Lower Postprandial Blood Glucose Research Articles

Whey Protein Premeal Lowers Postprandial Glucose Concentrations in Adults Compared with Water—The Effect of Timing, Dose, and Metabolic Status: a Systematic Review and Meta-analysis

BackgroundServing whey protein before a meal in order to lower postprandial blood glucose concentrations is known as a premeal. The underlying mechanisms are only partly understood but may involve stimulation of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and insulin secretion together with a slower gastric emptying rate. ObjectivesThe objective of this systematic review and meta-analysis was to review all randomized clinical trials investigating premeals with whey protein in comparison with a nonactive comparator (control) that evaluated plasma glucose, GLP-1, GIP, insulin, and/or gastric emptying rate. Secondary aims included subgroup analyses on the timing and dose of the premeal together with the metabolic state of the participants [lean, obese, and type 2 diabetes mellitus (T2DM)]. MethodsWe searched EMBASE, CENTRAL, PUBMED, and clinicaltrials.gov and found 16 randomized crossover trials with a total of 244 individuals. The last search was performed on 9 August, 2022. ResultsWhey protein premeals lowered peak glucose concentration by −1.4 mmol/L [−1.9 mmol/L; −0.9 mmol/L], and the area under the curve for glucose was −0.9 standard deviation (SD) [−1.2 SD; −0.6 SD] compared with controls (high certainty). In association with these findings, whey protein premeals elevated GLP-1 (low certainty) and peak insulin (high certainty) concentrations and slowed gastric emptying rate (high certainty) compared with controls. Subgroup analyses showed a more pronounced and prolonged glucose-lowering effect in individuals with T2DM compared with participants without T2DM. The available evidence did not elucidate the role of GIP. The protein dose used varied between 4 and 55 g, and meta-regression analysis showed that the protein dose correlated with the glucose-lowering effects. ConclusionsIn conclusion, whey protein premeals lower postprandial blood glucose, reduce gastric emptying rate, and increase peak insulin. In addition, whey protein premeals may elevate plasma concentrations of GLP-1. Whey protein premeals may possess clinical potential, but the long-term effects await future clinical trials.

Low glycemic index potato biscuits alleviate physio-histological damage and gut dysbiosis in rats with type-2 diabetes mellitus induced by high-sugar and high-fat diet and streptozotocin

Type 2 diabetes mellitus (T2DM) is the most common type of diabetes globally and poses a major concern for human health. This study aimed to investigate the effects on T2DM of low-glycemic index (GI) potato biscuits with oat bran and inulin as functional additives. T2DM was induced in rats by streptozotocin (STZ) and a high-sugar and high-fat diet. The alleviation of T2DM by low-GI potato biscuits at different doses was evaluated based on the analysis of glycolipid levels, histological observations, inflammatory markers, and gut microbiota structure. Compared to wheat biscuits, low-GI potato biscuits resulted in lower postprandial blood glucose levels. After 8 weeks of intervention, fasting blood sugar levels were 16.9% lower in T2DM rats fed high-dose low-GI potato biscuits than in untreated T2DM rats. Moreover, the intervention with low-GI potato biscuits significantly alleviated T2DM-induced pathological damage, glucose and lipid metabolic disorders, and inflammation by reversing the levels of total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, transforming growth factor-β, interleukin-1β, interleukin-6 and tumor necrosis factor-α. Moreover, the levels of short-chain fatty acids and gut microbiota structure in T2DM rats were significantly reversed. The abundance of beneficial bacteria (e.g., Bifidobacterium, Lachnoclostridium, Roseburia) in the gut of T2DM rats was significantly increased whereas the abundance of Escherichia-Shigella and Desulfovibrio decreased. The present study revealed that low-GI potato biscuits alleviated damages caused by high-sugar and high-fat diet- and STZ-induced T2DM in rats, as well as reversed disturbances in the gut microbiota. Thus, low-GI potato biscuits are potentially beneficial to T2DM patients.

Short Stair Stepping Bouts With Individualized Timing Lower Postprandial Blood Glucose

PURPOSE: Examine if stair stepping (SS) bouts at a self-selected intensity with individual timing can attenuate postprandial blood glucose (PBG). METHODS: Over 3 visits participants completed 3 mixed meal tolerance tests (700 kcal, 51% CHO, 34% fat, 15% PRO) with PBG measured at baseline and every 10 minutes after food consumption. The first visit was a seated control condition to find timing of peak PBG. The second and third visits were randomized and included either 1 or 3 min of SS timed to end right before individual peak PBG. Glycemic excursions were assessed as a glucose over time in a 3(condition)x7(time) RM ANOVA, baseline to peak PBG in a 3(condition)x2(time) RM ANOVA, and AUC and iAUC in one-way RM ANOVAs. RESULTS: For glucose over time there were main effects for condition [F(2,42) = 6.41, p < .004, η2 = .23] and time [F(6,126) = 24.584, p < .001, η2 = .54] but no interaction between condition and time [F(12, 252) = 1.12, p < .35, η2 = .05]. PBG was lower during the 3 min SS than the control and 1 min SS conditions at min 20 ((-16 (-24 to -8) mg/dL, p < .001) and (-9 (-18 to 0) mg/dL, p = .047)) and min 30 (((-11 (-20 to -2) mg/dL, p = .021) and (-10 (-20 to 0) mg/dL, p = .047))) but not at other timepoints (p = .078-.191). (Figure 1A) For baseline to peak PBG there were main effects for condition [F(2,42) = 7.27, p < .002, η2 = .26] and time [F(1,21) = 189.97, p < .001, η2 = .90] and an interaction between condition and time [F(2,42) = 5.10, p < .010, η2 = .20]. Peak PBG was lower than control in the 1 min SS (-7 (-12 to -1) mg/dL, p = .024) and 3 min SS (-14 (-21 to -7) mg/dL, p < .001) conditions. (Figure 1B) There was a main effect for AUC [F(2,42) = 6.416,p = .004,η2 = .234] with lower PBG in the 3 min SS than the control and 1 min SS conditions ((-7% (-11% to -3%) mg/dL/hr, p < .001) and (-5% (-10% to 0%) mg/dL/hr, p = .041)) (Figure 1C) but not for iAUC [F(2,42) = 2.541, p = .091,η2 = .108] (Figure 1D) CONCLUSION: SS with individualized timing for as little as 1 minute can lower PBG with greater reductions with 3 minutes of SS.

Increased Protein with Decreased Carbohydrate Intake Reduces Postprandial Blood Glucose Levels in Women with Gestational Diabetes: The iPRO Study.

Introduction:There is an urgent need to establish an evidence base for recommendations regarding proportions of macronutrients for optimized nutritional management of gestational diabetes mellitus (GDM). Our study compared isocaloric diets in women with GDM that differed in protein and carbohydrate content with fats held constant. We hypothesized that the glucose area under the curve (AUC) would be lower with the higher protein/lower carbohydrate diet.Research Design and Methods:This study used a random order crossover design within a controlled research unit environment. Nineteen women were randomized to treatment, with 12 participants completing both arms of the study. Blood sampling occurred preprandially and at t = 30, 60, 120, and 180" relative to meals. Inclusion criteria were confirmed diet-controlled GDMA1, singleton gestation, and with no pre-existing medical comorbidities. Mean gestational age at entrance to study = 32 (±1.76) weeks. Mean prepregnant body mass index of participants = 28.7 (±5.3) kg/m2 Participants were randomly assigned initially to either an increased protein/low carbohydrate (iPRO30%/CHO35%) diet or a lower protein/higher carbohydrate (LPRO15%/CHO50%) diet for a 36 hour inpatient stay on the research unit. All meals and snacks were prepared in a metabolic kitchen. After a 3–7 day washout period, participants were randomized to the opposite treatment.Results:On day 2 (with confirmed overnight fasting), the average 3-hour pre- through postprandial glucose AUC was lower in iPRO30%/CHO35% treatment arm (17395.20 ± 2493.47 vs. 19172.47 ± 3484.31, p = 0.01).Conclusion:This study is the first to demonstrate that a higher protein, lower carbohydrate meal, especially at breakfast, can result in lower postprandial blood glucose values in women with gestational diabetes. A lack of statistically significant differences at other collection time points could have been due to several factors, but most likely due to small sample size. Longer term outcomes of a higher protein diet, including maternal glycemic control, nitrogen balance, and impact on fetal growth outcomes, are needed.

Sex differences in the acute effect of stair-climbing on postprandial blood glucose levels: A randomized controlled trial

Backgrounds and aimsSingle, short stair climbing and descending (SCD) bouts of low to moderate intensity effectively lower postprandial blood glucose but previous reports have found conflicting results on interactions by sex during exercise. We hypothesize that SCD at a self-selected intensity will be equally effective at lowering postprandial blood glucose in males and females. Methods and Results: Thirty subjects (age: 23.8 (3.0) years) performed 0, 1, 3, and 10 min of SCD following consumption of a mixed meal. SCD was performed at a self-selected comfortable pace and all bouts ended at minute 28. Postprandial blood glucose was measured every 15 min for 1 h and analyzed as glucose over time, area under the curve (AUC), and incremental AUC (iAUC) using mixed-design ANOVAs with repeated measures. Although there was no interaction between sex and condition or time (p = .129 to .541) for glucose over time, AUC, or iAUC, there was a main effect for sex for glucose over time (p = .004) and AUC (p = .006), but not iAUC (p = .125). Females had higher blood glucose throughout each trial (22% (13 to 31%), p = .004) but both males' and females’ postprandial blood glucose was lowered following 10 min of SCD relative to the seated control condition. Conclusions: Males and females benefited equally from single, short SCD bouts of low to moderate intensity despite females having higher blood glucose at all time points. Previous findings of sex differences in the attenuating effect of exercise on postprandial blood glucose are likely due to the use of absolute workloads leading to varying relative intensities.

A Review of the Relationship between Lentil Serving and Acute Postprandial Blood Glucose Response: Effects of Dietary Fibre, Protein and Carbohydrates.

Pulse consumption has been shown to confer beneficial effects on blood glucose and insulin levels. Lentil consumption, in particular, consistently lowers acute blood glucose and insulin response when compared to starchy control foods. The mechanism by which lentils lower postprandial blood glucose response (PBGR) and insulin levels is unclear; however, evidence suggests that this effect may be linked to macronutrients and/or the amount of lentils consumed. This review attempts to consolidate existing studies that examined lentil consumption and glycemic and/or insulinemic responses and declared information on macronutrient composition and dietary fibre content of the foods tested. Collectively, these studies suggest that consumption of lentils reduces PBGR, with the minimum effective serving being ~110g cooked to reduce PBGR by 20%. Reductions in PBGR show modest-to-strong correlations with protein (45–57 g) and dietary fibre (22–30 g) content, but has weaker correlations with available carbohydrates. Increased lentil serving sizes were found to moderately influence relative reductions in peak blood glucose concentrations and lower the area under the blood glucose curve (BG AUC). However, no clear relationship was identified between serving and relative reductions in the BG AUC, making it challenging to characterize consistent serving–response effects.

Randomized clinical trial to evaluate the effect on postprandial glycemia of Nutren Control®, a glycemia-targeted specialized supplement, compared to standardized breakfast in patients with type-2 diabetes: the CONTROL DIABETES study.

to evaluate the effects of a new glycemia targeted specialized supplement (GTSS) compared to a standard breakfast on postprandial blood glucose (PPG). patients with type 2 diabetes (T2D) and suboptimal control (A1C between 6.5 and 8.5 %) in monotherapy with metformin were included to this prospective, randomized, crossover trial. The standardized breakfast was isoenergetic compared to the GTSS, differing on macronutrients distribution. Both interventions were used once a day in the morning, each replacing breakfast for 7 consecutive days (14 days of observation). Intermittent scanning continuous glucose monitoring system (isCGM) determined the difference between the interventions regarding the incremental area under the curve (iAUC) of the PPG (3 hours after intervention), as a primary endpoint; secondary endpoints were the difference between the interventions regarding the glycemic peak, postprandial glucose excursion (PPGE), mean blood glucose (MBG) and time in range (TIR). thirty-one T2D patients with ages between 39 and 69 years-old were enrolled. GTSS group had significantly lower iAUC of the PPG compared to standardized breakfast (33.3 [15.0 to 54.0] vs 46.8 [27.3 to 75.1] mg/dL), while also presenting a significantly lower PPG excursion (26.4 ± 17.2 vs 44.8 ± 24.4 mg/dL). There was no difference between the intervention periods regarding MBG, TIR and hypoglycemic events. The new GTSS, as a meal replacement in the breakfast, produced a 25 % reduction in the iAUC of the PPG, as accessed by isCGM, in comparison with an isocaloric-standardized meal.

Processing, digestion property and structure characterization of slowly digestible gorgon nut starch.

The online version contains supplementary material available at 10.1007/s10068-021-01007-6.

Impact of insufficient sleep on dysregulated blood glucose control under standardised meal conditions

Aims/hypothesisSleep, diet and exercise are fundamental to metabolic homeostasis. In this secondary analysis of a repeated measures, nutritional intervention study, we tested whether an individual’s sleep quality, duration and timing impact glycaemic response to a breakfast meal the following morning.MethodsHealthy adults’ data (N = 953 [41% twins]) were analysed from the PREDICT dietary intervention trial. Participants consumed isoenergetic standardised meals over 2 weeks in the clinic and at home. Actigraphy was used to assess sleep variables (duration, efficiency, timing) and continuous glucose monitors were used to measure glycaemic variation (>8000 meals).ResultsSleep variables were significantly associated with postprandial glycaemic control (2 h incremental AUC), at both between- and within-person levels. Sleep period time interacted with meal type, with a smaller effect of poor sleep on postprandial blood glucose levels when high-carbohydrate (low fat/protein) (pinteraction = 0.02) and high-fat (pinteraction = 0.03) breakfasts were consumed compared with a reference 75 g OGTT. Within-person sleep period time had a similar interaction (high carbohydrate: pinteraction = 0.001, high fat: pinteraction = 0.02). Within- and between-person sleep efficiency were significantly associated with lower postprandial blood glucose levels irrespective of meal type (both p < 0.03). Later sleep midpoint (time deviation from midnight) was found to be significantly associated with higher postprandial glucose, in both between-person and within-person comparisons (p = 0.035 and p = 0.051, respectively).Conclusions/interpretationPoor sleep efficiency and later bedtime routines are associated with more pronounced postprandial glycaemic responses to breakfast the following morning. A person’s deviation from their usual sleep pattern was also associated with poorer postprandial glycaemic control. These findings underscore sleep as a modifiable, non-pharmacological therapeutic target for the optimal regulation of human metabolic health.Trial registrationClinicalTrials.gov NCT03479866.Graphical abstract

A perspective on the benefits of consumption of parboiled rice over brown rice for glycaemic control.

Rice is a staple food for over 3.5 billion people worldwide. The nutritional content of rice varies with different post-harvest processing techniques. Major varieties include brown rice (BR), white rice (WR) and parboiled rice (PBR). While consumption of BR is advocated due to its higher nutritional content compared to other varieties, some studies have indicated lower post-prandial blood glucose (PPBG) levels when PBR is consumed. This apparent benefit of PBR consumption is not well publicised and no commentaries on underlying mechanisms are available in literature. In this review, we looked into differential nutrient content of PBR, as compared to BR and WR, and tried to understand how their consumption could be associated with glycaemic control. Various roles played by these nutrients in mechanisms of insulin secretion, insulin resistance, nutrient absorption and T2DM-associated inflammation were reviewed from literature-based evidence. We report differential nutritional factors in PBR, with respect to BR (and WR), such as higher calcium and selenium content, lower phytic acids, and enriched vitamin B6 which might aid PBR's ability to provide better glycaemic control than BR. Our interpretation of reviewed literature leads us to suggest the possible benefits of PBR consumption in glycaemic control and its inclusion as the preferred rice variant in diets of T2DM patients and at-risk individuals.

Preparation and Analysis of α-1,6 Glucan as a Slowly Digestible Carbohydrate.

Carbohydrate materials that produce lower postprandial blood glucose increase are required for diabetic patients. To develop slowly digestible carbohydrates, the effect of degree of polymerization (DP) of α-1,6 glucan on its digestibility was investigated in vitro and in vivo. We prepared four fractions of α-1,6 glucan composed primarily of DP 3–9, DP 10–30, DP 31–150, and DP 151+ by fractionating a dextran hydrolysate. An in vitro experiment using digestive enzymes showed that the glucose productions of DP 3–9, DP 10–30, DP 31–150, and DP 151+ were 70.3, 53.4, 28.2, and 19.2 % in 2 h, and 92.1, 83.9, 39.6, and 33.3 % in 24 h relative to dextrin, respectively. An in vivo glycemic response showed that the incremental area under the curve (iAUC) of blood glucose levels of α-1,6 glucan with DP 3–9, DP 10–30, DP 31–150, and DP 151+ were 99.5, 84.3, 65.4, and 40.1 % relative to dextrin, respectively. These results indicated that α-1,6 glucan with higher DP had stronger resistance to digestion and produced a smaller blood glucose response. DP 10–30 showed significantly lower maximum blood glucose levels than dextrin; however, no significant difference was observed in iAUC, indicating that DP 10–30 was slowly digestible. In addition, α-1,6 glucan was also produced using an enzymatic reaction with dextrin dextranase (DDase). This produced similar results to DP 10–30. The DDase product can be synthesized from dextrin at low cost. This glucan is expected to be useful as a slowly digestible carbohydrate source.

Inhibitory effects of acorn (Quercus variabilis Blume) kernel-derived polyphenols on the activities of α-amylase, α-glucosidase, and dipeptidyl peptidase IV

The chemical constituents of the free and bound polyphenols extracted from acorn kernels were analyzed, and the predominant chemical components in the free polyphenol extract were quercetin, azelaic acid, and gallic acid, while the bound polyphenol extract mainly contained ellagic acid, gallic acid, and ferulic acid. The inhibitory activities of the four main components on α-glucosidase showed the following trend: ellagic acid > quercetin > azelaic acid > gallic acid. The IC50 values of the free and bound polyphenol extracts on α-amylase were 5.25 and 1.37 mg/mL, respectively. The free polyphenol extract exhibited a greater ability to inhibit α-glucosidase and dipeptidyl peptidase IV (DPP-IV) than the bound polyphenol extract. The polyphenols were found to change the secondary structures of α-amylase, α-glucosidase and DPP-IV. The inhibitory effects of the polyphenols on the three enzymes may give rise to low postprandial blood glucose after eating acorn-containing foods and can be beneficial to diabetics.

Comparative Effects of the Branched-Chain Amino Acids, Leucine, Isoleucine and Valine, on Gastric Emptying, Plasma Glucose, C-Peptide and Glucagon in Healthy Men.

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

Effects of Bitter Substances on GI Function, Energy Intake and Glycaemia-Do Preclinical Findings Translate to Outcomes in Humans?

Bitter substances are contained in many plants, are often toxic and can be present in spoiled food. Thus, the capacity to detect bitter taste has classically been viewed to have evolved primarily to signal the presence of toxins and thereby avoid their consumption. The recognition, based on preclinical studies (i.e., studies in cell cultures or experimental animals), that bitter substances may have potent effects to stimulate the secretion of gastrointestinal (GI) hormones and modulate gut motility, via activation of bitter taste receptors located in the GI tract, reduce food intake and lower postprandial blood glucose, has sparked considerable interest in their potential use in the management or prevention of obesity and/or type 2 diabetes. However, it remains to be established whether findings from preclinical studies can be translated to health outcomes, including weight loss and improved long-term glycaemic control. This review examines information relating to the effects of bitter substances on the secretion of key gut hormones, gastric motility, food intake and blood glucose in preclinical studies, as well as the evidence from clinical studies, as to whether findings from animal studies translate to humans. Finally, the evidence that bitter substances have the capacity to reduce body weight and/or improve glycaemic control in obesity and/or type 2 diabetes, and potentially represent a novel strategy for the management, or prevention, of obesity and type 2 diabetes, is explored.

Beta-Glucan From Barley Attenuates Post-prandial Glycemic Response by Inhibiting the Activities of Glucose Transporters but Not Intestinal Brush Border Enzymes and Amylolysis of Starch

Beta (β)-glucan (BG) from cereal grains is associated with lowering post-prandial blood glucose but the precise mechanism is not well-elucidated. The main aim of this study was to understand the mechanism through which BG from barley affects post-prandial glycemic response. Waffles containing 0, 1, 2, and 3 g barley BG and the same amount of available carbohydrate (15 g) were fed to the TIM-1 dynamic gastrointestinal digestion system to study the effect of BG on starch hydrolysis. Intestinal acetone powder and Xenopus laevis oocytes were used to study BG's effect on mammalian intestinal α-glucosidase and glucose transporters. The presence of BG did not significantly affect the in vitro starch digestion profiles of waffles suggesting that BG does not affect α-amylase activity. Intestinal α-glucosidase and glucose transport activities were significantly (p < 0.0001) inhibited in the presence of barley BG. Interestingly, BG viscosity did not influence α-amylase, α-glucosidase, GLUT2, and SGLT1 activities. This study provides the first evidence for the mechanism by which BG from barley attenuates post-prandial glycemic response is via alteration of α-glucosidase, GLUT2, and SGLT1 activity, but not amylolysis of starch. The decrease in post-prandial blood glucose in the presence of BG is likely a consequence of the interaction between BG and membrane active proteins (brush border enzymes and glucose transporters) as opposed to the commonly held hypothesis that increased viscosity caused by BG inhibits starch digestion.

In vitro antidiabetic property and phytochemical profiling of Mangifera odorata pulp using UHPLC-ESI-Orbitrap-MS/MS

Mangifera odorata, or known as “kuini” in Malay, is considered an underutilised climacteric tropical fruit. Recent studies had suggested that the by-products of M. odorata may serve as functional food ingredients based on their nutritional values and biological activities. Thus, the present work was aimed to determine the nutritional composition, antidiabetic properties through α-glucosidase and α-amylase inhibition assays, and phytochemical profiling of M. odorata pulp using ultra-high-performance liquid chromatography-electrospray ionisation orbitrap tandem mass spectrometry (UHPLC-ESI-Orbitrap-MS/MS). Proximate analyses found that M. odorata pulp contained high amounts of soluble fibre and moisture. The main sugar in the pulp was identified as sucrose, while ß-carotene, potassium, calcium, iron, and zinc were the major vitamins and minerals. The extraction of the sample in water, acetone, methanol, and ethanol were performed for the determination of antidiabetic assay. The results showed that 60% of ethanolic extract had the highest α-amylase inhibitory activity among the four extraction solvents. The findings revealed high levels of mangiferin in the active extract, which may be responsible for the α-amylase inhibition activity, thus contributing to lower post-prandial blood glucose. The present work provides evidence on the nutritional benefits of M. odorata pulp, as well as the potential use of its ethanolic extract as an α-amylase inhibitor.

Consumption of Sourdough Breads Improves Postprandial Glucose Response and Produces Sourdough-Specific Effects on Biochemical and Inflammatory Parameters and Mineral Absorption.

To evaluate responses to different sourdough breads, six groups of rats were fed a conventional refined wheat bread with no sourdough content (C_WhB); a leavened spelt bread baked with Rebola sourdough (Re_SpB); a durum wheat bread with Rebola sourdough (Re_DuB); or a multigrain bread leavened with Rebola (Re_MGB), Carla (Ca_MGB), or San Francisco sourdough (SF_MGB). Compared to C_WhB-fed rats, Re_SpB-, Re_DuB-, and Re_MGB-fed animals showed lower postprandial blood glucose levels, whereas SF_MGB-fed rats displayed a decreased postprandial blood insulin response and glucose and insulin products. The 3 week intake of Ca_MGB decreased blood triacylglycerols and the relative apparent absorption (RAA) of Fe2+, Cu2+, and Zn2+, whereas Re_MGB-fed animals showed lower serum levels of the MCP-1 inflammatory marker and decreased the Fe RAA. The 3 week consumption of the multigrain bread produced sourdough-specific effects. Thus, Re_MGB-fed animals displayed higher insulin concentrations than Ca_MGB- and SF_MGB-fed rats and decreased blood MCP-1 levels compared to those of Ca_MGB-fed animals. In addition, Ca_MGB-fed rats showed lower serum triacylglycerol concentrations than those of Re_MGB- and SF_MGB-fed animals, whereas SF_MGB-fed rats displayed higher RAA values of Ca2+, Cu2+, Fe2+, Mg2+, and Zn2+ than their Re_MGB and Ca_MGB counterparts. These sourdough-specific effects could be related to changes in the contents of sugars and organic acids, acidity, microbial composition, and proteolytic activity among sourdoughs. Hence, the consumption of sourdough breads improved postprandial blood glucose and insulin responses and produced sourdough-specific effects on RAA and serum insulin and triacylglycerol and MCP-1 levels in rats, showing that SF_MGB has the most promising beneficial effects.

Effects of Type-2 Resistant Starch (High-Amylose Maize Starch) on the Glycemic Index of Chinese Steamed Buns and Its Influence on Glycemic Response in Healthy Human Subjects

The incorporation of resistant starch (RS) in food has gained importance to be a good replacement for carbohydrate. This study aimed to determine the effects of resistant starch (RS) known as high-amylose maize starch (HM) as wheat flour substitute in Chinese steamed bun (CSB) formulation on postprandial glycemic response in healthy human subjects. In the single-blind cross-over experimental trial, subjects (female, n=15) consuming 30% HM (HM30) composite CSB had significantly lower postprandial blood glucose response compared with control consuming CSB (without HM) within 2 hours after ingestion of both samples. Compared with control CSB, HM30 produced lower glycemic response with a mean iAUC of 105.2 mmol x min/L. The mean iAUC of control CSB was 186.1 mmol x min/L. The low GI property of HM30 stabilized the blood glucose concentration level and did not cause sudden rapid increase in blood glucose concentration similar to high-GI reference food and medium-GI control CSB. Funding Information: This study was supported through funding from the Ministry of Higher Education Malaysia (MoHE), project code: FRGS/1/2017/STG/UMS/02/5. Declaration of Interests: The authors declare no conflicts of interest. Ethics Approval Statement: The study was ethically approved by the Medical Research Ethics Committee of Universiti Malaysia Sabah [Refer to Appendix D; UMS/FPSK6.9/100-6/1/95; JKEtika 3/18(7)]. The informed consent form was signed by the subjects to ensure their voluntary enrolment to participate in the study.

Changes in peripheral inflammation-related gene expression by postprandial glycemic response in healthy Japanese men

ObjectivesContinuous postprandial hyperglycemia is associated with the onset of cardiovascular disease. In recent years, the mRNA expression of inflammation-related genes in peripheral blood leukocytes has been shown to be induced by an increase in blood glucose levels. The aim of this study was to investigate differences in the expression of inflammation-related genes in peripheral blood leukocytes in response to an increase in blood glucose from individuals who consumed two kinds of breakfast meals with different glycemic indexes (GIs). MethodsTwenty healthy Japanese men 40 to 70 y of age were given low- or high-GI meals for breakfast for 14 d. Clinical examinations were performed on days 7 and 14. Their blood glucose levels and insulin concentrations were measured from before breakfast ingestion to 120 min after. Additionally, using the blood obtained before and 120 min after breakfast, the mRNA expression levels of inflammation-related genes in peripheral leukocytes were measured. ResultsThe blood glucose levels were significantly lower in the low-GI meal intake group at 30, 60, and 120 min after breakfast than in the high-GI meal intake group. The intake of high-GI meals for 6 d led to an increase in the mRNA levels of interleukin-1β, S100A4, and CD18 compared with the period of low-GI meals. ConclusionThe intake of a low-GI breakfast for 1 wk in healthy Japanese men resulted in lower postprandial blood glucose and insulin levels, which were accompanied by a reduced expression of inflammation-related genes in peripheral blood leukocytes.

Dietary 5,6,7-Trihydroxy-flavonoid Aglycones and 1-Deoxynojirimycin Synergistically Inhibit the Recombinant Maltase-Glucoamylase Subunit of α-Glucosidase and Lower Postprandial Blood Glucose.

1-Deoxynojirimycin (1-DNJ) is the major effective component of mulberry leaves, exhibiting inhibitory activity against α-glucosidase. However, due to the low content of 1-DNJ in mulberry products, its level cannot meet the lowest dose to exhibit its activity. In this study, a combination of dietary 5,6,7-trihydroxy-flavonoid aglycones with 1-DNJ showed synergistic inhibitory activity against maltase of mice α-glucosidase and recombinant C- and N-termini of maltase-glucoamylase (MGAM) and baicalein with 1-DNJ exhibited the strongest synergistic effect. The synergistic effect of the combination was also confirmed by the maltose tolerance test in vivo. Enzyme kinetics, molecular docking, fluorescence spectrum, and circular dichroism spectrometry studies indicated that the major mechanism of the synergism is that baicalein was a positive allosteric inhibitor and bound to the noncompetitive site of MGAM, causing an increase of the binding affinity of 1-DNJ to MGAM. Our results might provide a theoretical basis for the design of dietary supplements containing mulberry products.