Antioxidant Supplementation Impairs Changes in Body Composition Induced by Strength Training in Young Women.

Strength training (ST) is known to promote muscle hypertrophy and body composition adaptations. However, only a few studies investigated the effects of ST combined with antioxidant supplementation (AS) on these adaptations. The aim of this study was to investigate chronic effects of ST combined with AS on fat mass (FM) and fat-free mass (FFM) of young women. In a double-blinded design, thirty-three subjects (22.9 ± 2.5 years, 57.7 ± 8.4 kg, 1.6 ± 0.6 m) were allocated into three groups: 1) vitamins (n=12), 2) placebo (n=11) and 3) control (n=10). Vitamins and placebo underwent a ST program for 10 weeks. Vitamins supplemented with vitamin C (1g/day) and E (400IU/day) during the training period. FM and FFM were assessed by DEXA. Multiple 3 x 2 (group x time) mixed-factor ANOVA with Tukey adjustment was performed to examine differences in the dependent variables. The significance level was set at ≤ .05. Only placebo increased total FFM (34.9 ± 4.9 36.3 ± 4.8 kg, <0.05) and decreased total FM (21.8 ± 7.8 21.0 ± 8.3 kg, <0.05) after training for 10 weeks. Moreover, only placebo presented a significantly greater FFM percent change from pre to post-intervention compared to control (4.0 ± 3.4 -0.7 ± 3.1%, respectively, < 0.05). These results suggest that chronic AS can mitigate ST related improvements of body composition in young women.