Effects of Whey Protein Supplementation on Muscle Damage, Hepatic Stress, and Inflammatory Markers in Power- and Endurance-Trained Athletes.

In 30 seconds

This randomized, double-blind, placebo-controlled trial examined 8 weeks of whey protein supplementation (30 g/day) in 59 male power- and endurance-trained athletes. Biomarkers of liver function, inflammation, and muscle damage were measured before and after the intervention. ALT, AST, and CK decreased significantly after supplementation across the training groups (p = 0.001, p = 0.015, p = 0.001, and p = 0.003 respectively, as reported). ALT alone showed a significant Time × Supplementation × Training modality interaction (p = 0.003), indicating a modality-specific response. CRP fell within the supplemented power group, but there was no significant interaction supporting a difference between modalities.

Key findings

• ALT, AST, and CK decreased significantly after supplementation across power- and endurance-trained athletes (p = 0.001, p = 0.015, p = 0.001, and p = 0.003 respectively, as reported).
• ALT was the only biomarker with a significant Time × Supplementation × Training modality interaction (p = 0.003).
• CRP decreased within the supplemented power-trained group (p = 0.039), but the overall interaction for CRP was not significant.

Why it matters

The findings suggest whey supplementation may influence biochemical markers associated with hepatic and muscular stress in trained athletes, while the ALT interaction indicates that responses may differ by training modality. The CRP result warrants cautious interpretation because it was a within-group change without evidence of a differential effect between modalities. These biomarker findings inform recovery research but do not establish long-term health or performance benefits.

What to keep in mind

The study included only male athletes and assessed biomarkers over 8 weeks; long-term outcomes and dose-response effects were not established.