc were, on average, adequate. Copper levels were similar in both groups and zinc levels were higher in runners. In the sedentary group, erythrocyte osmotic fragility was correlated with metallothionein and Cu-Zn superoxide dismutase (r=-0.50; p<0.005); in runners, erythrocyte superoxide dismutase and zinc were correlated (r=0.49; p<0.005). Conclusion Our results suggest that the regular practice of running did not affect the antioxidant capacity of the adolescents studied besides growth. However this practice seems to favor a more appropriate body composition in adolescents. More attention is necessary on the nutritional status of alpha-tocopherol in adolescents.