title: Endogenous proteins in the ileal digesta of adult humans given casein-, enzyme-hydrolyzed casein- or crystalline amino-acid-based diets in an acute feeding study.
abstract: OBJECTIVE
  To ascertain if the form of dietary nitrogen (free amino acids (AA), small peptides, or intact protein) affects the endogenous nitrogen containing substances lost from the upper digestive tract of humans.
  
  
  METHODS
  Digesta were collected via a naso-ileal tube from the terminal ileum of 16 adult humans in a single parallel study following an acute feeding regimen. Subjects were given an iso-nitrogenous and isocaloric test meal containing 150 g of casein (CAS) (n=6), enzyme-hydrolyzed casein (HCAS) (n=5) or crystalline AA (n=5) dissolved in 550 ml of water, as the sole sources of nitrogen.
  
  
  RESULTS
  The mean concentrations and flows of total nitrogen, protein nitrogen, and soluble protein nitrogen passing the terminal ileum were significantly higher (P <0.01) for the CAS and HCAS test-meal groups compared to the AA meal group. Dietary CAS and HCAS had a considerable influence on digesta mucin concentrations and flows compared to free AA (+41%). Only 3-4% of the total nitrogen remained unidentified.
  
  
  CONCLUSIONS
  The form of dietary nitrogen (protein, small peptides or free AA) had an acute effect upon the secretion or reabsorption of endogenous proteins in the small intestine of healthy humans, as evident from significant differences in both the quantity and composition of the proteins found in digesta at the end of the ileum.
authors.affiliation: Riddet Institute, Massey University, Palmerston North, New Zealand.
authors.forename: W
authors.initials: W
authors.lastname: Miner-Williams
authors.affiliation: The Unité de Recherche en Epidémiologie Nutritionnelle, L'unité mixte de recherche French Institute of Agricultural Research 1125, Institut national de la santé et de la recherche médicale 557, Conservatoire National des Arts et Métiers, Universite' Paris 13, Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Deglaire
authors.affiliation: The Gastroenterology Unit, Le Centre de Recherche en Nutrition Humaine d'Ile-de-France, Assistance Publique-Hôpitaux de Paris, University Paris 13, Hôpital Avicenne, Paris, France.
authors.forename: R
authors.initials: R
authors.lastname: Benamouzig
authors.affiliation: The State University of New York, Stony Brook, NY, USA.
authors.forename: M F
authors.initials: MF
authors.lastname: Fuller
authors.affiliation: French Institute of Agricultural Research, Le Centre de Recherche en Nutrition Humaine- d'Ile-de-France, L'unité mixte de recherche 914 Nutrition Physiology and Ingestive Behavior, Paris, France.
authors.forename: D
authors.initials: D
authors.lastname: Tomé
authors.affiliation: Riddet Institute, Massey University, Palmerston North, New Zealand.
authors.forename: P J
authors.initials: PJ
authors.lastname: Moughan
mesh_terms: D000328:Adult; D000596:Amino Acids / Q000008:administration & dosage* / Q000493:pharmacokinetics; D002364:Caseins / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D007082:Ileum / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D062407:Meals
chemical_list: D000596:Amino Acids; D002364:Caseins; D004044:Dietary Proteins