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Nutrients Aug 2019The interplay of gut microbiota, host metabolism, and metabolic health has gained increased attention. Gut microbiota may play a regulatory role in gastrointestinal... (Review)
Review
The interplay of gut microbiota, host metabolism, and metabolic health has gained increased attention. Gut microbiota may play a regulatory role in gastrointestinal health, substrate metabolism, and peripheral tissues including adipose tissue, skeletal muscle, liver, and pancreas via its metabolites short-chain fatty acids (SCFA). Animal and human data demonstrated that, in particular, acetate beneficially affects host energy and substrate metabolism via secretion of the gut hormones like glucagon-like peptide-1 and peptide YY, which, thereby, affects appetite, via a reduction in whole-body lipolysis, systemic pro-inflammatory cytokine levels, and via an increase in energy expenditure and fat oxidation. Thus, potential therapies to increase gut microbial fermentation and acetate production have been under vigorous scientific scrutiny. In this review, the relevance of the colonically and systemically most abundant SCFA acetate and its effects on the previously mentioned tissues will be discussed in relation to body weight control and glucose homeostasis. We discuss in detail the differential effects of oral acetate administration (vinegar intake), colonic acetate infusions, acetogenic fiber, and acetogenic probiotic administrations as approaches to combat obesity and comorbidities. Notably, human data are scarce, which highlights the necessity for further human research to investigate acetate's role in host physiology, metabolic, and cardiovascular health.
Topics: Acetic Acid; Animals; Appetite; Blood Glucose; Body Weight; Colon; Cytokines; Dietary Fiber; Energy Metabolism; Fatty Acids, Volatile; Gastrointestinal Hormones; Gastrointestinal Microbiome; Humans; Insulin; Insulin Resistance; Lipid Metabolism; Obesity; Probiotics
PubMed: 31426593
DOI: 10.3390/nu11081943 -
Clinical Nutrition (Edinburgh, Scotland) Feb 2023Butyrate is a key energy source for colonocytes and is produced by the gut microbiota through fermentation of dietary fiber. Butyrate is a histone deacetylase inhibitor... (Review)
Review
Butyrate is a key energy source for colonocytes and is produced by the gut microbiota through fermentation of dietary fiber. Butyrate is a histone deacetylase inhibitor and also signals through three G-protein coupled receptors. It is clear that butyrate has an important role in gastrointestinal health and that butyrate levels can impact both host and microbial functions that are intimately coupled with each other. Maintaining optimal butyrate levels improves gastrointestinal health in animal models by supporting colonocyte function, decreasing inflammation, maintaining the gut barrier, and promoting a healthy microbiome. Butyrate has also shown protective actions in the context of intestinal diseases such as inflammatory bowel disease, graft-versus-host disease of the gastrointestinal tract, and colon cancer, whereas lower levels of butyrate and/or the microbes which are responsible for producing this metabolite are associated with disease and poorer health outcomes. However, clinical efforts to increase butyrate levels in humans and reverse these negative outcomes have generated mixed results. This article discusses our current understanding of the molecular mechanisms of butyrate action with a focus on the gastrointestinal system, the links between host and microbial factors, and the efforts that are currently underway to apply the knowledge gained from the bench to bedside.
Topics: Animals; Humans; Butyrates; Colonic Neoplasms; Dietary Fiber; Gastrointestinal Diseases; Receptors, G-Protein-Coupled; Gastrointestinal Microbiome
PubMed: 36502573
DOI: 10.1016/j.clnu.2022.10.024 -
Nutrients Jun 2022There is an increasing interest in investigating dietary strategies able to modulate the gut microbial ecosystem which, in turn, may play a key role in human health.... (Review)
Review
There is an increasing interest in investigating dietary strategies able to modulate the gut microbial ecosystem which, in turn, may play a key role in human health. Dietary fibers (DFs) are widely recognized as molecules with prebiotic effects. The main objective of this systematic review was to: (i) analyze the results available on the impact of DF intervention on short chain fatty acids (SCFAs) production; (ii) evaluate the interplay between the type of DF intervention, the gut microbiota composition and its metabolic activities, and any other health associated outcome evaluated in the host. To this aim, initially, a comprehensive database of literature on human intervention studies assessing the effect of confirmed and candidate prebiotics on the microbial ecosystem was developed. Subsequently, studies performed on DFs and analyzing at least the impact on SCFA levels were extracted from the database. A total of 44 studies from 42 manuscripts were selected for the analysis. Among the different types of fiber, inulin was the DF investigated the most ( = 11). Regarding the results obtained on the ability of fiber to modulate total SCFAs, seven studies reported a significant increase, while no significant changes were reported in five studies, depending on the analytical methodology used. A total of 26 studies did not show significant differences in individual SCFAs, while the others reported significant differences for one or more SCFAs. The effect of DF interventions on the SCFA profile seemed to be strictly dependent on the dose and the type and structure of DFs. Overall, these results underline that, although affecting microbiota composition and derived metabolites, DFs do not produce univocal significant increase in SCFA levels in apparently healthy adults. In this regard, several factors (i.e., related to the study protocols and analytical methods) have been identified that could have affected the results obtained in the studies evaluated. Future studies are needed to better elucidate the relationship between DFs and gut microbiota in terms of SCFA production and impact on health-related markers.
Topics: Adult; Dietary Fiber; Fatty Acids, Volatile; Gastrointestinal Microbiome; Humans; Microbiota; Prebiotics
PubMed: 35807739
DOI: 10.3390/nu14132559 -
Mucosal Immunology May 2022Barrier integrity is central to the maintenance of healthy immunological homeostasis. Impaired skin barrier function is linked with enhanced allergen sensitization and...
Barrier integrity is central to the maintenance of healthy immunological homeostasis. Impaired skin barrier function is linked with enhanced allergen sensitization and the development of diseases such as atopic dermatitis (AD), which can precede the development of other allergic disorders, for example, food allergies and asthma. Epidemiological evidence indicates that children suffering from allergies have lower levels of dietary fibre-derived short-chain fatty acids (SCFA). Using an experimental model of AD-like skin inflammation, we report that a fermentable fibre-rich diet alleviates systemic allergen sensitization and disease severity. The gut-skin axis underpins this phenomenon through SCFA production, particularly butyrate, which strengthens skin barrier function by altering mitochondrial metabolism of epidermal keratinocytes and the production of key structural components. Our results demonstrate that dietary fibre and SCFA improve epidermal barrier integrity, ultimately limiting early allergen sensitization and disease development.The Graphical Abstract was designed using Servier Medical Art images ( https://smart.servier.com ).
Topics: Allergens; Child; Dermatitis, Atopic; Dietary Fiber; Fatty Acids, Volatile; Food Hypersensitivity; Humans; Keratinocytes
PubMed: 35672452
DOI: 10.1038/s41385-022-00524-9 -
Food Chemistry May 2024Dietary fiber (DF) was established as a key dietary constituent some decades ago, as were some of its mechanisms of action and health effects. Although there is... (Review)
Review
Dietary fiber (DF) was established as a key dietary constituent some decades ago, as were some of its mechanisms of action and health effects. Although there is consolidated evidence on many features regarding DF, at the same time there are still many aspects to be explored in the field, e.g., deeper explorations of the contribution of phenolic compounds linked to cell walls to the biological activities of DF, or of the relevance of the gut-brain axis. At the same time, increasing DF intake should be seen as a major public health problem since worldwide intakes are quite far from recommendations. The awareness of this fact by public bodies should lead, among others, to the assessment of effective strategies for promoting DF intake among general population or specific groups; and to consider potential regulatory modifications in order to clarify several aspects potentially misleading for consumers.
Topics: Humans; Dietary Fiber; Diet; Phenols; Public Health
PubMed: 38039615
DOI: 10.1016/j.foodchem.2023.138076 -
Gut Feb 2023Dietary fibres are essential for maintaining microbial diversity and the gut microbiota can modulate host physiology by metabolising the fibres. Here, we investigated...
OBJECTIVE
Dietary fibres are essential for maintaining microbial diversity and the gut microbiota can modulate host physiology by metabolising the fibres. Here, we investigated whether the soluble dietary fibre oligofructose improves host metabolism by modulating bacterial transformation of secondary bile acids in mice fed western-style diet.
DESIGN
To assess the impact of dietary fibre supplementation on bile acid transformation by gut bacteria, we fed conventional wild-type and TGR5 knockout mice western-style diet enriched or not with cellulose or oligofructose. In addition, we used germ-free mice and in vitro cultures to evaluate the activity of bacteria to transform bile acids in the caecal content of mice fed with western-style diet enriched with oligofructose. Finally, we treated wild-type and TGR5 knockout mice orally with hyodeoxycholic acid to assess its antidiabetic effects.
RESULTS
We show that oligofructose sustains the production of 6α-hydroxylated bile acids from primary bile acids by gut bacteria when fed western-style diet. Mechanistically, we demonstrated that the effects of oligofructose on 6α-hydroxylated bile acids were microbiota dependent and specifically required functional TGR5 signalling to reduce body weight gain and improve glucose metabolism. Furthermore, we show that the 6α-hydroxylated bile acid hyodeoxycholic acid stimulates TGR5 signalling, in vitro and in vivo, and increases GLP-1R activity to improve host glucose metabolism.
CONCLUSION
Modulation of the gut microbiota with oligofructose enriches bacteria involved in 6α-hydroxylated bile acid production and leads to TGR5-GLP1R axis activation to improve body weight and metabolism under western-style diet feeding in mice.
Topics: Animals; Mice; Bile Acids and Salts; Body Weight; Dietary Supplements; Glucose; Mice, Inbred C57BL; Mice, Knockout; Receptors, G-Protein-Coupled; Dietary Fiber; Gastrointestinal Microbiome; Diet, Western
PubMed: 35697422
DOI: 10.1136/gutjnl-2021-326541 -
Nutrition Reviews May 2022Chronic obstructive lung disease (COPD) is a progressive lung disease characterized by persistent airflow limitation. An increasing amount of evidence suggests an effect...
CONTEXT
Chronic obstructive lung disease (COPD) is a progressive lung disease characterized by persistent airflow limitation. An increasing amount of evidence suggests an effect of dietary quality on the risk of COPD in the general population and pulmonary function decline in patients with COPD.
OBJECTIVE
The association of dietary intake and nutrient status with COPD risk and onset, as well as pulmonary function decline (change in forced expiratory volume in 1 second, forced vital capacity, or the ratio of the former to the latter) in patients with COPD was investigated in this systematic review.
DATA SOURCES
The PubMed database was searched by combining terms of pulmonary function or COPD with diet, nutrient status, or nutritional supplementation.
DATA EXTRACTION
Original studies and systematic reviews and meta-analyses were included. Articles obtained were independently screened for relevance on the bases of title and abstract by 2 researchers. Eventually, 89 articles were included in the analysis.
RESULTS
The unhealthy Western-style diet is associated with an increased risk of COPD and an accelerated decline of pulmonary function. Intake of fruit, vegetables, dietary fibers, vitamins C and E, polyphenols, and β-carotene were individually associated with lower COPD risk, whereas consumption of processed meat was associated with higher COPD risk. Data on the effect of dietary quality on pulmonary function decline in patients with COPD are limited and inconsistent. Strong evidence for beneficial effects on pulmonary function decline was found only for vitamin D supplementation.
CONCLUSION
Considering the increasing burden of COPD, more attention should be given to dietary quality as a modifiable factor in disease development and progression in patients with COPD.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO registration no. CRD42021240183.
Topics: Diet; Dietary Fiber; Forced Expiratory Volume; Humans; Pulmonary Disease, Chronic Obstructive; Vitamins
PubMed: 34537848
DOI: 10.1093/nutrit/nuab077 -
Journal of the American Veterinary... Oct 2022Dietary fiber describes a diverse assortment of nondigestible carbohydrates that play a vital role in the health of animals and maintenance of gastrointestinal tract...
Dietary fiber describes a diverse assortment of nondigestible carbohydrates that play a vital role in the health of animals and maintenance of gastrointestinal tract homeostasis. The main roles dietary fiber play in the gastrointestinal tract include physically altering the digesta, modulating appetite and satiety, regulating digestion, and acting as a microbial energy source through fermentation. These functions can have widespread systemic effects. Fiber is a vital component of nearly all commercial canine and feline diets. Key features of fiber types, such as fermentability, solubility, and viscosity, have been shown to have clinical implications as well as health benefits in dogs and cats. Practitioners should know how to evaluate a diet for fiber content and the current knowledge on fiber supplementation as it relates to common enteropathies including acute diarrhea, chronic diarrhea, constipation, and hairball management. Understanding the fundamentals of dietary fiber allows the practicing clinician to use fiber optimally as a management modality.
Topics: Cats; Dogs; Animals; Cat Diseases; Digestion; Dog Diseases; Dietary Fiber; Diet; Gastrointestinal Diseases; Diarrhea; Animal Feed
PubMed: 36288203
DOI: 10.2460/javma.22.08.0351 -
BMJ Open Gastroenterology Aug 2020A diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) is an effective way to reduce gut symptoms in people with irritable bowel... (Randomized Controlled Trial)
Randomized Controlled Trial
Does Fibre-fix provided to people with irritable bowel syndrome who are consuming a low FODMAP diet improve their gut health, gut microbiome, sleep and mental health? A double-blinded, randomised controlled trial.
INTRODUCTION
A diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) is an effective way to reduce gut symptoms in people with irritable bowel syndrome (IBS). This diet reduces the intake of fermentable fibres, leading to changes of the gut microbiota and insufficient fermentation in the large bowel, resulting in reduced production of short-chain fatty acids (SCFAs), such as butyrate, which has unfavourable implications for gut health, sleep and mental health. This study will examine the effect of Fibre-fix, a supplement containing a mix of dietary fibres, on the human gut microbiome composition, fermentative capacity, sleep, quality of life (QOL) and mental health of people with IBS who consume a low FODMAP diet (LFD).
METHODS AND ANALYSIS
A randomised, double-blind, placebo-controlled, study design is proposed to examine whether Fibre-fix added to an existing LFD may help modulate gastrointestinal function, improve markers of sleep, mental health and promote QOL in patients with IBS. Participants will provide stool and blood samples, daily bowel symptoms diaries and 3-day diet records. Additionally, they will complete validated questionnaires relating to FODMAP intake, sleep, mental health and QOL before and after a 3-week intervention. Gut health will be assessed via faecal microbiome composition, faecal pH and SCFA levels. Alteration of sleep will be recorded using an actigraphy device worn by all participants over the whole study. Multivariate analysis will be used to examine the gut microbiome and repeated measures Analysis of variance (ANOVA) will be used for dependent variables from questionnaires related to bowel symptoms, stool type, sleep, mental health and QOL to assess the differences between intervention and control groups after adjustment for confounding variables.
ETHICS AND DISSEMINATION
Ethics approval was obtained from the Human Research Ethics Committee of Edith Cowan University (2019-00619-YAN). Results will be disseminated in peer-review journal publications, and conference presentations. Participants will be provided with a summary of findings once the study is completed. If Fibre-fix is shown to result in favourable changes in gut microbial composition, SCFA production, sleep and mental well-being without exacerbating symptoms, this will provide additional dietary management options for those with IBS following an LFD.
TRIAL REGISTRATION NUMBER
ACTRN12620000032954.
Topics: Adult; Aged; Case-Control Studies; Dietary Fiber; Disaccharides; Double-Blind Method; Fatty Acids, Volatile; Feces; Female; Fermentation; Gastrointestinal Diseases; Gastrointestinal Microbiome; Humans; Irritable Bowel Syndrome; Male; Mental Health; Middle Aged; Monosaccharides; Oligosaccharides; Outcome Assessment, Health Care; Polymers; Quality of Life; Sleep; Surveys and Questionnaires
PubMed: 32816830
DOI: 10.1136/bmjgast-2020-000448 -
Nutrients Oct 2023Grains are widely consumed all over the world, providing calories, macronutrients, micronutrients, dietary fiber, minerals, and plenty of phytochemicals [...].
Grains are widely consumed all over the world, providing calories, macronutrients, micronutrients, dietary fiber, minerals, and plenty of phytochemicals [...].
Topics: Humans; Edible Grain; Nutritional Status; Energy Intake; Dietary Fiber; Cardiovascular Diseases; Diet
PubMed: 37960258
DOI: 10.3390/nu15214605