Dose-response effects of dietary protein on muscle protein synthesis during recovery from endurance exercise in young men: a double-blind randomized trial

Tyler A. Churchward-Venne, Philippe J. M. Pinckaers, Joey S. J. Smeets, Milan W. Betz, Joan M. Senden, Joy P. B. Goessens, Annemie P. Gijsen, Ian Rollo, Lex B. Verdijk, Luc J. C. van Loon*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

42 Citations (Web of Science)


Background: Protein ingestion increases skeletal muscle protein synthesis rates during recovery from endurance exercise.

Objectives: We aimed to determine the effect of graded doses of dietary protein co-ingested with carbohydrate on whole-body protein metabolism, and skeletal muscle myofibrillar (MyoPS) and mitochondrial (MitoPS) protein synthesis rates during recovery from endurance exercise.

Methods: In a randomized, double-blind, parallel-group design, 48 healthy, young, endurance-trained men (mean +/- SEM age: 27 +/- 1 y) received a primed continuous infusion of L-[ring-H-2(5)]phenylalanine, L-[ring-3,5-H-2(2)]-tyrosine, and L-[1-C-13]-leucine and ingested 45 g carbohydrate with either 0 (0 g PRO), 15 (15 g PRO), 30 (30 g PRO), or 45 (45 g PRO) g intrinsically L-[1-C-13]-phenylalanine and L-[1-C-13]-leucine labeled milk protein after endurance exercise. Blood and muscle biopsy samples were collected over 360 min of postexercise recovery to assess whole-body protein metabolism and both MyoPS and MitoPS rates.

Results: Protein intake resulted in similar to 70%-74% of the ingested protein-derived phenylalanine appearing in the circulation. Whole-body net protein balance increased dose-dependently after ingestion of 0, 15, 30, or 45 g protein (mean +/- SEM: -0.31 +/- 0.16, 5.08 +/- 0.21, 10.04 +/- 0.30, and 13.49 +/- 0.55 mu mol phenylalanine . kg(-1) . h(-1), respectively; P <0.001). 30 g PRO stimulated a similar to 46% increase in MyoPS rates (%/h) compared with 0 g PRO and was sufficient to maximize MyoPS rates after endurance exercise. MitoPS rates were not increased after protein ingestion; however, incorporation of dietary protein-derived L-[1-C-13]-phenylalanine into de novo mitochondrial protein increased dose-dependently after ingestion of 15, 30, and 45 g protein at 360 min postexercise (0.018 +/- 0.002, 0.034 +/- 0.002, and 0.046 +/- 0.003 mole percentage excess, respectively; P <0.001).

Conclusions: Protein ingested after endurance exercise is efficiently digested and absorbed into the circulation. Whole-body net protein balance and dietary protein-derived amino acid incorporation into mitochondrial protein respond to increasing protein intake in a dose-dependent manner. Ingestion of 30 g protein is sufficient to maximize MyoPS rates during recovery from a single bout of endurance exercise.

Original languageEnglish
Pages (from-to)303-317
Number of pages15
JournalAmerican Journal of Clinical Nutrition
Issue number2
Publication statusPublished - Aug 2020


  • myofibrillar protein synthesis
  • mitochondrial protein synthesis
  • skeletal muscle
  • dose-response
  • dietary protein
  • carbohydrate
  • endurance exercise
  • young men

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