Effects of intragastric tryptophan on acute changes in the plasma tryptophan/large neutral amino acids ratio and relationship with subsequent energy intake in lean and obese men.

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dc.contributor.author Hajishafiee, Maryam
dc.contributor.author Ullrich, Sina S
dc.contributor.author Steinert, Robert E
dc.contributor.author Poppitt, Sally D
dc.contributor.author Luscombe-Marsh, Natalie D
dc.contributor.author Horowitz, Michael
dc.contributor.author Feinle-Bisset, Christine
dc.coverage.spatial England
dc.date.accessioned 2021-01-13T21:40:32Z
dc.date.available 2021-01-13T21:40:32Z
dc.date.issued 2020-8
dc.identifier.issn 2042-6496
dc.identifier.uri https://hdl.handle.net/2292/54214
dc.description.abstract Circulating tryptophan/large neutral amino acids (tryptophan/LNAA) ratio, an indicator of brain serotonin levels, may be important in appetite regulation, together with gastrointestinal (gastric emptying, plasma cholecystokinin) mechanisms. We have compared effects of intragastric tryptophan ('Trp') on the plasma tryptophan/LNAA ratio in lean and obese men, and the associations of the tryptophan/LNAA ratio, gastric emptying and CCK concentrations with energy intake. Lean and obese male participants (n = 16 each) received 3 g Trp or volume-matched control intragastrically, 15 min before a mixed-nutrient drink (300 mL, 400 kcal) (t = 0 min) in randomised, double-blind fashion. Plasma amino acid (for calculation of the plasma tryptophan/LNAA ratio) and CCK concentrations were measured from t = -20-60 min. Gastric emptying was assessed from t = 0-60 min, and ad-libitum energy intake from a standardised buffet-style meal from t = 60-90 min. The increase in the plasma tryptophan/LNAA ratio was less in obese, than lean, participants (P < 0.05), and greater in lean participants who reduced their energy intake (by >0 kcal) after Trp compared with those who did not (by ≤0 kcal) (P < 0.05). Moreover, in participants who reduced their energy intake, the ratio was lower in obese, than in lean (P < 0.05). There was a trend for an inverse correlation between energy intake with the plasma tryptophan/LNAA ratio in lean (r = -0.4, P = 0.08), but not in obese, participants. There was no significant difference in gastric emptying or CCK between participants who reduced their energy intake and those who did not. In conclusion, the plasma tryptophan/LNAA ratio appears to be a determinant of the suppression of energy intake in response to tryptophan in normal-weight people, but not in those with obesity. The role of the plasma tryptophan/LNAA ratio to regulate energy intake, and potential changes in obesity, warrant evaluation in prospective studies.
dc.format.medium Print-Electronic
dc.language eng
dc.publisher Royal Society of Chemistry (RSC)
dc.relation.ispartofseries Food & function
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher.
dc.rights.uri https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm
dc.subject Science & Technology
dc.subject Life Sciences & Biomedicine
dc.subject Biochemistry & Molecular Biology
dc.subject Food Science & Technology
dc.subject FOOD-INTAKE
dc.subject PEPTIDE YY
dc.subject APPETITE
dc.subject SEROTONIN
dc.subject HEALTHY
dc.subject GLYCEMIA
dc.subject 1103 Clinical Sciences
dc.subject Clinical
dc.subject Clinical Medicine and Science
dc.subject Obesity
dc.subject Digestive Diseases
dc.subject Nutrition
dc.subject Clinical Research
dc.subject Oral and Gastrointestinal
dc.subject Cardiovascular
dc.subject Stroke
dc.subject Metabolic and Endocrine
dc.subject Cancer
dc.subject 0908 Food Sciences
dc.title Effects of intragastric tryptophan on acute changes in the plasma tryptophan/large neutral amino acids ratio and relationship with subsequent energy intake in lean and obese men.
dc.type Journal Article
dc.identifier.doi 10.1039/d0fo00773k
pubs.issue 8
pubs.begin-page 7095
pubs.volume 11
dc.date.updated 2020-12-03T00:16:22Z
dc.rights.holder Copyright: The author en
pubs.author-url https://www.ncbi.nlm.nih.gov/pubmed/32729586
pubs.end-page 7103
pubs.publication-status Published
dc.rights.accessrights http://purl.org/eprint/accessRights/RestrictedAccess en
pubs.subtype Journal Article
pubs.elements-id 814487
dc.identifier.eissn 2042-650X
pubs.online-publication-date 2020

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