scholarly journals Intragastric administration of the bitter tastant quinine lowers the glycemic response to a nutrient drink without slowing gastric emptying in healthy men

2020 ◽  
Vol 318 (2) ◽  
pp. R263-R273 ◽  
Author(s):  
Vida Bitarafan ◽  
Penelope C. E. Fitzgerald ◽  
Tanya J. Little ◽  
Wolfgang Meyerhof ◽  
Karen L. Jones ◽  
...  

The rate of gastric emptying and the release of gastrointestinal (GI) hormones are major determinants of postprandial blood-glucose concentrations and energy intake. Preclinical studies suggest that activation of GI bitter-taste receptors potently stimulates GI hormones, including glucagon-like peptide-1 (GLP-1), and thus may reduce postprandial glucose and energy intake. We evaluated the effects of intragastric quinine on the glycemic response to, and the gastric emptying of, a mixed-nutrient drink and the effects on subsequent energy intake in healthy men. The study consisted of 2 parts: part A included 15 lean men, and part B included 12 lean men (aged 26 ± 2 yr). In each part, participants received, on 3 separate occasions, in double-blind, randomized fashion, intragastric quinine (275 or 600 mg) or control, 30 min before a mixed-nutrient drink ( part A) or before a buffet meal ( part B). In part A, plasma glucose, insulin, glucagon, and GLP-1 concentrations were measured at baseline, after quinine alone, and for 2 h following the drink. Gastric emptying of the drink was also measured. In part B, energy intake at the buffet meal was quantified. Quinine in 600 mg (Q600) and 275 mg (Q275) doses alone stimulated insulin modestly ( P < 0.05). After the drink, Q600 and Q275 reduced plasma glucose and stimulated insulin ( P < 0.05), Q275 stimulated GLP-1 ( P < 0.05), and Q600 tended to stimulate GLP-1 ( P = 0.066) and glucagon ( P = 0.073) compared with control. Quinine did not affect gastric emptying of the drink or energy intake. In conclusion, in healthy men, intragastric quinine reduces postprandial blood glucose and stimulates insulin and GLP-1 but does not slow gastric emptying or reduce energy intake under our experimental conditions.

Nutrients ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1613
Author(s):  
Rachel A. Elovaris ◽  
Vida Bitarafan ◽  
Shahram Agah ◽  
Sina S. Ullrich ◽  
Kylie Lange ◽  
...  

(1) Background: Whey protein lowers postprandial blood glucose in health and type 2 diabetes, by stimulating insulin and incretin hormone secretion and slowing gastric emptying. The branched-chain amino acids, leucine, isoleucine and valine, abundant in whey, may mediate the glucoregulatory effects of whey. We investigated the comparative effects of intragastric administration of leucine, isoleucine and valine on the plasma glucose, C-peptide and glucagon responses to and gastric emptying of a mixed-nutrient drink in healthy men. (2) Methods: 15 healthy men (27 ± 3 y) received, on four separate occasions, in double-blind, randomised fashion, either 10 g of leucine, 10 g of isoleucine, 10 g of valine or control, intragastrically, 30 min before a mixed-nutrient drink. Plasma glucose, C-peptide and glucagon concentrations were measured before, and for 2 h following, the drink. Gastric emptying of the drink was quantified using 13C-acetate breath-testing. (3) Results: Amino acids alone did not affect plasma glucose or C-peptide, while isoleucine and valine, but not leucine, stimulated glucagon (p < 0.05), compared with control. After the drink, isoleucine and leucine reduced peak plasma glucose compared with both control and valine (all p < 0.05). Neither amino acid affected early (t = 0–30 min) postprandial C-peptide or glucagon. While there was no effect on overall gastric emptying, plasma glucose at t = 30 min correlated with early gastric emptying (p < 0.05). (4) Conclusion: In healthy individuals, leucine and isoleucine lower postprandial blood glucose, at least in part by slowing gastric emptying, while valine does not appear to have an effect, possibly due to glucagon stimulation.


Nutrients ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1788 ◽  
Author(s):  
Penelope C. E. Fitzgerald ◽  
Benoit Manoliu ◽  
Benjamin Herbillon ◽  
Robert E. Steinert ◽  
Michael Horowitz ◽  
...  

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 13C-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.


Nutrients ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1451 ◽  
Author(s):  
Caroline Giezenaar ◽  
Kylie Lange ◽  
Trygve Hausken ◽  
Karen Jones ◽  
Michael Horowitz ◽  
...  

Whey protein, when ingested on its own, load-dependently slows gastric emptying and stimulates gut hormone concentrations in healthy young men. The aim of this study was to determine the effects of substitution, and addition, of carbohydrate (dextrose) and fat (olive oil) to whey protein. In randomized, double-blind order, 13 healthy young men (age: 23 ± 1 years, body mass index: 24 ± 1 kg/m2) ingested a control drink (450 mL; ~2 kcal/‘control’) or iso-volumetric drinks containing protein/carbohydrate/fat: (i) 14 g/28 g/12.4 g (280 kcal/‘M280′), (ii) 70 g/28 g/12.4 g (504kcal/‘M504′), and (iii) 70 g/0 g/0 g (280 kcal/‘P280′), on 4 separate study days. Gastric emptying (n = 11, 3D-ultrasonography), blood glucose, plasma insulin, ghrelin, cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1) concentrations (0–180 min), appetite (visual analogue scales), and ad-libitum buffet-meal energy intake (180–210 min) were determined. Substitution of protein with carbohydrate and fat was associated with faster gastric emptying (lower 50% emptying time (T50)), reduced suppression of ghrelin, and stimulation of GLP-1 (all P < 0.001); while the addition of carbohydrate and fat to protein did not affect gastric emptying or gut hormone responses significantly. Total energy intake (i.e., drink plus meal) was greater after all caloric drinks than control (P < 0.001). In conclusion, substitution of whey protein with dextrose and olive oil accelerated gastric emptying. Higher protein content of a mixed macronutrient drink increased gut hormone and insulin responses.


Nutrients ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2697 ◽  
Author(s):  
Christina McVeay ◽  
Penelope C. E. Fitzgerald ◽  
Michael Horowitz ◽  
Christine Feinle-Bisset

The fatty acid, lauric acid (‘C12’), and the amino acid, tryptophan (‘Trp’), when given intraduodenally at loads that individually do not affect energy intake, have recently been shown to stimulate plasma cholecystokinin, suppress ghrelin and reduce energy intake much more markedly when combined. Both fatty acids and amino acids stimulate insulin secretion by distinct mechanisms; fatty acids enhance glucose-stimulated insulin secretion, while amino acids may have a direct effect on pancreatic β cells. Therefore, it is possible that, by combining these nutrients, their effects to lower blood glucose may be enhanced. We have investigated the potential for the combination of C12 and Trp to have additive effects to reduce blood glucose. To address this question, plasma concentrations of glucose, insulin and glucagon were measured in 16 healthy, lean males during duodenal infusions of saline (control), C12 (0.3 kcal/min), Trp (0.1 kcal/min), or C12+Trp (0.4 kcal/min), for 90 min. Both C12 and C12+Trp moderately reduced plasma glucose compared with control (p < 0.05). C12+Trp, but not C12 or Trp, stimulated insulin and increased the insulin-to-glucose ratio (p < 0.05). There was no effect on plasma glucagon. In conclusion, combined intraduodenal administration of C12 and Trp reduced fasting glucose in healthy men, and this decrease was driven primarily by C12. The effects of these nutrients on postprandial blood glucose and elevated fasting blood glucose in type 2 diabetes warrant evaluation.


2001 ◽  
Vol 280 (2) ◽  
pp. R570-R576 ◽  
Author(s):  
Katherine Beckoff ◽  
Caroline G. MacIntosh ◽  
Ian M. Chapman ◽  
Judith M. Wishart ◽  
Howard A. Morris ◽  
...  

The aims of this study were to evaluate the effects of dietary glucose supplementation on gastric emptying (GE) of both glucose and fat, postprandial blood glucose homeostasis, and appetite in eight older subjects (4 males, 4 females, aged 65–84 yr). GE of a drink (15 ml olive oil and 33 g glucose dissolved in 185 ml water), blood glucose, insulin, gastric inhibitory polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), and appetite (diet diaries, visual analog scales, and food intake at a buffet meal consumed after the GE study) were evaluated twice, after 10 days on a standard or a glucose-supplemented diet (70 g glucose 3 times a day). Glucose supplementation accelerated GE of glucose ( P < 0.05), but not oil; there was a trend for an increase in GIP (at 15 min, P = 0.06), no change in GLP-1, an earlier insulin peak ( P < 0.01), and a subsequent reduction in blood glucose (at 75 min, P < 0.01). Glucose supplementation had no effect on food intake during each diet so that energy intake was greater ( P < 0.001) during the glucose-supplemented diet. Appetite ratings and energy intake at the buffet meal were not different. We conclude that, in older subjects, glucose supplementation 1) accelerates GE of glucose, but not fat; 2) modifies postprandial blood glucose homeostasis; and 3) increases energy intake.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maryam Hajishafiee ◽  
Rachel A. Elovaris ◽  
Karen L. Jones ◽  
Leonie K. Heilbronn ◽  
Michael Horowitz ◽  
...  

Abstract Background The rate of gastric emptying and glucoregulatory hormones are key determinants of postprandial glycaemia. Intragastric administration of L-tryptophan slows gastric emptying and reduces the glycaemic response to a nutrient drink in lean individuals and those with obesity. We investigated whether tryptophan decreases postprandial glycaemia and slows gastric emptying in type 2 diabetes (T2D). Methods Twelve men with T2D (age: 63 ± 2 years, HbA1c: 49.7 ± 2.5 mmol/mol, BMI: 30 ± 1 kg/m2) received, on three separate occasions, 3 g (‘Trp-3’) or 1.5 g (‘Trp-1.5’) tryptophan, or control (0.9% saline), intragastrically, in randomised, double-blind fashion, 30 min before a mixed-nutrient drink (500 kcal, 74 g carbohydrates), containing 3 g 3-O-methyl-D-glucose (3-OMG) to assess glucose absorption. Venous blood samples were obtained at baseline, after tryptophan, and for 2 h post-drink for measurements of plasma glucose, C-peptide, glucagon and 3-OMG. Gastric emptying of the drink was quantified using two-dimensional ultrasound. Results Tryptophan alone stimulated C-peptide (P = 0.002) and glucagon (P = 0.04), but did not affect fasting glucose. In response to the drink, Trp-3 lowered plasma glucose from t = 15–30 min and from t = 30–45 min compared with control and Trp-1.5, respectively (both P < 0.05), with no differences in peak glucose between treatments. Gastric emptying tended to be slower after Trp-3, but not Trp-1.5, than control (P = 0.06). Plasma C-peptide, glucagon and 3-OMG increased on all days, with no major differences between treatments. Conclusions In people with T2D, intragastric administration of 3 g tryptophan modestly slows gastric emptying, associated with a delayed rise, but not an overall lowering of, postprandial glucose.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 375
Author(s):  
Saori Deguchi ◽  
Fumihiko Ogata ◽  
Takumi Isaka ◽  
Hiroko Otake ◽  
Yosuke Nakazawa ◽  
...  

Postprandial hyperglycemia, a so-called blood glucose spike, is associated with enhanced risks of diabetes mellitus (DM) and its complications. In this study, we attempted to design nanoparticles (NPs) of protamine zinc insulin (PZI) by the bead mill method, and prepare ophthalmic formulations based on the PZI-NPs with (nPZI/P) or without polyacrylic acid (nPZI). In addition, we investigated whether the instillation of the newly developed nPZI and nPZI/P can prevent postprandial hyperglycemia in a rabbit model involving the oral glucose tolerance test (OGTT). The particle size of PZI was decreased by the bead mill to a range for both nPZI and nPZI/P of 80–550 nm with no observable aggregation for 6 d. Neither nPZI nor nPZI/P caused any noticeable corneal toxicity. The plasma INS levels in rabbits instilled with nPZI were significantly higher than in rabbits instilled with INS suspensions (commercially available formulations, CA-INS), and the plasma INS levels were further enhanced with the amount of polyacrylic acid in the nPZI/P. In addition, the rapid rise in plasma glucose levels in OGTT-treated rabbits was prevented by a single instillation of nPZI/P, which was significantly more effective at attenuating postprandial hyperglycemia (blood glucose spike) in comparison with nPZI. In conclusion, we designed nPZI/P, and show that a single instillation before OGTT attenuates the rapid enhancement of plasma glucose levels. These findings suggest a better management strategy for the postprandial blood glucose spike, which is an important target of DM therapy.


2009 ◽  
Vol 8 (1) ◽  
Author(s):  
Joanna Hlebowicz ◽  
Jenny Maria Jönsson ◽  
Sandra Lindstedt ◽  
Ola Björgell ◽  
Gassan Darwich ◽  
...  

1989 ◽  
Vol 61 (2) ◽  
pp. 285-290 ◽  
Author(s):  
K. M. Cunningham ◽  
N. W. Read

1. Three studies were carried out in each of six normal volunteers to investigate how lipid, when given at different stages during the course of a meal, affects gastric emptying and postprandial blood glucose and insulin concentrations.2. The control meal consisted of 300 ml beef consommé (50 kJ, 12 kcal), followed 20 min later by 300 g mashed potato (908 kJ, 217 kcal). In the two test meals, 60 g margarine were incorporated into either the soup or the mashed potato.3. The addition of margarine to either component of the meal delayed gastric emptying of the mashed potato (P< 0.05), but the pattern varied according to the component to which the fat was added.4. Incorporation of fat into the soup increased the lag phase (P< 0.05) but did not influence the slope of emptying of the mashed potato, while incorporation of fat into the mashed potato reduced the slope of emptying of the mashed potato (P< 0.05) but did not influence the lag phase.5. Addition of fat to either component of the meal reduced postprandial blood glucose (P< 0.05) and insulin responses, but when the fat was incorporated in the soup, peak glucose and insulin responses were delayed as well (P< 0.05).6. The results show that the effect of fat on gastric emptying and absorption of nutrients depends on when, in relation to the other components of the meal, the fat is consumed.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
İsmail Mücahit Alptekin ◽  
Ece Erdoğan ◽  
Aylin İşler ◽  
Esma Cansu Yanalak ◽  
Funda Pınar Çakiroğlu ◽  
...  

Purpose Previous studies have reported that dietary fibers such as polydextrose and maltodextrin can reduce food intake; however, the studies on the differences of this effect are insufficient. The purpose of this paper is to compare the effects of dietary fibers maltodextrin and polydextrose on alterations of short-term satiety, energy intake and postprandial blood glucose in healthy females. Design/methodology/approach This study was designed as a randomized, crossover and double blind research. For this purpose, 21 healthy females consumed a milkshake containing 0 g (control), 15 g polydextrose (PDX) and 15 g maltodextrin (MDX), and an ad libitum lunch meal was served 150 min later. Subjective appetite scores (hunger, satiety, prospective food consumption and desire to eat) were measured using a visual analog scale. Appetite scores and blood glucose were measured before preload and once per 15 min after milkshake consumption. Findings Visual analog scale scores showed that PDX had an improved effect on satiety and hunger feelings. Compared to the control, dietary fiber increased the Area Under Curve (AUC) scores of satiety (p < 0.001) and decreased the AUC scores of hunger (p < 0.001), prospective food consumption (p < 0.001) and desire to eat (p < 0.001). Energy intake during ad libitum meal was significantly lower in PDX (Control: 862 (54.3) Kcal versus PDX: 679 (35.4) Kcal and MDX: 780 (49.3) Kcal. Moreover, the blood glucose levels were significantly lower in MDX. Originality/value This study conducted with healthy females demonstrated that PDX was more effective in inducing satiety during subsequent food intake, and that postprandial blood glucose were within more healthy levels in MDX.


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