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Effects of L-Phenylalanine on Energy Intake and Glycaemia—Impacts on Appetite Perceptions, Gastrointestinal Hormones and Gastric Emptying in Healthy Males
In humans, phenylalanine stimulates plasma cholecystokinin (CCK) and pyloric pressures, both of which are important in the regulation of energy intake and gastric emptying. Gastric emptying is a key determinant of postprandial blood glucose. We evaluated the effects of intragastric phenylalanine on...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7353198/ https://www.ncbi.nlm.nih.gov/pubmed/32560181 http://dx.doi.org/10.3390/nu12061788 |
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author | Fitzgerald, Penelope C. E. Manoliu, Benoit Herbillon, Benjamin Steinert, Robert E. Horowitz, Michael Feinle-Bisset, Christine |
author_facet | Fitzgerald, Penelope C. E. Manoliu, Benoit Herbillon, Benjamin Steinert, Robert E. Horowitz, Michael Feinle-Bisset, Christine |
author_sort | Fitzgerald, Penelope C. E. |
collection | PubMed |
description | In humans, phenylalanine stimulates plasma cholecystokinin (CCK) and pyloric pressures, both of which are important in the regulation of energy intake and gastric emptying. Gastric emptying is a key determinant of postprandial blood glucose. We evaluated the effects of intragastric phenylalanine on appetite perceptions and subsequent energy intake, and the glycaemic response to, and gastric emptying of, a mixed-nutrient drink. The study consisted of two parts, each including 16 healthy, lean males (age: 23 ± 1 years). In each part, participants received on three separate occasions, in randomised, double-blind fashion, 5 g (Phe-5 g) or 10g (‘Phe-10 g) L-phenylalanine, or control, intragastrically, 30 min before a standardised buffet-meal (part A), or a standardised mixed-nutrient drink (part B). In part A, plasma CCK and peptide-YY (PYY), and appetite perceptions, were measured at baseline, after phenylalanine alone, and following the buffet-meal, from which energy intake was assessed. In part B, plasma glucose, glucagon-like peptide-1 (GLP-1), insulin and glucagon were measured at baseline, after phenylalanine alone, and for 2 h following the drink. Gastric emptying of the drink was also measured by (13)C-acetate breath-test. Phe-10 g, but not Phe-5 g, stimulated plasma CCK (p = 0.01) and suppressed energy intake (p = 0.012); energy intake was correlated with stimulation of CCK (r = −0.4, p = 0.027), and tended to be associated with stimulation of PYY (r = −0.31, p = 0.082). Both Phe-10 g and Phe-5 g stimulated insulin and glucagon (all p < 0.05), but not GLP-1. Phe-10 g, but not Phe-5 g, reduced overall plasma glucose (p = 0.043) and peak plasma glucose (p = 0.017) in response to the mixed-nutrient drink. Phenylalanine had no effect on gastric emptying of the drink. In conclusion, our observations indicate that the energy intake-suppressant effect of phenylalanine is related to the stimulation of CCK and PYY, while the glucoregulatory effect may be independent of stimulation of plasma GLP-1 or slowing of gastric emptying. |
format | Online Article Text |
id | pubmed-7353198 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-73531982020-07-15 Effects of L-Phenylalanine on Energy Intake and Glycaemia—Impacts on Appetite Perceptions, Gastrointestinal Hormones and Gastric Emptying in Healthy Males Fitzgerald, Penelope C. E. Manoliu, Benoit Herbillon, Benjamin Steinert, Robert E. Horowitz, Michael Feinle-Bisset, Christine Nutrients Article In humans, phenylalanine stimulates plasma cholecystokinin (CCK) and pyloric pressures, both of which are important in the regulation of energy intake and gastric emptying. Gastric emptying is a key determinant of postprandial blood glucose. We evaluated the effects of intragastric phenylalanine on appetite perceptions and subsequent energy intake, and the glycaemic response to, and gastric emptying of, a mixed-nutrient drink. The study consisted of two parts, each including 16 healthy, lean males (age: 23 ± 1 years). In each part, participants received on three separate occasions, in randomised, double-blind fashion, 5 g (Phe-5 g) or 10g (‘Phe-10 g) L-phenylalanine, or control, intragastrically, 30 min before a standardised buffet-meal (part A), or a standardised mixed-nutrient drink (part B). In part A, plasma CCK and peptide-YY (PYY), and appetite perceptions, were measured at baseline, after phenylalanine alone, and following the buffet-meal, from which energy intake was assessed. In part B, plasma glucose, glucagon-like peptide-1 (GLP-1), insulin and glucagon were measured at baseline, after phenylalanine alone, and for 2 h following the drink. Gastric emptying of the drink was also measured by (13)C-acetate breath-test. Phe-10 g, but not Phe-5 g, stimulated plasma CCK (p = 0.01) and suppressed energy intake (p = 0.012); energy intake was correlated with stimulation of CCK (r = −0.4, p = 0.027), and tended to be associated with stimulation of PYY (r = −0.31, p = 0.082). Both Phe-10 g and Phe-5 g stimulated insulin and glucagon (all p < 0.05), but not GLP-1. Phe-10 g, but not Phe-5 g, reduced overall plasma glucose (p = 0.043) and peak plasma glucose (p = 0.017) in response to the mixed-nutrient drink. Phenylalanine had no effect on gastric emptying of the drink. In conclusion, our observations indicate that the energy intake-suppressant effect of phenylalanine is related to the stimulation of CCK and PYY, while the glucoregulatory effect may be independent of stimulation of plasma GLP-1 or slowing of gastric emptying. MDPI 2020-06-16 /pmc/articles/PMC7353198/ /pubmed/32560181 http://dx.doi.org/10.3390/nu12061788 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Fitzgerald, Penelope C. E. Manoliu, Benoit Herbillon, Benjamin Steinert, Robert E. Horowitz, Michael Feinle-Bisset, Christine Effects of L-Phenylalanine on Energy Intake and Glycaemia—Impacts on Appetite Perceptions, Gastrointestinal Hormones and Gastric Emptying in Healthy Males |
title | Effects of L-Phenylalanine on Energy Intake and Glycaemia—Impacts on Appetite Perceptions, Gastrointestinal Hormones and Gastric Emptying in Healthy Males |
title_full | Effects of L-Phenylalanine on Energy Intake and Glycaemia—Impacts on Appetite Perceptions, Gastrointestinal Hormones and Gastric Emptying in Healthy Males |
title_fullStr | Effects of L-Phenylalanine on Energy Intake and Glycaemia—Impacts on Appetite Perceptions, Gastrointestinal Hormones and Gastric Emptying in Healthy Males |
title_full_unstemmed | Effects of L-Phenylalanine on Energy Intake and Glycaemia—Impacts on Appetite Perceptions, Gastrointestinal Hormones and Gastric Emptying in Healthy Males |
title_short | Effects of L-Phenylalanine on Energy Intake and Glycaemia—Impacts on Appetite Perceptions, Gastrointestinal Hormones and Gastric Emptying in Healthy Males |
title_sort | effects of l-phenylalanine on energy intake and glycaemia—impacts on appetite perceptions, gastrointestinal hormones and gastric emptying in healthy males |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7353198/ https://www.ncbi.nlm.nih.gov/pubmed/32560181 http://dx.doi.org/10.3390/nu12061788 |
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