Nutrients related to GLP1 secretory responses

Identification and utility exploration of a highly potent and long-acting bullfrog GLP-1 analogue in GLP-1 and amylin combination therapy

This study assesses the efficacy of an innovative therapeutic approach that combines GLP-1 and amylin analogues for weight reduction. Focusing on GLP-1 analogues from bullfrog (Rana catesbeiana), we designed ten bGLP-1 analogues with various modifications. Among them, bGLP-10 showed high potency in binding and activating GLP-1 receptors, with superior albumin affinity. In diet-induced obesity (DIO) mice fed a high-fat diet, bGLP-10 demonstrated significant superiority over semaglutide in reducing blood sugar and food intake at a dose of 10 nmol/kg (P < 0.001). Notably, in a chronic study involving DIO mice, the combination of bGLP-10 with the amylin analogue cagrilintide led to a more substantial weight loss (-38.4%, P < 0.001) compared to either the semaglutide-cagrilintide combination (-23.0%) or cagrilintide (-5.7%), bGLP-10 (-16.1%), and semaglutide (-10.9%) alone. Furthermore, the bGLP-10 and cagrilintide combination exhibited superior glucose control and liver lipid management compared to the semaglutide-cagrilintide combination (P < 0.001). These results highlight bGLP-10's potential in GLP-1 and amylin-based therapies and suggest exploring more GLP-1 analogues from natural sources for anti-obesity and anti-diabetic treatments.

Dietary impact on fasting and stimulated GLP-1 secretion in different metabolic conditions - a narrative review

Glucagon-like peptide 1 (GLP-1), a gastrointestinal peptide and central mediator of glucose metabolism, is secreted by L cells in the intestine in response to food intake. Postprandial secretion of GLP-1 is triggered by nutrient-sensing via transporters and G-protein-coupled receptors (GPCRs). GLP-1 secretion may be lower in adults with obesity/overweight (OW) or type 2 diabetes mellitus (T2DM) than in those with normal glucose tolerance (NGT), but these findings are inconsistent. Because of the actions of GLP-1 on stimulating insulin secretion and promoting weight loss, GLP-1 and its analogs are used in pharmacologic preparations for the treatment of T2DM. However, physiologically stimulated GLP-1 secretion through the diet might be a preventive or synergistic method for improving glucose metabolism in individuals who are OW, or have impaired glucose tolerance (IGT) or T2DM. This narrative review focuses on fasting and postprandial GLP-1 secretion in individuals with different metabolic conditions and degrees of glucose intolerance. Further, the influence of relevant diet-related factors (e.g., specific diets, meal composition, and size, phytochemical content, and gut microbiome) that could affect fasting and postprandial GLP-1 secretion are discussed. Some studies showed diminished glucose- or meal-stimulated GLP-1 response in participants with T2DM, IGT, or OW compared with those with NGT, whereas other studies have reported an elevated or unchanged GLP-1 response in T2DM or IGT. Meal composition, especially the relationship between macronutrients and interventions targeting the microbiome can impact postprandial GLP-1 secretion, although it is not clear which macronutrients are strong stimulants of GLP-1. Moreover, glucose tolerance, antidiabetic treatment, grade of overweight/obesity, and sex were important factors influencing GLP-1 secretion. The results presented in this review highlight the potential of nutritional and physiologic stimulation of GLP-1 secretion. Further research on fasting and postprandial GLP-1 concentrations and the resulting metabolic consequences under different metabolic conditions is needed.

Dietary Glutamine and Glutamate in Relation to Cardiovascular Disease Incidence and Mortality in the United States Men and Women with Diabetes Mellitus

BACKGROUND

Evidence regarding the potential health effects of dietary amino acids glutamine and glutamate among individuals with type 2 diabetes (T2D) is limited.

OBJECTIVES

The aim was to examine dietary glutamine and glutamate in relation to subsequent risk of cardiovascular disease (CVD) and mortality among individuals with T2D.

METHODS

We prospectively followed 15,040 men and women with T2D at baseline or diagnosed during follow-up (Nurses' Health Study: 1980-2014 and Health Professionals Follow-Up Study: 1986-2018). Diet was repeatedly assessed using validated food frequency questionnaires every 2-4 y. Associations of energy-adjusted glutamine and glutamate intake, as well as their ratio, with CVD risk and mortality, were assessed using Cox proportional-hazards models with adjustments for demographics, dietary and lifestyle factors, and medical history.

RESULTS

During 196,955 and 225,371 person-years of follow-up in participants with T2D, there were 2927 incident CVD cases and 4898 deaths, respectively. Higher intake of glutamine was associated with lower risk of CVD incidence, CVD mortality, and total mortality: comparing extreme quintiles, the hazard ratios (HRs) (95% confidence intervals [CIs]) were 0.88 (0.77, 0.99), 0.78 (0.65, 0.92), and 0.84 (0.76, 0.92), respectively (all P-trend < 0.05). In contrast, higher intake of glutamate was associated with a higher risk of CVD incidence, CVD mortality, and total mortality; the HRs were 1.30 (1.15, 1.46), 1.46 (1.24, 1.72), and 1.20 (1.09, 1.32), respectively (all P-trend < 0.05). Furthermore, comparing extreme quintiles, a higher dietary glutamine-to-glutamate ratio was associated with a lower risk of CVD incidence (0.84 [0.75, 0.95]), CVD mortality (0.66 [0.57, 0.77]), and total mortality (0.82 [0.75, 0.90]). In addition, compared with participants with stable or decreased consumption of glutamine-to-glutamate ratio from prediabetes to postdiabetes diagnosis, those who increased the ratio had a 17% (5%, 27%) lower CVD mortality.

CONCLUSIONS

In adults with T2D, dietary glutamine was associated with a lower risk of CVD incidence and mortality, whereas the opposite was observed for glutamate intake.

Determinants of blood glucose concentrations following a high carbohydrate meal in type 2 diabetes: A multiple linear regression analysis

This study showed that in relatively well-controlled type 2 diabetes blood glucose levels after a high carbohydrate meal were associated positively with fasting blood glucose, but also positively with gastric emptying in the first hour and negatively with the increments in plasma glucagon-like peptide-1 (GLP-1) in the later postprandial phase.

Dietary carbohydrate influences the colocalization pattern of Glucagon-like Peptide-1 with neurotensin in the chicken ileum

Glucagon-like peptide (GLP)-1 colocalizes with neurotensin (NT) in the same enteroendocrine cells (EECs) of the chicken ileum. The present study was designed to clarify the influence of dietary carbohydrate (CHO) on the colocalization pattern of GLP-1 with NT in the chicken distal ileum. Male White Leghorn chickens at 6 weeks of age (n = 15) were divided into three groups, a control and two experimental (low-CHO and CHO-free), with five chickens in each, and fed control or experimental diets for 7 d. Distal ileum was collected from each bird as a tissue sample and subjected to double immunofluorescence staining to detect GLP-1 and NT. Three types of EEC, GLP-1+/NT+, GLP-1+/NT- and GLP-1-/NT+, were demonstrated in the chicken ileum. GLP-1+/NT+ cells in the control group had a spindle-like shape with a long cytoplasmic process, but those in the experimental groups were round and lacked a cytoplasmic process. The ratio of GLP-1+/NT+ cells was significantly decreased in the two experimental groups compared with that in the control group. The ratio of GLP-1+/NT+ cells was significantly lower than those of GLP-1+/NT- and GLP-1-/NT+ cells in the two experimental groups. Most cells that were immunoreactive for GLP-1 and NT antisera lacked signals of proglucagon (PG) and NT precursor (NTP) mRNA in the experimental groups. The number of EECs expressing PG and NTP mRNA signals showed tendencies for decreases with a reduction of dietary CHO level. These findings suggest that dietary CHO could be a significant regulator of the pattern of colocalization pattern of GLP-1 with NT in the chicken ileum.

Improvement of Glucose Tolerance by Food Factors Having Glucagon-Like Peptide-1 Releasing Activity

Glucagon-like peptide-1 (GLP-1) is a gastrointestinal hormone released from enteroendocrine L cells in response to meal ingestion. GLP-1 receptor agonists and GLP-1 enhancers have been clinically employed to treat diabetes owing to their glucose-dependent insulin-releasing activity. The release of GLP-1 is primarily stimulated by macronutrients such as glucose and fatty acids, which are nutritionally indispensable; however, excessive intake of sugar and fat is responsible for the development of obesity and diabetes. Therefore, GLP-1 releasing food factors, such as dietary peptides and non-nutrients, are deemed desirable for improving glucose tolerance. Human and animal studies have revealed that dietary proteins/peptides have a potent effect on stimulating GLP-1 secretion. Studies in enteroendocrine cell models have shown that dietary peptides, amino acids, and phytochemicals, such as quercetin, can directly stimulate GLP-1 secretion. In our animal experiments, these food factors improved glucose metabolism and increased GLP-1 secretion. Furthermore, some dietary peptides not only stimulated GLP-1 secretion but also reduced plasma peptidase activity, which is responsible for GLP-1 inactivation. Herein, we review the relationship between GLP-1 and food factors, especially dietary peptides and flavonoids. Accordingly, utilization of food factors with GLP-1-releasing/enhancing activity is a promising strategy for preventing and treating obesity and diabetes.

Effect of glutamine supplementation on cardiometabolic risk factors and inflammatory markers: a systematic review and meta-analysis

Background

Evidence exists that glutamine plays multiple roles in glucose metabolism, insulin sensitivity, and anti-inflammatory effects. This systematic review and meta-analysis of controlled trials aimed to assess the effect of glutamine supplementation on cardio-metabolic risk factors and inflammatory markers.

Methods

The processes of systematic reviews and meta-analyses were performed according to the PRISMA checklist. PubMed, Web of Sciences, Cochrane library, and Scopus databases were search for relevant studies without time or language restrictions up to December 30, 2020. All randomized clinical trials which assessed the effect of glutamine supplementation on “glycemic indices”, “level of triglyceride, “and “inflammatory markers” were included in the study. The effect of glutamine supplementation on cardio-metabolic risk factors and inflammatory markers was assessed using a standardized mean difference (SMD) and 95% confidence interval (CI). Heterogeneity between among studies was assessed using Cochran Q-statistic and I-square. Random/fixed-effects meta-analysis method was used to estimate the pooled SMD. The risk of bias for the included trials was evaluated using the Cochrane quality assessment tool.

Results

In total, 12 studies that assessed the effect of glutamine supplementation on cardio-metabolic risk factors were included in the study. Meta-analysis showed that glutamine supplementation significantly decreased significantly serum levels of FPG [SMD: − 0.73, 95% CI − 1.35, − 0.11, I²: 84.1%] and CRP [SMD: − 0.58, 95% CI − 0.1, − 0.17, I²: 0%]. The effect of glutamine supplementation on other cardiometabolic risk factors was not statistically significant (P > 0.05).

Conclusion

Our findings showed that glutamine supplementation might have a positive effect on FPG and CRP; both of which are crucial as cardio-metabolic risk factors. However, supplementation had no significant effect on other cardio-metabolic risk factors.

Glutamine metabolism in adipocytes: a bona fide epigenetic modulator of inflammation

A chronic low-grade inflammation of white adipose tissue (WAT) is one of the hallmarks of obesity and is proposed to contribute to insulin resistance and type 2 diabetes. Despite this, the causal mechanisms underlying WAT inflammation remain unclear. Based on metabolomic analyses of human WAT, Petrus et al. showed that the amino acid glutamine was the most markedly reduced polar metabolite in the obese state. Reduced glutamine levels in adipocytes induce an increase of Uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) levels via induction of glycolysis and the hexosamine biosynthetic pathways. This promotes nuclear O-GlcNAcylation, a posttranslational modification that activates the transcription of pro-inflammatory genes. Conversely, glutamine supplementation in vitro and in vivo, reversed these effects. Altogether, dysregulation of intracellular glutamine metabolism in WAT establishes an epigenetic link between adipocytes and inflammation. This commentary discusses these findings and their possibly therapeutic relevance in relation to insulin resistance and type 2 diabetes.

Effect of Increasing the Dietary Protein Content of Breakfast on Subjective Appetite, Short-Term Food Intake and Diet-Induced Thermogenesis in Children

Dietary protein affects energy balance by decreasing food intake (FI) and increasing energy expenditure through diet-induced thermogenesis (DIT) in adults. Our objective was to investigate the effects of increasing the dietary protein in an isocaloric breakfast on subjective appetite, FI, blood glucose, and DIT in 9-14 y children. Two randomized repeated measures designs were used. In experiment 1, 17 children (9 boys, 8 girls) consumed isocaloric meals (450 kcal) on four separate mornings containing: 7 g (control), 15 g (low protein, LP), 30 g (medium protein, MP) or 45 g (high protein, HP) of protein. Blood glucose and subjective appetite were measured at baseline and regular intervals for 4 h, and FI was measured at 4 h. In experiment 2, 9 children (6 boys, 3 girls) consumed the control or HP breakfast on two separate mornings, and both DIT and subjective appetite were determined over 5 h. In experiment 1, all dietary protein treatments suppressed subjective appetite compared to control (p < 0.001), and the HP breakfast suppressed FI compared with the LP breakfast and control (p < 0.05). In experiment 2, DIT was higher after HP than control (p < 0.05). In conclusion, increasing the dietary protein content of breakfast had favorable effects on satiety, FI, and DIT in children.

Postprandial glycemia and insulin secretion following glutamine administration: A randomized controlled trial

Objective: The objective of the present study is to investigate the effects of glutamine administration on postprandial glycemia, insulin, and C-peptide concentration in patients with type 2 diabetes. Methods: A randomized, double-blind, placebo-controlled trial was conducted on patients with type 2 diabetes so that 33 subjects were recruited in each group. The patients were randomly allocated to receive either 30 g/d glutamine or placebo (with instructions to take in half glass of ice-cold water 5 to 10 min before each main meal) for 6 weeks. Postprandial C-peptide, insulin, and glucose were measured at the baseline and at the end of the study at 30 and 90 min after consuming a meal comprising wheat-cake and reduced fat milk. Results: The repeated measures ANOVA revealed no significant difference between the groups for glucose and insulin after 6 weeks of intervention (p > 0.05). However, C-peptide was reduced in both intervention groups at all measurement points. Between-group differences remained significant by the end of the study (p = 0.02). Conclusions: Glutamine supplementation before each main meal does not represent an effective nutritional strategy to improve postprandial glycemic control or postprandial insulin secretion in type 2 diabetes patients.

ID1-Mediated BMP Signaling Pathway Potentiates Glucagon-Like Peptide-1 Secretion in Response to Nutrient Replenishment

Glucagon-like peptide-1 (GLP-1) is a well-known incretin hormone secreted from enteroendocrinal L cells in response to nutrients, such as glucose and dietary fat, and controls glycemic homeostasis. However, the detailed intracellular mechanisms of how L cells control GLP-1 secretion in response to nutrients still remain unclear. Here, we report that bone morphogenetic protein (BMP) signaling pathway plays a pivotal role to control GLP-1 secretion in response to nutrient replenishment in well-established mouse enteroendocrinal L cells (GLUTag cells). Nutrient starvation dramatically reduced cellular respiration and GLP-1 secretion in GLUTag cells. Transcriptome analysis revealed that nutrient starvation remarkably reduced gene expressions involved in BMP signaling pathway, whereas nutrient replenishment rescued BMP signaling to potentiate GLP-1 secretion. Transient knockdown of inhibitor of DNA binding (ID)1, a well-known target gene of BMP signaling, remarkably reduced GLP-1 secretion. Consistently, LDN193189, an inhibitor of BMP signaling, markedly reduced GLP-1 secretion in L cells. In contrast, BMP4 treatment activated BMP signaling pathway and potentiated GLP-1 secretion in response to nutrient replenishment. Altogether, we demonstrated that BMP signaling pathway is a novel molecular mechanism to control GLP-1 secretion in response to cellular nutrient status. Selective activation of BMP signaling would be a potent therapeutic strategy to stimulate GLP-1 secretion in order to restore glycemic homeostasis.

Fructo-oligosaccharides alleviate inflammation-associated apoptosis of GLP-1 secreting L cells via inhibition of iNOS and cleaved caspase-3 expression

Glucagon-like peptide 1 (GLP-1) released from enteroendocrine (L) cells regulates insulin secretion. Intestinal inflammation and impaired GLP-1 release have been found in type 2 diabetes mellitus (T2DM) patients. Fructo-oligosaccharides (FOS), a known prebiotic, improve GLP-1 release and glucose homeostasis in T2DM models. This study aimed to investigate the effect of tumor necrosis factor-α (TNF-α), a proinflammatory cytokine associated with intestinal inflammation in T2DM, on L cell apoptosis and the effect of FOS on inflammation-associated impairment of GLP-1 secretion. Herein, using cell death assays, immunofluorescence staining, real time PCR and Western blot analyses, we found that TNF-α induced L cell apoptosis via nuclear factor kappa B (NF-κB)- inducible nitric oxide synthase (iNOS)-cleaved caspase-3-dependent pathways. Interestingly, FOS did not suppress TNF-α-induced NF-κB nuclear translocation, but inhibited expression of iNOS and cleaved caspase-3. In addition, FOS alleviated apoptosis and rescued impaired GLP-1 release in TNF-α-treated L cells. Altogether, our data indicate that TNF-α induces L cell apoptosis via an NF-κB-iNOS-caspase-3-dependent pathway. FOS may be useful in suppressing inflammation-associated L cell apoptosis and maintaining GLP-1 level in T2DM patients.

Assessing the effect of starch digestion characteristics on ileal brake activation in broiler chickens

The objective of this research was to evaluate activation of the ileal brake in broiler chickens using diets containing semi-purified wheat (WS; rapidly and highly digested) and pea (PS; slowly and poorly digested) starch. Diets were formulated to contain six WS:PS ratios (100:0, 80:20, 60:40, 40:60, 20:80, 0:100) and each starch ratio was fed to 236 Ross 308 male broilers housed in 4 litter floor pens. At 28 d of age, the effect of PS concentration was assessed on starch digestion, digestive tract morphology, and digesta pH and short-chain fatty acid (SCFA) concentration. Glucagon-like peptide-1 (GLP-1) and peptide tyrosine-tyrosine (PYY) status were assessed in serum (ELISA) and via gene expression in jejunal and ileal tissue (proglucagon for GLP-1). Data were analyzed using regression analyses, and significance was accepted at P ≤ 0.05. Increasing dietary PS resulted in reduced starch digestibility in the small intestine, but had no effect in the colon. Crop content pH responded quadratically to PS level with an estimated minimum at 55% PS. Total SCFA increased linearly in the crop with PS level, but changed in a quadratic fashion in the ileum (estimated maximum at 62% PS). Ceacal SCFA concentrations were highest for the 80 and 100% PS levels. The relative empty weight (crop, small intestine, colon), length (small intestine) and content (crop jejunum, Ileum) of digestive tract sections increased linearly with increasing PS concentration. Dietary treatment did not affect serum GLP-1 or PYY or small intestine transcript abundance. In conclusion, feeding PS increased the presence of L-cell activators (starch, SCFA) and increased trophic development and content of the digestive tract, suggestive of L-cell activation. However, no direct evidence of ileal brake activation was found by measuring venous blood levels of GLP-1 or PYY or corresponding gene expression in small intestine tissue.

What Is GLP-1 Really Doing in Obesity?

Glucagon-like peptide-1 (GLP-1) is a gastrointestinal hormone released in response to meal ingestion and enhances insulin secretion from pancreatic β cells. In several human studies, GLP-1 secretory responses to oral glucose load or a meal were decreased in subjects with obesity, glucose intolerance, or diabetes compared with those in healthy subjects. However, the results of meta-analysis and cohort studies do not necessarily support this concept. Results from animal studies are also inconsistent; in multiple studies, GLP-1 secretory responses to a meal were repeatedly higher in diet-induced obese rats than in control rats. Thus, the postprandial GLP-1 response is not necessarily decreased but rather enhanced during obesity development, which is likely to play a protective role against glucose intolerance.

Leucine-glycine and carnosine dipeptides prevent diabetes induced by multiple low-doses of streptozotocin in an experimental model of adult mice

AIMS/INTRODUCTION

Peptides are considered to be quasi-hormones and effective molecules for regulation of the cells function and prevention of metabolic disorders. Di- and tripeptides gastrointestinal absorption ability have been proposed to prevent diabetes progression.

MATERIALS AND METHODS

Small peptides with different sequences of specific amino acids were synthesized based on a solid phase peptide synthesis protocol, and carnosine (A) and glutathione were examined for the prevention of diabetes induced by multiple low-doses of streptozotocin in mice.

RESULTS

The peptides A, Leu-Gly (D) and Pro-Pro showed preventive effects on blood glucose elevation and impairment of the signaling and performance of β-cells. The β-cell function assessed by immunofluorescence and blood glucose level in mice exposed to diabetes treated by the peptides A and D was similar to the normal mice. The peptide D prevented bodyweight loss caused by diabetes induction. The use of D and A peptides dramatically prevented the incidence of disruption in β-cells signaling by maintaining the natural balance of intracellular Akt-2 and cyclic adenosine monophosphate.

CONCLUSIONS

The results proved that peptide D (Leu-Gly), named Hannaneh, inhibits the bodyweight loss caused by diabetes induction. The Hannaneh and carnosine dipeptides, with preservation of normal β-cell signaling and anti dipeptidyl peptidase-4 activity, prevented blood glucose increases in mice at risk of diabetes. These dipeptides might be regarded as the pharmaceutical agents for the prevention of diabetes.

Role of Peptide Hormones in the Adaptation to Altered Dietary Protein Intake

Dietary protein profoundly influences organismal traits ultimately affecting healthspan. While intracellular signalling downstream of altered amino acid supply is undoubtedly important, peptide hormones have emerged as critical factors determining systemic responses to variations in protein intake. Here the regulation and role of certain peptides hormones in such responses to altered dietary protein intake is reviewed.

The effect of a low-carbohydrate high-fat diet and ethnicity on daily glucose profile in type 2 diabetes determined by continuous glucose monitoring

BACKGROUND AND AIMS

Nutrition is an integral part of type 2 diabetes (T2DM) treatment, but the optimal macronutrient composition is still debated and previous studies have not addressed the role of ethnicity in dietary response. The current study aims were to compare the effect of short-term glycemic response to low-carbohydrate high-fat (LC-HF) diet vs. high-carbohydrate low-fat (HC-LF) diet using continuous glucose monitoring (CGM) and to evaluate the response of individuals with T2DM of Yemenite (Y-DM) and non-Yemenite origin (NY-DM).

METHODS

Twenty T2DM males, ten Y-DM and ten NY-DM underwent meal tolerance test and indexes of insulin resistance and secretion were calculated. Subsequently, patients were connected to CGM to assess daily glycemic control and glucose variability in response to isocaloric HC-LF or LC-HF diet, receiving each diet for 2 days by providing prepared meals. Daily glucose levels, area under the glucose curve (G-AUC) and parameters of glucose variability [standard deviation (SD), mean amplitude of glycemic excursions (MAGE) and mean absolute glucose (MAG)] were evaluated.

RESULTS

The LC-HF resulted in a significantly lower G-AUC (p < 0.001) and in lower variability parameters (p < 0.001) vs. the HC-LF diet. However, Y-DM showed less reduction in glucose variability indices upon diet-switching vs. NY-DM; MAGE decreased, respectively, by 69% vs. 89%, p = 0.043 and MAG by 34% vs. 45%, p = 0.007 in Y-DM compared to NY-DM.

CONCLUSIONS

These results suggest that LC-HF diet is effective in reducing glycemic fluctuation in T2DM and that ethnicity may have a role in the response to dietary regime.

Practice Guidelines for Enteral Nutrition Management in Dysglycemic Critically Ill Patients: A Relook for Indian Scenario

Background and aim

Intensive-care practices and settings differ for India in comparison to other countries. While guidelines are available to direct the use of enteral nutrition (EN), there are no recommendations specific to nutritional management of EN in dysglycemic patients, specific to patients in Indian critical care settings. Advisory board meetings were arranged to develop the practice guidelines specific to the Indian context, for the use of EN in dysglycemic critically ill patients and to overcome challenges in this field.

Materials and methods

Two advisory board meetings were organized to review various existing guidelines, meta-analyses, randomized controlled trials (RCTs), controlled trials and review articles, for their contextual relevance and strength. Three rounds of Delphi voting were done to arrive at consensus on certain recommendations. A systematic grading of practice guidelines by the advisory board was done based on strength of the consensus voting and reviewed supporting evidences.

Results

Based on the literature review, the recommendations for developing the practice guidelines were made as per the grading criteria agreed upon by the advisory board. The recommendations were to address challenges regarding prediction and assessment of dysglycemia (DG), acceptable glycemic targets in such settings, general nutritional aspects pertaining to DG nutrition, and nutrition in various superspecialty cases in critical care settings, where DG is commonly encountered.

Conclusion

This paper summarizes the optimum EN practices for managing DG in critically ill patients. The practical solutions to overcome the challenges in this field are presented as practice guidelines at the end of each section. These guidelines are expected to provide guidance for EN management in dysglycemic critically ill patients. These guidelines also outline the model glycemic control task force and its roles in nutrition care as well as an intensive care unit DG nutrition protocol.

How to cite this article

Mehta Y, Mithal A, Kulkarni A, Reddy BR, Sharma J, Dixit S, et al. Practice Guidelines for Enteral Nutrition Management in Dysglycemic Critically Ill Patients: A Relook for Indian Scenario. Indian J Crit Care Med 2019;23(12):594–603.

Gastrointestinal effects of extra-virgin olive oil associated with lower postprandial glycemia in type 1 diabetes

OBJECTIVE

To explore the possible mechanisms behind the lower glycemic response observed when extra-virgin olive oil (EVOO) is added to a high-glycemic index meal in patients with type 1 diabetes (T1D).

RESEARCH DESIGN AND METHODS

According to a randomized cross-over design, eleven T1D patients (6 women, 5 men) on insulin pump consumed in the metabolic ward, one week apart, three high-glycemic index meals differing only for amount and quality of fat: high-monounsaturated fat (EVOO), high-saturated fat (Butter), and low-fat (LF). Before and after the meals, blood glucose (continuous glucose monitoring), gastric emptying rate (ultrasound technique), and plasma concentrations of glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide GIP (ELISA), glucagon (RIA), and lipids (colorimetric assays) were evaluated.

RESULTS

Blood glucose iAUC (mmol/lx360 min) was lower after the EVOO (690 ± 431) than after the Butter (1320 ± 600) and LF meals (1007 ± 990) (M ± SD, p = 0.041 by repeated measures ANOVA). Gastric antrum volume was significantly larger in the early (60-90 min) postprandial phase (106 ± 21 vs. 90 ± 16 ml, p = 0.048) and significantly smaller in the late phase (330-360 min) (46 ± 10 vs. 57 ± 22 ml, p = 0.045) after the EVOO than after Butter meal. EVOO significantly increased postprandial GLP-1 iAUC (261 ± 311) compared to Butter (189 ± 349) (pmol/Lx180 min, p = 0.009). Postprandial GIP and glucagon responses were not significantly different between EVOO and Butter. Postprandial triglyceride iAUC was significantly higher after EVOO (100 ± 53) than after Butter (65 ± 60) (mmol/l × 360 min, p = 0.048).

CONCLUSIONS

Changes in gastric emptying and GLP-1 secretion and reduced glucose absorption through glucose-lipid competition may contribute to lower glycemia after a high-glycemic index meal with EVOO in T1D patients.

CLINICAL TRIALS NUMBER

NCT02330939.

Lacto-Vegetarian Diet and Correlation of Fasting Blood Sugar with Lipids in Population Practicing Sedentary Lifestyle

Rising burden of diabetes in India requires quick intervention that integrates policies and programs for effective prevention and control of disease. This retrospective cross-sectional study was conducted to observe effect of diet in two Indian communities practicing sedentary lifestyle. Fasting blood samples were analyzed for blood sugar, glycated-hemoglobin (HbA1C), and lipid profile. Body mass index (BMI) and waist circumference (WC) measurements were recorded. Diabetes incidence was lower in lacto-vegetarian (1.7%) than in non-vegetarian group (5.3%) despite similar lipid profiles and BMI/WC between the groups. Fasting blood sugar (FBS) was positively correlated with LDL and VLDL levels and negatively correlated with HDL, only in lacto-vegetarian group. Study suggests: (1) Indian lacto-vegetarian diet has beneficial effects on diabetes incidence irrespective of high body weight and sedentary lifestyle; (2) intervention to reduce body lipids, such as lipid-lowering drugs and exercise, may have greater effect in reducing FBS levels in this lacto-vegetarian group.

AMPK-dependent regulation of GLP1 expression in L-like cells

This study examined whether AMPK, an evolutionarily conserved sensor of cellular energy status, determines the production of glucagon-like peptide-1 (GLP1). A negative relation existed between phosphorylation of AMPKα and the expression and secretion of GLP1 during changes in energy status in STC-1 cells, an L-like cell line. High concentration of glucose (25 mmol/L) decreased AMPKα phosphorylation, whereas it stimulated the expression and secretion of GLP1 relative to 5.6 mmol/L glucose. Serum starvation upregulated AMPKα phosphorylation, whereas it reduced GLP1 production significantly. Stimulation of AMPK phosphorylation by AICAR and overexpression of wild-type AMPKα1, constitutively active AMPKα1 plasmids, or AMPKα1 lentivirus particles suppressed proglucagon mRNA and protein contents in STC-1 cells. Inactivation of AMPK by Compound C, AMPKα1 siRNA or kinase-inactive AMPKα1 mutant increased the expression and secretion of GLP1. Our results suggest that AMPKα1 may link energy supply with the production of GLP1 in L-like cells.

Mechanisms for the cardiovascular effects of glucagon-like peptide-1

Over the past three decades, at least 10 hormones secreted by the enteroendocrine cells have been discovered, which directly affect the cardiovascular system through their innate receptors expressed in the heart and blood vessels or through a neural mechanism. Glucagon-like peptide-1 (GLP-1), an important incretin, is perhaps best studied of these gut-derived hormones with important cardiovascular effects. In this review, I have discussed the mechanism of GLP-1 release from the enteroendocrine L-cells and its physiological effects on the cardiovascular system. Current evidence suggests that GLP-1 has positive inotropic and chronotropic effects on the heart and may be important in preserving left ventricular structure and function by direct and indirect mechanisms. The direct effects of GLP-1 in the heart may be mediated through GLP-1R expressed in atria as well as arteries and arterioles in the left ventricle and mainly involve in the activation of multiple pro-survival kinases and enhanced energy utilization. There is also good evidence to support the involvement of a second, yet to be identified, GLP-1 receptor. Further, GLP-1(9-36)amide, which was previously thought to be the inactive metabolite of the active GLP-1(7-36)amide, may also have direct cardioprotective effects. GLP-1's action on GLP-1R expressed in the central nervous system, kidney, vasculature and the pancreas may indirectly contribute to its cardioprotective effects.

Oleic acid stimulates glucagon-like peptide-1 release from enteroendocrine cells by modulating cell respiration and glycolysis

OBJECTIVE

Glucagon-like peptide-1 (GLP-1) is a potent satiating and incretin hormone released by enteroendocrine L-cells in response to eating. Dietary fat, in particular monounsaturated fatty acids, such as oleic acid (OA), potently stimulates GLP-1 secretion from L-cells. It is, however, unclear whether the intracellular metabolic handling of OA is involved in this effect.

METHODS

First we determined the optimal medium for the bioenergetics measurements. Then we examined the effect of OA on the metabolism of the immortalized enteroendocrine GLUTag cell model and assessed GLP-1 release in parallel. We measured oxygen consumption rate and extracellular acidification rate in response to OA and to different metabolic inhibitors with the Seahorse extracellular flux analyzer.

RESULTS

OA increased cellular respiration and potently stimulated GLP-1 release. The fatty acid oxidation inhibitor etomoxir did neither reduce OA-induced respiration nor affect the OA-induced GLP-1 release. In contrast, inhibition of the respiratory chain or of downstream steps of aerobic glycolysis reduced the OA-induced GLP-1 release, and an inhibition of the first step of glycolysis by addition of 2-deoxy-d-glucose even abolished it.

CONCLUSION

These findings indicate that an indirect stimulation of glycolysis is crucial for the OA-induced release of GLP-1.

In vitro bioactive properties of intact and enzymatically hydrolysed whey protein: targeting the enteroinsular axis

Enzymatically hydrolysed milk proteins have a variety of biofunctional effects some of which may be beneficial in the management of type 2 diabetes mellitus. The purpose of this study was to evaluate the effect of commercially available intact and hydrolysed whey protein ingredients (DH 32, DH 45) on markers of the enteroinsular axis (glucagon like peptide-1 secretion, dipeptidyl peptidase IV inhibition, insulin secretion and antioxidant activity) before and after simulated gastrointestinal digestion (SGID). A whey protein hydrolysate, DH32, significantly enhanced (P < 0.05) insulin secretion from BRIN BD11 β-cells compared to the positive control (16.7 mM glucose and 10 mM Ala). The whey protein hydrolysates inhibited dipeptidyl peptidase IV activity, yielding half maximal inhibitory concentration values (IC50) of 1.5 ± 0.1 and 1.1 ± 0.1 mg mL(-1) for the DH 32 and DH 45, samples respectively, and were significantly more potent than the intact whey (P < 0.05). Enzymatic hydrolysis of whey protein significantly enhanced (P < 0.05) its antioxidant activity compared to intact whey, as measured by the oxygen radical absorbance capacity assay (ORAC). This antioxidant activity was maintained (DH 32, P > 0.05) or enhanced (DH 45, P < 0.05) following SGID. Intact whey stimulated GLP-1 secretion from enteroendocrine cells compared to vehicle control (P < 0.05). This data confirm that whey proteins and peptides can act through multiple targets within the enteroinsular axis and as such may have glucoregulatory potential.

Increased gut hormones and insulin sensitivity index following a 3-d intervention with a barley kernel-based product: a randomised cross-over study in healthy middle-aged subjects

Certain purified indigestible carbohydrates such as inulin have been shown to stimulate gut-derived hormones involved in glycaemic regulation and appetite regulation, and to counteract systemic inflammation through a gut microbiota-mediated mechanism. Less is known about the properties of indigestible carbohydrates intrinsic to food. The aim of this study was to investigate the possibility to affect release of endogenous gut hormones and ameliorate appetite control and glycaemic control by ingestion of a whole-grain cereal food product rich in NSP and resistant starch in healthy humans. In all, twenty middle-aged subjects were provided with a barley kernel-based bread (BB) or a reference white wheat bread during 3 consecutive days, respectively, in a randomised cross-over design study. At a standardised breakfast the following day (day 4), blood was collected for the analysis of blood (b) glucose regulation, gastrointestinal hormones, markers of inflammation and markers of colonic fermentation; 3 d of intervention with BB increased gut hormones in plasma (p) the next morning at fasting (p-glucagon-like peptide-1; 56 %) and postprandially (p-glucagon-like peptide-2; 13 % and p-peptide YY; 18 %). Breath H2 excretion and fasting serum (s) SCFA concentrations were increased (363 and 18 %, respectively), and b-glucose (22 %) and s-insulin responses (17 %) were decreased after BB intervention. Insulin sensitivity index (ISIcomposite) was also improved (25 %) after BB. In conclusion, 3 d of intervention with BB increased systemic levels of gut hormones involved in appetite regulation, metabolic control and maintenance of gut barrier function, as well as improved markers of glucose homoeostasis in middle-aged subjects, altogether relevant for the prevention of obesity and the metabolic syndrome.

Intestinal mTOR regulates GLP-1 production in mouse L cells

AIMS/HYPOTHESIS

Glucagon-like peptide (GLP-1), an intestinal incretin produced in L cells through proglucagon processing, is released in response to meal intake. The intracellular mechanism by which L cells sense the organism energy level to coordinate the production of GLP-1 remains unclear. Mechanistic target of rapamycin (mTOR) is an intracellular fuel sensor critical for energy homeostasis. In this study, we investigated whether intestinal mTOR regulates GLP-1 production in L cells.

METHODS

The effects of mTOR on GLP-1 production were examined in lean- or high-fat diet (HFD) induced diabetic C57/BL6, db/db, Neurog3-Tsc1(-/-) mice, and STC-1 cells. GLP-1 expression was investigated by real-time PCR and western blotting. Plasma GLP-1 and insulin were detected by enzyme immunoassay and radioimmunoassay, respectively.

RESULTS

Fasting downregulated mTOR activity, which was associated with a decrement of intestinal proglucagon and circulating GLP-1. Upon re-feeding, these alterations returned to the levels of fed animals. In HFD induced diabetic mice, ileal mTOR signalling, proglucagon and circulating GLP-1 were significantly decreased. Inhibition of mTOR signalling by rapamycin decreased levels of intestinal and plasma GLP-1 in both normal and diabetic mice. Activation of the intestinal mTOR signalling by L-leucine or Tsc1 gene deletion increased levels of intestinal proglucagon and plasma GLP-1. Overexpression of mTOR stimulated proglucagon promoter activity and GLP-1 production, whereas inhibition of mTOR activity by overexpression of tuberous sclerosis 1 (TSC1) or TSC2 decreased proglucagon promoter activity and GLP-1 production in STC-1 cells.

CONCLUSIONS/INTERPRETATION

mTOR may link energy supply with the production of GLP-1 in L cells.

Resistant maltodextrin promotes fasting glucagon-like peptide-1 secretion and production together with glucose tolerance in rats

Glucagon-like peptide-1 (GLP-1), which is produced and released from enteroendocrine L cells, plays pivotal roles in postprandial glycaemia. The ingestion of resistant maltodextrin (RMD), a water-soluble non-digestible saccharide, improves the glycaemic response. In the present study, we examined whether the continuous feeding of RMD to rats affected GLP-1 levels and glycaemic control. Male Sprague-Dawley rats (6 weeks of age) were fed an American Institute of Nutrition (AIN)-93G-based diet containing either cellulose (5 %) as a control, RMD (2.5 or 5 %), or fructo-oligosaccharides (FOS, 2.5 or 5 %) for 7 weeks. During the test period, an intraperitoneal glucose tolerance test (IPGTT) was performed after 6 weeks. Fasting GLP-1 levels were significantly higher in the 5 % RMD group than in the control group after 6 weeks. The IPGTT results showed that the glycaemic response was lower in the 5 % RMD group than in the control group. Lower caecal pH, higher caecal tissue and content weights were observed in the RMD and FOS groups. Proglucagon mRNA levels were increased in the caecum and colon of both RMD and FOS groups, whereas caecal GLP-1 content was increased in the 5 % RMD group. In addition, a 1 h RMD exposure induced GLP-1 secretion in an enteroendocrine L-cell model, and single oral administration of RMD increased plasma GLP-1 levels in conscious rats. The present study demonstrates that continuous ingestion of RMD increased GLP-1 secretion and production in normal rats, which could be stimulated by its direct and indirect (enhanced gut fermentation) effects on GLP-1-producing cells, and contribute to improving glucose tolerance.

Plant-rich mixed meals based on Palaeolithic diet principles have a dramatic impact on incretin, peptide YY and satiety response, but show little effect on glucose and insulin homeostasis: an acute-effects randomised study

There is evidence for health benefits from 'Palaeolithic' diets; however, there are a few data on the acute effects of rationally designed Palaeolithic-type meals. In the present study, we used Palaeolithic diet principles to construct meals comprising readily available ingredients: fish and a variety of plants, selected to be rich in fibre and phyto-nutrients. We investigated the acute effects of two Palaeolithic-type meals (PAL 1 and PAL 2) and a reference meal based on WHO guidelines (REF), on blood glucose control, gut hormone responses and appetite regulation. Using a randomised cross-over trial design, healthy subjects were given three meals on separate occasions. PAL2 and REF were matched for energy, protein, fat and carbohydrates; PAL1 contained more protein and energy. Plasma glucose, insulin, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP) and peptide YY (PYY) concentrations were measured over a period of 180 min. Satiation was assessed using electronic visual analogue scale (EVAS) scores. GLP-1 and PYY concentrations were significantly increased across 180 min for both PAL1 (P= 0·001 and P< 0·001) and PAL2 (P= 0·011 and P= 0·003) compared with the REF. Concomitant EVAS scores showed increased satiety. By contrast, GIP concentration was significantly suppressed. Positive incremental AUC over 120 min for glucose and insulin did not differ between the meals. Consumption of meals based on Palaeolithic diet principles resulted in significant increases in incretin and anorectic gut hormones and increased perceived satiety. Surprisingly, this was independent of the energy or protein content of the meal and therefore suggests potential benefits for reduced risk of obesity.

Deletion of intestinal epithelial insulin receptor attenuates high-fat diet-induced elevations in cholesterol and stem, enteroendocrine, and Paneth cell mRNAs

The insulin receptor (IR) regulates nutrient uptake and utilization in multiple organs, but its role in the intestinal epithelium is not defined. This study developed a mouse model with villin-Cre (VC) recombinase-mediated intestinal epithelial cell (IEC)-specific IR deletion (VC-IR(Δ/Δ)) and littermate controls with floxed, but intact, IR (IR(fl/fl)) to define in vivo roles of IEC-IR in mice fed chow or high-fat diet (HFD). We hypothesized that loss of IEC-IR would alter intestinal growth, biomarkers of intestinal epithelial stem cells (IESC) or other lineages, body weight, adiposity, and glucose or lipid handling. In lean, chow-fed mice, IEC-IR deletion did not affect body or fat mass, plasma glucose, or IEC proliferation. In chow-fed VC-IR(Δ/Δ) mice, mRNA levels of the Paneth cell marker lysozyme (Lyz) were decreased, but markers of other differentiated lineages were unchanged. During HFD-induced obesity, IR(fl/fl) and VC-IR(Δ/Δ) mice exhibited similar increases in body and fat mass, plasma insulin, mRNAs encoding several lipid-handling proteins, a decrease in Paneth cell number, and impaired glucose tolerance. In IR(fl/fl) mice, HFD-induced obesity increased circulating cholesterol; numbers of chromogranin A (CHGA)-positive enteroendocrine cells (EEC); and mRNAs encoding Chga, glucose-dependent insulinotrophic peptide (Gip), glucagon (Gcg), Lyz, IESC biomarkers, and the enterocyte cholesterol transporter Scarb1. All these effects were attenuated or lost in VC-IR(Δ/Δ) mice. These results demonstrate that IEC-IR is not required for normal growth of the intestinal epithelium in lean adult mice. However, our findings provide novel evidence that, during HFD-induced obesity, IEC-IR contributes to increases in EEC, plasma cholesterol, and increased expression of Scarb1 or IESC-, EEC-, and Paneth cell-derived mRNAs.

Vegetarian diets and glycemic control in diabetes: a systematic review and meta-analysis

INTRODUCTION

Previous studies have suggested an association between vegetarian diets and improvements in glycemic control in diabetes, although this relationship is not well established. No meta-analysis of these studies has been performed.

METHODS

To conduct a systematic review and meta-analysis of controlled clinical trials examining the association between vegetarian diets and glycemic control in type 2 diabetes.

DATA SOURCE

The electronic databases Medline, Web of Science, Excerpta Medica Database (EMBASE), and Cochrane Central Register of Controlled Trials were searched for articles published in any language through December 9, 2013.

STUDY SELECTION

The following criteria were used for study inclusion: (I) age of participants >20 years; (II) vegetarian diet as intervention; (III) mean difference in hemoglobin A1c (HbA1c) and/or fasting blood glucose levels used as outcomes; and (IV) controlled trials, duration ≥4 weeks. Exclusion criteria were: (I) not an original investigation; (II) duplicate samples; (III) diabetes other than type 2; (IV) multiple interventions; and (V) uncontrolled studies.

DATA EXTRACTION AND SYNTHESIS

The data collected included study design, baseline population characteristics, dietary data, and outcomes. Data were pooled using a random-effects model.

MAIN OUTCOMES AND MEASURES

Differences in HbA1c and fasting blood glucose levels associated with vegetarian diets were assessed.

RESULTS

Of 477 studies identified, six met the inclusion criteria (n=255, mean age 42.5 years). Consumption of vegetarian diets was associated with a significant reduction in HbA1c [-0.39 percentage point; 95% confidence interval (CI), -0.62 to -0.15; P=0.001; I(2)=3.0; P for heterogeneity =0.389], and a non-significant reduction in fasting blood glucose concentration (-0.36 mmol/L; 95% CI, -1.04 to 0.32; P=0.301; I(2)=0; P for heterogeneity =0.710), compared with consumption of comparator diets.

CONCLUSIONS

Consumption of vegetarian diets is associated with improved glycemic control in type 2 diabetes. PROSPERO registration number is CRD42013004370.

A high-protein diet for reducing body fat: mechanisms and possible caveats

High protein diets are increasingly popularized in lay media as a promising strategy for weight loss by providing the twin benefits of improving satiety and decreasing fat mass. Some of the potential mechanisms that account for weight loss associated with high-protein diets involve increased secretion of satiety hormones (GIP, GLP-1), reduced orexigenic hormone secretion (ghrelin), the increased thermic effect of food and protein-induced alterations in gluconeogenesis to improve glucose homeostasis. There are, however, also possible caveats that have to be considered when choosing to consume a high-protein diet. A high intake of branched-chain amino acids in combination with a western diet might exacerbate the development of metabolic disease. A diet high in protein can also pose a significant acid load to the kidneys. Finally, when energy demand is low, excess protein can be converted to glucose (via gluconeogenesis) or ketone bodies and contribute to a positive energy balance, which is undesirable if weight loss is the goal. In this review, we will therefore explore the mechanisms whereby a high-protein diet may exert beneficial effects on whole body metabolism while we also want to present possible caveats associated with the consumption of a high-protein diet.

Effect of glutamine supplementation on cardiovascular risk factors in patients with type 2 diabetes

OBJECTIVE

The aim of this study was to assess clinical relevance of long-term oral glutamine supplementation on lipid profile and inflammatory and metabolic factors in patients with diabetes.

METHOD

Sixty-six patients with type 2 diabetes between the ages of 18 and 65 y were randomized to receive glutamine 30 g/d (10 g powder, three times a day) or placebo, in a double-blind, placebo-controlled trial during a 6-wk treatment period. Fifty-three patients completed the trial. Independent samples t test and analysis of covariance were used.

RESULTS

After a 6-wk treatment period, a significant difference was observed between the two groups in body fat mass (P = 0.01) and percentage of body fat (P = 0.008). Moreover, a significant reduction in waist circumference (P < 0.001) and a tendency for an increase in fat-free mass (P = 0.03), with no change in body weight and body mass index (BMI) was found. Enhancement in body fat-free mass was mainly attributed to trunk (P = 0.03). There was a downward trend in systolic blood pressure (P = 0.005) but not diastolic. Fasting blood glucose (mmol/L) concentration significantly decreased after the 6-wk intervention (P = 0.04). Mean hemoglobin A1c was significantly different between the groups at week 6 (P = 0.04). No significant difference was detected for fasting insulin, homeostasis model assessment for insulin resistance and quantitative insulin sensitivity index between groups (P > 0.05). No significant difference was observed between groups in total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and triglyceride. No treatment effect on C-reactive protein was found (P = 0.44).

CONCLUSION

We demonstrated that the 6-wk supplementation with 30 g/d glutamine markedly improved some cardiovascular risk factors, as well as body composition, in patients with type 2 diabetes. Future glutamine dose-response studies are warranted in these areas.

Isolation and characterization of peptides with dipeptidyl peptidase-IV inhibitory activity from pepsin-treated bovine whey proteins

Inhibition of the enzyme dipeptidyl peptidase (DPP)-IV is one of the strategies used for the treatment of type 2 diabetes. In the present study, pepsin-treated whey protein isolate (WPI) and α-lactalbumin displaying DPP-IV inhibitory activity were fractionated by successive chromatographic steps and the resulting active fractions analyzed for their constituent peptides by liquid chromatography-electrospray ionization-tandem mass spectrometry. Among the identified sequences, 24 peptides derived from α-lactalbumin and 11 from β-lactoglobulin were synthesized and their effects on DPP-IV activity assessed. The most potent fragments, LKPTPEGDL and LKPTPEGDLEIL (IC50=45 and 57 μM, respectively), were found to inhibit DPP-IV in an un-competitive manner. Although several of the peptides tested showed some inhibitory activity, only two were as effective as the un-fractionated WPI hydrolysate and none were as potent as the un-fractionated α-lactalbumin hydrolysate. The peptides' structural features, including length and amino acid composition, were found to impact their inhibitory activity. This study provides new insights on the active components responsible for the DPP-IV inhibitory activity of pepsin-treated whey proteins.

Postprandial effects of test meals including concentrated arabinoxylan and whole grain rye in subjects with the metabolic syndrome: a randomised study

BACKGROUND/OBJECTIVES

Prospective studies have shown an inverse relationship between whole grain consumption and the risk of type 2 diabetes, where short chain fatty acids (SCFA) may be involved. Our objective was to determine the effect of isolated arabinoxylan alone or in combination with whole grain rye kernels on postprandial glucose, insulin, free fatty acids (FFA), gut hormones, SCFA and appetite in subjects with the metabolic syndrome (MetS).

SUBJECTS/METHODS

Fifteen subjects with MetS participated in this acute, randomised, cross-over study. The test meals each providing 50 g of digestible carbohydrate were as follows: semolina porridge added concentrated arabinoxylan (AX), rye kernels (RK) or concentrated arabinoxylan combined with rye kernels (AXRK) and semolina porridge as control (SE). A standard lunch was served 4 h after the test meals. Blood samples were drawn during a 6-h period, and appetite scores and breath hydrogen were assessed every 30 min.

RESULTS

The AXRK meal reduced the acute glucose (P=0.005) and insulin responses (P<0.001) and the feeling of hunger (P=0.005; 0-360 min) compared with the control meal. The AX and AXRK meals increased butyrate and acetate concentrations after 6 h. No significant differences were found for the second meal responses of glucose, insulin, FFA, glucagon-like peptide-1 or ghrelin.

CONCLUSIONS

Our results indicate a stimulatory effect of arabinoxylan on butyrate and acetate production, however, with no detectable effect on the second meal glucose response. It remains to be tested in a long-term study if a beneficial effect on the glucose response of the isolated arabinoxylan will be related to the SCFA production.

In vitrotransport and satiety of a beta-lactoglobulin dipeptide and beta-casomorphin-7 and its metabolites

In vitrotransport of β-CM7 occurs through rapid hydrolysis into three peptide metabolites that transport at variable rates.

Peripheral Pathways in the Food-Intake Control towards the Adipose-Intestinal Missing Link

In the physiological state a multitude of gut hormones are released into the circulation at the same time depending on the quality and quantity of the diet. These hormones interact with receptors at various points in the "gut-brain axis" to affect short-term and intermediate-term feelings of hunger and satiety. The combined effects of macronutrients on the predominant gut hormone secretion are still poorly understood. Besides, adipokines form an important part of an "adipoinsular axis" dysregulation which may contribute to β -cell failure and hence to type 2 diabetes mellitus (T2DM). Even more, gestational diabetes mellitus (GDM) and T2DM seem to share a genetic basis. In susceptible individuals, chronic exaggerated stimulation of the proximal gut with fat and carbohydrates may induce overproduction of an unknown factor that causes impairment of incretin production and/or action, leading to insufficient or untimely production of insulin, so that glucose intolerance develops. The bypass of the duodenum and jejunum might avoid a putative hormone overproduction in the proximal foregut in diabetic patients that might counteract the action of insulin, while the early presentation of undigested or incompletely digested food to the ileum may anticipate the production of hormones such as GLP1, further improving insulin action.