The bioavailability and postprandial utilisation of sweet lupin (Lupinus albus)-flour protein is similar to that of purified soyabean protein in human subjects: a study using intrinsically 15N-labelled proteins.
Sweet lupin (Lupinus albus), a protein-rich legume devoid of anti-nutritional factors, is considered to have a high potential for protein nutrition in man. Results concerning the nutritional value of lupin protein are, however, conflicting in animals and very scarce in human subjects. Furthermore, where fibre-rich protein sources are concerned, the long-term nutritional results are often obscured, particularly since fibre-promoted colonic fermentation may bias the energy supply and redistribute N flux. We therefore studied, during the postprandial phase, the bioavailability and utilisation of lupin-flour protein in nine healthy men who had ingested a mixed meal containing intrinsically 15N-labelled lupin flour as the protein source (Expt 1). The real ileal digestibility (RID) and ileal endogenous N losses (IENL) were assessed using a perfusion technique at the terminal ileum, and the N content and 15N enrichment of ileal samples. Lupin flour exhibited a high RID of 91 (SD 3)% and low IENL (5-4 (SD 1.3) mmol N/h). Postprandial dietary deamination was also assessed from body dietary urea and urinary dietary N excretion, and compared with results in nine healthy men following an iso-energetic meal containing a 15N-soyabean-protein isolate with a similar RID, as a control (Expt 2). Postprandial dietary deamination was similar after lupin and soyabean meals (17 (SD 2) and 18 (SD 4)% ingested N respectively). We therefore conclude that lupin protein is highly bioavailable, even if included in fibre-rich flour, and that it can be used with the same efficiency as soyabean protein to achieve postprandial protein gain in healthy human subjects.
Mariotti
François
F
UMR INRA-INAPG de Physiologie de la Nutrition et du Comportement Alimentaire, Institut National Agronomique Paris-Grignon. mariotti@inapg.inra.fr
Pueyo
Maria E
ME
Tomé
Daniel
D
Mahé
Sylvain
S
D000328:Adult; D000596:Amino Acids / Q000378:metabolism; D000704:Analysis of Variance; D001682:Biological Availability; D004063:Digestion; D007887:Fabaceae / Q000737:chemistry*; D006801:Humans; D007082:Ileum / Q000378:metabolism*; D008297:Male; D009584:Nitrogen / Q000378:metabolism*; D009587:Nitrogen Isotopes; D009753:Nutritive Value; D010940:Plant Proteins / Q000378:metabolism*; D019518:Postprandial Period; D030262:Soybean Proteins / Q000737:chemistry*
D000596:Amino Acids; D009587:Nitrogen Isotopes; D010940:Plant Proteins; D030262:Soybean Proteins; D009584:Nitrogen