Carbohydrate co-ingestion with protein does not further augment post-prandial muscle protein accretion in older men

H.M.H. Hamer, B.T. Wall, A. Kiskini, A. de Lange, B.B. Groen, J.A. Bakker, A.P. Gijsen, L.B. Verdijk, L.J.C. van Loon

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Abstract

ABSTRACT: BACKGROUND: A blunted muscle protein synthetic response to protein ingestion may contribute to the age related loss of muscle tissue. We hypothesized that the greater endogenous insulin release following co-ingestion of carbohydrate facilitates post-prandial muscle protein accretion after ingesting a meal-like bolus of protein in older males. METHODS: Twenty-four healthy older men (75+/-1 y) were randomly assigned to ingest 20 g intrinsically L-[1-13C] phenylalanine-labeled casein protein with (PRO-CHO) or without (PRO) 40 g carbohydrate. Ingestion of specifically produced intrinsically L-[1-13C] phenylalanine labeled protein allowed us to assess post-prandial incorporation of dietary protein derived amino acids into muscle protein. Blood samples were collected at regular intervals, with muscle biopsies being obtained prior to and 2 and 6 h after protein ingestion. RESULTS: Plasma glucose and insulin concentrations showed a greater increase in PRO-CHO compared with PRO (P<0.001). Muscle protein-bound L-[1-13C] phenylalanine enrichments tended to increase to a greater extent in PRO-CHO compared with PRO during the first 2 h after protein ingestion (0.0072+/-0.0013 vs 0.0046+/-0.010 MPE, respectively; P=0.13). However, 6 h after protein ingestion, differences in muscle protein-bound L-[1-13C] phenylalanine enrichments were no longer observed between experiments (0.0213+/-0.0024 vs 0.0185+/-0.0010 MPE, respectively; P=0.30). CONCLUSIONS: This study shows that carbohydrate ingestion may accelerate, but does not further augment post-prandial incorporation of dietary protein derived amino acids into muscle protein in healthy elderly men.
Original languageEnglish
Article number15
Number of pages9
JournalNutrition & Metabolism
Volume10
Issue number1
DOIs
Publication statusPublished - 25 Jan 2013

Keywords

  • Skeletal muscle
  • Ageing
  • Sarcopenia
  • Amino acids
  • Anabolic resistance
  • HUMAN SKELETAL-MUSCLE
  • INTRINSICALLY LABELED MILK
  • HUMAN-NUTRITION RESEARCH
  • HEALTHY-HUMAN SUBJECTS
  • AMINO-ACIDS
  • BLOOD-FLOW
  • DIFFERENTIAL REGULATION
  • ANABOLIC RESISTANCE
  • IN-VIVO
  • INSULIN

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