title: Validation of a new test meal for a protein digestion breath test in humans.
abstract: Previously, overall protein assimilation after the ingestion of a pure protein meal was studied. In this study, the kinetics of protein assimilation in humans were investigated after the ingestion of a complex meal, which more closely represents a physiologically normal situation. Overall protein assimilation in humans after the ingestion of a pancake meal, containing 12 g of fat, 27 g of carbohydrate, and 19 g of protein, was evaluated in 26 normal volunteers. Both the egg white and yolk of L-[1-(13)C]-leucine-substituted eggs were used to make the batter. The labeled eggs were produced by feeding laying hens a standard chicken diet supplemented with 3 g/kg of L-[1-(13)C]-leucine (99%, mol:mol). High enrichment levels of protein with adequate labeling patterns were obtained in eggs from laying hens fed the L-[1-(13)C]-leucine-substituted diet. The isotopic enrichment of leucine at plateau was equal in egg white and yolk. The overall tracer recovery in egg proteins was 22.5%. The overall protein assimilation parameters in subjects that consumed the pancake meal did not differ from those obtained in subjects that consumed a single protein meal (mean cumulative (13)C recovery/6 h = 17.22 +/- 4.74%, with a maximal (13)C recovery/h of 5.65 +/- 1.48%, which was attained 145 +/- 25 min after ingestion of the meal). The pancake test meal prepared with eggs intrinsically labeled with L-[1-(13)C]-leucine is ideal for the study of protein assimilation. The incorporation of differently labeled substrates into a single test meal allows the assessment of different gastrointestinal processes in the overall assimilation of proteins.
authors.affiliation: Department of Gastroenterology, University Hospital Gasthuisberg, Catholic University of Leuven, 3000 Leuven, Belgium. karen.geboes@uz.kuleuven.ac.be
authors.forename: Karen P
authors.initials: KP
authors.lastname: Geboes
authors.forename: Bert
authors.initials: B
authors.lastname: Bammens
authors.forename: Anja
authors.initials: A
authors.lastname: Luypaerts
authors.forename: Ramon
authors.initials: R
authors.lastname: Malheiros
authors.forename: Johan
authors.initials: J
authors.lastname: Buyse
authors.forename: Pieter
authors.initials: P
authors.lastname: Evenepoel
authors.forename: Paul
authors.initials: P
authors.lastname: Rutgeerts
authors.forename: Kristin
authors.initials: K
authors.lastname: Verbeke
mesh_terms: D001944:Breath Tests; D002247:Carbon Isotopes; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000493:pharmacokinetics; D004044:Dietary Proteins / Q000008:administration & dosage / Q000493:pharmacokinetics*; D004063:Digestion; D004529:Egg White / Q000032:analysis; D004530:Egg Yolk / Q000737:chemistry; D004531:Eggs; D005260:Female; D005502:Food; D005746:Gastric Emptying; D005772:Gastrointestinal Transit; D006801:Humans; D007553:Isotope Labeling; D007700:Kinetics; D007930:Leucine / Q000032:analysis; D008297:Male
chemical_list: D002247:Carbon Isotopes; D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D007930:Leucine