Efficacy of increased resistant starch consumption in human type 2 diabetes

Metabolic phenotypes and the gut microbiota in response to dietary resistant starch type 2 in normal-weight subjects: a randomized crossover trial

Resistant starch (RS) has been reported to reduce body fat in obese mice. However, this effect has not been demonstrated in humans. In this study, we tested the effects of RS in 19 volunteers with normal body weights. A randomized, double-blinded and crossover design clinical trial was conducted. The study subjects were given either 40 g high amylose RS2 or energy-matched control starch with three identical diets per day throughout the study. The effect of RS was evaluated by monitoring body fat, glucose metabolism, gut hormones, gut microbiota, short-chain fatty acids (SCFAs) and metabolites. The visceral and subcutaneous fat areas were significantly reduced following RS intake. Acetate and early-phase insulin, C-peptide and glucagon-like peptide-1 (GLP-1) secretion were increased, and the low-density lipoprotein cholesterol (LDL-C) and blood urea nitrogen (BUN) levels were decreased after the RS intervention. Based on 16S rRNA sequencing, certain gut microbes were significantly decreased after RS supplementation, whereas the genus Ruminococcaceae_UCG-005 showed an increase in abundance. Other potential signatures of the RS intervention included Akkermansia, Ruminococcus_2, Victivallis, and Comamonas. Moreover, the baseline abundance of the genera Streptococcus, Ruminococcus_torques_group, Eubacterium_hallii_group, and Eubacterium_eligens_group was significantly associated with the hormonal and metabolic effects of RS. These observations suggest that a daily intake of 40 g of RS is effective in modulating body fat, SCFAs, early-phase insulin and GLP-1 secretion and the gut microbiota in normal-weight subjects.

Modulation of the Gut Microbiota by Resistant Starch as a Treatment of Chronic Kidney Diseases: Evidence of Efficacy and Mechanistic Insights

Chronic kidney disease (CKD) has been associated with changes in gut microbial ecology, or "dysbiosis," which may contribute to disease progression. Recent studies have focused on dietary approaches to favorably alter the composition of the gut microbial communities as a treatment method in CKD. Resistant starch (RS), a prebiotic that promotes proliferation of gut bacteria such as Bifidobacteria and Lactobacilli, increases the production of metabolites including short-chain fatty acids, which confer a number of health-promoting benefits. However, there is a lack of mechanistic insight into how these metabolites can positively influence renal health. Emerging evidence shows that microbiota-derived metabolites can regulate the incretin axis and mitigate inflammation via expansion of regulatory T cells. Studies from animal models and patients with CKD show that RS supplementation attenuates the concentrations of uremic retention solutes, including indoxyl sulfate and p-cresyl sulfate. Here, we present the current state of knowledge linking the microbiome to CKD, we explore the efficacy of RS in animal models of CKD and in humans with the condition, and we discuss how RS supplementation could be a promising dietary approach for slowing CKD progression.

The Effects of Prebiotics and Substances with Prebiotic Properties on Metabolic and Inflammatory Biomarkers in Individuals with Type 2 Diabetes Mellitus: A Systematic Review

BACKGROUND

Intestinal bacteria composition and prebiotics may play a role in the management of type 2 diabetes mellitus (T2DM).

OBJECTIVE

The objective of this systematic review was to evaluate the effect of prebiotics and substances with prebiotic properties on the metabolic and inflammatory biomarkers of individuals with T2DM compared with placebo.

METHODS

A literature search to identify articles published up to March 31, 2018, was conducted utilizing PubMed, Science Direct, and Cochrane Central Register of Controlled Trials. Individuals at aged 18 years or older with T2DM from randomized controlled trials investigating prebiotics or substances with prebiotic properties were included. Metabolic and inflammatory biomarkers associated with T2DM were the primary outcome measures.

RESULTS

Twenty-seven publications were analyzed. All but seven of these publications reported a beneficial effect on metabolic and/or inflammatory biomarkers. Interventions included mostly women, lasted 4 days to 12 weeks, and diabetes duration ranged from 6 months to 11 years. Nineteen publications reported improvements in glycemia, 15 in cardiovascular markers, nine in body weight, and nine in inflammatory markers. Benefits from resistant starch, resistant dextrin, and oligofructose-enriched inulin were most frequent. A smaller number of studies utilizing other substances with prebiotic properties also yielded improvements.

CONCLUSIONS

Based on these results, there is fair evidence that prebiotics and substances with prebiotic properties may improve metabolic and inflammatory biomarkers related to T2DM in women aged 18 years at least. Interventions with resistant starch, resistant dextrin, and oligofructose-enriched inulin exhibited the strongest evidence for improvements due to the quantity of publications and quality grades. Other prebiotics and substances with prebiotic properties show promise but the number of studies is few. Additional studies that are longer in duration, include both sexes, and include other prebiotics or substances with prebiotic properties are needed.

Dietary Patterns Affect the Gut Microbiome-The Link to Risk of Cardiometabolic Diseases

Clusters of bacterial species within the gut microenvironment, or gut enterotype, have been correlated with cardiometabolic disease risk. The metabolic products and metabolites that bacteria produce, such as short-chain fatty acids, secondary bile acids, and trimethylamine, may also affect the microbial community and disease risk. Diet has a direct impact on the gut microenvironment by providing substrates to and promoting the colonization of resident bacteria. To date, few dietary patterns have been evaluated for their effect on the gut microbiome, but the Mediterranean diet and Vegetarian diets have shown favorable effects for both the gut microbiome and cardiometabolic disease risk. This review examines the gut microbiome as a mediator between these dietary patterns and cardiometabolic disease risk.

Effect of 12 wk of resistant starch supplementation on cardiometabolic risk factors in adults with prediabetes: a randomized controlled trial

Background

Type 2 resistant starch (RS2) has been shown to improve glycemic control and some cardiovascular endpoints in rodent and human studies.

Objective

The aim of this study was to perform one of the first randomized clinical trials in adults with prediabetes and one of the longest trials to test whether RS2 can improve cardiometabolic health.

Design

68 overweight [body mass index (BMI) ≥27 kg/m2] adults aged 35-75 y with prediabetes were randomized to consume 45 g/d of high-amylose maize (RS2) or an isocaloric amount of the rapidly digestible starch amylopectin (control) for 12 wk. At baseline and postintervention, ectopic fat depots (visceral adipose tissue, intrahepatic lipids, and intramyocellular lipids) were measured by magnetic resonance imaging/spectroscopy, energy metabolism by respiratory chamber, and carbohydrate metabolism by glycated hemoglobin (HbA1c), an intravenous glucose tolerance test, and a meal tolerance test. Cardiovascular risk factors-serum lipids, blood pressure, heart rate, and inflammatory markers (high-sensitivity C-reactive protein [hs-CRP], interleukin-6, and tumor necrosis factor [TNF]-α)-were also measured. The primary endpoints were insulin sensitivity, insulin secretion, ectopic fat, and markers of inflammation. Data were primarily analyzed as treatment effects via a linear mixed model both with and without the addition of covariates.

Results

Relative to the control group, RS2 lowered HbA1c by a clinically insignificant 0.1 ± 0.2% (Δ = -1 ± 2 mmol/mol; P = 0.05) but did not affect insulin secretion, insulin sensitivity, the disposition index, or glucose or insulin areas under the curve relative to baseline (P ≥ 0.23). RS2 decreased heart rate by 5 ± 9 beats/min (P = 0.02) and TNF-α concentrations by 2.1 ± 2.7 pg/mL (P = 0.004), relative to the control group. Ectopic fat, energy expenditure, substrate oxidation, and all other cardiovascular risk factors were unaffected (P ≥ 0.06).

Conclusions

12 wk of supplementation with resistant starch reduced the inflammatory marker TNF-α and heart rate, but it did not significantly improve glycemic control and other cardiovascular disease risk factors, in adults with prediabetes. This trial was registered at clinicaltrials.gov as NCT01708694.

Probiotics, prebiotics, synbiotics and insulin sensitivity

Animal studies indicate that the composition of gut microbiota may be involved in the progression of insulin resistance to type 2 diabetes. Probiotics and/or prebiotics could be a promising approach to improve insulin sensitivity by favourably modifying the composition of the gut microbial community, reducing intestinal endotoxin concentrations and decreasing energy harvest. The aim of the present review was to investigate the effects of probiotics, prebiotics and synbiotics (a combination of probiotics and prebiotics) on insulin resistance in human clinical trials and to discuss the potential mechanisms whereby probiotics and prebiotics improve glucose metabolism. The anti-diabetic effects of probiotics include reducing pro-inflammatory cytokines via a NF-κB pathway, reduced intestinal permeability, and lowered oxidative stress. SCFA play a key role in glucose homeostasis through multiple potential mechanisms of action. Activation of G-protein-coupled receptors on L-cells by SCFA promotes the release of glucagon-like peptide-1 and peptide YY resulting in increased insulin and decreased glucagon secretion, and suppressed appetite. SCFA can decrease intestinal permeability and decrease circulating endotoxins, lowering inflammation and oxidative stress. SCFA may also have anti-lipolytic activities in adipocytes and improve insulin sensitivity via GLUT4 through the up-regulation of 5'-AMP-activated protein kinase signalling in muscle and liver tissues. Resistant starch and synbiotics appear to have favourable anti-diabetic effects. However, there are few human interventions. Further well-designed human clinical studies are required to develop recommendations for the prevention of type 2 diabetes with pro- and prebiotics.

Resistant starch can improve insulin sensitivity independently of the gut microbiota

BACKGROUND

Obesity-related diseases, including type 2 diabetes and cardiovascular disease, have reached epidemic proportions in industrialized nations, and dietary interventions for their prevention are therefore important. Resistant starches (RS) improve insulin sensitivity in clinical trials, but the mechanisms underlying this health benefit remain poorly understood. Because RS fermentation by the gut microbiota results in the formation of physiologically active metabolites, we chose to specifically determine the role of the gut microbiota in mediating the metabolic benefits of RS. To achieve this goal, we determined the effects of RS when added to a Western diet on host metabolism in mice with and without a microbiota.

RESULTS

RS feeding of conventionalized mice improved insulin sensitivity and redressed some of the Western diet-induced changes in microbiome composition. However, parallel experiments in germ-free littermates revealed that RS-mediated improvements in insulin levels also occurred in the absence of a microbiota. RS reduced gene expression of adipose tissue macrophage markers and altered cecal concentrations of several bile acids in both germ-free and conventionalized mice; these effects were strongly correlated with the metabolic benefits, providing a potential microbiota-independent mechanism to explain the physiological effects of RS.

CONCLUSIONS

This study demonstrated that some metabolic benefits exerted by dietary RS, especially improvements in insulin levels, occur independently of the microbiota and could involve alterations in the bile acid cycle and adipose tissue immune modulation. This work also sets a precedent for future mechanistic studies aimed at establishing the causative role of the gut microbiota in mediating the benefits of bioactive compounds and functional foods.

The acute effects of inulin and resistant starch on postprandial serum short-chain fatty acids and second-meal glycemic response in lean and overweight humans

BACKGROUND/OBJECTIVES

Colonic fermentation of dietary fiber to short-chain fatty acids (SCFA) may protect against obesity and diabetes, but excess production of colonic SCFA has been implicated in the promotion of obesity. We aimed to compare the effects of two fermentable fibers on postprandial SCFA and second-meal glycemic response in healthy overweight or obese (OWO) vs lean (LN) participants.

SUBJECTS/METHODS

Using a randomized crossover design, 13 OWO and 12 LN overnight fasted participants were studied for 6 h on three separate days after consuming 300 ml water containing 75 g glucose (GLU) as control or with 24 g inulin (IN) or 28 g resistant starch (RS). A standard lunch was served 4 h after the test drink.

RESULTS

Within the entire group, compared with control, IN significantly increased serum SCFA (P<0.001) but had no effect on free-fatty acids (FFA) or second-meal glucose and insulin responses. In contrast, RS had no significant effect on SCFA but reduced FFA rebound (P<0.001) and second-meal glucose (P=0.002) and insulin responses (P=0.024). OWO had similar postprandial serum SCFA and glucose concentrations but significantly greater insulin and FFA than LN. However, the effects of IN and RS on SCFA, glucose, insulin and FFA responses were similar in LN and OWO.

CONCLUSIONS

RS has favorable second-meal effects, likely related to changes in FFA rather than SCFA concentrations. However, a longer study may be needed to demonstrate an effect of RS on SCFA. We found no evidence that acute increases in SCFA after IN reduce glycemic responses in humans, and we were unable to detect a significant difference in SCFA responses between OWO vs LN subjects.

Effects of a diet rich in arabinoxylan and resistant starch compared with a diet rich in refined carbohydrates on postprandial metabolism and features of the metabolic syndrome

PURPOSE

Low intake of dietary fibre is associated with the development of type 2 diabetes. Dyslipidaemia plays a key role in the pathogenesis of type 2 diabetes. Knowledge of the impact of dietary fibres on postprandial lipaemia is, however, sparse. This study aimed in subjects with metabolic syndrome to assess the impact on postprandial lipaemia and features of the metabolic syndrome of a healthy carbohydrate diet (HCD) rich in cereal fibre, arabinoxylan and resistant starch compared to a refined-carbohydrate western-style diet (WSD).

METHODS

Nineteen subjects completed the randomised, crossover study with HCD and WCD for 4-week. Postprandial metabolism was evaluated by a meal-challenge test and insulin sensitivity was assessed by HOMA-IR and Matsuda index. Furthermore, fasting cholesterols, serum-fructosamine, circulating inflammatory markers, ambulatory blood pressure and intrahepatic lipid content were measured.

RESULTS

We found no diet effects on postprandial lipaemia. However, there was a significant diet × statin interaction on total cholesterol (P = 0.02) and LDL cholesterol (P = 0.002). HCD decreased total cholesterol (-0.72 mmol/l, 95% CI (-1.29; -0.14) P = 0.03) and LDL cholesterol (-0.61 mmol/l, 95% CI (-0.86; -0.36) P = 0.002) compared with WSD in subjects on but not without statin treatment. We detected no other significant diet effects.

CONCLUSIONS

In subjects with metabolic syndrome on statins a 4-week diet rich in arabinoxylan and resistant starch improved fasting LDL and total cholesterol compared to subjects not being on statins. However, we observed no diet related impact on postprandial lipaemia or features of the metabolic syndrome. The dietary fibre x statin interaction deserves further elucidation.

Host-microbiome interactions in human type 2 diabetes following prebiotic fibre (galacto-oligosaccharide) intake

Aberrant microbiota composition and function have been linked to several pathologies, including type 2 diabetes. In animal models, prebiotics induce favourable changes in the intestinal microbiota, intestinal permeability (IP) and endotoxaemia, which are linked to concurrent improvement in glucose tolerance. This is the first study to investigate the link between IP, glucose tolerance and intestinal bacteria in human type 2 diabetes. In all, twenty-nine men with well-controlled type 2 diabetes were randomised to a prebiotic (galacto-oligosaccharide mixture) or placebo (maltodextrin) supplement (5·5 g/d for 12 weeks). Intestinal microbial community structure, IP, endotoxaemia, inflammatory markers and glucose tolerance were assessed at baseline and post intervention. IP was estimated by the urinary recovery of oral 51Cr-EDTA and glucose tolerance by insulin-modified intravenous glucose tolerance test. Intestinal microbial community analysis was performed by high-throughput next-generation sequencing of 16S rRNA amplicons and quantitative PCR. Prebiotic fibre supplementation had no significant effects on clinical outcomes or bacterial abundances compared with placebo; however, changes in the bacterial family Veillonellaceae correlated inversely with changes in glucose response and IL-6 levels (r -0·90, P=0·042 for both) following prebiotic intake. The absence of significant changes to the microbial community structure at a prebiotic dosage/length of supplementation shown to be effective in healthy individuals is an important finding. We propose that concurrent metformin treatment and the high heterogeneity of human type 2 diabetes may have played a significant role. The current study does not provide evidence for the role of prebiotics in the treatment of type 2 diabetes.

Resistant Starch Bagels Reduce Fasting and Postprandial Insulin in Adults at Risk of Type 2 Diabetes

BACKGROUND

Type 2 diabetes (T2D) incidence continues to rise. Although increasing dietary fiber intake is an established strategy for improved glycemic control, most adults consume insufficient amounts. Fiber-enhanced functional foods can increase fiber intake, and there is particular interest in resistant starch (RS) as a high-fiber ingredient. Studies show that high-amylose maize resistant starch, type 2 (HAM-RS2) improves acute and chronic glycemic responses, but more studies are needed in individuals at high risk of T2D with RS delivered in commonly consumed foods.

OBJECTIVE

The objective of this study was to examine the chronic effects of consuming bagels high in HAM-RS2 on fasting and postprandial glycemic markers in adults at increased risk of T2D.

METHODS

With the use of a randomized, double-blind crossover design, 24 men and women with a mean ± SE age of 55.3 ± 1.59 y and body mass index (in kg/m²) of 30.2 ± 0.57 consumed 1 bagel containing 25 g HAM-RS2/d or 1 control wheat bagel/d for 56 d each, separated by a 4-wk washout. Fasting and postprandial oral-glucose-tolerance test (OGTT) glucose and insulin were measured on study days 1 and 57 of each bagel treatment.

RESULTS

The RS bagel treatment resulted in significantly lower fasting (22.1%, P = 0.04), 2-h (23.3%, P < 0.008), and 3-h (18.9%, P = 0.05) insulin incremental areas under the curve and fasting insulin resistance (homeostasis model assessment of insulin resistance; 23.1%, P = 0.04) than did the control bagel treatment. Fasting and postprandial OGTT glucose concentrations did not differ between the RS and control bagel treatments on study days 1 or 57.

CONCLUSIONS

These data suggest that consumption of a high-HAM-RS2 bagel improves glycemic efficiency by reducing the amount of insulin required to manage postprandial glucose while improving fasting insulin sensitivity in adults at increased risk of T2D. This research provides support for a feasible dietary strategy for T2D risk reduction. This trial was registered at clinicaltrials.gov as NCT02129946.

Dietary Resistant Starch Supplementation Increases High-Density Lipoprotein Particle Number in Pigs Fed a Western Diet

Resistant starch (RS) has been well characterized for its glycemic control properties; however, there is little consensus regarding the influence of RS on blood lipid concentrations and lipoprotein distribution and size. Therefore, this study aimed to characterize the effect of daily RS supplementation in a controlled capsule delivery on biomarkers of cardiovascular (blood lipids, lipoproteins) and diabetes (glucose, insulin) risk in a pig model. Twelve 8-week-old male Yorkshire pigs were placed on a synthetic Western diet and randomly divided into two groups (n = 6/group) for 30 days: (1) a placebo group supplemented with capsules containing unmodified pre-gelatinized potato starch (0 g/RS/day); and (2) an RS group supplemented with capsules containing resistant potato starch (10 g/RS/day). Serum lipids including total-cholesterol (C), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides did not differ (p > 0.05) between the RS and placebo groups. Although the total numbers of very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) particles were similar (p > 0.05) between the two groups, total high-density lipoprotein (HDL) particles were higher (+28%, p < 0.05) in the RS group compared with placebo, resulting from an increase (p < 0.05) in the small HDL subclass particles (+32%). Compared with the placebo group, RS supplementation lowered (p < 0.05) fasting serum glucose (-20%) and improved (p < 0.05) insulin resistance as estimated by Homeostatic Model Assessment-Insulin Resistance (HOMA-IR) without a change in insulin. Additionally, total serum glucagon-like-peptide 1 (GLP-1) was higher (+141%, p < 0.05) following RS supplementation compared with placebo. This data suggests that in addition to the more well-characterized effect of RS intake in lowering blood glucose and improving insulin sensitivity, the consumption of RS may be beneficial in lipid management strategies by enhancing total HDL particle number.

Characterization and Prebiotic Effect of the Resistant Starch from Purple Sweet Potato

Purple sweet potato starch is a potential resource for resistant starch production. The effects of heat-moisture treatment (HMT) and enzyme debranching combined heat-moisture treatment (EHMT) on the morphological, crystallinity and thermal properties of PSP starches were investigated. The results indicated that, after HMT or EHMT treatments, native starch granules with smooth surface was destroyed to form a more compact, irregular and sheet-like structure. The crystalline pattern was transformed from C-type to B-type with decreasing relative crystallinity. Due to stronger crystallites formed in modified starches, the swelling power and solubility of HMT and EHMT starch were decreased, while the transition temperatures and gelatinization enthalpy were significantly increased. In addition, HMT and EHMT exhibited greater effects on the proliferation of bifidobacteria compared with either glucose or high amylose maize starch.

An improved course of glycaemia after a bread based breakfast is associated with beneficial effects on acute and semi-acute markers of appetite

A breakfast giving low and sustained glycaemia results in beneficial effects on appetite, both acute and after a subsequentad libmeal.

Bioactive Plant Metabolites in the Management of Non-Communicable Metabolic Diseases: Looking at Opportunities beyond the Horizon

There has been an unprecedented worldwide rise in non-communicable metabolic diseases (NCDs), particularly cardiovascular diseases (CVD) and diabetes. While modern pharmacotherapy has decreased the mortality in the existing population, it has failed to stem the rise. Furthermore, a large segment of the world population cannot afford expensive pharmacotherapy. Therefore, there is an urgent need for inexpensive preventive measures to control the rise in CVD and diabetes and associated co-morbidities. The purpose of this review is to explore the role of food bioactives in prevention of NCDs. To this end, we have critically analyzed the possible utility of three classes of food bioactives: (a) resistant starch, a metabolically resistant carbohydrate known to favorably modulate insulin secretion and glucose metabolism; (b) cyclo (His-Pro), a food-derived cyclic dipeptides; and (c) polyphenol-rich berries. Finally, we have also briefly outlined the strategies needed to prepare these food-bioactives for human use.

Resistant starches for the management of metabolic diseases

PURPOSE OF REVIEW

Recent clinical trials and animal studies indicate that resistant starches may be beneficial therapeutic tools for the management of metabolic diseases. The purpose of this review is to summarize these findings and discuss the established and proposed mechanisms by which resistant starches exert their benefits. We also examine open questions regarding how resistant starches improve metabolism and propose future research directions for the field.

RECENT FINDINGS

Data from both humans and animal models clearly support a role for resistant starches in improving a variety of metabolic features; however, discrepancies do exist regarding specific effects. Concomitant improvements in both insulin levels and body fat depots are often reported in rodents fed resistant starches, whereas resistant starch feeding in humans improves insulin sensitivity without having a major impact on fat mass. These differences could be explained by the coexistence of several mechanisms (both gut microbiota-dependent and gut microbiota-independent) underpinning the metabolic benefits of resistant starches.

SUMMARY

Together, the studies presented in this review offer new insights into the potential pathways by which resistant starches enhance metabolic health, including modulation of the gut microbiota, gut peptides, circulating inflammatory mediators, innate immune cells, and the bile acid cycle.

Improving healthspan via changes in gut microbiota and fermentation

Dietary resistant starch impact on intestinal microbiome and improving healthspan is the topic of this review. In the elderly population, dietary fiber intake is lower than recommended. Dietary resistant starch as a source of fiber produces a profound change in gut microbiota and fermentation in animal models of aging. Dietary resistant starch has the potential for improving healthspan in the elderly through multiple mechanisms as follows: (1) enhancing gut microbiota profile and production of short-chain fatty acids, (2) improving gut barrier function, (3) increasing gut peptides that are important in glucose homeostasis and lipid metabolism, and (4) mimicking many of the effects of caloric restriction including upregulation of genes involved in xenobiotic metabolism.

Is there any place for resistant starch, as alimentary prebiotic, for patients with type 2 diabetes?

OBJECTIVE

The aim of the present study was to determine effects of Resistant Starch (RS2) on metabolic parameters and inflammation in women with type 2 diabetes (T2DM).

METHODS

In this randomized controlled clinical trial, 60 females with T2DM were divided into intervention (n = 28) and placebo groups (n = 32). They received 10 g/d RS2 or placebo for 8 weeks, respectively. Fasting blood sugar (FBS), glycated hemoglobin (HbA1c), lipid profile, high-sensitive C-reactive protein (hs-CRP), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) were measured at baseline and at the end of the trial. Paired t test, unpaired t-test and ANCOVA were used to compare the quantitative variables. The data were analyzed using SPSS software version 13.0.

RESULTS

RS2 decreased HbA1c (-0.3%, -3.6%), TNF-α (-3.4 pg/mL, -18.9%), triglyceride (-33.4 mg/dL, -15.4%), and it increased HDL-c (+9.4 mg/dL, +24.6%) significantly compared with the placebo group (p < 0.05). Changes in FBS, total cholesterol, low-density lipoprotein, hs-CRP and IL-6 were not significant in the RS2 group compared with the control group. RS2 can improve glycemic status, inflammatory markers and lipid profile in women with T2DM.

CONCLUSIONS

Although findings of the present study indicated positive effects of RS2 on inflammation and metabolic parameters, more studies are needed to confirm efficacy of RS2 as an adjunct therapy in diabetes.

Effects of Acute Ingestion of Native Banana Starch on Glycemic Response Evaluated by Continuous Glucose Monitoring in Obese and Lean Subjects

An abnormal glycemic profile, including postprandial glycemia and acute glucose spikes, precedes the onset of overt diabetes in obese subjects. Previous studies have shown the beneficial effects of chronic native banana starch (NBS) supplementation. In this study, we examined the effects of acute ingestion of NBS on glycemic profiles by means of continuous glucose monitoring in obese and lean subjects. In a crossover study, obese and lean subjects consumed beverages containing either 38.3 g of NBS or 38.3 g of digestible corn starch (DCS) twice daily during 4 days. On day 5, a 3-h meal tolerance test (MTT) was performed to evaluate glucose and insulin responses. After 1 week of washout period, treatments were inverted. NBS supplementation reduced the 48-h glycemia AUC in lean, obese, and in the combined group of lean and obese subjects in comparison with DCS. Postprandial glucose and insulin responses at MTT were reduced after NBS in comparison with DCS in all groups. However, no changes were observed in glycemic variability (GV) indexes between groups. In conclusion, acute NBS supplementation improved postprandial glucose and insulin responses in obese and lean subjects during 48 h of everyday life and at MTT. Further research to elucidate the mechanism behind these changes is required.

Reevaluating the hype: four bacterial metabolites under scrutiny

With microbiome research being a fiercely contested playground in science, new data are being published at tremendous pace. The review at hand serves to critically revise four microbial metabolites widely applied in research: butyric acid, flagellin, lipoteichoic acid, and propionic acid. All four metabolites are physiologically present in healthy humans. Nevertheless, all four are likewise involved in pathologies ranging from cancer to mental retardation. Their inflammatory potential is equally friend and foe. The authors systematically analyze positive and negative attributes of the aforementioned substances, indicating chances and dangers with the use of pre- and probiotic therapeutics. Furthermore, the widespread actions of microbial metabolites on distinct organs and diseases are reconciled. Moreover, the review serves as critical discourse on scientific methods commonly employed in microbiome research and comparability as well as reproducibility issues arising thereof.

Role of resistant starch in improving gut health, adiposity, and insulin resistance

The realization that low-glycemic index diets were formulated using resistant starch led to more than a decade of research on the health effects of resistant starch. Determination of the metabolizable energy of the resistant starch product allowed for the performance of isocaloric studies. Fermentation of resistant starch in rodent studies results in what appears to be a healthier gut, demonstrated by increased amounts of short-chain fatty acids, an apparent positive change in the microbiota, and increased gene expression for gene products involved in normal healthy proliferation and apoptosis of potential cancer cells. Additionally, consumption of resistant starch was associated with reduced abdominal fat and improved insulin sensitivity. Increased serum glucagon-like peptide 1 (GLP-1) likely plays a role in promoting these health benefits. One rodent study that did not use isocaloric diets demonstrated that the use of resistant starch at 8% of the weight of the diet reduced body fat. This appears to be approximately equivalent to the human fiber requirement. In human subjects, insulin sensitivity is increased with the feeding of resistant starch. However, only 1 of several studies reports an increase in serum GLP-1 associated with resistant starch added to the diet. This means that other mechanisms, such as increased intestinal gluconeogenesis or increased adiponectin, may be involved in the promotion of improved insulin sensitivity. Future research may confirm that there will be improved health if human individuals consume the requirement for dietary fiber and a large amount of the fiber is fermentable.

Role of resistant starch in improving gut health, adiposity, and insulin resistance

The realization that low-glycemic index diets were formulated using resistant starch led to more than a decade of research on the health effects of resistant starch. Determination of the metabolizable energy of the resistant starch product allowed for the performance of isocaloric studies. Fermentation of resistant starch in rodent studies results in what appears to be a healthier gut, demonstrated by increased amounts of short-chain fatty acids, an apparent positive change in the microbiota, and increased gene expression for gene products involved in normal healthy proliferation and apoptosis of potential cancer cells. Additionally, consumption of resistant starch was associated with reduced abdominal fat and improved insulin sensitivity. Increased serum glucagon-like peptide 1 (GLP-1) likely plays a role in promoting these health benefits. One rodent study that did not use isocaloric diets demonstrated that the use of resistant starch at 8% of the weight of the diet reduced body fat. This appears to be approximately equivalent to the human fiber requirement. In human subjects, insulin sensitivity is increased with the feeding of resistant starch. However, only 1 of several studies reports an increase in serum GLP-1 associated with resistant starch added to the diet. This means that other mechanisms, such as increased intestinal gluconeogenesis or increased adiponectin, may be involved in the promotion of improved insulin sensitivity. Future research may confirm that there will be improved health if human individuals consume the requirement for dietary fiber and a large amount of the fiber is fermentable.