Postprandial Glucose Homeostasis Research Articles

Evaluating GIP and glucagon as key regulators of insulin secretion in the pancreatic islet.

The incretin axis is an essential component of postprandial insulin secretion and glucose homeostasis. There are two incretin hormones, glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), which exert multiple actions throughout the body. A key cellular target for the incretins are pancreatic b-cells, where they potentiate nutrient-stimulated insulin secretion. This feature of incretins have made this system an attractive target for therapeutic interventions aimed at controlling glycemia. Here, we discuss the role of GIP in both b-cells and a-cells within the islet, to stimulate insulin and glucagon secretion, respectively. Moreover, we discuss how glucagon secretion from a-cells has important insulinotropic actions in b-cells through an axis termed a- to b-cell communication. These recent advances have elevated the potential of GIP and glucagon as a therapeutic targets, coinciding with emerging compounds that pharmacologically leverage the actions of these two peptides in the context of diabetes and obesity.

Assessment of the incretin effect in healthy subjects: Concordance between clamp and OGTT methods.

The incretin effect describes the insulin response to nutrient ingestion that exceeds the response to glycemia per se. It is mediated by gastrointestinal factors and is necessary to maintain postprandial glucose homeostasis. The incretin effect results in a more than 2-fold increase of the insulin response to a meal in healthy people and two different techniques have been used in the past to measure its magnitude. Most studies employ an OGTT on one day, followed by a matching glucose infusion on a separate day. Another study design employs a hyperglycemic glucose clamp that is maintained after oral ingestion of glucose. Both protocols allow quantification of the incretin effect by comparing the insulin response to an identical glycemic stimulus. Here we performed a within-subject comparison of both techniques to quantify the incretin effect and suggest different calculation methods to interpret the results derived from the clamp experiment in a cohort of healthy young adults (N=10, age 33±4y). All subjects participated on 4 different study days: a) OGTT, b) isoglycemic glucose infusion (Iso-IV), c) hyperglycemic clamp with oral glucose ingestion (clamp-OGTT), d) hyperglycemic clamp (clamp). With the classic OGTT/Iso-IV method the insulin response to glucose ingestion increased more than 2-fold and was 60±6% and 49±5% for insulin and c-peptide. Different estimates of the incretin effect based on the clamp method ranged from 58-79% for insulin and 38-61% for c-peptide, both significantly higher than values derived from the OGTT/isoglycemic infusion method. However, when the effect of continuous hyperglycemia on insulin secretion was accounted for, using extrapolation from early timepoints of the clamp, good agreement was noted between the two methods. Based on these results both techniques seem to be equally suited to measure the incretin effect and should be employed according to the scientific questions, experimental contingencies and investigator experience.

The Effect of Soy and Whey Protein Supplementation on Glucose Homeostasis in Healthy Normal Weight Asian Indians.

Milk and legumes are good source of protein foods used to sustain muscle mass, but their effects on postprandial glucose homeostasis and energy metabolism may be different. This is relevant, for example, in the dietetic response to obesity or diabetes, where the intake of high-quality protein is often increased significantly. The objective of this study was to characterize the acute effect of whey and soy protein (15% vs. 30%) on glucose homeostasis, energy metabolism, and satiety. Healthy, normal body mass index (BMI) Indian adult males aged 20-35 years (n = 15) received 4 test meals (2 proteins (soy vs. whey) and 2 doses (15% vs. 30% protein: energy ratio)). Blood samples were collected serially after the meal to calculate the incremental area under the curve for plasma glucose and insulin. Energy expenditure and substrate oxidation were measured after the meal. Satiety was measured with a visual analogue scale. The insulin response, represented by the incremental area under the curve, was significantly higher for the 30% whey compared to the 30% soy protein meal (p < 0.01) but was not significantly different between the 15% protein doses. There were no differences in the plasma glucose response across protein sources or doses. The mean peak fat and carbohydrate oxidation, satiety, and energy expenditure did not differ between the protein sources and doses. In conclusion, at higher doses, whey protein has a greater insulinogenic response, compared to soy protein, and exhibits a dose-response effect. However, at lower doses, whey and soy protein elicit similar insulinogenic responses, making them equally effective protein sources in relation to glucose homoeostasis.

Structural changes of thermally treated starch during digestion and the impact on postprandial glucose homeostasis

Intake of foods upon thermal treatment is typically associated with an elevated postprandial glycemic response, which is one of the risk factors for type 2 diabetes development and progression. In this study, rice starch was thermally treated using aqueous phase (boil), air phase (bake), and lipid phase (fry). Peak blood glucose levels in C57 mice increased by 16.94 %, 12.60 %, and 8.1 % after ingestion of thermally treated starch (20.23, 19.48, and 18.70 mmol/L), compared with raw starch (17.30 mmol/L). The insulin response to the intake of thermally treated starch increased (4.73 %–6.83 % higher than the control), whereas the concentration of GLP-1, a hormone used to promote insulin secretion, decreased (1.54 %–8.56 % lower than the control). Furthermore, thermally treated starch accelerated food absorption by enhancing gastrointestinal digestion, exacerbating postprandial glucose fluctuation at the next meal. Structural characterization showed thermal treatment reduced starch branching density and degree of structure order, which were not conducive to preventing the attack of enzymes. During digestion, they were highly hydrolyzed into low-molecular-weight fragments, and the proportion of ultrashort chains substantially increased. These findings provide a better understanding of the fine structure of starch that promotes hypoglycemia and initially explain how diets high in thermally treated starch impair glucose balance.

Distinct Roles for Brain and Pancreas in Basal and Postprandial Glucose Homeostasis.

The glucose homeostasis system ensures that the circulating glucose level is maintained within narrow physiological limits both in the fasting (or basal) state and following a nutrient challenge. Although glucose homeostasis is traditionally conceptualized as a single overarching system, evidence reviewed here suggests that basal glycemia and glucose tolerance are governed by distinct control systems. Specifically, whereas glucose tolerance appears to be determined largely by interactions between insulin secretion and insulin sensitivity, basal-state glucose homeostasis is predominated by insulin-independent mechanisms governed largely by the brain. In addition to a new perspective on how glucose homeostasis is achieved, this "dual control system" hypothesis offers a feasible and testable explanation for observations that are otherwise difficult to reconcile and sheds new light on the integration of central and peripheral metabolic control mechanisms. The implications of this model for the pathogenesis and treatment of impaired fasting glucose, impaired glucose tolerance, and type 2 diabetes are also discussed.

RF04 | PSUN297 Genetic Knockout of Intestinal Hexokinase Domain Containing Protein-1 Affects Enterocyte Glucose Transport in Mice Fed High Fat Diet

Abstract Hexokinase domain containing protein-1, or HKDC1, is a widely expressed novel hexokinase that is genetically associated with elevated 2-hour gestational blood glucose levels during an oral glucose tolerance test, suggesting a role for HKDC1 in postprandial glucose regulation during pregnancy. Our earlier studies utilizing transgenic mice containing whole-body HKDC1 knockdown, or mice in which hepatic HKDC1 was overexpressed or knocked out, indicated that HKDC1 is important for whole-body glucose homeostasis in aging and pregnancy, through modulation of glucose tolerance, peripheral tissue glucose utilization, and hepatic energy storage. However, our knowledge of the precise mechanisms by which HKDC1 regulates postprandial glucose homeostasis under normal and diabetic conditions is lacking. As the intestine is the main entry portal for dietary glucose, and since HKDC1 is highly expressed within the intestine, in this study we assessed and characterized the in vivo significance of intestine-specific HKDC1 in regulating glucose homeostasis under normal and obesogenic conditions. We developed an intestine-specific HKDC1 knockout mouse model, HKDC1Int-/-, utilizing Cre-mediated recombination of HKDC1 in which Cre was expressed under the control of the villin gene promoter, leading to genetic knockout of HKDC1 solely within the intestinal epithelium. Mice were maintained until 28 weeks of age on either a normal chow diet or a high fat diet to develop obesity, hyperglycemia, and insulin resistance. While no overt glycemic phenotype was observed, 28-week-old HKDC1Int-/- mice fed a high fat diet exhibited an increased glucose excursion following an oral glucose load compared to mice expressing intestinal HKDC1. This finding was not due to differences in insulin levels, whole-body insulin tolerance, or gluconeogenesis, nor was it a result of alterations in enterocyte glucose utilization or a reduction in peripheral skeletal muscle glucose uptake. Furthermore, the enhanced glucose excursion was related to transport of glucose through the intestinal epithelium, as mice administered an intraperitoneal glucose load did not exhibit alterations in post-load glycemic excursion. Assessment of intestinal glucose transporters in high fat diet-fed HKDC1Int-/- mice indicated an increased expression of GLUT2 in the enterocyte apical membrane in the fasting state. Taken together, our results indicate that intestine-specific HKDC1 contributes to postprandial glycemic regulation by modulating dietary glucose transport across the intestinal epithelium under conditions of enhanced metabolic stress, such as obesity, hyperglycemia, and diabetes. Presentation: Saturday, June 11, 2022 1:24 p.m. - 1:29 p.m., Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

The Location of Missense Variants in the Human GIP Gene Is Indicative for Natural Selection.

The intestinal hormone, glucose-dependent insulinotropic polypeptide (GIP), is involved in important physiological functions, including postprandial blood glucose homeostasis, bone remodeling, and lipid metabolism. While mutations leading to physiological changes can be identified in large-scale sequencing, no systematic investigation of GIP missense variants has been performed. Here, we identified 168 naturally occurring missense variants in the human GIP genes from three independent cohorts comprising ~720,000 individuals. We examined amino acid changing variants scattered across the pre-pro-GIP peptide using in silico effect predictions, which revealed that the sequence of the fully processed GIP hormone is more protected against mutations than the rest of the precursor protein. Thus, we observed a highly species-orthologous and population-specific conservation of the GIP peptide sequence, suggestive of evolutionary constraints to preserve the GIP peptide sequence. Elucidating the mutational landscape of GIP variants and how they affect the structural and functional architecture of GIP can aid future biological characterization and clinical translation.

Dynamic Methods for Childhood Hypoglycemia Phenotyping: A Narrative Review.

Hypoglycemia results from an imbalance between glucose entering the blood compartment and glucose demand, caused by a defect in the mechanisms regulating postprandial glucose homeostasis. Hypoglycemia represents one of the most common metabolic emergencies in childhood, potentially leading to serious neurologic sequelae, including death. Therefore, appropriate investigation of its specific etiology is paramount to provide adequate diagnosis, specific therapy and prevent its recurrence. In the absence of critical samples for biochemical studies, etiological assessment of children with hypoglycemia may include dynamic methods, such as in vivo functional tests, and continuous glucose monitoring. By providing detailed information on actual glucose fluxes in vivo, proof-of-concept studies have illustrated the potential (clinical) application of dynamic stable isotope techniques to define biochemical and clinical phenotypes of inherited metabolic diseases associated with hypoglycemia. According to the textbooks, individuals with glycogen storage disease type I (GSD I) display the most severe hypoglycemia/fasting intolerance. In this review, three dynamic methods are discussed which may be considered during both diagnostic work-up and monitoring of children with hypoglycemia: 1) functional in vivo tests; 2) in vivo metabolic profiling by continuous glucose monitoring (CGM); 3) stable isotope techniques. Future applications and benefits of dynamic methods in children with hypoglycemia are also discussed.

Enterocyte HKDC1 Modulates Intestinal Glucose Absorption in Male Mice Fed a High-fat Diet.

Hexokinase domain containing protein-1, or HKDC1, is a widely expressed hexokinase that is genetically associated with elevated 2-hour gestational blood glucose levels during an oral glucose tolerance test, suggesting a role for HKDC1 in postprandial glucose regulation during pregnancy. Our earlier studies utilizing mice containing global HKDC1 knockdown, as well as hepatic HKDC1 overexpression and knockout, indicated that HKDC1 is important for whole-body glucose homeostasis in aging and pregnancy, through modulation of glucose tolerance, peripheral tissue glucose utilization, and hepatic energy storage. However, our knowledge of the precise role(s) of HKDC1 in regulating postprandial glucose homeostasis under normal and diabetic conditions is lacking. Since the intestine is the main entry portal for dietary glucose, here we have developed an intestine-specific HKDC1 knockout mouse model, HKDC1Int–/–, to determine the in vivo role of intestinal HKDC1 in regulating glucose homeostasis. While no overt glycemic phenotype was observed, aged HKDC1Int–/– mice fed a high-fat diet exhibited an increased glucose excursion following an oral glucose load compared with mice expressing intestinal HKDC1. This finding resulted from glucose entry via the intestinal epithelium and is not due to differences in insulin levels, enterocyte glucose utilization, or reduction in peripheral skeletal muscle glucose uptake. Assessment of intestinal glucose transporters in high-fat diet–fed HKDC1Int–/– mice suggested increased apical GLUT2 expression in the fasting state. Taken together, our results indicate that intestinal HKDC1 contributes to the modulation of postprandial dietary glucose transport across the intestinal epithelium under conditions of enhanced metabolic stress, such as high-fat diet.

A Study on the Blood Sugar Improvement Effect and Safety of &lt;italic&gt;Galgunhwangryunhwanggum-tang&lt;/italic&gt; for Type 2 Diabetes without Complications: A Systemic Review and Meta-Analysis

Objectives: The purpose of this study is to assess the antidiabetic effect and safety of Galgunhwangryunhwanggum-tang for type 2 diabetes without complications by analyzing related research.Methods: For a systematic review and meta-analysis, we searched for the antidiabetic effect and safety of Galgunhwangryunhwanggum-tang for type 2 diabetes without complications in 10 databases up to September 2021. Only randomized controlled trials were chosen.Results: In the treatment effectiveness analysis and meta-analysis, Galgunhwangryunhwanggum-tang had significant improvement effects on fasting plasma glucose level, 2-hour postprandial glucose level, glycated hemoglobin, fasting insulin, and homeostasis model assessment for insulin resistance compared to the control group when treated in parallel with oral glycemic drugs.Conclusion: Galgunhwangryunhwanggum-tang is effective in improving blood sugar and insulin resistance in type 2 diabetes patients without complications and can especially be considered in parallel treatment with oral hypoglycemic drugs. A large-scale randomized controlled clinical trial is required to complement the limitations presented in this study in the future.

Slowly digestible property of highly branched α-limit dextrins produced by 4,6-α-glucanotransferase from Streptococcus thermophilus evaluated in vitro and in vivo

Starch molecules are first degraded to slowly digestible α-limit dextrins (α-LDx) and rapidly hydrolyzable linear malto-oligosaccharides (LMOs) by salivary and pancreatic α-amylases. In this study, we designed a slowly digestible highly branched α-LDx with maximized α-1,6 linkages using 4,6-α-glucanotransferase (4,6-αGT), which creates a short length of α-1,4 side chains with increasing branching points. The results showed that a short length of external chains mainly composed of 1–8 glucosyl units was newly synthesized in different amylose contents of corn starches, and the α-1,6 linkage ratio of branched α-LDx after the chromatographical purification was significantly increased from 4.6% to 22.1%. Both in vitro and in vivo studies confirmed that enzymatically modified α-LDx had improved slowly digestible properties and extended glycemic responses. Therefore, 4,6-αGT treatment enhanced the slowly digestible properties of highly branched α-LDx and promises usefulness as a functional ingredient to attenuate postprandial glucose homeostasis.

Normal Versus Slowly Processed Pasta and Post-Prandial Glucose Homeostasis in Healthy Subjects: A Pilot Study.

Nutritional science is gaining increasing attention due to the implicit potential to prevent cardio-metabolic diseases. It is also becoming clear that food-making process might influence the metabolic response to the meal. We have conducted a proof-of-concept study to investigate whether slowly processed pasta might positively impact glucose homeostasis. A total of 14 healthy male volunteers underwent two different mixed-meal tests in a randomized order. One meal was composed of 100 g of normally processed pasta and the other 100 g of slowly processed pasta. Each meal was completed with 10 g of olive oil and 10 g of parmesan cheese. Glucose, insulin, and incretin post-prandial responses were assessed at 15, 30, 60, 90, 120, 150, and 180 min. Glucose tolerance, insulin, and incretin response were unaffected by the two different pasta types. However, a slight difference was evident in the shape of the curve of post-prandial insulin (i.e., mildly delayed with the slowly processed pasta). Despite the common belief of a different impact of normally processed and slowly processed pasta on glucose metabolism, they show a superimposable post-prandial metabolic response after a single meal in male healthy individuals. Further studies are required to confirm these results also in chronic, real-life settings and then to translate them to metabolically impaired individuals.

Metabolic Messengers: glucagon-like peptide 1.

Glucagon like peptide-1 (GLP-1), a peptide hormone from the intestinal tract, plays a central role in the coordination of postprandial glucose homeostasis through actions on insulin secretion, food intake and gut motility. GLP-1 forms the basis for a variety of current drugs for the treatment of type 2 diabetes and obesity, as well as new agents currently being developed. Here, we provide a concise overview of the core physiology of GLP-1 secretion and action, and the role of the peptide in human health, disease and therapeutics.

Regulation of Postabsorptive and Postprandial Glucose Metabolism by Insulin-Dependent and Insulin-Independent Mechanisms: An Integrative Approach.

Glucose levels in blood must be constantly maintained within a tight physiological range to sustain anabolism. Insulin regulates glucose homeostasis via its effects on glucose production from the liver and kidneys and glucose disposal in peripheral tissues (mainly skeletal muscle). Blood levels of glucose are regulated simultaneously by insulin-mediated rates of glucose production from the liver (and kidneys) and removal from muscle; adipose tissue is a key partner in this scenario, providing nonesterified fatty acids (NEFA) as an alternative fuel for skeletal muscle and liver when blood glucose levels are depleted. During sleep at night, the gradual development of insulin resistance, due to growth hormone and cortisol surges, ensures that blood glucose levels will be maintained within normal levels by: (a) switching from glucose to NEFA oxidation in muscle; (b) modulating glucose production from the liver/kidneys. After meals, several mechanisms (sequence/composition of meals, gastric emptying/intestinal glucose absorption, gastrointestinal hormones, hyperglycemia mass action effects, insulin/glucagon secretion/action, de novo lipogenesis and glucose disposal) operate in concert for optimal regulation of postprandial glucose fluctuations. The contribution of the liver in postprandial glucose homeostasis is critical. The liver is preferentially used to dispose over 50% of the ingested glucose and restrict the acute increases of glucose and insulin in the bloodstream after meals, thus protecting the circulation and tissues from the adverse effects of marked hyperglycemia and hyperinsulinemia.

An Innovative Short-Clustered Maltodextrin as Starch Substitute for Ameliorating Postprandial Glucose Homeostasis.

Dietary starch is usually associated with elevated postprandial glycemic response. This is a potential risk factor of type 2 diabetes. Here, a 1,4-α-glucan branching enzyme (GBE) was employed to reassemble α-1,4 and α-1,6 glycosidic bonds in starch molecules. Structural characterization showed that GBE-catalyzed molecular reassembly created an innovative short-clustered maltodextrin (SCMD), which showed a dense internal framework along with shortened external chains. Such short-clustered molecules obstructed digestive enzymes attack and displayed dramatically reduced digestibility. Therefore, SCMD was served as a dietary starch substitute to improve postprandial glucose homeostasis. A 22.3% decrease in glycemic peak was therefore detected in ICR mice following SCMD intake (10.7 mmol/L), compared with that in the control (13.8 mmol/L). Moreover, an attenuated insulin response (40.5% lower than that in control) to SCMD intake was regarded suitable for diabetes management. These novel discoveries demonstrate that enzymatically rebuilding starch molecules may be a meaningful strategy for diabetes management.

A novel nutritional supplement containing amino acids and chromium decreases postprandial glucose response in a randomized, double-blind, placebo-controlled study.

High postprandial blood glucose levels are associated with increased mortality, cardiovascular events and development of diabetes in the general population. Interventions targeting postprandial glucose have been shown to prevent both cardiovascular events and diabetes. This study evaluates the efficacy and safety of a novel nutritional supplement targeting postprandial glucose excursions in non-diabetic adults. Sixty overweight healthy male and female participants were recruited at two centers and randomized in a double-blind, placebo-controlled, crossover design. The supplement, a water-based drink containing 2.6g of amino acids (L-Leucine, L-Threonine, L-Lysine Monohydrochloride, L-Isoleucine, L-Valine) and 250 mcg of chromium picolinate, was consumed with a standardized carbohydrate-rich meal. The primary endpoint was the incremental area under the curve (iAUC) for venous blood glucose from 0 to 120 minutes. Secondary endpoints included glucose iAUC 0-180 minutes and the maximum glucose concentration (Cmax), for both venous and capillary blood glucose. In the intention-to-treat-analysis (n = 60) the supplement resulted in a decreased venous blood glucose iAUC0-120min compared to placebo, mean (SE) of 68.7 (6.6) versus 52.2 (6.8) respectively, a difference of -16.5 mmol/L•min (95% CI -3.1 to -30.0, p = 0.017). The Cmax for venous blood glucose for the supplement and placebo were 6.45 (0.12) versus 6.10 (<0.12), respectively, a difference of -0.35 mmol/L (95% CI -0.17 to -0.53, p<0.001). In the per protocol-analysis (n = 48), the supplement resulted in a decreased Cmax compared to placebo from 6.42 (0.14) to 6.12 (0.14), a difference of -0.29 mmol/L (95% CI -0.12 to -0.47, p = 0.002). No significant differences in capillary blood glucose were found, as measured by regular bed-side glucometers. The nutritional supplement drink containing amino acids and chromium improves the postprandial glucose homeostasis in overweight adults without diabetes. Future studies should clarify, whether regular consumption of the supplement improves markers of disease or could play a role in a diet aiming at preventing the development of diabetes.

226-OR: The Mediterranean Diet Increases GLP-1 and Oxyntomodulin Compared with Vegetarian Diet in Type 2 Diabetes Subjects

Aim: To compare a Mediterranean dietetic pattern with a vegetarian pattern in terms of hunger-satiety perception through post-prandial assessment of appetite-related hormones glucagon-like peptide 1 (GLP-1) and Oxyntomodulin (OXM), as well as self-rated Visual Analogue Scale (VAS) quantification, in overweight/obese type-2 diabetes (T2D) subjects. Methods: Twelve T2D subjects (M:F = 7:5), mean age 63 ± 8.5 years, were enrolled in our randomized, controlled, crossover study. Participants were given a vegetarian meal high in complex carbohydrate and dietary fiber (HFV, 35g fiber/1000 Kcal) as well as a Mediterranean (MED) meal in two different days over a one-week washout period. The two meals were isocaloric. Appetite ratings, glucose/insulin and gastrointestinal hormone concentrations were measured at fasting and every 30’ until 4 hours following meal consumption. Results: GLP-1 and OXM levels were significantly higher following MED meal consumption compared with HFV meal (240’ AUC, P &amp;lt;.022 and P &amp;lt;.023, respectively). Both MED and HFV meal resulted in a biphasic secretion pattern of GLP-1 and OXM, although MED meal was related to a delayed, significantly higher second GLP-1 peak at 150’ compared with that of HFV meal (P &amp;lt;.05). MED meal was related to lower glucose trend compared with HFV meal (P &amp;lt;.039), whereas we did not observe significant changes in terms of self-reported VAS scores and insulin trend. Conclusions: In T2D overweight/obese subjects, a MED-like meal is more effective than a vegetarian meal in terms of post-prandial plasma glucose homeostasis and GLP-1 and OXM release. These changes were not confirmed by VAS appetite self-assessment over a 4 hours period. Disclosure A. Di Mauro: None. D. Tuccinardi: None. R. Del Toro: None. L. Monte: None. R. Giorgino: None. L. Rampa: None. G. Rossini: None. S. Kyanvash: None. A. Soare: None. M.M. Rosati: None. Y. Khazrai: None. A. Piccoli: None. N. Napoli: None. P. Pozzilli: Advisory Panel; Self; Abbott, AstraZeneca, Eli Lilly and Company. Research Support; Self; Medtronic, Sanofi. S. Manfrini: None.

Highly branched α-limit dextrins attenuate the glycemic response and stimulate the secretion of satiety hormone peptide YY

Starch molecules are hydrolyzed to linear malto-oligosaccharides and branched α-limit dextrins (α-LDx) by salivary and pancreatic α-amylases in the gastrointestinal tract. In this study, we investigated the physiological responses to chromatographically purified branched α-LDx, which are slowly hydrolyzed owing to their high α-1,6 linkage ratios. Our results demonstrate that the digestion of branched α-LDx by mammalian α-glucosidases is slower than that of malto-oligosaccharides in vitro. In vivo experiments using mice showed that the glucose spike at the initial stage of α-LDx hydrolysis was significantly (p < 0.05) attenuated owing to an extended glycemic response. Branched α-LDx stimulated the secretion of peptide YY, which controls the satiety level and rate of gastric emptying by regulating the hypothalamus activity. In conclusion, the slow digestibility of branched α-LDx decelerated glucogenesis in vitro and in vivo; this phenomenon may result in beneficial physiological effects for regulate type 2 diabetes, obesity, and related chronic diseases by controlling post-prandial glucose homeostasis.

High or low glycemic index (GI) meals at dinner results in greater postprandial glycemia compared with breakfast: a randomized controlled trial

IntroductionWhile circadian control of glucose metabolism is well known, how glycemic index (GI) of carbohydrate-rich meals interacts with time of consumption (breakfast or dinner) to influence postprandial (PP) glucose homeostasis...

Postprandial glycaemic responses in women co-ingesting green leafy vegetables with a carbohydrate meal: interactions with the sirtuin system

AbstractThe addition of vegetable to carbohydrate-based meals has been shown to improve postprandial glucose homeostasis. Inter-individual variation in responses preclude conclusive evidence, particularly in women. The sirtuins and associated genes involved in producing the chemical, nicotinamide adenine dinucleotide (NAD), are emerging as key players in blood glucose control and may contribute to variable responses. This study aimed to investigate effects of co-ingesting green leafy vegetables (GLV) on postprandial glucose regulation following a carbohydrate meal and factors affecting inter-individual variation particularly around the sirtuin system.Twenty-five women (BMI 24.8–30.5 kg/m2) were recruited to ‘The impact of Vegetables’ (VegGI) study on acute glycaemia and Glycaemia induced CVD risk in women: metabolic effects and Inter-individual variations. Postprandial glycaemic responses (GR) following rice (75 g of available carbohydrate), rice with bok choy (150g) or spinach (150g) were measured every 5 minutes for 4 hours using a Continuous Glucose Monitoring system (Medtronic Ltd). Anthropometric, cholesterol (Cholestech LDX, Alere), HbA1c (Afinion AS100, Alere) and insulin (Mercodia AB) measures were made in a fasted state. Oestradiol, progesterone, follicular stimulating hormone and testosterone were measured (ADVIA Centaur). Total RNA was extracted from postprandial blood collected at 0 h, 30 min, 1 h and 2 h in PAXgene blood RNA tubes (PreAnalytiX GmbH) using a Blood RNA Kit (Qiagen, Crawley, UK) and quality assessed by Agilent Bioanalyser (Agilent Technologies, Bracknell, UK). Gene expression was measured using the GenomeLab System and a custom designed multiplex assay, the hSIRTNADPlex (25 targets involved in the sirtuin signalling).Linear mixed models (ver.24.0; SPSS Inc) revealed no effect of GLV consumption on postprandial GR. Principal component analysis (SIMCA-P + 12.0 software, MKS Instruments UK Ltd.) of postprandial GR indicated inter-individual variation in the responses associated with the test meals. Partial Least Square (PLS) stratified the cohort into two subgroups based on sirtuin system gene expression profiles. Postprandial GR was a contributing factor in the stratification observed, together with BMI, plasma lipid, insulin and glucose levels, but not menopausal status.Preliminary evidence indicates that co-ingesting GLV with a carbohydrate meal does not reduce postprandial GR in women (BMI 24.8–30.5 kg/m2) and that significant inter-individual variation in postprandial GR may be linked to the sirtuin system, BMI, plasma lipid, insulin, and glucose levels but not menopausal status. Recruitment and data analysis are ongoing to increase group size and further assess contributing factors.This work was supported by Scottish Government's Rural and Environment Science and Analytical Services Division