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Guillin FM, Gaudichon C, Guérin-Deremaux L, Lefranc-Millot C, Airinei G, Khodorova N, Benamouzig R, Pomport PH, Martin J, Calvez J. Values for the Digestibility of Pea Protein Isolate or Casein Amino Acids Determined using the Dual Isotope Method Are Not Similar to Those Derived with the Standard Ileal Balance Method in Healthy Volunteers. J Nutr 2024; 154:516-525. [PMID: 38160805 DOI: 10.1016/j.tjnut.2023.12.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 12/15/2023] [Accepted: 12/22/2023] [Indexed: 01/03/2024] Open
Abstract
BACKGROUND The measurement of ileal amino acid (AA) digestibility is invasive and inappropriate when applied to vulnerable populations. The dual isotope method has been developed over the past 5 y as an alternative method. OBJECTIVE The aim of this work was to compare the indispensable amino acid (IAA) digestibility values of 2 different proteins obtained using the dual isotope and the standard ileal balance methods in the same subjects. METHODS Fifteen healthy adults completed the study. Over 4 h, they ingested 9 successive portions of mashed potatoes containing the test protein (pea protein or casein) labeled intrinsically with 15N and 2H, and a 13C-free AA mixture as a reference for the dual isotope method. Plasma was sampled regularly over the 8-h postprandial period, whereas the ileal digesta was collected continuously via a naso-ileal tube. Isotopic enrichments (15N and 13C) were measured in the digesta for the direct determination of ileal IAA digestibility, whereas plasma enrichments (2H and 13C) were measured to determine IAA digestibility using the dual isotope method. RESULTS The 4-h repeated meal procedure enabled the almost complete digestion of test proteins at 8 h and the attainment of a plasma isotopic plateau between 2.5 and 4 h. These conditions were necessary to perform the ileal balance and dual isotope methods simultaneously. For pea protein, the mean IAA digestibility was similar between the 2 methods, but significant differences (from 10% to 20%) were observed for individual IAA values. For casein, IAA digestibility was significantly lower with the dual isotope method for all the IAA analyzed. CONCLUSIONS Under our experimental conditions, the degree of agreement between the dual isotope and ileal balance methods varied among AAs and depended on the protein source. Further research is needed to validate the dual isotope method. This study was registered at clinicaltrials.gov as NCT04072770.
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Affiliation(s)
- Florence M Guillin
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, Palaiseau, France; Roquette, Nutrition & Health R&D, Lestrem, France
| | - Claire Gaudichon
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, Palaiseau, France
| | | | | | - Gheorghe Airinei
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, Palaiseau, France
| | - Nadezda Khodorova
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, Palaiseau, France
| | - Robert Benamouzig
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, Palaiseau, France
| | | | - Juliette Martin
- Unité expérimentale du Domaine d'Epoisses, INRAE, U2E, Bretenière, France
| | - Juliane Calvez
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, Palaiseau, France.
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Moughan PJ. Use of Isotope-Labeled Body or Dietary Proteins to Determine Dietary Amino Acid Digestibility. J Nutr 2023; 153:1858-1865. [PMID: 37207803 DOI: 10.1016/j.tjnut.2023.05.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 05/02/2023] [Accepted: 05/15/2023] [Indexed: 05/21/2023] Open
Abstract
Amino acid (AA) digestibility in humans has been determined conventionally based on oro-ileal AA disappearance. With this approach, it is necessary to account for undigested AAs of body origin (endogenous AAs) found in the ileal digesta. Determination of the endogenous AAs under physiological conditions is not straightforward, and the use of isotopes (labeled foods or body tissues) has been pivotal to advancing our understanding. The application of isotopes for determining gut endogenous AAs and AA digestibility is discussed as well as the types of digestibility coefficient generated (apparent, true, real) dependent upon methodology. Recently a new dual isotope-based method for determining ileal AA digestibility in humans has been developed that obviates the collection of ileal digesta. The dual isotope method, which awaits full validation, offers considerable promise for making noninvasive measures of AA digestibility in humans of different ages and physiological states.
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Affiliation(s)
- Paul J Moughan
- Riddet Institute, Massey University, Palmerston North, New Zealand.
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Tessier R, Calvez J, Airinei G, Khodorova N, Kapel R, Quinsac A, Galet O, Piedcoq J, Benamouzig R, Tomé D, Gaudichon C. The True Amino Acid Digestibility of 15N-Labelled Sunflower Biscuits Determined with Ileal Balance and Dual Isotope Methods in Healthy Humans. J Nutr 2022; 152:698-706. [PMID: 34910189 DOI: 10.1093/jn/nxab423] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 11/29/2021] [Accepted: 12/09/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Sunflower is a promising protein source but data on amino acid (AA) digestibility are lacking in humans. Classically, the determination of AA digestibility requires ileal digesta sampling. The dual isotope method is minimally invasive but has not been compared to the conventional approach. OBJECTIVES This study aimed to determine the true ileal digestibility of sunflower AAs in healthy volunteers who ate biscuits containing 15nitrogen (N) protein isolate, in comparison with the dual isotope method. METHODS Twelve healthy volunteers (men and women; 40.4 ± 10.5 years old; BMI, 23.7 ± 2.9 kg/m2) were equipped with a naso-ileal tube. For 4 hours, they consumed 9 repeated meals comprising 15N-sunflower protein biscuits together with 13carbon (C)-AAs, carried either in chocolate (SUN + Ch; n = 7) or apple puree (SUN + P; n = 5). Ileal digesta and blood were sampled throughout 8 hours after ingestion of the first meal. The 15N and 13C AA enrichments were measured in digesta to determine ileal digestibility directly and in plasma to determine lysine and threonine digestibility using the dual isotope method. Differences between methods and between vector groups were analyzed using paired and unpaired t-tests, respectively. RESULTS The ileal digestibility of sunflower indispensable AAs (IAA) was 89% ± 5.3%, with threonine and lysine having the lowest digestibility. In the SUN + Ch meal, IAA digestibility was 3% below that of SUN + P (P < 0.05). The mean free 13C-AA ileal digestibility was 98.1% ± 0.9%. No matter which matrix was used to carry 13C-AAs, plasma 15N and 13C-AA kinetics displayed a 1-hour offset. Digestibility obtained with the dual isotope method (70.4% ± 6.0% for threonine and 75.9% ± 22.3% for lysine) was below the target values. CONCLUSIONS The ileal digestibility of IAAs from a sunflower isolate incorporated in a biscuit was close to 90% in healthy adults. Under our experimental conditions, the dual isotope method provided lower values than the usual method. Further protocol developments are needed to validate the equivalence between both methods. This trial was registered at clinicaltrials.gov as NCT04024605.
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Affiliation(s)
- Romain Tessier
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, Paris, France
| | - Juliane Calvez
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, Paris, France
| | - Gheorghe Airinei
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, Paris, France.,Service d'Hépatogastroentérologie, Hôpital Avicenne, APHP, Bobigny, France
| | - Nadezda Khodorova
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, Paris, France
| | - Romain Kapel
- LRGP Unité Mixte de Recherche CNRS 7274, Université de Lorraine, Plateforme SVS, Vandoeuvre-les-Nancy, France
| | | | | | - Julien Piedcoq
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, Paris, France
| | - Robert Benamouzig
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, Paris, France.,Service d'Hépatogastroentérologie, Hôpital Avicenne, APHP, Bobigny, France
| | - Daniel Tomé
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, Paris, France
| | - Claire Gaudichon
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, Paris, France
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Tessari P. Leucine Transamination Is Lower in Middle-Aged Compared with Younger Adults. J Nutr 2017; 147:2025-2030. [PMID: 28931590 DOI: 10.3945/jn.117.250852] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 04/28/2017] [Accepted: 08/22/2017] [Indexed: 11/14/2022] Open
Abstract
Background: Insulin and age affect leucine (and protein) kinetics in vivo. However, to our knowledge, leucine transamination and the effects of insulin have not been studied in participants of different ages.Objective: The aims of the study were to measure whole-body leucine deamination to α-ketoisocaproate (KIC) and KIC reamination to leucine in middle-aged and younger healthy adults, both in the postabsorptive state and after hyperinsulinemia.Methods: Younger (mean ± SE age: 26 ± 2 y) and middle-aged (54 ± 3 y) healthy men and women were enrolled. Isotope dilution methods with 2 independent leucine and KIC tracers, a dual isotope model and the euglycemic, hyperinsulinemic clamp technique, were used.Results: Leucine deamination [expressed as μmol/(kg × min)] was consistently greater than KIC reamination. In middle-aged adults, postabsorptive leucine deamination (0.77 ± 0.05), reamination (0.49 ± 0.04), and net deamination (0.28 ± 0.04) were ∼30% lower than in the younger group (deamination: 1.12 ± 0.07; reamination: 0.70 ± 0.09; net deamination: 0.42 ± 0.04) (P < 0.002, P < 0.05, and P < 0.015, respectively). After the hyperinsulinemic clamp, plasma leucine and KIC concentrations were reduced by ∼50% in both groups. Deamination and reamination also were suppressed by ∼40-50% in both groups (P < 0.001); however, they remained lower [-35% (P = 0.02) and -25% (P = 0.036), respectively] in the middle-aged than in the younger participants. The leucine rate of appearance and its suppression by insulin were similar in the middle-aged and in the younger subjects. By using both the basal and the clamp data, deamination was directly correlated with the plasma leucine concentration (r = 0.61, P < 0.0025) and reamination to that of plasma KIC (r = 0.79, P < 0.00002). Expressing the data relative to lean body mass did not substantially alter the results.Conclusions: Leucine deamination and reamination are lower in middle-aged than in younger adults, both in the postabsorptive and in the insulin-stimulated state. In middle age, a decreased net leucine transamination may represent a mechanism to spare this essential amino acid.
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Affiliation(s)
- Paolo Tessari
- Department of Medicine, Division of Metabolic Diseases, University of Padova, Padova, Italy
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