Whey protein precludes lipid and protein oxidation and improves body weight gain in resistance-exercised rats.

Background: Resistance exercise such as weight-lifting (WL) increases oxidation products in plasma, but less is known regarding the effect of WL on oxidative damage to tissues. Dietary compounds are known to improve antioxidant defences. Whey protein (WP) is a source of protein in a variety of sport supplements and can enhance physical performance.

Aim: To evaluate the effect of WL on biomarkers of lipid and protein oxidation, on liver antioxidants and on muscle growth in the absence or presence of WP in rats.

Methods: Thirty-two male Fisher rats were randomly assigned to sedentary or exercise-trained groups and were fed with control or WP diets. The WL programme consisted of inducing the animals to perform sets of jumps with weights attached to the chest. After 8 weeks, arteriovenous blood samples, abdominal fat, liver and gastrocnemius muscle were collected for analysis.

Results: WP precludes WL-mediated increases in muscle protein carbonyl content and maintains low levels of TBARS in exercised and sedentary animals. WL reduced liver CAT activity, whereas WP increased hepatic glutathione content. In addition, WL plus WP generated higher body and muscle weight than exercise without WP.

Conclusions: These data suggest that WP improves antioxidant defences, which contribute to the reduction of lipid and protein oxidation as well as body and muscle weight gain in resistance-exercised rats.