This study, published in the European Journal of Sport Science, explores the effects of whey protein supplementation on muscle damage, hepatic stress, and inflammatory markers in power- and endurance-trained athletes. Conducted over 8 weeks, the randomized controlled trial involved 59 male athletes who were divided into power-trained and endurance-trained groups.
Participants were randomly assigned to either a whey protein group (WG) or a placebo control group (CG), with the whey protein dosage set at 30 g/day. The study measured several biomarkers before and after the intervention, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), C-reactive protein (CRP), and creatine kinase (CK).
Results indicated significant reductions in ALT, AST, and CK levels in both endurance- and power-trained athletes following supplementation. Specifically, the reductions were statistically significant with p-values of 0.001 for ALT, 0.015 for AST, and 0.003 for CK, suggesting that whey protein may help attenuate hepatic and muscular stress during exercise.
Among the biomarkers assessed, only ALT exhibited a significant three-way interaction (Time × Supplementation × Training modality; p = 0.003), indicating a modality-specific response to whey protein supplementation. Additionally, a significant within-group reduction in CRP was noted in the power-trained athletes (p = 0.039), while endurance athletes showed minor, non-significant changes. The placebo groups, in contrast, demonstrated stable or increased enzyme and CRP values, particularly in endurance-trained athletes.
The findings suggest that whey protein supplementation may be beneficial in reducing exercise-induced hepatic and muscular stress across different training modalities. The study highlights a specific effect on hepatic stress markers, particularly ALT, in power-trained athletes. The authors propose that these benefits may be mediated by antioxidant and anti-inflammatory mechanisms inherent in whey protein.
Further research is warranted to investigate long-term outcomes and dose-response effects of whey protein supplementation across various training profiles. The study’s results underscore the potential of whey protein as a nutritional aid to enhance recovery and physiological adaptation in athletes.
What this study does not show
This study does not demonstrate the long-term effects of whey protein supplementation beyond the 8-week intervention period, nor does it establish a direct causal relationship between supplementation and improved athletic performance.
Evidence scorecard
- Analytic validity: established
- Clinical validity: established
- Clinical utility: established