The digestion rate of protein is an independent regulating factor of postprandial
protein retention.
Dangin, Martial, Yves Boirie, Clara Garcia-Rodenas, Pierre Gachon, Jacques Fauquant,
Philippe Callier, Olivier Ballèvre, and Bernard Beaufrère.
1Laboratoire de Nutrition Humaine, Université Clermont Auvergne, Centre de
Recherche en Nutrition Humaine, 63009 Clermont-Ferrand; 2Laboratoire de Technologie
Laitière, Institut National de la Recherche Agronomique, 35042 Rennes, France; and
3Nestec, Nestlé Research Center, CH 1000 Lausanne 26 Switzerland
APStracts 7:0223E, 2000.
To evaluate the importance of protein digestion rate on protein deposition, we
characterized leucine kinetics after ingestion of "protein" meals of identical
amino acid composition and nitrogen contents but of different digestion rates. Four
groups of five or six young men received an l-[1-13C]leucine infusion and one of the the
following 30-g protein meals: a single meal of slowly digested casein (CAS), a single
meal of free amino acid mimicking casein composition (AA), a single meal of rapidly
digested whey proteins (WP), or repeated meals of whey proteins (RPT-WP) mimicking
slow digestion rate. Comparisons were made between "fast" (AA, WP) and
"slow" (CAS, RPT-WP) meals of identical amino acid composition (AA vs.
CAS, and WP vs. RPT-WP). The fast meals induced a strong, rapid, and transient
increase of aminoacidemia, leucine flux, and oxidation. After slow meals, these
parameters increased moderately but durably. Postprandial leucine balance over 7 h was
higher after the slow than after the fast meals (CAS: 38 ± 13 vs. AA: «minus»12 ± 11, P
< 0.01; RPT-WP: 87 ± 25 vs. WP: 6 ± 19 µmol/kg, P < 0.05). Protein digestion rate is
an independent factor modulating postprandial protein deposition.
Received 23 June 2000; accepted in final form 16 October 2000
APS Manuscript Number E284-0.
Article publication pending Am J Physiol Endocrinol Metab
ISSN 1080-4757 Copyright 2000 The American Physiological Society.
Published in APStracts on 7 November 2000