Resistant Starch Supplementation Research Articles

Understanding the Dynamics of Gut Microbiota Composition and Function Following Short-Term Resistant Starch Supplementation

ObjectivesIncreased dietary fiber intake is recommended as a potential gut microbiota-targeted nutritional strategy to reduce the risk of metabolic diseases. However, individuals’ gut microbiome composition can change differently in response to specific dietary fibers. The objective of this study is to assess, through a resistant starch intervention, the factors that could be responsible for this heterogeneity in gut microbial alterations such as baseline gut microbiota and usual dietary fiber intake.MethodsHealthy adults (n = 75) were enrolled in a 7.5-week randomized crossover dietary intervention study consisting of three 10-day treatment periods during which they consumed resistant starch type 2 (RS2), resistant starch type 4 (RS4), or a control digestible starch, in the form of crackers. The three treatment periods were separated by 5-day washouts with no cracker consumption. We performed 16S rRNA gene sequencing on fecal samples to characterize the gut microbiota, and measured fecal short-chain fatty acids (SCFA) and bile acids. We used QIIME2 to identify amplicon sequence variants (ASVs) in the 16S rRNA sequence data, MaAsLin2 to evaluate the effect of predictor variables on differential abundances of microbes, and linear mixed models to analyze changes in fecal SCFA and bile acids.ResultsWe found significant changes in microbial composition after RS consumption but not after the control. Specifically, six ASVs were enriched including R. bromii and F. prausnitzii, which have been associated with butyrate production, after RS2 but not after RS4. Twelve ASVs increased after RS4, including Parabacteroides distasonis, which has been shown to be associated with protection against diseases like type 2 diabetes. There were no ASVs that significantly differed after the control. For all reported significant findings, q < 0.05.ConclusionsA short-term RS intervention resulted in RS type-specific gut microbial composition changes in healthy individuals. Ongoing analyses will further evaluate the predictors of gut microbiome changes in response to RS consumption by incorporating usual dietary intake, baseline gut microbiome composition, and host genetics.Funding SourcesNIH NIDDK T32 Award and the President's Council of Cornell Women.

P172. Effects of dietary crude protein content and resistant starch supplementation on growth performance, histomorphology, and microbial metabolites in weaned pigs

P172. Effects of dietary crude protein content and resistant starch supplementation on growth performance, histomorphology, and microbial metabolites in weaned pigs

Role of dietary resistant starch in the regulation of broiler immunological characteristics.

Resistant starch (RS) has received increased attention due to its potential health benefits. This study was aimed to investigate the effects of dietary corn RS on immunological characteristics of broilers. A total of 320 broiler chicks were randomly allocated to five dietary treatments: normal corn-soyabean (NC) diet group, corn starch diet group, 4 %, 8 % and 12 % RS diet groups. This trial lasted for 42 d. The relative weights of spleen, thymus and bursa, the concentrations of nitric oxide (NO) and IL-4 in plasma at 21 d of age, as well as the activities of total nitric oxide synthase (TNOS) and inducible nitric oxide synthase (iNOS) in plasma at 21 and 42 d of age showed positive linear responses (P < 0·05) to the increasing dietary RS level. Meanwhile, compared with the birds from the NC group at 21 d of age, birds fed 4 % RS, 8 % RS and 12 % RS diets exhibited higher (P < 0·05) relative weight of bursa and concentrations of NO and interferon-γ in plasma. Birds fed 4 % RS and 8 % RS diets showed higher (P < 0·05) number of IgA-producing cells in the jejunum. While compared with birds from the NC group at 42 d of age, birds fed 12 % RS diet showed higher (P < 0·05) relative weight of spleen and activities of TNOS and iNOS in plasma. These findings suggested that dietary corn RS supplementation can improve immune function in broilers.

Resistant starch-An accessible fiber ingredient acceptable to the Western palate.

Dietary fiber intakes in Western societies are concerningly low and do not reflect global recommended dietary fiber intakes for chronic disease prevention. Resistant starch (RS) is a fermentable dietary fiber that has attracted research interest. As an isolated ingredient, its fine particle size, relatively bland flavor, and white appearance may offer an appealing fiber source to the Western palate, accustomed to highly refined, processed grains. This review aims to provide a comprehensive insight into the current knowledge (classification, production methods, and characterization methods), health benefits, applications, and acceptability of RS. It further discusses the present market for commercially available RS ingredients and products containing ingredients high in RS. The literature currently highlights beneficial effects for dietary RS supplementation with respect to glucose metabolism, satiety, blood lipid profiles, and colonic health. An exploration of the market for commercial RS ingredients indicates a diverse range of products (from isolated RS2, RS3, and RS4) with numerous potential applications as partial or whole substitutes for traditional flour sources. They may increase the nutritional profile of a food product (e.g., by increasing the fiber content and lowering energy values) without significantly compromising its sensory and functional properties. Incorporating RS ingredients into staple food products (such as bread, pasta, and sweet baked goods) may thus offer an array of nutritional benefits to the consumer and a highly accessible functional ingredient to be greater exploited by the food industry.

Tolerability and SCFA production after resistant starch supplementation in humans: a systematic review of randomized controlled studies

Resistant starches (RSs) have been advocated as a dietary supplement to address microbiota dysbiosis. They are postulated to act through the production of SCFAs. Their clinical tolerability and effect on SCFA production has not been systematically evaluated. We conducted a systematic review of RS supplementation as an intervention in adults (healthy individuals and persons with medical conditions) participating in randomized controlled trials. The primary outcome was tolerability of RS supplementation, the secondary outcome was SCFA production. MEDLINE, Embase, and the Cochrane Central Register were searched. Articles were screened, and data extracted, independently and in duplicate. A total of 39 trials met eligibility criteria, including a total of 2263 patients. Twenty-seven (69%) studies evaluated the impact of RS supplementation in healthy subjects whereas 12 (31%) studies included individuals with an underlying medical condition (e.g., obesity, prediabetes). Type 2 RS was most frequently investigated (29 studies). Of 12 studies performed in subjects with health conditions, 11 reported on tolerability. All studies showed that RS supplementation was tolerated; 9 of these studies used type 2 RS with doses of 20-40g/d for >4 wk. Of 27 studies performed in healthy subjects, 20 reported on tolerability. In 14 studies, RS supplementation was tolerated, and the majority used type 2 RS with a dose between 20 and 40g/d. Twenty-one (78%) studies reporting SCFAs used type 2 RS with a dose of 20-40g/d for 1-4 wk. In 16 of 23 studies (70%), SCFA production was increased, in 7 studies there was no change in SCFA concentration before and after RS supplementation, and in 1 study SCFA concentration decreased. Available evidence suggests that RS supplementation is tolerated in both healthy subjects and in those with an underlying medical condition. In addition, SCFA production was increased in most of the studies.

Does a high dietary intake of resistant starch affect glycaemic control and alter the gut microbiome in women with gestational diabetes? A randomised control trial protocol

BackgroundGestational Diabetes Mellitus (GDM) is prevalent with lasting health implications for the mother and offspring. Medical nutrition therapy is the foundation of GDM management yet achieving optimal glycaemic control often requires treatment with medications, like insulin. New dietary strategies to improve GDM management and outcomes are required.Gut dysbiosis is a feature of GDM pregnancies, therefore, dietary manipulation of the gut microbiota may offer a new avenue for management. Resistant starch is a fermentable dietary fibre known to alter the gut microbiota and enhance production of short-chain fatty acids. Evidence suggests that short-chain fatty acids improve glycaemia via multiple mechanisms, however, this has not been evaluated in GDM.MethodsAn open-label, parallel-group design study will investigate whether a high dietary resistant starch intake or resistant starch supplement improves glycaemic control and changes the gut microbiome compared with standard dietary advice in women with newly diagnosed GDM. Ninety women will be randomised to one of three groups - standard dietary treatment for GDM (Control), a high resistant starch diet or a high resistant starch diet plus a 16 g resistant starch supplement. Measurements taken at Baseline (24 to 30-weeks’ gestation), Day 10 and Day 56 (approximately 36 weeks’ gestation) will include fasting plasma glucose levels, microbial composition and short-chain fatty acid concentrations in stool, 3-day dietary intake records and bowel symptoms questionnaires. One-week post-natal data collection will include microbial composition and short-chain fatty acid concentrations of maternal and neonatal stools, microbial composition of breastmilk, birthweight, maternal and neonatal outcomes. Mixed model analysis of variance will assess change in glycaemia and permutation-based multivariate analysis of variance will assess changes in microbial composition within and between intervention groups. Distance-based linear modelling will identify correlation between change in stool microbiota, short-chain fatty acids and measures of glycaemia.DiscussionTo improve outcomes for GDM dyads, evaluation of a high dietary intake of resistant starch to improve glycaemia through the gut microbiome needs to be established. This will expand the dietary interventions available to manage GDM without medication.Trial registrationAustralian New Zealand Clinical Trial Registry, ACTRN12620000968976p. Registered 28 September 2020

The Effects of Resistant Starch Consumption in Adult Patients With Chronic Kidney Disease: A Systematic Review.

Background:Resistant starches (RSs) are not digested by human digestive enzymes and pass through the upper digestive tract to become substrates for colonic bacteria. Resistant starch supplementation has shown promising results in altering the microbiota of animal models of chronic kidney disease (CKD). Resistant starch consumption may influence the production of uremic toxins in CKD.Objective:To conduct a systematic review to determine whether the consumption of RS reduces the progression of kidney disease in adult patients with CKD.Design:We included randomized controlled trials comparing RS supplementation to placebo, no treatment, or standard care. Cochrane Central, Embase, MEDLINE, Web of Science, and CINAHL databases were searched. There was no limitation on publication date, but only English manuscripts were included. The search was conducted in July 2020.Patients:Adult outpatient populations with CKD, using any recognized diagnostic criteria.Measurements:The primary outcome was change in glomerular filtration rate (GFR) from baseline through the end of the trial in patients not on dialysis; secondary outcomes included change in uremic toxin concentrations (p-cresol/p-cresyl sulfate [p-CS], indoxyl sulfate [IS]) and inflammatory markers (tumor necrosis factor alpha [TNF-α], C-reactive protein [CRP], interleukin 6 [IL-6]) from baseline through the end of the trial, and changes in self-reported symptom scores.Methods:The Cochrane Collaboration Risk of Bias tool was used to assess risk of bias in included studies. The systematic review results are reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines.Results:We identified 4 unique studies, reported in 9 publications that met our inclusion criteria, including a total of 215 enrolled participants. Results were calculated using data from the longest reported follow-up time. The primary outcome of changes in kidney function markers was only studied in 1 trial; this trial reported an increase in creatinine and a decrease in blood urea nitrogen; no changes in GFR were reported. A review of the secondary outcomes showed an overall decline in IS, TNF-α, and IL-6, in RS groups, but with mixed results in p-CS and CRP/high-sensitivity CRP. Safety data showed that RS was well tolerated with no reports of excessive side effects.Limitations:We determined a meta-analysis was not feasible due to clinical heterogeneity between study populations and differences in reported outcomes in the included studies.Conclusion:There is limited and inconsistent evidence on the impact of RS in adult patients with CKD. Further research is needed to determine the safety and efficacy of RS supplementation in this population.

Effects of resistant starch supplementation on oxidative stress and inflammation biomarkers: A systematic review and meta-analysis of randomized controlled trials.

Animal experiments showed that resistant starch (RS) had an antioxidant and antiinflammatory effect. However, clinical studies showed both insignificant and significant effects of RS on inflammation and oxidative stress. The purpose of this work is to conduct a systematic review and meta-analysis of previous randomized controlled trials (RCTs) to investigate these effects. A systematic literature search was conducted on Web of Science, Scopus, PubMed and Cochrane electronic databases, which included studies from the earliest date of the database to September 2021. Key inclusion criteria were: RCTs; reporting at least one inflammatory or oxidative stress biomarker as endpoint; more than seven day intervention. Key exclusion criteria were: using a mixture of RS and other functional food ingredients as intervention substance; inappropriate controls. A total of 16 RCTs including 706 subjects were included. RS supplementation significantly improved total antioxidant capacity [standard mean difference (SMD) (95% CI): 2.64 (0.34, 4.94), p=0.03], and significantly reduced blood malondialdehyde concentration [SMD (95% CI): -0.55 (- 0.94, -0.17), p=0.01]. RS supplementation significantly reduced blood C-reactive protein concentration in type 2 diabetes mellitus (T2DM) patients [SMD (95% CI): -0.35 (-0.65, -0.05), p=0.02]. RS consumption significantly reduced blood interlukin-6 and tumor necrosis factor- concentration if removing one distinct trial. RS supplementation may significantly reduce a few oxidative-stress and inflammation biomarkers such as malondialdehyde and C-reactive protein, particularly in T2DM patients. Future work should investigate the optimal dosage of RS supplementation for modulating oxidative stress and inflammation biomarkers related to T2DM.

Thermally Processed Diet-Induced Albuminuria, Complement Activation and Intestinal Permeability Are Attenuated by Resistant Starch in Experimental Diabetes

Abstract Objectives The primary objective of this study was to ascertain whether thermally processed diets influence albuminuria and intestinal permeability via alterations in the complement cascade. A secondary objective was to see whether these pathological alterations could be ameliorated by a gut-targeted dietary intervention, resistant starch. Methods Six-week-old Sprague Dawley rats were randomised to receive a control (CON; AIN93G), thermally processed diet (TPD) (AIN93G baked at 160°C for 1h) or TPD with daily gavage of either 10 mg/kg/d alagebrium chloride (ALA), an inhibitor of advanced glycation end products or daily gavage of 2mg/kg/d PMX-53, a C5a receptor inhibitor for 24 weeks. Six-week-old diabetic mice (db/db) received the CON diet or TPD with or without 12.5% resistant starch (RS) for 10 weeks. Albumin, MCP-1 and C5a were measured by ELISA. Endotoxin was measured using a limulus amoebocyte lysate kit. Intestinal permeability was assessed in vivo by the clearance of FITC-labelled dextran. Transcriptomic profiling of renal cortex was determined by RNA-Sequencing. Results The TPD increased albuminuria, plasma endotoxin and MCP-1 which were ameliorated with ALA or PMX-53. TPD increased urinary C5a, which was decreased with ALA. In db/db mice, RS supplementation of the TPD reduced albuminuria and intestinal permeability. Gene set enrichment analysis showed an upregulation in the complement cascade in TPD db/db mice, which was normalized by RS. Similarly, RS supplementation reduced urinary C5a in TPD-fed db/db mice. Conclusions These results demonstrate that thermally processed diets lead to worsening albuminuria via activation of the complement cascade. These results also indicate that resistant starch supplementation may ameliorate some of the negative effects observed with excessive intake of thermally processed. Funding Sources This study was funded by the National Health and Medical Research Council of Australia (NHMRC) and the Australian and New Zealand Society of Nephrology (ANZSN).

The effect of acute consumption of resistant starch on appetite in healthy adults; a systematic review and meta-analysis of the controlled clinical trials.

Although several clinical trials have assessed the effect of Resistant Starch (RS) supplementation on appetite, the results have been inconsistent. Therefore, this study aimed to assess the effect of RS on the healthy adults' rating of appetite. To this end, Pubmed, CENTRAL, Web of science, Scopus, Medline, and Proquest were systematically searched to find the relevant randomized, and placebo-controlled human trials up to June 2019. As a result, the area under curve (AUC) and standard deviations of the participants' rating appetite were extracted from four eligible studies. Meta-analysis showed a lower appetite in RS group compared to the controls (weighted mean difference [WMD]=-1.375mmmin, 95% confidence interval [95%CI]:-1.673,-1.076). Since high heterogeneity was observed among the included studies (I2=94.5%, P<0.001), subgroup analysis was carried out by RS dose, RS type, duration of supplementation, and time of AUC measuring. In studies that used RS dose of ≥25 gr, heterogeneity disappeared (P=0.560, I2=0%). In such studies, a significant reduction was observed in rating of appetite (WMD=-4.513mmmin, 95%CI:-5.270,-3.755; P<0.001) than studies with RS dose of <25 gr (WMD=-0.799mmmin, 95%CI:-1.123,-0.474; P<0.001). Additionally, subgroup analysis based on the type of RS showed a significant decrease of appetite in studies that used RS2 (WMD=-4.808mmmin, 95%CI:-5.834,-3.782; P<0.001) than RS1 (WMD=-0.128mmmin, 95%CI:-0.457, 0.202; P=0.448). To decrease the rate of appetite more effectively, we suggest other researchers to identify RS dose and type.

Kudzu Resistant Starch: An Effective Regulator of Type 2 Diabetes Mellitus.

Kudzu is a traditional medicinal dietary supplement, and recent research has shown its significant benefits in the prevention/treatment of type 2 diabetes mellitus (T2DM). Starch is one of the main substances in Kudzu that contribute decisively to the treatment of T2DM. However, the underlying mechanism of the hypoglycemic activity is not clear. In this study, the effect of Kudzu resistant starch supplementation on the insulin resistance, gut physical barrier, and gut microbiota was investigated in T2DM mice. The result showed that Kudzu resistant starch could significantly decrease the value of fasting blood glucose and the levels of total cholesterol, total triglyceride, and high-density lipoprotein, as well as low-density lipoprotein, in the blood of T2DM mice. The insulin signaling sensitivity in liver tissue was analyzed; the result indicated that intake of different doses of Kudzu resistant starch can help restore the expression of IRS-1, p-PI3K, p-Akt, and Glut4 and thus enhance the efficiency of insulin synthesis. Furthermore, the intestinal microorganism changes before and after ingestion of Kudzu resistant starch were also analyzed; the result revealed that supplementation of KRS helps to alleviate and improve the dysbiosis of the gut microbiota caused by T2DM. These results validated that Kudzu resistant starch could improve the glucose sensitivity of T2DM mice by modulating IRS-1/PI3K/AKT/Glut4 signaling transduction. Kudzu resistant starch can be used as a promising prebiotic, and it also has beneficial effects on the gut microbiota structure of T2DM mice.

Effect of Resistant Starch (RS) Rich Sorghum Food Consumption on Lipids and Glucose Levels of Diabetic Subjects

Resistant starches are an important class, which gives benefits of fiber without affecting the sensory characteristics. Few studies reported the beneficial effect of resistant starch supplementation in reduction of lipid and glucose levels in diabetic subjects. In the present study we investigated the Resistant Starch (RS) rich millet food on lipid and glucose levels in diabetic subjects. Supplementation of 65 g of RS rich rawa (broken sorghum) for 90 days, significantly reduced Body Mass Index (BMI), Fasting Glucose (FG), TC (Total Cholesterol) and LDL-C (Low Density Lipo protein) (p,0.05) in diabetic subjects (n=15), while a non-significant reduction was found in HbA1c, eAG (estimated Average Glucose), TG, HDL-C and VLDL-C. The study indicated that regular consumption of RS rich foods might be beneficial for the diabetic population. Studies in larger population further strengthen the present understanding.

Resistant starch slows the progression of CKD in the 5/6 nephrectomy mouse model.

BackgroundResistant Starch (RS) improves CKD outcomes. In this report, we study how RS modulates host‐microbiome interactions in CKD by measuring changes in the abundance of proteins and bacteria in the gut. In addition, we demonstrate RS‐mediated reduction in CKD‐induced kidney damage.MethodsEight mice underwent 5/6 nephrectomy to induce CKD and eight served as healthy controls. CKD and Healthy (H) groups were further split into those receiving RS (CKDRS, n = 4; HRS, n = 4) and those on normal diet (CKD, n = 4, H, n = 4). Kidney injury was evaluated by measuring BUN/creatinine and by histopathological evaluation. Cecal contents were analyzed using mass spectrometry‐based metaproteomics and de novo sequencing using PEAKS. All the data were analyzed using R/Bioconductor packages.ResultsThe 5/6 nephrectomy compromised kidney function as seen by an increase in BUN/creatinine compared to healthy groups. Histopathology of kidney sections showed reduced tubulointerstitial injury in the CKDRS versus CKD group; while no significant difference in BUN/creatinine was observed between the two CKD groups. Identified proteins point toward a higher population of butyrate‐producing bacteria, reduced abundance of mucin‐degrading bacteria in the RS fed groups, and to the downregulation of indole metabolism in CKD groups.ConclusionRS slows the progression of chronic kidney disease. Resistant starch supplementation leads to active bacterial proliferation and the reduction of harmful bacterial metabolites.

Effect of Resistant Starch (RS) Wheat Supplementation on Satiety

Abstract Objectives The objective of this analysis is to determine whether intake of wheat products high in resistant starch (RS) increase satiety relative to conventional wheat products via blunting of the glycemic response and stimulation of hormones such as glucose-dependent insulinotropic polypeptide (GIP), peptide YY (PYY), glucagon-like peptide-1 (GLP-1), leptin, or ghrelin. Methods Metabolic responses generated from a double-blind, placebo controlled, crossover clinical trial of RS and regular wheat were used to investigate whether RS supplementation affects subjective and objective measures of satiety relative to conventional wheat. Women and men consumed 3 or 4 rolls per day, respectively, made from RS (14–18 g total dietary fiber, TDF) or conventional wheat (4–5.5 g TDF) for 7 days during each arm of the trial. Linear mixed models of glycemic and satiety outcomes were used to determine the effect RS supplementation. Results A total of 30 healthy adults ages 40–65 completed the study. We observed a significant effect of RS wheat on glycemic response such that postprandial glucose and insulin incremental area under the curve (iAUC) during RS supplementation were lower than during regular wheat consumption (P = 0.004, P &amp;lt; 0.001, respectively). Biological indicators of satiety showed lower iAUC and peak GIP (piAUC &amp;lt; 0.001, ppeak &amp;lt; 0.001) as well as higher fasting and peak PYY (pfasting = 0.004, ppeak = 0.004). There were no significant effects of treatment observed for ghrelin, leptin, or GLP-1. Additionally, there were no significant effects of treatment on subjective measures of fullness or hunger during test days (P = 0.57 and P = 0.20, respectively). Conclusions The results of this analysis indicate that RS supplementation is effective at blunting the postprandial glycemic response but has marginal effects on objective and subjective measures of satiety. Further research is needed to determine the potential effects of providing RS in different doses, volumes (e.g., supplement versus whole food), food matrix (e.g., pasta versus rolls), or duration of exposure on satiety. Funding Sources Funding was provided by the University of California Innovation Institute for Food and Health with gifts from Arcadia Biosciences and Ardent Mills.

Resistant starch supplementation increases crypt cell proliferative state in the rectal mucosa of older healthy participants.

There is strong evidence that foods containing dietary fibre protect against colorectal cancer, resulting at least in part from its anti-proliferative properties. This study aimed to investigate the effects of supplementation with two non-digestible carbohydrates, resistant starch (RS) and polydextrose (PD), on crypt cell proliferative state (CCPS) in the macroscopically normal rectal mucosa of healthy individuals. We also investigated relationships between expression of regulators of apoptosis and of the cell cycle on markers of CCPS. Seventy-five healthy participants were supplemented with RS and/or PD or placebo for 50 d in a 2 × 2 factorial design in a randomised, double-blind, placebo-controlled trial (the Dietary Intervention, Stem cells and Colorectal Cancer (DISC) Study). CCPS was assessed, and the expression of regulators of the cell cycle and of apoptosis was measured by quantitative PCR in rectal mucosal biopsies. SCFA concentrations were quantified in faecal samples collected pre- and post-intervention. Supplementation with RS increased the total number of mitotic cells within the crypt by 60 % (P = 0·001) compared with placebo. This effect was limited to older participants (aged ≥50 years). No other differences were observed for the treatments with PD or RS as compared with their respective controls. PD did not influence any of the measured variables. RS, however, increased cell proliferation in the crypts of the macroscopically-normal rectum of older adults. Our findings suggest that the effects of RS on CCPS are not only dose, type of RS and health status-specific but are also influenced by age.

Exploring the role of the metabolite-sensing receptor GPR109a in diabetic nephropathy

Alterations in gut homeostasis may contribute to the progression of diabetic nephropathy. There has been recent attention on the renoprotective effects of metabolite-sensing receptors in chronic renal injury, including the G-protein-coupled-receptor (GPR)109a, which ligates the short chain fatty acid butyrate. However, the role of GPR109a in the development of diabetic nephropathy, a milieu of diminished microbiome-derived metabolites, has not yet been determined. This study aimed to assess the effects of insufficient GPR109a signalling via genetic deletion of GPR109a on the development of renal injury in diabetic nephropathy. Gpr109a-/- mice or their wildtype littermates (Gpr109a+/+) were rendered diabetic with streptozotocin (STZ). Mice received a control diet or an isocaloric high fiber diet (12.5% resistant starch) for 24 weeks and gastrointestinal permeability and renal injury were determined. Diabetes was associated with increased albuminuria, glomerulosclerosis and inflammation. In comparison, Gpr109a-/- mice with diabetes did not show an altered renal phenotype. Resistant starch supplementation did not afford protection from renal injury in diabetic nephropathy. Whilst diabetes was associated with alterations in intestinal morphology, intestinal permeability assessed in vivo using the FITC-dextran test was unaltered. GPR109a deletion did not worsen gastrointestinal permeability. Further, 12.5% resistant starch supplementation, at physiological concentrations, had no effect on intestinal permeability or morphology. These studies indicate that GPR109a does not play a critical role in intestinal homeostasis in a model of type 1 diabetes or in the development of diabetic nephropathy.

Resistant starch supplementation attenuates inflammation in hemodialysis patients: a pilot study.

In chronic kidney disease (CKD) patients, dysbiosis is associated with inflammation and cardiovascular risk, so many nutritional strategies are being studied to reduce these complications. Resistant starch (RS) can be considered a prebiotic that promotes many benefits, including modulation of gut microbiota which is linked to immune-modulatory effects. The aim of this study was to evaluate the effects of RS supplementation on proinflammatory cytokines in CKD patients on hemodialysis (HD). A double-blind, placebo-controlled, randomized trial was conducted with sixteen HD patients (55.3 ± 10.05years, body mass index (BMI) 25.9 ± 5.42kg/m2, 56% men, time on dialysis 38.9 ± 29.23months). They were allocated to the RS group (16g RS/day) or placebo group (manioc flour). The serum concentration of ten cytokines and growth factors was detected through a multiparametric immunoassay based on XMap-labeled magnetic microbeads (Luminex Corp, USA) before and after 4weeks with RS supplementation. After RS supplementation, there was a reduction of Regulated upon Activation, Normal T-Cell Expressed and Secreted (p < 0.001), platelet-derived growth factor (two B subunits) (p = 0.014) and interferon-inducible protein 10 (IP-10) (p = 0.027). The other parameters did not change significantly. This preliminary result indicates that RS may contribute to a desirable profile of inflammatory markers in CKD patients.

Resistant starch supplementation effects on plasma indole 3-acetic acid and aryl hydrocarbon receptor mRNA expression in hemodialysis patients: Randomized, double blind and controlled clinical trial.

ABSTRACTIntroduction:Gut microbiota imbalance is linked to high uremic toxins production such as indole-3-acetic acid (IAA) in chronic kidney disease patients. This toxin can activate the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor involved with inflammation. Strategies to restore gut microbiota balance can be associated with reduced production of IAA and its deleterious effects. This study aimed to evaluate prebiotic resistant starch (RS) supplementation effects on IAA plasma levels and AhR mRNA expression in CKD patients on hemodialysis (HD).Methods:This randomized, double-blind and placebo-controlled clinical trial evaluated forty-two stable HD patients allocated in RS (n=22) or placebo (n=20) groups. Patients received, alternately, cookies and sachets containing 16 g/day of RS (Hi-Maize 260®) or manioc flour for four weeks. Fasting pre-dialysis blood samples were collected and IAA plasma levels measured by high performance liquid chromatography. Peripheral blood mononuclear cells were isolated and processed for AhR and nuclear factor kappa B (NF-κB) mRNA expression analyzes by quantitative real-time PCR. Anthropometric and biochemical parameters, as well as food intake were also evaluated.Results:Thirty-one patients completed the study, 15 in the RS group and 16 in the placebo group. Although there was no significant alteration in IAA plasma levels, neither in AhR mRNA expression and NF-κB mRNA expression after RS supplementation, a positive correlation (r=0.48; p=0.03) was observed between IAA plasma levels and AhR expression at baseline.Conclusion:Even though prebiotic RS supplementation did not influence IAA levels or AhR expression, their positive association reinforces a possible interaction between them.

Research on the mechanism of microwave-toughened starch on glucolipid metabolism in mice.

Potato resistant starch (RS) was prepared by microwave-toughening treatment (MTT). This study investigated the beneficial effects of RS on high-fat diet (HFD)-induced hyperlipidemia in C57BL/6J mice by evaluating changes in the gut microbiota. The mice were fed low-fat diet with corn starch, HFD with corn starch, HFD with potato starch (HFP), or HFD with RS (HFR) for 6 weeks. The results showed that the HFR group had lower body weight and total cholesterol, triglyceride, and low-density lipoprotein cholesterol levels compared with the HFP group. Moreover, the brown adipose tissue levels of uncoupling protein 1 (UCP-1), β3-adrenoceptor (β3-AR), peroxisome proliferator-activated receptor-γ (PPAR-γ), and PPAR-γ coactivator-1α (PGC-1α) were increased. Our results showed that RS supplementation increased the Bacteroidetes/Firmicutes ratio and the abundance of short-chain fatty acid-producing Allobaculum, Ruminococcus, and Blautia. Our data suggest that RS prepared by MTT may be used as a prebiotic agent to prevent gut dysbiosis and obesity-related chronic diseases, such as hyperlipidemia, and obesity.

Effect of resistant starch supplementation on blood lipids in metabolic&amp;ensp;disorder adults: A meta analysis of randomized controlled trials

Resistant starch (RS) acts as insoluble fiber and by definition is resistant to enzymatic digestion in the small intestine and is non-viscous. The results of randomized controlled trials (RCTs) investigated that resistant starch(RS) supplementation on the effect of blood lipids in metabolic disorder adults have been inconsistent. The present meta-analysis aimed to quantitatively evaluate the effect of RS intervention on the concentration of blood lipids.PubMed, Cochrane, and Web of Science databases were searched up to July 2019. Mean differences were calculated on the effect of lipids by using a random-effects model. Pre-specified subgroup analyses were carried out to explore the sources of heterogeneity. Six studies (10 treatment arms) with 320 participants were identified. The result showed that RS supplementation had no significant effect on concentration of TC (-0.28 mmol/L, 95% CI: -0.68 to 0.12 mmol/L, <italic>P</italic>=0.16, I²=94%), TG (-0.42 mmol/L, 95% CI: -1.02 to 0.19 mmol/L, <italic>P</italic>=0.18, I²=99%), HDL (0.06 mmol/L, 95% CI: -0.15 to 0.27 mmol/L, <italic>P</italic>=0.57, I²=96%) and LDL(-0.17 mmol/L, 95% CI: -0.70 to 0.37 mmol/L, <italic>P</italic>=0.54, I²=94%). Subgroup analysis showed that there were decreased effect on TC concentration when RS was less than or equal to 30 g, but increased effect on TG and LDL concentration when the dose of RS was more than 30 g, and increased effect on TG in people who were overweight; no significant effect on HDL concentration no matter the dose of RS, the intervention time or the disorder status of people.