Alterations in gut microbiota composition and metabolic parameters after dietary intervention with barley beta glucans in patients with high risk for metabolic syndrome development

The heart of the matter: How gut microbiota-targeted interventions influence cardiovascular diseases

The human body is habitat to a wide spectrum of microbial populations known as microbiota, which play an important role in overall health. The considerable research has mostly focused on the gut microbiota due to its potential to impact numerous physiological functions and its correlation with a variety of disorders, such as cardiovascular diseases (CVDs). Imbalances in the gut microbiota, known as dysbiosis, have been linked to the development and progression of CVDs through various processes, including the generation of metabolites like trimethylamine-N-oxide and short-chain fatty acids. Studies have also looked at the idea of using therapeutic interventions, like changing your diet, taking probiotics or prebiotics, or even fecal microbiota transplantation (FMT), to change the gut microbiota's make-up and how it works in order to prevent or treat CVDs. Exploring the cause-and-effect connection between the gut microbiota and CVDs offers a hopeful path for creating innovative microbiome-centered strategies to prevent and cure CVDs. This review presents an in-depth review of the correlation between the gut microbiota and CVDs, as well as potential therapeutic approaches for manipulating the gut microbiota to enhance cardiovascular health.

The Role of Short-Chain Fatty Acids in Metabolic Dysfunction-Associated Steatotic Liver Disease and Other Metabolic Diseases

With its increasing prevalence, metabolic dysfunction-associated steatotic liver disease (MASLD) has emerged as a major global public health concern over the past few decades. Growing evidence has proposed the microbiota-derived metabolites short-chain fatty acids (SCFAs) as a potential factor in the pathophysiology of MASLD and related metabolic conditions, such as obesity and type 2 diabetes mellitus (T2DM). By influencing key pathways involved in energy homeostasis, insulin sensitivity, and inflammation, SCFAs play an important role in gut microbiota composition, intestinal barrier function, immune modulation, and direct metabolic signaling. Furthermore, recent animal and human studies on therapeutic strategies targeting SCFAs demonstrate their potential for treating these metabolic disorders.

Microbiome analysis reveals dynamic changes of gut microbiota in Guizhou horse and Dutch Warmblood horses

In recent years, the importance of gut microbiota in digestive absorption, metabolism, and immunity has garnered increasing attention. China possess abundant horse breed resources, particularly Guizhou horses, which play vital roles in local agriculture, tourism, and transportation. Despite this, there is a lack of comparative studies on the gut microbiota of native Guizhou horses (GZH) and imported Dutch Warmblood horses (WH). To address this gap, fecal samples were collected from both GZH and WH, and 16S rRNA high-throughput sequencing was utilized to analyze the differences in their gut microbiota. The results indicated that compared with GZH, the abundance of the gut bacterial community in WH was significantly higher, whereas the abundance of the gut fungal community was lower. Furthermore, PCoA-based scatter plot analysis demonstrated distinct differences in the structure of gut bacteria and fungi between the two breeds. While both types of horses share similar major bacterial and fungal phyla, significant differences were observed in numerous bacterial and fungal genera. Moreover, functional predictions of gut bacterial communities suggested that WH exhibit a more robust digestive system and enhanced glycan biosynthesis and metabolism capabilities. This is the first report on the comparative analysis of the gut microbiota in GZH and WH. The results emphasize the significant differences in gut microbiota among various horse breeds and offer valuable insights into the composition and structure of gut microbiota in different horse breeds.

Understanding the complex function of gut microbiota: its impact on the pathogenesis of obesity and beyond: a comprehensive review

Obesity is a multifactorial condition influenced by genetic, environmental, and microbiome-related factors. The gut microbiome plays a vital role in maintaining intestinal health, increasing mucus creation, helping the intestinal epithelium mend, and regulating short-chain fatty acid (SCFA) production. These tasks are vital for managing metabolism and maintaining energy balance. Dysbiosis-an imbalance in the microbiome-leads to increased appetite and the rise of metabolic disorders, both fuel obesity and its issues. Furthermore, childhood obesity connects with unique shifts in gut microbiota makeup. For instance, there is a surge in pro-inflammatory bacteria compared to children who are not obese. Considering the intricate nature and variety of the gut microbiota, additional investigations are necessary to clarify its exact involvement in the beginnings and advancement of obesity and related metabolic dilemmas. Currently, therapeutic methods like probiotics, prebiotics, synbiotics, fecal microbiota transplantation (FMT), dietary interventions like Mediterranean and ketogenic diets, and physical activity show potential in adjusting the gut microbiome to fight obesity and aid weight loss. Furthermore, the review underscores the integration of microbial metabolites with pharmacological agents such as orlistat and semaglutide in restoring microbial homeostasis. However, more clinical tests are essential to refine the doses, frequency, and lasting effectiveness of these treatments. This narrative overview compiles the existing knowledge on the multifaceted role of gut microbiota in obesity and much more, showcasing possible treatment strategies for addressing these health challenges.

The nutritional contribution and relationship with health of bread consumption: a narrative review

Bread consumption dates back thousands of years, being one of the oldest and most widespread staple food worldwide. While bread is often associated with taste, pleasure, and tradition, its perception as a vehicle of nutrition and health remains complex. Today, there is no scientific consensus on whether bread consumption is beneficial or deleterious to human health. The objective of this review is therefore to present and discuss epidemiological and clinical evidence on the nutritional contribution of bread and its relationship with health. We also present different aspects of bread such as flour type and inclusions that may modulate this relationship. Studies included in this review investigate bread as part of a dietary pattern as well as the effect of bread alone on overweight, cardiometabolic health, and digestive health. Bread is an integral part of diets around the world, with a significant contribution to key nutrients. Although evidence on the impact of bread consumption on health is still lacking and depends on the overall diet, whole grain breads have shown consistent beneficial effects on human health. Substitution modeling studies and well-designed clinical trials are warranted to fill the research gaps and understand the role of bread consumption in health and disease.

Harnessing Prebiotics to Improve Type 2 Diabetes Outcomes

The gut microbiota, a complex ecosystem of microorganisms in the human gastrointestinal tract (GI), plays a crucial role in maintaining metabolic health and influencing disease susceptibility. Dysbiosis, or an imbalance in gut microbiota, has been linked to the development of type 2 diabetes mellitus (T2DM) through mechanisms such as reduced glucose tolerance and increased insulin resistance. A balanced gut microbiota, or eubiosis, is associated with improved glucose metabolism and insulin sensitivity, potentially reducing the risk of diabetes-related complications. Various strategies, including the use of prebiotics like inulin, fructooligosaccharides, galactooligosaccharides, resistant starch, pectic oligosaccharides, polyphenols, β-glucan, and Dendrobium officinale have been shown to improve gut microbial composition and support glycemic control in T2DM patients. These prebiotics can directly impact blood sugar levels while promoting the growth of beneficial bacteria, thus enhancing glycemic control. Studies have shown that T2DM patients often exhibit a decrease in beneficial butyrate-producing bacteria, like Roseburia and Faecalibacterium, and an increase in harmful bacteria, such as Escherichia and Prevotella. This review aims to explore the effects of different prebiotics on T2DM, their impact on gut microbiota composition, and the potential for personalized dietary interventions to optimize diabetes management and improve overall health outcomes.

Effect of Barley and Oat Consumption on Immune System, Inflammation and Gut Microbiota: A Systematic Review of Randomized Controlled Trials

PURPOSE OF REVIEW

The aim of this systematic review was to investigate the effects of whole grain Avena sativa and Hordeum vulgare L., or their isolated fractions, on immune and inflammatory functions, as well as their influence on gut microbiota. A structured literature search was undertaken in line with PRISMA guidelines. Randomized controlled trials (RCTs) that investigated the effects of oats or barley consumption in adults and reported ≥ 1 of the following: C-reactive protein (CRP), tumor necrosis factor (TNF-α), interleukin-6 (IL-6), IL-2, IL-8, IL-18, lipopolysacharide binding protein (LBP) or gut microbiota-related outcomes, were included.

RECENT FINDINGS

A total of 16 RCTs were included, among which 6 studies recruited metabolically at-risk population, including individuals with overweight and obesity, metabolic syndrome or hypercholesterolemia. Additionally, 3 trials involved young healthy population, 5 trials targeted older individuals (aged over 50 years), and 2 studies encompassed populations with other disease states. A total of 1091 individuals were included in the evaluation of short-term (up to 14 days) and long-term (beyond 14 days, up to 90 days) supplementation with oats or barley-based products. 9 studies measured inflammatory biomarkers and 5 of them reported significant reductions, specifically in long-term studies. Notably, no evidence of anti-inflammatory benefits was found in healthy individuals, whereas studies involving metabolically at-risk populations showed promising reductions in inflammation. 13 studies measured the impact on gut microbiota, and collectively suggest that oats and barley food products can influence the composition of gut microbiota, associated in some cases with metabolic improvements. Oats and barley consumption may confer anti-inflammatory effects in metabolically at-risk populations and influence gut microbiota outcomes. However, no anti-inflammatory benefits were observed in healthy individuals. Results from this systematic review suggests caution in interpreting findings due to limited trials and variations in interventions and health conditions.

An encompassing review of meta-analyses and systematic reviews of the effect of oats on all-cause mortality, cardiovascular risk, diabetes risk, body weight/adiposity and gut health

The ability of oats to reduce blood cholesterol is well established but there is increasing evidence that its health benefits extend well beyond that. The purpose of this review was to critically evaluate the state of the science of oats in relation to all-cause mortality, cardiovascular and diabetes risk and the effects of oats on blood lipids, blood glucose, blood pressure, weight management and gut health from meta-analyses and systematic reviews. Limited epidemiological data indicated a possible beneficial effect of oats on all-cause mortality and incident diabetes when high versus low oat consumers were compared, but its effect on cardiovascular events was not adequately discerned. Observational data also showed an inverse association between oat intake and blood cholesterol, blood pressure, body weight and obesity variables in different populations. Randomized controlled oat intervention studies demonstrated a significant reduction in postprandial blood glucose in both diabetic and non-diabetic subjects, fasting blood glucose in diabetic subjects, blood pressure in prehypertensive individuals, and body weight and adiposity in overweight individuals. Increased fecal bulk was observed but clinical data for a potential gut barrier effect is lacking. The mechanism of action of each health effect was reviewed. While beta-glucan viscosity was once considered the only mode of action, it is evident that the fermentation products of beta-glucan and the associated gut microbial changes, as well as other components in oats (i.e., avenanthramides etc.) also play an important role.

Lipid metabolism regulation by dietary polysaccharides with different structural properties

Lipid metabolism plays an important role in energy homeostasis maintenance in response to stress. Nowadays, hyperlipidemia-related chronic diseases such as obesity, diabetes, atherosclerosis, and fatty liver pose significant health challenges. Dietary polysaccharides (DPs) have gained attention for their effective lipid-lowering properties. This review examines the multifaceted mechanisms that DPs employ to lower lipid levels in subjects with hyperlipidemia. DPs could directly inhibit lipid intake and absorption, promote lipid excretion, and regulate key enzymes involved in lipid metabolism pathways, including triglyceride and cholesterol anabolism and catabolism, fatty acid oxidation, and bile acid synthesis. Additionally, DPs indirectly improve lipid homeostasis by modulating gut microbiota composition and alleviating oxidative stress. Moreover, the lipid-lowering mechanisms of particular structural DPs (including β-glucan, pectin, glucomannan, inulin, arabinoxylan, and fucoidan) are summarized. The relationship between the structure and lipid-lowering activity of DPs is also discussed based on current researches. Finally, potential breakthroughs and future directions in the development of DPs in lipid-lowering activity are discussed. The paper could provide a reference for further exploring the mechanism of DPs for lipid regulations and utilizing DPs as lipid-lowering dietary ingredients.

A Novel Foodstuff Mixture Improves the Gut-Liver Axis in MASLD Mice and the Gut Microbiota in Overweight/Obese Patients

Microbial community control is crucial for maintaining homeostasis of the gut-liver axis in metabolic dysfunction-associated steatotic liver disease (MASLD). Here, we show that supplementation with a mixture of Mexican foodstuffs (MexMix)-Opuntia ficus indica (nopal), Theobroma cacao (cocoa) and Acheta domesticus (crickets)-enriches several beneficial taxa in MASLD mice and overweight/obese humans. Thus, MexMix induces an important prebiotic effect. In mice, a restoration of intestinal health was observed due to the increased short-chain fatty acids (SCFAs) and intestinal crypt depth, Ocln and Cldn1 expression, and decreased Il6 and Tnfa expression. MexMix significantly reduced steatosis in the mice's liver and modified the expression of 1668 genes. By PCR, we corroborated a Tnfa and Pparg decrease, and a Cat and Sod increase. In addition, MexMix increased the hepatic NRF2 nuclear translocation and miRNA-34a, miRNA-103, and miRNA-33 decline. In overweight/obese humans, MexMix improved the body image satisfaction and reduced the fat intake. These findings indicate that this new food formulation has potential as a therapeutic approach to treat conditions associated with excessive consumption of fats and sugars.

Translating Human and Animal Model Studies to Dogs' and Cats' Veterinary Care: Beta-Glucans Application for Skin Disease, Osteoarthritis, and Inflammatory Bowel Disease Management

The inclusion of beta-glucans in dog and cat food is associated with numerous beneficial effects on the health of these animals. In this regard, there is an effort to elucidate the potential of this nutraceutical in chronic patients. Since there is a lack of a review on the topic, this review article aims to compile and discuss the evidence found to date. Atopic dermatitis, inflammatory bowel disease, and osteoarthritis are diseases of significant clinical relevance in dogs and cats. In general, the pathophysiology of these chronic conditions is related to immune-mediated and inflammatory mechanisms. Therefore, the immunomodulation and anti-inflammatory effects of beta-glucans are highlighted throughout this review. The available information seems to indicate that the studies on beta-glucans' impact on allergic processes in dogs indicate a reduction in clinical signs in atopic dermatitis cases. Additionally, while beta-glucans show promise as a safe supplement, particularly for osteoarthritis, further clinical trials are imperative, especially in uncontrolled environments. Beta-glucans emerge as a potential nutraceutical offering immune benefits for inflammatory bowel disease patients, although extensive research is required to define its optimal origin, molecular weight, dosage, and specific applications across animals suffering from this disease.

Structural characteristics and biological activities of polysaccharides from barley: a review

Barley (Hordeum vulgare L.) is rich in starch and non-starch polysaccharides (NSPs), especially β-glucan and arabinoxylan. Genotypes and isolation methods may affect their structural characteristics, properties and biological activities. The structure-activity relationships of NSPs in barley have not been paid much attention. This review summarizes the extraction methods, structural characteristics and physicochemical properties of barley polysaccharides. Moreover, the roles of barley β-glucan and arabinoxylan in the immune system, glucose metabolism, regulation of lipid metabolism and absorption of mineral elements are summarized. This review may help in the development of functional products in barley.

The Microbiota-Gut-Brain Axis in Metabolic Syndrome and Sleep Disorders: A Systematic Review

BACKGROUND

Over recent decades, a growing body of evidence has emerged linking the composition of the gut microbiota to sleep regulation. Interestingly, the prevalence of sleep disorders is commonly related to cardiometabolic comorbidities such as diabetes, impaired lipid metabolism, and metabolic syndrome (MetS). In this complex scenario, the role of the gut-brain axis as the main communicating pathway between gut microbiota and sleep regulation pathways in the brain reveals some common host-microbial biomarkers in both sleep disturbances and MetS. As the biological mechanisms behind this complex interacting network of neuroendocrine, immune, and metabolic pathways are not fully understood yet, the present systematic review aims to describe common microbial features between these two unrelated chronic conditions.

RESULTS

This systematic review highlights a total of 36 articles associating the gut microbial signature with MetS or sleep disorders. Specific emphasis is given to studies evaluating the effect of dietary patterns, dietary supplementation, and probiotics on MetS or sleep disturbances.

CONCLUSIONS

Dietary choices promote microbial composition and metabolites, causing both the amelioration and impairment of MetS and sleep homeostasis.

Human gut microbiome: Therapeutic opportunities for metabolic syndrome-Hype or hope?

Shifts in gut microbiome composition and metabolic disorders are associated with one another. Clinical studies and experimental data suggest a causal relationship, making the gut microbiome an attractive therapeutic goal. Diet, intake of probiotics or prebiotics and faecal microbiome transplantation (FMT) are methods to alter a person's microbiome composition. Although FMT may allow establishing a proof of concept to use microbiome modulation to treat metabolic disorders, studies show mixed results regarding the effects on metabolic parameters as well as on the composition of the microbiome. This review summarizes the current knowledge on diet, probiotics, prebiotics and FMT to treat metabolic diseases, focusing on studies that also report alterations in microbiome composition. Furthermore, clinical trial results on the effects of common drugs used to treat metabolic diseases are synopsized to highlight the bidirectional relationship between the microbiome and metabolic diseases. In conclusion, there is clear evidence that microbiome modulation has the potential to influence metabolic diseases; however, it is not possible to distinguish which intervention is the most successful. In addition, a clear commitment from all stakeholders is necessary to move forward in the direction of developing targeted interventions for microbiome modulation.

High-fiber diet and rope-skipping benefit cardiometabolic health and modulate gut microbiota in young adults: A randomized controlled trial

Previous studies have shown that high intake of dietary fiber (DF) and efficient levels of physical activity are beneficial for cardiometabolic health in middle-aged and elderly populations with cardiometabolic disease. However, evidence from young adults with low cardiometabolic risk is lacking. This study aimed to investigate the effects of various interventions including a high-fiber (HF) diet and the rope-skipping (RS) exercise on cardiometabolic risk factors (CRFs) and the composition of the gut microbiota in young adults. A 12-week parallel-designed randomized controlled trial was conducted in undergraduates (n = 96), who were randomly assigned to the HF group (≥20 g/d DF), the RS group (2000 jumps/week), and the control (CON) group. Among the 84 people who completed the trial, measurements of anthropometric characteristics, biochemical parameters, and gut microbiota were taken at the beginning and end of the intervention. After the intervention, the RS exercise led to a significant decrease in the heart rate and triglyceride levels compared to the CON group (all P < 0.05), but there was no significant difference in CRFs between the HF and CON groups. When compared to baseline, the 12-week HF diet intervention resulted in an increase in fat-free mass, and a decrease in the percentage of body fat and waist circumference (all P < 0.05). With regard to gut microbiota alterations after intervention, we found that compared with the CON group, the relative abundance of Lactobacillus decreased significantly in both the HF group and the RS group, Muribaculaceae decreased in the RS group, and Eubacterium_coprostanoligenes_group decreased in the HF group (all P < 0.05). Finally, shifts in 7 metabolic pathways were detected in the RS group using predictive functional profiling, while only one pathway was altered in the HF group (all P < 0.05). In conclusion, the RS exercise improved body composition compared to the CON group in young adults, while the HF diet just enhanced CRFs in contrast to baseline. Furthermore, both RS and HF interventions altered Lactobacillus and various other gut microbiota. The results indicated that the HF diet and RS exercise could partly benefit cardiometabolic health and modulate gut microbiota in young adults. Trial registration: ClinicalTrials.gov, NCT04834687.

Differential effects of plant-based flours on metabolic homeostasis and the gut microbiota in high-fat fed rats

BACKGROUND

The gut microbiome is a salient contributor to the development of obesity, and diet is the greatest modifier of the gut microbiome, which highlights the need to better understand how specific diets alter the gut microbiota to impact metabolic disease. Increased dietary fiber intake shifts the gut microbiome and improves energy and glucose homeostasis. Dietary fibers are found in various plant-based flours which vary in fiber composition. However, the comparative efficacy of specific plant-based flours to improve energy homeostasis and the mechanism by which this occurs is not well characterized.

METHODS

In experiment 1, obese rats were fed a high fat diet (HFD) supplemented with four different plant-based flours for 12 weeks. Barley flour (BF), oat bran (OB), wheat bran (WB), and Hi-maize amylose (HMA) were incorporated into the HFD at 5% or 10% total fiber content and were compared to a HFD control. For experiment 2, lean, chow-fed rats were switched to HFD supplemented with 10% WB or BF to determine the preventative efficacy of flour supplementation.

RESULTS

In experiment 1, 10% BF and 10% WB reduced body weight and adiposity gain and increased cecal butyrate. Gut microbiota analysis of WB and BF treated rats revealed increases in relative abundance of SCFA-producing bacteria. 10% WB and BF were also efficacious in preventing HFD-induced obesity; 10% WB and BF decreased body weight and adiposity, improved glucose tolerance, and reduced inflammatory markers and lipogenic enzyme expression in liver and adipose tissue. These effects were accompanied by alterations in the gut microbiota including increased relative abundance of Lactobacillus and LachnospiraceaeUCG001, along with increased portal taurodeoxycholic acid (TDCA) in 10% WB and BF rats compared to HFD rats.

CONCLUSIONS

Therapeutic and preventative supplementation with 10%, but not 5%, WB or BF improves metabolic homeostasis, which is possibly due to gut microbiome-induced alterations. Specifically, these effects are proposed to be due to increased concentrations of intestinal butyrate and circulating TDCA.

Intestinal organoids: A thriving and powerful tool for investigating dietary nutrients-intestinal homeostasis axis

Dietary nutrients regulate intestinal homeostasis through a variety of complex mechanisms, to affect the host health. Nowadays, various models have been used to investigate the dietary nutrients-intestinal homeostasis axis. Different from the limited flux in animal experiments, limited intestinal cell types and distorted simulation of intestinal environment of 2D cells, intestinal organoid (IO) is a 3D culture system of mini-gut with various intestinal epithelial cells (IECs) and producibility of intestinal biology. Therefore, IOs is a powerful tool to evaluate dietary nutrients-intestinal homeostasis interaction. This review summarized the application of IOs in the investigation of mechanisms for macronutrients (carbohydrates, proteins and fats) and micronutrients (vitamins and minerals) affecting intestinal homeostasis directly or indirectly (polysaccharides-intestinal bacteria, proteins-amino acids). In addition, new perspectives of IOs in combination with advanced biological techniques and their applications in precise nutrition were proposed.

The Immunomodulatory Effect of β-Glucan Depends on the Composition of the Gut Microbiota

This study aimed to elucidate the relationship between the immunomodulatory effects of β-glucan and the composition of gut microbiota in mice. The mice were fed a diet containing β-glucan for 3 weeks, and feces, blood, and tissues were then collected to analyze the immunomodulatory effect and gut microbiota composition. Based on the results of the analysis of the expression level of immune-associated proteins, the high immunomodulatory effect group (HIE) and low immunomodulatory effect group (LIE) were categorized. Before the β-glucan diet, the proportions of the phylum Bacteroidota, family Muribaculaceae, and family Lactobacillaceae were significantly higher in HIE than in LIE. Furthermore, the genus Akkermansia was absent before the β-glucan diet and increased after β-glucan diet. These microbes had the ability to metabolize β-glucan or were beneficial to health. In conclusion, our findings demonstrate that variation in the composition of gut microbiota among individuals can result in varying expressions of β-glucan functionality. This outcome supports the notion that β-glucan may be metabolized through diverse pathways by gut microbes originally possessed by mice, subsequently producing various metabolites, such as short-chain fatty acids. Alternatively, the viscosity of the intestinal mucosa could be enhanced by β-glucan, potentially promoting the growth of certain bacteria (e.g., the genus Akkermansia). This study provides insights into the intricate interplay between β-glucan, gut microbiota, and immunomodulation.

Individual and Group-Based Effects of In Vitro Fiber Interventions on the Fecal Microbiota

The development of microbiome-targeted strategies is limited by individual differences in gut microbiome composition and metabolic responses to interventions. In vitro models that can replicate this variation allow us to conduct pre-clinical studies and assess efficacy. This study describes the exposure of 16 individual fecal microbiota samples to 5 different fibers using an in vitro system for the anaerobic cultivation of bacteria. The individual microbiota differed in composition and metabolite profiles (short-chain fatty acids and branched-chain fatty acids) after incubation with the fibers. Furthermore, microbiota composition after fiber incubation was significantly different between subjects with good intestinal health and subjects with Inflammatory Bowel Disease (IBD). α-diversity was differently affected by dietary fibers; for example, exposure to psyllium resulted in increased diversity in the healthy group and in decreased diversity in the IBD group. Instead, the functional metabolic profile did not differ between the two groups. Finally, the combination of all fibers, tested on the microbiota from IBD subjects, resulted in stronger overall effects on both microbiota composition and metabolite production compared to the single fibers. These results confirm that incubation with dietary fiber results in different compositional and functional effects on individual microbiota and that in vitro models represent successful tools for studying individual fiber effects.

Functional and Nutritional Characteristics of Natural or Modified Wheat Bran Non-Starch Polysaccharides: A Literature Review

Wheat bran (WB) consists mainly of different histological cell layers (pericarp, testa, hyaline layer and aleurone). WB contains large quantities of non-starch polysaccharides (NSP), including arabinoxylans (AX) and β-glucans. These dietary fibres have long been studied for their health effects on management and prevention of cardiovascular diseases, cholesterol, obesity, type-2 diabetes, and cancer. NSP benefits depend on their dose and molecular characteristics, including concentration, viscosity, molecular weight, and linked-polyphenols bioavailability. Given the positive health effects of WB, its incorporation in different food products is steadily increasing. However, the rheological, organoleptic and other problems associated with WB integration are numerous. Biological, physical, chemical and combined methods have been developed to optimise and modify NSP molecular characteristics. Most of these techniques aimed to potentially improve food processing, nutritional and health benefits. In this review, the physicochemical, molecular and functional properties of modified and unmodified WB are highlighted and explored. Up-to-date research findings from the clinical trials on mechanisms that WB have and their effects on health markers are critically reviewed. The review points out the lack of research using WB or purified WB fibre components in randomized, controlled clinical trials.

Effects of FODMAPs and Gluten on Gut Microbiota and Their Association with the Metabolome in Irritable Bowel Syndrome: A Double-Blind, Randomized, Cross-Over Intervention Study

BACKGROUND

A mechanistic understanding of the effects of dietary treatment in irritable bowel syndrome (IBS) is lacking. Our aim was therefore to investigate how fermentable oligo- di-, monosaccharides, and polyols (FODMAPs) and gluten affected gut microbiota and circulating metabolite profiles, as well as to investigate potential links between gut microbiota, metabolites, and IBS symptoms.

METHODS

We used data from a double-blind, randomized, crossover study with week-long provocations of FODMAPs, gluten, and placebo in participants with IBS. To study the effects of the provocations on fecal microbiota, fecal and plasma short-chain fatty acids, the untargeted plasma metabolome, and IBS symptoms, we used Random Forest, linear mixed model and Spearman correlation analysis.

RESULTS

FODMAPs increased fecal saccharolytic bacteria, plasma phenolic-derived metabolites, 3-indolepropionate, and decreased isobutyrate and bile acids. Gluten decreased fecal isovalerate and altered carnitine derivatives, CoA, and fatty acids in plasma. For FODMAPs, modest correlations were observed between microbiota and phenolic-derived metabolites and 3-indolepropionate, previously associated with improved metabolic health, and reduced inflammation. Correlations between molecular data and IBS symptoms were weak.

CONCLUSIONS

FODMAPs, but not gluten, altered microbiota composition and correlated with phenolic-derived metabolites and 3-indolepropionate, with only weak associations with IBS symptoms. Thus, the minor effect of FODMAPs on IBS symptoms must be weighed against the effect on microbiota and metabolites related to positive health factors.

Interaction of beta-glucans with gut microbiota: Dietary origins, structures, degradation, metabolism, and beneficial function

Beta-glucan (BG), a polysaccharide comprised of interfacing glucose monomers joined via beta-glycosidic linkages, can be defined as a type of dietary fiber with high specificity based on its interaction with the gut microbiota. It can induce similar interindividual microbiota responses, thereby having beneficial effects on the human body. In this paper, we review the four main sources of BG (cereals, fungi, algae, and bacteria) and their differences in structure and content. The interaction of BG with gut microbiota and the resulting health effects have been highlighted, including immune enhancement, regulation of serum cholesterol and insulin levels, alleviation of obesity and improvement of cognitive disorders. Finally, the application of BG in food products and its beneficial effects on the gut microbiota of consumers were discussed. Although some of the mechanisms of action remain unclear, revealing the beneficial functions of BG from the perspective of gut microbiota can help provide theoretical support for the development of diets that target the regulation of microbiota.

β-glucans: a potential source for maintaining gut microbiota and the immune system

The human gastrointestinal (GI) tract holds a complex and dynamic population of microbial communities, which exerts a marked influence on the host physiology during homeostasis and disease conditions. Diet is considered one of the main factors in structuring the gut microbiota across a lifespan. Intestinal microbial communities play a vital role in sustaining immune and metabolic homeostasis as well as protecting against pathogens. The negatively altered gut bacterial composition has related to many inflammatory diseases and infections. β-glucans are a heterogeneous assemblage of glucose polymers with a typical structure comprising a leading chain of β-(1,4) and/or β-(1,3)-glucopyranosyl units with various branches and lengths as a side chain. β-glucans bind to specific receptors on immune cells and initiate immune responses. However, β-glucans from different sources differ in their structures, conformation, physical properties, and binding affinity to receptors. How these properties modulate biological functions in terms of molecular mechanisms is not known in many examples. This review provides a critical understanding of the structures of β-glucans and their functions for modulating the gut microbiota and immune system.

Are all fibres created equal with respect to lipid lowering? Comparing the effect of viscous dietary fibre to non-viscous fibre from cereal sources: a systematic review and meta-analysis of randomised controlled trials

Although compelling evidence from observational studies supports a positive association between consumption of cereal fibre and CVD risk reduction, randomised controlled trials (RCT) often target viscous fibre type as the prospective contributor to lipid lowering to reduce CVD risk. The objective of our study is to compare the lipids-lowering effects of viscous dietary fibre to non-viscous, cereal-type fibre in clinical studies. RCT that evaluated the effect of viscous dietary fibre compared with non-viscous, cereal fibre on LDL cholesterol and alternative lipid markers, with a duration of ≥ 3 weeks, in adults with or without hypercholesterolaemia were included. Medline, EMBASE, CINAHL and the Cochrane Central Register were searched through October 19, 2021. Data were extracted and assessed by two independent reviewers. The generic inverse variance method with random effects model was utilised to pool the data which were expressed as mean differences (MD) with 95 % CI. Eighty-nine trials met eligibility criteria (n 4755). MD for the effect of viscous dietary fibre compared with non-viscous cereal fibre were LDL cholesterol (MD = -0·26 mmol/l; 95 % CI: -0·30, -0·22 mmol/l; P < 0·01), non-HDL cholesterol (MD = -0·33 mmol/l; 95 % CI: -0·39, -0·28 mmol/l; P < 0·01) and Apo-B (MD = -0·04 g/l; 95 % CI: -0·06, -0·03 g/l; P < 0·01). Viscous dietary fibre reduces LDL cholesterol and alternative lipid markers relative to the fibre from cereal sources, hence may be a preferred type of fibre-based dietary intervention targeting CVD risk reduction.

Interaction between β-glucans and gut microbiota: a comprehensive review

Gut microbiota (GMB) in humans plays a crucial role in health and diseases. Diet can regulate the composition and function of GMB which are associated with different human diseases. Dietary fibers can induce different health benefits through stimulation of beneficial GMB. β-glucans (BGs) as dietary fibers have gained much interest due to their various functional properties. They can have therapeutic roles on gut health based on modulation of GMB, intestinal fermentation, production of different metabolites, and so on. There is an increasing interest in food industries in commercial application of BG as a bioactive substance into food formulations. The aim of this review is considering the metabolizing of BGs by GMB, effects of BGs on the variation of GMB population, influence of BGs on the gut infections, prebiotic effects of BGs in the gut, in vivo and in vitro fermentation of BGs and effects of processing on BG fermentability.

The separate effects of whole oats and isolated beta-glucan on lipid profile: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND & AIMS

It is well known that dietary fiber positively impacts the microbiome and health as a whole. However, the health effects of β-glucan, a dietary fiber extracted from oats, have been questioned when administered alone or incorporated into other foods. The purpose of this systematic review and meta-analysis was to evaluate the impact of oats or β-glucan supplements on the lipid profile.

METHODS

Randomized controlled trials with parallel-arm or crossover blinded interventions at least two weeks in duration, for hyperlipidemic or non-hyperlipidemic men and women ≥18 years of age were selected. Only single (participants blinded) or double-blinded studies that compared oat or isolated β-glucan with a placebo/control group were considered for this review. The databases EMBASE, PubMed, Web of science and CINHAL were searched, from the earliest indexed year available online to the end of January 2022. Random-effects models were used to combine the estimated effects extracted from individual studies, and data were summarized as standardized mean difference (SMD) and 95% confidence interval (95%CI).

RESULTS

A total of 811 articles were screened for eligibility, and relevant data were extracted from 28 studies, totaling 1494 subjects. Oat interventions TC (-0.61, 95%CI: -0.84;-0.39, p < 0.00001, and -0.70, 95%CI: -1.07;-0.34, p = 0.0002, respectively) and LDL (-0.51, 95%CI: -0.71;-0.31, p < 0.00001, and -0.38, 95%CI: -0.60;-0.15, p = 0.001, respectively). Moreover, isolated β-glucan interventions from parallel-arm studies decreased TC (-0.73, 95%CI: -1.01;-0.45, p < 0.00001), LDL (-0.58, 95%CI: -0.85;-0.32, p < 0.0001) and triglycerides (-0.30, 95%CI: -0.49;-0.12, p = 0.001). HDL was not altered by either oat or isolated β-glucan (p > 0.05).

CONCLUSION

Overall, this review showed that both oat and isolated β-glucan interventions improved lipid profiles. Furthermore, the ingestion of oats or isolated β-glucan supplements are effective tools to combat dyslipidemia and should be considered in cardiovascular disease prevention.

Treatment of Dyslipidemia through Targeted Therapy of Gut Microbiota

Dyslipidemia is a multifaceted condition with various genetic and environmental factors contributing to its pathogenesis. Further, this condition represents an important risk factor for its related sequalae including cardiovascular diseases (CVD) such as coronary artery disease (CAD) and stroke. Emerging evidence has shown that gut microbiota and their metabolites can worsen or protect against the development of dyslipidemia. Although there are currently numerous treatment modalities available including lifestyle modification and pharmacologic interventions, there has been promising research on dyslipidemia that involves the benefits of modulating gut microbiota in treating alterations in lipid metabolism. In this review, we examine the relationship between gut microbiota and dyslipidemia, the impact of gut microbiota metabolites on the development of dyslipidemia, and the current research on dietary interventions, prebiotics, probiotics, synbiotics and microbiota transplant as therapeutic modalities in prevention of cardiovascular disease. Overall, understanding the mechanisms by which gut microbiota and their metabolites affect dyslipidemia progression will help develop more precise therapeutic targets to optimize lipid metabolism.

The Effect of Regular Consumption of Reformulated Breads on Glycemic Control: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

Bread is a major source of grain-derived carbohydrates worldwide. High intakes of refined grains, low in dietary fiber and high in glycemic index, are linked with increased risk for type 2 diabetes mellitus (T2DM) and other chronic diseases. Hence, improvements in the composition of bread could influence population health. This systematic review evaluated the effect of regular consumption of reformulated breads on glycemic control among healthy adults, adults at cardiometabolic risk or with manifest T2DM. A literature search was performed using MEDLINE, Embase, Web of Science and the Cochrane Central Register of Controlled Trials. Eligible studies employed a bread intervention (≥2 wk) in adults (healthy, at cardiometabolic risk or manifest T2DM) and reported glycemic outcomes (fasting blood glucose, fasting insulin, HOMA-IR, HbA1c, and postprandial glucose responses). Data were pooled using generic inverse variance with random-effects model and presented as mean difference (MD) or standardized MD between treatments with 95% CIs. Twenty-two studies met the inclusion criteria (n = 1037 participants). Compared with "regular" or comparator bread, consumption of reformulated intervention breads yielded lower fasting blood glucose concentrations (MD: -0.21 mmol/L; 95% CI: -0.38, -0.03; I² = 88%, moderate certainty of evidence), yet no differences in fasting insulin (MD: -1.59 pmol/L; 95% CI: -5.78, 2.59; I² = 38%, moderate certainty of evidence), HOMA-IR (MD: -0.09; 95% CI: -0.35, 0.23; I² = 60%, moderate certainty of evidence), HbA1c (MD: -0.14; 95% CI: -0.39, 0.10; I² = 56%, very low certainty of evidence), or postprandial glucose response (SMD: -0.46; 95% CI: -1.28, 0.36; I² = 74%, low certainty of evidence). Subgroup analyses revealed a beneficial effect for fasting blood glucose only among people with T2DM (low certainty of evidence). Our findings suggest a beneficial effect of reformulated breads high in dietary fiber, whole grains, and/or functional ingredients on fasting blood glucose concentrations in adults, primarily among those with T2DM. This trial was registered at PROSPERO as CRD42020205458.

Effect of synbiotic bread containing lactic acid on blood lipids and apolipoproteins in patients with type 2 diabetes: A randomized controlled trial

Recently, the use of synbiotics for managing various diseases has dramatically increased. Synbiotics have been shown to be a good approach to influence the composition of the gut microbiota with positive health effects. Management of type 2 diabetes mellitus (T2DM) complications is one of the reasons for the ingestion of synbiotics and so the aim of the current study was to determine the effects of synbiotic bread intake on markers of lipid profile in T2DM patients. One hundred T2DM patients (age between 20 and 60 years) were randomly assigned to four groups to consume different types of synbiotic bread, three times/day, for 8 weeks: "synbiotic + lactic acid" (n = 25; IV), "synbiotic" (n = 25; III), "lactic acid brad" (n = 25; II), or "control" (n = 25; I). The measured outcomes included anthropometric characteristics, glycemic control parameters, blood lipids, and apolipoproteins. The consumption of "synbiotic + lactic acid bread" (group IV) and "lactic acid bread" (group II) led to a significant decrease in total cholesterol (TC) and glycated hemoglobin (HbA1c) compared to the "control bread." The HbA1c levels were also significantly lower when compared to group II. Additionally, apolipoprotein A (Apo A1) levels were significantly decreased in group IV, compared to control and other groups (post hoc analysis). No significant differences between groups were observed for triglyceride (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and apolipoprotein B100 (Apo B100) levels. The observed results show that the synbiotic bread (with or without lactic acid) promoted a decrease in total cholesterol (TC) and Apo A1 in diabetic patients when consumed daily for 8 weeks.

Interactions between Dietary Micronutrients, Composition of the Microbiome and Efficacy of Immunotherapy in Cancer Patients

The effectiveness of immunotherapy in cancer patients depends on the activity of the host's immune system. The intestinal microbiome is a proven immune system modulator, which plays an important role in the development of many cancers and may affect the effectiveness of anti-cancer therapy. The richness of certain bacteria in the gut microbiome (e.g., Bifidobacterium spp., Akkermanisa muciniphila and Enterococcus hire) improves anti-tumor specific immunity and the response to anti-PD-1 or anti-PD-L1 immunotherapy by activating antigen-presenting cells and cytotoxic T cells within the tumor. Moreover, micronutrients affect directly the activities of the immune system or regulate their function by influencing the composition of the microbiome. Therefore, micronutrients can significantly influence the effectiveness of immunotherapy and the development of immunorelated adverse events. In this review, we describe the relationship between the supply of microelements and the abundance of various bacteria in the intestinal microbiome and the effectiveness of immunotherapy in cancer patients. We also point to the function of the immune system in the case of shifts in the composition of the microbiome and disturbances in the supply of microelements. This may in the future become a therapeutic target supporting the effects of immunotherapy in cancer patients.

Yeast β-Glucan Improves Insulin Sensitivity and Hepatic Lipid Metabolism in Mice Humanized with Obese Type 2 Diabetic Gut Microbiota

SCOPE

Gut microbiota alterations are associated with obesity and type 2 diabetes. Yeast β-glucans are potential modulators of the innate immune-metabolic response, by impacting glucose, lipid, and cholesterol homeostasis. The study examines whether yeast β-glucan interacts differentially with either an obese healthy or obese diabetic gut microbiome, to impact metabolic health through hepatic effects under high-fat dietary challenge.

METHODS AND RESULTS

Male C57BL/6J mice are pre-inoculated with gut microbiota from obese healthy (OBH) or obese type 2 diabetic (OBD) subjects, in conjunction with a high-fat diet (HFD) with/without yeast β-glucan. OBD microbiome colonization adversely impacts metabolic health compared to OBH microbiome engraftment. OBD mice are more insulin resistant and display hepatic lipotoxicity compared to weight matched OBH mice. Yeast β-glucan supplementation resolves this adverse metabolic phenotype, coincident with increasing the abundance of health-related bacterial taxa. Hepatic proteomics demonstrates that OBD microbiome transplantation increases HFD-induced hepatic mitochondrial dysfunction, disrupts oxidative phosphorylation, and reduces protein synthesis, which are partly reverted by yeast β-glucan supplementation.

CONCLUSIONS

Hepatic metabolism is adversely affected by OBD microbiome colonization with high-fat feeding, but partially resolved by yeast β-glucan. More targeted dietary interventions that encompass the interactions between diet, gut microbiota, and host metabolism may have greater treatment efficacy.

Diet-Related Changes of Short-Chain Fatty Acids in Blood and Feces in Obesity and Metabolic Syndrome

Obesity-related illnesses are one of the leading causes of death worldwide. Metabolic syndrome has been associated with numerous health issues. Short-chain fatty acids (SCFAs) have been shown to have multiple effects throughout the body, both directly as well as through specific G protein-coupled receptors. The main SCFAs produced by the gut microbiota are acetate, propionate, and butyrate, which are absorbed in varying degrees from the large intestine, with some acting mainly locally and others systemically. Diet has the potential to influence the gut microbial composition, as well as the type and amount of SCFAs produced. High fiber-containing foods and supplements increase the production of SCFAs and SCFA-producing bacteria in the gut and have been shown to have bodyweight-lowering effects. Dietary supplements, which increase SCFA production, could open the way for novel approaches to weight loss interventions. The aim of this review is to analyze the variations of fecal and blood SCFAs in obesity and metabolic syndrome through a systematic search and analysis of existing literature.

Dietary Polysaccharides as Modulators of the Gut Microbiota Ecosystem: An Update on Their Impact on Health

A polysaccharide is a macromolecule composed of more than ten monosaccharides with a wide distribution and high structural diversity and complexity in nature. Certain polysaccharides are immunomodulators and play key roles in the regulation of immune responses during the progression of some diseases. In addition to stimulating the growth of certain intestinal bacteria, polysaccharides may also promote health benefits by modulating the gut microbiota. In the last years, studies about the triad gut microbiota-polysaccharides-health have increased exponentially. In consequence, in the present review, we aim to summarize recent knowledge about the function of dietary polysaccharides on gut microbiota composition and how these effects affect host health.

Sex hormones, intestinal inflammation, and the gut microbiome: Major influencers of the sexual dimorphisms in obesity

Obesity is defined as the excessive accumulation of body fat and is associated with an increased risk of developing major health problems such as cardiovascular disease, diabetes and stroke. There are clear sexual dimorphisms in the epidemiology, pathophysiology and sequelae of obesity and its accompanying metabolic disorders, with females often better protected compared to males. This protection has predominantly been attributed to the female sex hormone estrogen and differences in fat distribution. More recently, the sexual dimorphisms of obesity have also been attributed to the differences in the composition and function of the gut microbiota, and the intestinal immune system. This review will comprehensively summarize the pre-clinical and clinical evidence for these sexual dimorphisms and discuss the interplay between sex hormones, intestinal inflammation and the gut microbiome in obesity. Major gaps and limitations of this rapidly growing area of research will also be highlighted in this review.

The potential impact of a probiotic: Akkermansia muciniphila in the regulation of blood pressure—the current facts and evidence

Akkermansia muciniphila (A. muciniphila) is present in the human gut microbiota from infancy and gradually increases in adulthood. The potential impact of the abundance of A. muciniphila has been studied in major cardiovascular diseases including elevated blood pressure or hypertension (HTN). HTN is a major factor in premature death worldwide, and approximately 1.28 billion adults aged 30–79 years have hypertension. A. muciniphila is being considered a next-generation probiotic and though numerous studies had highlighted the positive role of A. muciniphila in lowering/controlling the HTN, however, few studies had highlighted the negative impact of increased abundance of A. muciniphila in the management of HTN. Thus, in the review, we aimed to discuss the current facts, evidence, and controversy about the role of A. muciniphila in the pathophysiology of HTN and its potential effect on HTN management/regulation, which could be beneficial in identifying the drug target for the management of HTN.

Effect of β-1,3/1,6-glucan on gut microbiota of yellow-feathered broilers

β-1,3/1,6-glucan as a prebiotic improves immune performance in animals. These functions are closely related to the effect of β-1,3/1,6-glucan on gut microbiota structure. However, the effect of β-1,3/1,6-glucan on the gut microbiota structure of broilers is unclear. The aim of this study was to confirm the effects of β-1,3/1,6-glucan on the cecal microflora structure of yellow-feathered broilers. This study monitored the antimicrobial resistance (AMR) level of Escherichia coli in feces of yellow-feathered broilers by standard broth dilution method and mastered the AMR level of chickens selected. The effects of β-1,3/1,6-glucan on gut microbiota were investigated by 16S rRNA sequencing. The results showed that the number of isolated multidrug-resistant E. coli strains accounted for 98.41%. At 14, 21, and 28 days of age, supplemented of 0.2%, 0.1%, and 0.1% β-1,3/1,6-glucan in yellow-feathered broiler diets significantly altered gut microbial composition, and beneficial bacteria Alistipes, Bacteroides and Faecalibacterium were significantly increased. These findings provide guidance and recommendations for β-1,3/1,6-glucan as a broiler feed additive to improve the growth of broilers.

Synbiotics and Gut Microbiota: New Perspectives in the Treatment of Type 2 Diabetes Mellitus

The number of people with type 2 diabetes mellitus (T2DM) has increased sharply over the past decades. Apart from genetic predisposition, which may cause some of the diagnosed cases, an unhealthy diet and lifestyle are incentive triggers of this global epidemic. Consumption of probiotics and prebiotics to gain health benefits has become increasingly accepted by the public in recent years, and their critical roles in alleviating T2DM symptoms are confirmed by accumulating studies. Microbiome research reveals gut colonization by probiotics and their impacts on the host, while oral intake of prebiotics may stimulate existing metabolisms in the colon. The use of synbiotics (a combination of prebiotics and probiotics) can thus show a synergistic effect on T2DM through modulating the gastrointestinal microenvironment. This review summarizes the research progress in the treatment of T2DM from the perspective of synbiotics and gut microbiota and provides a class of synbiotics which are composed of lactulose, arabinose, and Lactobacillus plantarum, and can effectively adjust the blood glucose, blood lipid, and body weight of T2DM patients to ideal levels.

The Effects of High Fiber Rye, Compared to Refined Wheat, on Gut Microbiota Composition, Plasma Short Chain Fatty Acids, and Implications for Weight Loss and Metabolic Risk Factors (the RyeWeight Study)

Consumption of whole grain and cereal fiber have been inversely associated with body weight and obesity measures in observational studies but data from large, long-term randomized interventions are scarce. Among the cereals, rye has the highest fiber content and high rye consumption has been linked to increased production of gut fermentation products, as well as reduced risks of obesity and metabolic disease. The effects on body weight and metabolic risk factors may partly be mediated through gut microbiota and/or their fermentation products. We used data from a randomized controlled weight loss trial where participants were randomized to a hypocaloric diet rich in either high fiber rye foods or refined wheat foods for 12 weeks to investigate the effects of the intervention on gut microbiota composition and plasma short chain fatty acids, as well as the potential association with weight loss and metabolic risk markers. Rye, compared to wheat, induced some changes in gut microbiota composition, including increased abundance of the butyrate producing Agathobacter and reduced abundance of [Ruminococcus] torques group, which may be related to reductions in low grade inflammation caused by the intervention. Plasma butyrate increased in the rye group. In conclusion, intervention with high fiber rye foods induced some changes in gut microbiota composition and plasma short chain fatty acid concentration, which were associated with improvements in metabolic risk markers as a result of the intervention.

Impact of fiber-fortified food consumption on anthropometric measurements and cardiometabolic outcomes: A systematic review, meta-analyses, and meta-regressions of randomized controlled trials

The consumption of processed and refined food lacking in fiber has led to global prevalence of obesity and cardiometabolic diseases. Fiber-fortification into these foods can yield potential health improvements to reduce disease risk. This meta-analyses aimed to evaluate how fiber-fortified food consumption changes body composition, blood pressure, blood lipid-lipoprotein panel, and glycemic-related markers. Searches were performed from 5 databases, with 31 randomized controlled trial eventually analyzed. Hedges' g values (95% confidence interval [CI]) attained from outcome change values were calculated using random-effects model. Fiber-fortified food significantly reduced body weight (-0.31 [-0.59, -0.03]), fat mass (-0.49 [-0.72, -0.26]), total cholesterol (-0.54 [-0.71, -0.36]), low-density lipoprotein cholesterol (-0.49 [-0.65, -0.33]), triglycerides (-0.24 [-0.36, -0.12]), fasting glucose (-0.30 [-0.49, -0.12]), and HbA1c (-0.44 [-0.74, -0.13]). Subgroup analysis differentiated soluble fiber as significantly reducing triglycerides and insulin while insoluble fiber significantly reduced body weight, BMI, and HbA1c. Greater outcome improvements were observed with solid/semi-solid food state than liquid state. Additionally, fiber fortification of <15 g/day induced more health outcome benefits compared to ≥15 g/day, although meta-regression found a dose-dependent improvement to waist circumference (p-value = 0.036). Findings from this study suggest that consuming food fortified with dietary fiber can improve anthropometric and cardiometabolic outcomes.Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2022.2053658.

Nutrition and Microbiome

The prevalence of overweight and obesity has reached epidemic proportions globally over the past few decades. The search for new management approaches continues and among them, targeting the gut microbiota can be envisioned. To date, numerous data showed the involvement of the gut microbes in the regulation and control of host metabolism. There are also increasing evidences highlighting the interactions between environmental factors, intrinsic factors, gut microbiota, and metabolic diseases. Diet emerges as the most relevant factor influencing the gut microbiome. Eating habits, as well as short-term consumption of specific diets, alter the gut microbiota composition. Moreover, nutritional disorders are associated with changes of the gut microbiota composition and/or function, as shown in obesity or type 2 diabetic patients versus healthy lean subjects. Targeting the gut microbiota for improving metabolic health appears as a new approach to manage obesity and cardio-metabolic risk. In this review, we have detailed the results of human interventions targeting the gut microbiome by prebiotic supplementation, prebiotics being defined as "substrates that are selectively utilized by the host microorganisms conferring a health benefit." If the potential benefit of this approach is obvious in preclinical models, the efficacy of prebiotics in humans is less reproducible. The inter-individual variability of response to dietary intervention can be dependent on the gut microbiota and we summarized the basal gut microbiota characteristics driving the metabolic response to dieting, prebiotic and dietary fiber intervention in the context of obesity and related metabolic diseases.

A Review on the Structure and Anti-Diabetic (Type 2) Functions of β-Glucans

Type 2 diabetes, a long-term chronic metabolic disease, causes severe and increasing economic and health problems globally. There is growing evidence that β-glucans can function as bioactive macromolecules that help control type 2 diabetes with minimal side effects. However, conflicting conclusions about the antidiabetic activities of β-glucans have been published, potentially resulting from incomplete understanding of their precise structural characteristics. This review aims to increase clarity on the structure-function relationships of β-glucans in treating type 2 diabetes by examining detailed structural and conformational features of naturally derived β-glucans, as well as both chemical and instrumental methods used in their characterization, and their underlying anti-diabetic mechanisms. This may help to uncover additional structure and function relationships and to expand applications of β-glucans.

The Prebiotic Effects of Oats on Blood Lipids, Gut Microbiota, and Short-Chain Fatty Acids in Mildly Hypercholesterolemic Subjects Compared With Rice: A Randomized, Controlled Trial

Phytochemicals derived from oats are reported to possess a beneficial effect on modulating dyslipidemia, specifically on lowering total and LDL cholesterol. However, deeper insights into its mechanism remain unclear. In this randomized controlled study, we assigned 210 mildly hypercholesterolemic subjects from three study centers across China (Beijing, Nanjing, and Shanghai) to consume 80 g of oats or rice daily for 45 days. Plasma lipid profiles, short chain fatty acids (SCFAs), and fecal microbiota were measured. The results showed that total cholesterol (TC) and non-high-density lipoprotein cholesterol (non-HDL-C) decreased significantly with both oats and rice intake after 30 and 45 days. The reduction in TC and non-HDL-C was greater in the participants consuming oats compared with rice at day 45 (p = 0.011 and 0.049, respectively). Oat consumption significantly increased the abundance of Akkermansia muciniphila and Roseburia, and the relative abundance of Dialister, Butyrivibrio, and Paraprevotella, and decreased unclassified f-Sutterellaceae. In the oat group, Bifidobacterium abundance was negatively correlated with LDL-C (p = 0.01, r = -0.31) and, TC and LDL-C were negatively correlated to Faecalibacterium prausnitzii (p = 0.02, r = -0.29; p = 0.03, r = -0.27, respectively). Enterobacteriaceae, Roseburia, and Faecalibacterium prausnitzii were positively correlated with plasma butyric acid and valeric acid concentrations and negatively correlated to isobutyric acid. HDL-C was negatively correlated with valeric acid (p = 0.02, r = -0.25) and total triglyceride (TG) was positively correlated to isovaleric acid (p = 0.03, r = 0.23). Taken together, oats consumption significantly reduced TC and LDL-C, and also mediated a prebiotic effect on gut microbiome. Akkermansia muciniphila, Roseburia, Bifidobacterium, and Faecalibacterium prausnitzii, and plasma SCFA correlated with oat-induced changes in plasma lipids, suggesting prebiotic activity of oats to modulate gut microbiome could contribute towards its cholesterol-lowering effect.

The Beneficial Effect of Coarse Cereals on Chronic Diseases through Regulating Gut Microbiota

In recent years, chronic diseases including obesity, diabetes, cancer, cardiovascular, and neurodegenerative disorders have been the leading causes of incapacity and death globally. Increasing evidence suggests that improvements of lifestyle habits and diet is the most commonly adopted strategy for the prevention of chronic disorders. Moreover, many dietary compounds have revealed health-promoting benefits beyond their nutritional effects. It is worth noting that diet plays an important role in shaping the intestinal microbiota. Coarse cereals constitute important sources of nutrients for the gut microbiota and contribute to a healthy gut microbiome. Furthermore, the gut microbiota converts coarse cereals into functional substances and mediates the interaction between the host and these components. In this study, we summarize the recent findings concerning functional components of cereal grains and their potential chemopreventive activity via modulating the gut microbiota.

The effect of cereal Β-glucan on body weight and adiposity: A review of efficacy and mechanism of action

The current review examines the totality of the evidence to determine if there exists a relationship between β-glucan and body weight and adiposity and whether such a relationship is a consistent, causal and plausible one. Observational studies suggest an association between oat (i.e., β-glucan) intake and reduced body weight, waist circumference and adiposity. High and moderate quality randomized controlled trials that were specifically designed to evaluate the efficacy of β-glucan on anthropometric outcomes were given the highest weight. Several of these studies indicated a causal relationship between β-glucan consumption and reduction in body weight, BMI, and at least one measure of body fat within diets that were not calorie-restricted. A review of additional animal and human evidence suggests multiple plausible mechanisms by which β-glucan may impact satiety perception, gastric emptying, gut hormones, gut microbiota and short chain fatty acids in the complex interplay of appetite and energy regulation.

Effects of Different Concentrations of Ganpu Tea on Fecal Microbiota and Short Chain Fatty Acids in Mice

Ganpu tea is composed of tangerine peel and Pu-erh tea. Current research suggests that both products can interact with gut microbes and thus affect health. However, as a kind of compound health food, little information is available about the effect of Ganpu tea on intestinal microorganisms. In this study, the basic physiological parameters (body weight, white adipose tissue and serum fat), the regulation of intestinal microorganisms and content of short-chain fatty acids (SCFAs) in feces of healthy mice were studied. The Ganpu tea can reduce the weight gain of mice and the increase in white adipose tissue (p < 0.01). After the intake of Ganpu tea, the abundance of Bacteroidetes increased (p < 0.05), whereas that of Firmicutes decreased (p < 0.01), indicating the latent capacity of Ganpu tea in adjusting the gut microbiota. Moreover, Ganpu tea differentially affected the content of different types of SCFAs in feces. Ganpu tea at the lowest concentrations showed positive effects on the concentrations of SCFAs such as acetic acid and propionic acid, whereas the concentration of butyric acid was decreased. For branched short-chain fatty acids (BSCFAs) such as isobutyric acid, isovaleric acid, etc., Ganpu tea reduced their concentrations. Our results indicated that Ganpu tea may have positive effects on preventing obesity in humans, but further research is needed before introducing such dietary therapy.

Does algae β-glucan affect the fecal bacteriome in dairy calves?

β-glucans has been reported to be associated with many health-promoting and improvements in animal performance, however, information about their effects on the bacterial community remains unknown. This study aimed to investigate how the addition of β-glucans can affect the fecal bacterial community with possible consequences on animal growth and health. For this, newborn Holstein calves (n = 14) were individually housed in tropical shelters and blocked according to sex, date, and weight at birth and randomly assigned to one of the following treatments: (1) Control: milk replacer (14% solids, 24% CP, 18.5% fat); (2) β-glucans: milk replacer supplemented with β-glucans (2 g/d). All calves were bucket fed 6 L/d of milk replacer and received water and starter concentrate ad libitum starting on d 2. To evaluate the bacteriome, fecal samples were collected at weeks 1, 2, 4, and 8. The bacterial community was assessed through sequencing of the V3-V4 region of the 16S rRNA gene on the Illumina MiSeq platform and analyzed using the DADA2 pipeline. No differences for Shannon and Chao1 indexes were observed for treatments, but both indexes increased with age (P < 0.001). There were dissimilarities in the structure of the bacterial community during the pre-weaning period (P = 0.01). In a deeper taxonomic level, Collinsella (Actinobacteriota), Prevotella (Bacteroidota), and Lactobacillus (Firmicutes) were the most abundant genera (9.84, 9.54, and 8.82% of the sequences, respectively). β-glucans promoted a higher abundance of Alloprevotella and Holdemanella, which may indicate a beneficial effect of supplementation on dairy calves. The bacterial community was highly correlated with the fecal score at weeks 1 and 2 and with starter concentrate intake at week 8. In conclusion, algae β-glucan supplementation could be beneficial to fecal bacteriome and consequently to the health and performance of dairy calves.