Carbohydrate Coingestion Delays Dietary Protein Digestion and Absorption but Does Not Modulate Postprandial Muscle Protein Accretion

S.H. Gorissen, N.A. Burd, H.M. Hamer, A.P. Gijsen, B.B. Groen, L.J. van Loon

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Background: Dietary protein digestion and absorption is an important factor modulating muscle protein accretion. However, there are few data available on the effects of co-ingesting other macronutrients with protein on digestion and absorption kinetics and the subsequent muscle protein synthetic response. Objective: To determine the impact of carbohydrate co-ingestion with protein on dietary protein digestion and absorption and muscle protein accretion in healthy young and older men. Design: Twenty-four healthy young (age: 21+/-1 y, BMI: 21.8+/-0.5 kg.m-2) and 25 older (age: 75+/-1 y, BMI: 25.4+/-0.6 kg.m-2) men received a primed continuous L-[ring-2H5]-phenylalanine and L-[ring-3,5-2H2]-tyrosine infusion and ingested 20 g intrinsically L-[1-13C]-phenylalanine-labeled protein with (Pro+CHO) or without (Pro) 60 g carbohydrate. Plasma samples and muscle biopsies were collected in a postabsorptive and postprandial state. Results: Carbohydrate co-ingestion delayed the appearance of exogenous phenylalanine in the circulation (P=0.001). Dietary protein-derived phenylalanine availability over the 5 h postprandial period was lower in the older (62+/-2%) when compared with the young subjects (74+/-2%; P=0.007), with no differences between conditions (P=0.20). Carbohydrate co-ingestion did not modulate postprandial muscle protein synthesis rates (0.035+/-0.003 vs 0.043+/-0.004 and 0.033+/-0.002 vs 0.035+/-0.003 %.h-1 following Pro vs Pro+CHO in the young and older group, respectively). In accordance, no differences in muscle protein-bound L-[1-13C]-phenylalanine enrichments were observed between conditions (0.020+/-0.002 vs 0.020+/-0.002 and 0.019+/-0.003 vs 0.022+/-0.004 mole percent excess following Pro vs Pro+CHO in the young and older subjects, respectively). Conclusion: Carbohydrate co-ingestion with protein delays dietary protein digestion and absorption, but does not modulate postprandial muscle protein accretion in healthy young or older men.
Original languageEnglish
Pages (from-to)2250-2258
Number of pages9
JournalJournal of Clinical Endocrinology & Metabolism
Volume99
Issue number6
DOIs
Publication statusPublished - Jun 2014

Keywords

  • INTRINSICALLY LABELED MILK
  • HUMAN-NUTRITION RESEARCH
  • ESSENTIAL AMINO-ACIDS
  • RESISTANCE EXERCISE
  • ANABOLIC RESPONSE
  • POSTABSORPTIVE STATE
  • ELDERLY-MEN
  • OLDER MEN
  • HUMANS
  • INSULIN

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