Effects of whey protein on body composition, biochemical profile, and high intensity physical performances in well-trained endurance runners.

To assess the effects of 2-months of 30 g/day whey protein supplementation on body composition, selected biochemical parameters and high intensity physical performance in 29 well-trained endurance athletes. Subjects were randomly divided into 2 groups: whey group (n = 20), and control group (n = 9). Body composition, selected biochemical parameters, and Wingate peak power (PP) and mean power (MP), and maximal aerobic speed (MAS) were assessed before and after the intervention in both groups. The two groups continued to follow their specific training regimens during the 2-month intervention. After this period, body mass was increased in the whey group (3.8%, P < 0.001), with a decrease in percentage body fat (P < 0.004), and an increase in leg muscle volume (P < 0.001). These parameters were unchanged in the control group. Resting values of plasma ASAT, ALAT, CK, total cholesterol, LDL-cholesterol (all at P < 0.05), and urea (P < 0.01) were reduced in the whey group after the intervention. The control group showed no changes. The whey group had increased PP and MP, (P < 0.001 both) and MAS (P < 0.05), and decreased fatigue index (P < 0.05) after the 2-month intervention. The control group showed no significant changes of these measures. Whey protein supplementation combined with 2-month endurance training leads to a reduction of body fat, and increased leg muscle volume. ASAT, ALAT, and CK, were also reduced. These changes were accompanied by improvements in PP, and MP, as well as MAS in well-trained endurance athletes. These data suggest that protein supplementation could also be recommended for endurance athletes to support recovery and high intensity physical performances. [ABSTRACT FROM AUTHOR]