title: Hydrolyzed dietary casein as compared with the intact protein reduces postprandial peripheral, but not whole-body, uptake of nitrogen in humans.
abstract: BACKGROUND
  Compared with slow proteins, fast proteins are more completely extracted in the splanchnic bed but contribute less to peripheral protein accretion; however, the independent influence of absorption kinetics and the amino acid (AA) pattern of dietary protein on AA anabolism in individual tissues remains unknown.
  
  
  OBJECTIVE
  We aimed to compare the postprandial regional utilization of proteins with similar AA profiles but different absorption kinetics by coupling clinical experiments with compartmental modeling.
  
  
  METHODS
  Experimental data pertaining to the intestine, blood, and urine for dietary nitrogen kinetics after a 15N-labeled intact (IC) or hydrolyzed (HC) casein meal were obtained in parallel groups of healthy adults (n = 21) and were analyzed by using a 13-compartment model to predict the cascade of dietary nitrogen absorption and regional metabolism.
  
  
  RESULTS
  IC and HC elicited a similar whole-body postprandial retention of dietary nitrogen, but HC was associated with a faster rate of absorption than was IC, resulting in earlier and stronger hyperaminoacidemia and hyperinsulinemia. An enhancement of both catabolic (26%) and anabolic (37%) utilization of dietary nitrogen occurred in the splanchnic bed at the expense of its further peripheral availability, which reached 18% and 11% of ingested nitrogen 8 h after the IC and HC meals, respectively.
  
  
  CONCLUSIONS
  The form of delivery of dietary AAs constituted an independent factor of modulation of their postprandial regional metabolism, with a fast supply favoring the splanchnic dietary nitrogen uptake over its peripheral anabolic use. These results question a possible effect of ingestion of protein hydrolysates on tissue nitrogen metabolism and accretion. This trial was registered at clinicaltrials.gov as NCT00873951.
authors.affiliation: INRA, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France.
authors.forename: Amélie
authors.initials: A
authors.lastname: Deglaire
authors.forename: Claire
authors.initials: C
authors.lastname: Fromentin
authors.forename: Hélène
authors.initials: H
authors.lastname: Fouillet
authors.forename: Gheorghe
authors.initials: G
authors.lastname: Airinei
authors.forename: Claire
authors.initials: C
authors.lastname: Gaudichon
authors.forename: Claire
authors.initials: C
authors.lastname: Boutry
authors.forename: Robert
authors.initials: R
authors.lastname: Benamouzig
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Moughan
authors.forename: Daniel
authors.initials: D
authors.lastname: Tomé
authors.forename: Cécile
authors.initials: C
authors.lastname: Bos
mesh_terms: D000328:Adult; D000596:Amino Acids / Q000493:pharmacokinetics*; D001775:Blood Circulation / Q000502:physiology; D002364:Caseins / Q000378:metabolism*; D004044:Dietary Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D006868:Hydrolysis; D006946:Hyperinsulinism / Q000209:etiology; D007408:Intestinal Absorption / Q000502:physiology*; D008297:Male; D008954:Models, Biological; D009584:Nitrogen / Q000493:pharmacokinetics*; D019518:Postprandial Period; D013152:Splanchnic Circulation / Q000502:physiology
chemical_list: D000596:Amino Acids; D002364:Caseins; D004044:Dietary Proteins; D009584:Nitrogen