Diminished postprandial secretion of incretins and insulin represents one of the key pathophysiological mechanisms behind type 2 diabetes (T2D). We tested the effects of two energy- and macronutrient-matched meals: A standard meat (M-meal) and a vegan (V-meal) on postprandial incretin and insulin secretion in participants with T2D. A randomized crossover design was used in 20 participants with T2D. Plasma concentrations of glucose, insulin, C-peptide, glucagon-like peptide-1 (GLP-1), amylin, and gastric inhibitory peptide (GIP) were determined at 0, 30, 60, 120, and 180 min. Beta-cell function was assessed with a mathematical model, using C-peptide deconvolution. Repeated-measures ANOVA was used for statistical analysis. Postprandial plasma glucose responses were similar after both test meals (p = 0.64). An increase in the stimulated secretion of insulin (by 30.5%; 95% CI 21.2 to 40.7%; p < 0.001), C-peptide (by 7.1%; 95% CI 4.1 to 9.9%; p < 0.001), and amylin (by 15.7%; 95% CI 11.8 to 19.7%; p < 0.001) was observed following consumption of the V-meal. An increase in stimulated secretion of GLP-1 (by 19.2%; 95% CI 12.4 to 26.7%; p < 0.001) and a decrease in GIP (by -9.4%; 95% CI -17.3 to -0.7%; p = 0.02) were observed after the V-meal. Several parameters of beta-cell function increased after the V-meal, particularly insulin secretion at a fixed glucose value 5 mmol/L, rate sensitivity, and the potentiation factor. Our results showed an increase in postprandial incretin and insulin secretion, after consumption of a V-meal, suggesting a therapeutic potential of plant-based meals for improving beta-cell function in T2D.

• Keywords
• beta-cell function, incretins, insulin resistance, nutrition, plant-based, type 2 diabetes,
• MeSH
• Diabetes Mellitus, Type 2 diet therapy   metabolism   MeSH
• Diet, Vegan MeSH
• Adult MeSH
• Energy Intake MeSH
• Incretins metabolism   MeSH
• Insulin metabolism   MeSH
• Meals * MeSH
• Cross-Over Studies MeSH
• Middle Aged MeSH
• Humans MeSH
• Meat MeSH
• Vegetables MeSH
• Nutrients MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Publication type
• Journal Article MeSH
• Randomized Controlled Trial MeSH
• Names of Substances
• Incretins MeSH
• Insulin MeSH

Gastrointestinal hormones are involved in regulation of glucose metabolism and satiety. We tested the acute effect of meal composition on these hormones in three population groups. A randomized crossover design was used to examine the effects of two energy- and macronutrient-matched meals: a processed-meat and cheese (M-meal) and a vegan meal with tofu (V-meal) on gastrointestinal hormones, and satiety in men with type 2 diabetes (T2D, n = 20), obese men (O, n = 20), and healthy men (H, n = 20). Plasma concentrations of glucagon-like peptide -1 (GLP-1), amylin, and peptide YY (PYY) were determined at 0, 30, 60, 120 and 180 min. Visual analogue scale was used to assess satiety. We used repeated-measures Analysis of variance (ANOVA) for statistical analysis. Postprandial secretion of GLP-1 increased after the V-meal in T2D (by 30.5%; 95%CI 21.2 to 40.7%; p < 0.001) and H (by 15.8%; 95%CI 8.6 to 23.5%; p = 0.01). Postprandial plasma concentrations of amylin increased in in all groups after the V-meal: by 15.7% in T2D (95%CI 11.8 to 19.6%; p < 0.001); by 11.5% in O (95%CI 7.8 to 15.3%; p = 0.03); and by 13.8% in H (95%CI 8.4 to 19.5%; p < 0.001). An increase in postprandial values of PYY after the V-meal was significant only in H (by 18.9%; 95%CI 7.5 to 31.3%; p = 0.03). Satiety was greater in all participants after the V-meal: by 9% in T2D (95%CI 4.4 to 13.6%; p = 0.004); by 18.7% in O (95%CI 12.8 to 24.6%; p < 0.001); and by 25% in H (95%CI 18.2 to 31.7%; p < 0.001). Our results indicate there is an increase in gut hormones and satiety, following consumption of a single plant-based meal with tofu when compared with an energy- and macronutrient-matched processed-meat meat and cheese meal, in healthy, obese and diabetic men.

• Keywords
• gastrointestinal hormones, nutrition, plant-based, satiety, type 2 diabetes,
• MeSH
• Cholesterol blood   MeSH
• Diabetes Mellitus, Type 2 blood   MeSH
• Diet, Vegetarian * MeSH
• Dietary Proteins administration & dosage   MeSH
• Dietary Carbohydrates administration & dosage   MeSH
• Dietary Fats administration & dosage   MeSH
• Adult MeSH
• Gastrointestinal Hormones blood   MeSH
• Glycated Hemoglobin metabolism   MeSH
• Body Mass Index MeSH
• Insulin blood   MeSH
• Meals * MeSH
• Cross-Over Studies MeSH
• Blood Glucose metabolism   MeSH
• Middle Aged MeSH
• Humans MeSH
• Meat Products MeSH
• Obesity blood   MeSH
• Postprandial Period MeSH
• Aged MeSH
• Triglycerides blood   MeSH
• Satiation * MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Publication type
• Journal Article MeSH
• Randomized Controlled Trial MeSH
• Names of Substances
• Cholesterol MeSH
• Dietary Proteins MeSH
• Dietary Carbohydrates MeSH
• Dietary Fats MeSH
• Gastrointestinal Hormones MeSH
• Glycated Hemoglobin A MeSH
• Insulin MeSH
• Blood Glucose MeSH
• Triglycerides MeSH

The aim of this study was to test the effect of a plant-based dietary intervention on beta-cell function in overweight adults with no history of diabetes. Participants (n = 75) were randomized to follow a low-fat plant-based diet (n = 38) or to make no diet changes (n = 37) for 16 weeks. At baseline and 16 weeks, beta-cell function was quantified with a mathematical model. Using a standard meal test, insulin secretory rate was calculated by C-peptide deconvolution. The Homeostasis Model Assessment (HOMA-IR) index was used to assess insulin resistance while fasting. A marked increase in meal-stimulated insulin secretion was observed in the intervention group compared with controls (interaction between group and time, Gxt, p < 0.001). HOMA-IR index fell significantly (p < 0.001) in the intervention group (treatment effect -1.0 (95% CI, -1.2 to -0.8); Gxt, p = 0.004). Changes in HOMA-IR correlated positively with changes in body mass index (BMI) and visceral fat volume (r = 0.34; p = 0.009 and r = 0.42; p = 0.001, respectively). The latter remained significant after adjustment for changes in BMI (r = 0.41; p = 0.002). Changes in glucose-induced insulin secretion correlated negatively with BMI changes (r = -0.25; p = 0.04), but not with changes in visceral fat. Beta-cell function and insulin sensitivity were significantly improved through a low-fat plant-based diet in overweight adults.

• Keywords
• beta-cell function, diabetes, diet, nutrition, vegan,
• MeSH
• Absorptiometry, Photon MeSH
• Adiposity MeSH
• Insulin-Secreting Cells metabolism   MeSH
• Diet, Fat-Restricted * MeSH
• Diet, Vegan * MeSH
• Adult MeSH
• Energy Intake MeSH
• Weight Loss MeSH
• Body Mass Index MeSH
• Insulin blood   metabolism   MeSH
• Insulin Resistance * MeSH
• Middle Aged MeSH
• Humans MeSH
• Overweight blood   diagnostic imaging   diet therapy   metabolism   MeSH
• Intra-Abdominal Fat diagnostic imaging   MeSH
• Obesity blood   diagnostic imaging   diet therapy   metabolism   MeSH
• Postprandial Period MeSH
• Diet, Reducing * MeSH
• Insulin Secretion MeSH
• Aged MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Randomized Controlled Trial MeSH
• Geographicals
• District of Columbia MeSH
• Names of Substances
• Insulin MeSH

BACKGROUND: Appetite and gastrointestinal hormones (GIHs) participate in energy homeostasis, feeding behavior and regulation of body weight. We demonstrated previously the superior effect of a hypocaloric diet regimen with lower meal frequency (B2) on body weight, hepatic fat content, insulin sensitivity and feelings of hunger compared to the same diet divided into six smaller meals a day (A6). Studies with isoenergetic diet regimens indicate that lower meal frequency should also have an effect on fasting and postprandial responses of GIHs. The aim of this secondary analysis was to explore the effect of two hypocaloric diet regimens on fasting levels of appetite and GIHs and on their postprandial responses after a standard meal. It was hypothesized that lower meal frequency in a reduced-energy regimen leading to greater body weight reduction and reduced hunger would be associated with decreased plasma concentrations of GIHs: gastric inhibitory peptide (GIP), glucagon-like peptide-1(GLP-1), peptide YY(PYY), pancreatic polypeptide (PP) and leptin and increased plasma concentration of ghrelin. The postprandial response of satiety hormones (GLP-1, PYY and PP) and postprandial suppression of ghrelin will be improved. METHODS: In a randomized crossover study, 54 patients suffering from type 2 diabetes (T2D) underwent both regimens. The concentrations of GLP-1, GIP, PP, PYY, amylin, leptin and ghrelin were determined using multiplex immunoanalyses. RESULTS: Fasting leptin and GIP decreased in response to both regimens with no difference between the treatments (p = 0.37 and p = 0.83, respectively). Fasting ghrelin decreased in A6 and increased in B2 (with difference between regimens p = 0.023). Fasting PP increased in B2with no significant difference between regimens (p = 0.17). Neither GLP-1 nor PYY did change in either regimen. The decrease in body weight correlated negatively with changes in fasting ghrelin (r = -0.4, p<0.043) and the postprandial reduction of ghrelin correlated positively with its fasting level (r = 0.9, p<0.001). The postprandial responses of GIHs and appetite hormones were similar after both diet regimens. CONCLUSIONS: Both hypocaloric diet regimens reduced fasting leptin and GIP and postprandial response of GIP comparably. The postprandial responses of GIHs and appetite hormones were similar after both diet regimens. Eating only breakfast and lunch increased fasting plasma ghrelin more than the same caloric restriction split into six meals. The changes in fasting ghrelin correlated negatively with the decrease in body weight. These results suggest that for type 2 diabetic patients on a hypocaloric diet, eating larger breakfast and lunch may be more efficient than six smaller meals during the day.

• MeSH
• Time Factors MeSH
• Diabetes Mellitus, Type 2 diet therapy   pathology   physiopathology   psychology   MeSH
• Adult MeSH
• Ghrelin blood   MeSH
• Glucagon-Like Peptide 1 blood   MeSH
• Hunger physiology   MeSH
• Insulin Resistance MeSH
• Meals * physiology   psychology   MeSH
• Caloric Restriction methods   MeSH
• Cross-Over Studies MeSH
• Leptin blood   MeSH
• Middle Aged MeSH
• Humans MeSH
• Pancreatic Polypeptide blood   MeSH
• Peptide YY blood   MeSH
• Aged MeSH
• Body Weight MeSH
• Treatment Outcome MeSH
• Gastric Inhibitory Polypeptide blood   MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Randomized Controlled Trial MeSH
• Names of Substances
• Ghrelin MeSH
• Glucagon-Like Peptide 1 MeSH
• Leptin MeSH
• Pancreatic Polypeptide MeSH
• Peptide YY MeSH
• Gastric Inhibitory Polypeptide MeSH