Effects of Whey Protein Supplementation on Muscle Damage, Hepatic Stress, and Inflammatory Markers in Power‐ and Endurance‐Trained Athletes
5 affiliations
- 1Higher Institute of Sport and Physical Education of Kef University of Jandouba Kef Tunisia
- 2Biology, Medicine, and Health Faculty of Medicine of Sousse Research Laboratory (LR19ES09) Exercise Physiology and Pathophysiology: From Integrated to Molecular University of Sousse Sousse Tunisia
- 3Laboratory of Clinical Biochemistry and Hormonology Pasteur Institute of Tunis University of Tunis‐El Manar Tunis Tunisia
- 4Higher Institute of Sport and Physical Education of Kssar Saïd University of Manouba Tunis Tunisia
- 5Institute of Primary Care University of Zurich and University Hospital of Zurich Zurich Switzerland
Abstract
This study investigated the effects of 8 weeks of whey protein supplementation (30 g/day) on biomarkers of liver function, inflammation, and muscle damage in trained power‐trained (predominantly speed‐power/anaerobic‐power disciplines) and endurance‐trained athletes, in a randomized, double‐blind, placebo‐controlled design. Fifty‐nine male athletes were stratified into power (n = 30) and endurance (n = 29) groups, then randomly assigned to a whey protein group (WG) or a placebo control group (CG). Biomarkers assessed pre‐ and post‐intervention included alanine aminotransferase (ALT), aspartate aminotransferase (AST), C‐reactive protein (CRP), and creatine kinase (CK). Significant reductions in ALT, AST, and CK were observed in both endurance‐ and power‐trained athletes after supplementation (p = 0.001, p = 0.015, p = 0.001, and p = 0.003 respectively), indicating attenuated hepatic and muscular stress. Among the four biomarkers, only ALT displayed a statistically significant three‐way interaction (Time × Supplementation × Training modality; p = 0.003), identifying it as the sole marker showing a genuine modality‐specific differential response to supplementation. A significant within‐group reduction in CRP was additionally observed in the supplemented power‐trained athletes (p = 0.039), whereas endurance athletes showed only minor, non‐significant changes; because the omnibus three‐way interaction for CRP was not significant, this finding is reported as a within‐group trend rather than evidence of a differential effect between modalities. Placebo groups demonstrated stable or increased enzyme and CRP values, particularly in endurance athletes. These findings suggest that whey protein may attenuate exercise‐induced hepatic and muscular stress across training modalities, with a modality‐specific effect on hepatic stress markers (ALT) observed in power‐trained athletes. The results highlight whey protein's potential as a nutritional aid to promote recovery and physiological adaptation, possibly mediated by antioxidant and anti‐inflammatory mechanisms. Further studies are warranted to examine long‐term outcomes and dose‐response effects across different training profiles.
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BibTeX
@article{mhamed2026effects,
title = {{Effects of Whey Protein Supplementation on Muscle Damage, Hepatic Stress, and Inflammatory Markers in Power‐ and Endurance‐Trained Athletes}},
author = {Mouna Ben Mhamed and Mounir Landolsi and Mehdi M'rad and Afef Bahlous and Faysal Zarrouk and Hejer Trabelsi and Katja Weiss and Thomas Rosemann and Ezdine Bouhlel and Beat Knechtle},
journal = {European Journal of Sport Science},
year = {2026},
month = oct,
doi = {10.1002/ejsc.70279},
url = {https://doi.org/10.1002/ejsc.70279},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Effects of Whey Protein Supplementation on Muscle Damage, Hepatic Stress, and Inflammatory Markers in Power‐ and Endurance‐Trained Athletes
AU - Mouna Ben Mhamed
AU - Mounir Landolsi
AU - Mehdi M'rad
AU - Afef Bahlous
AU - Faysal Zarrouk
AU - Hejer Trabelsi
AU - Katja Weiss
AU - Thomas Rosemann
AU - Ezdine Bouhlel
AU - Beat Knechtle
PY - 2026
DA - 2026/10/26
JO - European Journal of Sport Science
DO - 10.1002/ejsc.70279
UR - https://doi.org/10.1002/ejsc.70279
AB - This study investigated the effects of 8 weeks of whey protein supplementation (30 g/day) on biomarkers of liver function, inflammation, and muscle damage in trained power‐trained (predominantly speed‐power/anaerobic‐power disciplines) and endurance‐trained athletes, in a randomized, double‐blind, placebo‐controlled design. Fifty‐nine male athletes were stratified into power (n = 30) and endurance (n = 29) groups, then randomly assigned to a whey protein group (WG) or a placebo control group (CG). Biomarkers assessed pre‐ and post‐intervention included alanine aminotransferase (ALT), aspartate aminotransferase (AST), C‐reactive protein (CRP), and creatine kinase (CK). Significant reductions in ALT, AST, and CK were observed in both endurance‐ and power‐trained athletes after supplementation (p = 0.001, p = 0.015, p = 0.001, and p = 0.003 respectively), indicating attenuated hepatic and muscular stress. Among the four biomarkers, only ALT displayed a statistically significant three‐way interaction (Time × Supplementation × Training modality; p = 0.003), identifying it as the sole marker showing a genuine modality‐specific differential response to supplementation. A significant within‐group reduction in CRP was additionally observed in the supplemented power‐trained athletes (p = 0.039), whereas endurance athletes showed only minor, non‐significant changes; because the omnibus three‐way interaction for CRP was not significant, this finding is reported as a within‐group trend rather than evidence of a differential effect between modalities. Placebo groups demonstrated stable or increased enzyme and CRP values, particularly in endurance athletes. These findings suggest that whey protein may attenuate exercise‐induced hepatic and muscular stress across training modalities, with a modality‐specific effect on hepatic stress markers (ALT) observed in power‐trained athletes. The results highlight whey protein's potential as a nutritional aid to promote recovery and physiological adaptation, possibly mediated by antioxidant and anti‐inflammatory mechanisms. Further studies are warranted to examine long‐term outcomes and dose‐response effects across different training profiles.
SN - 1746-1391
SN - 1536-7290
ER -