title: Post-Prandial Protein Handling: You Are What You Just Ate.
abstract: BACKGROUND
  Protein turnover in skeletal muscle tissue is highly responsive to nutrient intake in healthy adults.
  
  
  OBJECTIVE
  To provide a comprehensive overview of post-prandial protein handling, ranging from dietary protein digestion and amino acid absorption, the uptake of dietary protein derived amino acids over the leg, the post-prandial stimulation of muscle protein synthesis rates, to the incorporation of dietary protein derived amino acids in de novo muscle protein.
  
  
  METHODS
  12 healthy young males ingested 20 g intrinsically [1-13C]-phenylalanine labeled protein. In addition, primed continuous L-[ring-2H5]-phenylalanine, L-[ring-2H2]-tyrosine, and L-[1-13C]-leucine infusions were applied, with frequent collection of arterial and venous blood samples, and muscle biopsies throughout a 5 h post-prandial period. Dietary protein digestion, amino acid absorption, splanchnic amino acid extraction, amino acid uptake over the leg, and subsequent muscle protein synthesis were measured within a single in vivo human experiment.
  
  
  RESULTS
  55.3±2.7% of the protein-derived phenylalanine was released in the circulation during the 5 h post-prandial period. The post-prandial rise in plasma essential amino acid availability improved leg muscle protein balance (from -291±72 to 103±66 μM·min-1·100 mL leg volume-1; P<0.001). Muscle protein synthesis rates increased significantly following protein ingestion (0.029±0.002 vs 0.044±0.004%·h-1 based upon the muscle protein bound L-[ring-2H5]-phenylalanine enrichments (P<0.01)), with substantial incorporation of dietary protein derived L-[1-13C]-phenylalanine into de novo muscle protein (from 0 to 0.0201±0.0025 MPE).
  
  
  CONCLUSIONS
  Ingestion of a single meal-like amount of protein allows ~55% of the protein derived amino acids to become available in the circulation, thereby improving whole-body and leg protein balance. About 20% of the dietary protein derived amino acids released in the circulation are taken up in skeletal muscle tissue following protein ingestion, thereby stimulating muscle protein synthesis rates and providing precursors for de novo muscle protein synthesis.
  
  
  BACKGROUND
  trialregister.nl 3638.
authors.affiliation: Top Institute Food and Nutrition, Wageningen, The Netherlands.|Department of Human Movement Sciences, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: Bart B L
authors.initials: BB
authors.lastname: Groen
authors.affiliation: Top Institute Food and Nutrition, Wageningen, The Netherlands.|Department of Human Movement Sciences, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: Astrid M
authors.initials: AM
authors.lastname: Horstman
authors.affiliation: Top Institute Food and Nutrition, Wageningen, The Netherlands.|Department of Human Movement Sciences, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: Henrike M
authors.initials: HM
authors.lastname: Hamer
authors.affiliation: Department of Radiology, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: Michiel
authors.initials: M
authors.lastname: de Haan
authors.affiliation: Department of Human Movement Sciences, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: Janneau
authors.initials: J
authors.lastname: van Kranenburg
authors.affiliation: Laboratory Biochemical Genetics, Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: Jörgen
authors.initials: J
authors.lastname: Bierau
authors.affiliation: Department of Surgery, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: Martijn
authors.initials: M
authors.lastname: Poeze
authors.affiliation: Central Diagnostic Laboratory, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: Will K W H
authors.initials: WK
authors.lastname: Wodzig
authors.affiliation: Department of Nutrition and Metabolism, University of Texas Medical Branch, Galveston, Texas, United States of America.
authors.forename: Blake B
authors.initials: BB
authors.lastname: Rasmussen
authors.affiliation: Top Institute Food and Nutrition, Wageningen, The Netherlands.|Department of Human Movement Sciences, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: Luc J C
authors.initials: LJ
authors.lastname: van Loon
mesh_terms: D000328:Adult; D000596:Amino Acids / Q000097:blood / Q000493:pharmacokinetics*; D001706:Biopsy; D001786:Blood Glucose / Q000032:analysis; D002247:Carbon Isotopes / Q000032:analysis; D002364:Caseins / Q000493:pharmacokinetics; D004044:Dietary Proteins / Q000493:pharmacokinetics*; D005263:Femoral Artery; D005268:Femoral Vein; D006801:Humans; D007208:Indocyanine Green / Q000493:pharmacokinetics; D007328:Insulin / Q000097:blood; D007408:Intestinal Absorption; D007866:Leg; D007930:Leucine / Q000097:blood / Q000493:pharmacokinetics; D008297:Male; D009124:Muscle Proteins / Q000096:biosynthesis; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000378:metabolism*; D009928:Organ Specificity; D010649:Phenylalanine / Q000097:blood / Q000493:pharmacokinetics; D019518:Postprandial Period; D055815:Young Adult
chemical_list: D000596:Amino Acids; D001786:Blood Glucose; D002247:Carbon Isotopes; D002364:Caseins; D004044:Dietary Proteins; D007328:Insulin; D009124:Muscle Proteins; D010649:Phenylalanine; D007930:Leucine; D007208:Indocyanine Green