Branched short-chain fatty acids modulate glucose and lipid metabolism in primary adipocytes

Gut microbiome and function are altered for individuals living in high fluoride concentration areas in Pakistan

BACKGROUND

Endemic fluorosis refers to the condition when individuals are exposed to excessive amounts of fluoride ion due to living in a region characterized by elevated levels of fluorine in the drinking water, food, and/or air. In Pakistan, a substantial proportion of the population is thereby affected, posing a public health concern.

OBJECTIVES

Assessing how the gut microbiota and its metabolic profiles are impacted by chronic exposure to fluoride in drinking water (that caused Dental Fluorosis) as well as to perceive how this microbiota is connected to adverse health outcomes prevailing with fluoride exposure.

METHODS

Drinking water (n=27) and biological samples (n=100) of blood, urine and feces were collected from 70 high fluoride exposed (with Dental Fluorosis) and 30 healthy control (without Dental Fluorosis) subjects. Water and urinary fluoride concentrations were determined. Serum/plasma biochemical testing was performed. Fecal DNA extraction, 16S rRNA analysis of microbial taxa, their predicted metabolic function and fecal short chain fatty acids (SCFAs) quantification were carried out.

RESULTS

The study revealed that microbiota taxonomic shifts and their metabolic characterization had been linked to certain host clinical parameters under the chronic fluoride exposure. Some sets of genera showed strong specificity to water and urine fluoride concentrations, Relative Fat Mass index and SCFAs. The SCFAs response in fluoride-exposed samples was observed to be correlated with bacterial taxa that could contribute to adverse health effects.

CONCLUSIONS

Microbial dysbiosis as a result of endemic fluorosis exhibits a structure that is associated with risk of metabolic deregulation and is implicated in various diseases. Our results may form the development of novel interventions and may have utility in diagnosis and monitoring.

Intestinal-level anti-inflammatory bioactivities of whole wheat: Rationale, design, and methods of a randomized, controlled, crossover dietary trial in adults with prediabetes

Randomized controlled trials (RCT) demonstrate that whole wheat consumption improves glycemia. However, substantial inter-individual variation is often observed, highlighting that dietary whole grain recommendations may not support the health of all persons. The objective of this report is to describe the rationale and design of a planned RCT aimed at establishing the gut microbiota and metabolome signatures that predict whole wheat-mediated improvements in glucose tolerance in adults with prediabetes. It is hypothesized that a controlled diet containing wheat bread (WHEAT; 160 g/day) compared with refined bread (WHITE) will improve glucose tolerance in a gut microbiota-mediated manner. Biospecimens will be collected before and after each 2-week study arm. Testing for oral glucose tolerance and gastrointestinal permeability will be performed post-intervention. Assessments will include oral glucose tolerance (primary outcome) and secondary outcomes including gut microbiota, targeted and untargeted metabolomics of fecal and plasma samples, intestinal and host inflammatory responses, and intestinal permeability. WHEAT is predicted to alleviate glucose intolerance by shifting microbiota composition to increase short-chain fatty acid-producing bacteria while reducing populations implicated in intestinal inflammation, barrier dysfunction, and systemic endotoxemia. Further, benefits from WHEAT are anticipated to correlate with gut-level and systemic metabolomic responses that can help to explain the expected inter-individual variability in glucose tolerance. Thus, knowledge gained from integrating multi-omic responses associating with glucose tolerance could help to establish a precision nutrition-based framework that can alleviate cardiometabolic risk. This framework could inform novel dietary whole grain recommendations by enhancing our understanding of inter-individual responsiveness to whole grain consumption.

Food-breastmilk combinations alter the colonic microbiome of weaning infants: an in silico study

The introduction of solid foods to infants, also known as weaning, is a critical point for the development of the complex microbial community inhabiting the human colon, impacting host physiology in infancy and later in life. This research investigated in silico the impact of food-breastmilk combinations on growth and metabolite production by colonic microbes of New Zealand weaning infants using the metagenome-scale metabolic model named Microbial Community. Eighty-nine foods were individually combined with breastmilk, and the 12 combinations with the strongest influence on the microbial production of short-chain fatty acids (SCFAs) and branched-chain fatty acids (BCFAs) were identified. Fiber-rich and polyphenol-rich foods, like pumpkin and blackcurrant, resulted in the greatest increase in predicted fluxes of total SCFAs and individual fluxes of propionate and acetate when combined, respectively, with breastmilk. Identified foods were further combined with other foods and breastmilk, resulting in 66 multiple food-breastmilk combinations. These combinations altered in silico the impact of individual foods on the microbial production of SCFAs and BCFAs, suggesting that the interaction between the dietary compounds composing a meal is the key factor influencing colonic microbes. Blackcurrant combined with other foods and breastmilk promoted the greatest increase in the production of acetate and total SCFAs, while pork combined with other foods and breastmilk decreased the production of total BCFAs.IMPORTANCELittle is known about the influence of complementary foods on the colonic microbiome of weaning infants. Traditional in vitro and in vivo microbiome methods are limited by their resource-consuming concerns. Modeling approaches represent a promising complementary tool to provide insights into the behavior of microbial communities. This study evaluated how foods combined with other foods and human milk affect the production of short-chain fatty acids and branched-chain fatty acids by colonic microbes of weaning infants using a rapid and inexpensive in silico approach. Foods and food combinations identified here are candidates for future experimental investigations, helping to fill a crucial knowledge gap in infant nutrition.

Macleaya cordata extract exhibits some potential as a surrogate antibiotic by improving gastrointestinal epithelial status and humoral response in goats

Macleaya cordata extract (MCE) is a potential replacement for antibiotics. In the current study, effects of MCE on the gastrointestinal health and humoral responses of host animals were explored. A total of 30 weanling goats with similar body weight of 9.15 ± 1.36 kg were randomly allocated into three groups (n = 10 per group): control group (CON group, fed with a basal diet), antibiotic group (Abx group, fed with the basal diet supplemented with 0.18 g/d vancomycin and 0.36 g/d neomycin), and MCE group (fed with the basal diet supplemented with 5 g/d MCE), for three weeks. Results showed that antibiotic addition decreased the height and area of rumen papillae, ruminal mucosa Toll-like receptor 8 (TLR8), interleukin-8 (IL-8) and interleukin-1β (IL-1β) gene relative expression levels and microbial diversity, altered the volatile fatty acid (VFA) profile in the rumen, and increased monocytes amount and CD4+ T cells percentage in the peripheral blood (P < 0.05) compared to CON group. MCE addition increased the average daily gain, ileal villus height, villus height/crypt depth, and immunoglobulin M (IgM) content in the peripheral blood (P < 0.05) compared to the CON. Additionally, MCE addition decreased the proportion of isobutyric acid in the chyme of the ileum (P = 0.005) compared to the CON group. These results suggest that antibiotic supplementation may suppress the epithelial state and microbial diversity and fermentation in goats, but stimulate cellular response to maintain the growth performance of goats. MCE administration improved the epithelial state and humoral response to promote the growth performance in goats.

Effect of green banana and pineapple fibre powder consumption on host gut microbiome

Purpose

To determine whether green banana powder (GBP) and pineapple fibre powder (PFP) promote beneficial bacterial species, directly improve human gut health and modulate the gut microbiome and understand their utility as functional foods and dietary supplements.

Methods

Over 14 days, 60 adults followed protocol requirements, completed food diaries and study questionnaires, avoided consuming supplements with prebiotics, probiotics or postbiotics, and ingested food containing 5 g of total daily fibre [placebo (10.75 g), GBP (10.75 g) or PFP (7.41 g)]. Participants' medical and baseline wellness histories, as well as stool samples, were collected at baseline, day 7 and 14. Stool DNA was processed for sequencing.

Results

Dietary fibre and resistant starches (RS) in GBP and PFP promoted temporal increases in beneficial bacteria. GBP significantly elevated 7 species (F. prausnitzii, B. longum, B. bifidum, B. adolescentis, B. pseudocatenulatum, B. obeum, and R. inulinivorans), while PFP enriched 6 species (B. ovatus, B. cellulosilyticus, B. bifidum, B. intestinalis, R. inulinivorans, and E. siraeum). These bacteria, found to be deficient in younger adults, were promoted by both powders. PFP benefitted both genders aged 16-23, while GBP benefitted overweight/obese individuals, including females. GBP and PFP fiber and RS improved bowel regularity and health as well as metabolism by promoting histidine, branched-chain amino acids, short-chain fatty acids, and biotin production. The additional fiber caused "low" bloatedness and reduced "fairly bad" sleep disruptions, without affecting sleep durations.

Conclusion

GBP and PFP supplementation increased beneficial bacteria and metabolites, improved host gut health, and present a valuable nutritional strategy for enhancing human health.

Clinical trial registration

AMILI Institutional Review Board, Identifier 2023/0301.

The role of fiber in modulating plant protein-induced metabolic responses

The rising consumption of plant protein foods and the emergence of meat alternatives have prompted interest in the health benefits of such products, which contain fiber in addition to protein. This review investigates the effect of fiber on plant-based protein metabolism and evaluates its contribution to gut-derived health impacts. Plant proteins, which often come with added fiber, can have varying health outcomes. Factors such as processing and the presence of fiber and starch influence the digestibility of plant proteins, potentially leading to increased proteolytic fermentation in the gut and the production of harmful metabolites. However, fermentable fiber can counteract this effect by serving as a primary substrate for gut microbes, decreasing proteolytic activity. The increased amount of fiber, rather than the protein source itself, plays a significant role in the observed health benefits of plant-based diets in human studies. Differences between extrinsic and intrinsic fiber in the food matrix further impact protein fermentation and digestibility. Thus, in novel protein products without naturally occurring fiber, the health impact may differ from conventional plant protein sources. The influence of various fibers on plant-based protein metabolism throughout the gastrointestinal tract is not fully understood, necessitating further research.

Gubra Amylin-NASH Diet Induced Nonalcoholic Fatty Liver Disease Associated with Histological Damage, Oxidative Stress, Immune Disorders, Gut Microbiota, and Its Metabolic Dysbiosis in Colon

SCOPE

The overall changes of colon under nonalcoholic fatty liver disease (NAFLD) remain to be further elucidated.

METHODS AND RESULTS

This study establishes a mouse model of NAFLD through a long-term Gubra Amylin-nonalcoholic steatohepatitis (NASH) diet (GAN diet). The results show that GAN diet significantly induces weight gain, liver steatosis, colonic oxidative stress, and lipid accumulation in blood, liver, and adipose tissue in mice. GAN feeding reduces the diversity of the gut microbiota, alters the composition and abundance of the gut microbiota, and leads to an increase in microbial metabolites such as long-chain fatty acids (LCFAs) and secondary bile acids (BAs), as well as a decrease in short-chain fatty acids (SCFAs). The RNA-seq and immunofluorescence results reveal that the GAN diet alters the expression of proteins and their coding genes involved in oxidative stress, immune response, and barrier function in colon tissue, such as lipocalin-2 (Lcn2, p < 0.05), heme oxygenase-1 (HO-1/Hmox1, p < 0.05), interferon-gamma (IFN-γ), and claudin-3/7. In addition, correlation analysis indicates a strong correlation between the changes in gut microbiota and lipid biomarkers. Additionally, the expression of immune related genes in colon tissue is related to the LCFAs produced by microbial metabolism.

CONCLUSION

GAN-induced NAFLD is related to microbiota and its metabolic imbalance, oxidative stress, immune disorders, and impaired barrier function in colon.

Food and human health applications of edible mushroom by-products

Mushroom waste can account for up to 50% of the total mushroom mass. Spent mushroom substrate, misshapen mushrooms, and mushroom stems are examples of mushroom byproducts. In ancient cultures, fungi were prized for their medicinal properties. Aqueous extracts containing high levels of β-glucans as functional components capable of providing prebiotic polysaccharides and improved texture to foods have been widely used and new methods have been tested to improve extraction yields. Similarly, the addition of insoluble polysaccharides controls the glycemic index, counteracting the effects of increasingly high-calorie diets. Numerous studies support these benefits in vitro, but evidence in vivo is scarce. Nonetheless, many authors have created a variety of functional foods, ranging from yogurt to noodles. In this review, we focus on the pharmacological properties of edible mushroom by-products, and the possible risks derived from its consumption. By incorporating these by-products into human or animal feed formulations, mushroom producers will be able to fully optimize crop use and pave the way for the industry to move toward a zero-waste paradigm.

Impact of a Fruit-Vegetable Preparation Fortified with Potato Starch Resistant Dextrin on Selected Health Indicators in Overweight Children

Developing modified dietary fibers that maintain prebiotic benefits without significantly affecting meal taste is of high importance in the midst of the obesity pandemic. These benefits include regulating the composition of gut microbiota, increasing feelings of fullness, and improving human metabolic parameters. This study investigated the use of a resistant dextrin (RD) derived from potato starch, which possesses prebiotic properties, as a potential additive in vegetable-fruit preparations that aid weight loss and improve health markers in overweight children. HPLC was employed to examine metabolites like lactic acid, short-chain fatty acids (SCFAs; formic, acetic, propionic, butyric, and valeric acids), and branched-chain fatty acids (BCFAs; isobutyric and isovaleric acids). The activities of α-glucosidase, β-glucosidase, α-galactosidase, β-galactosidase, and β-glucuronidase enzymes in fecal samples were measured using spectrophotometric analysis at a wavelength of 400 nm. Incorporating the RD into vegetable-fruit preparations yielded favorable outcomes in terms of increased concentrations of the tested metabolites (SCFAs and BCFAs) and enhanced fecal enzyme activities after 6 months of consuming the preparations. Furthermore, these effects were found to last for an extended period of 3 months even after discontinuing the treatment. The study has shown that including RD into vegetable-fruit preparations enhances the metabolic parameters of obese and overweight children, hence providing a strong rationale for the widespread usage of these preparations in the industry.

Disrupted Microbiota of Colon Results in Worse Immunity and Metabolism in Low-Birth-Weight Jinhua Newborn Piglets

The Jinhua pig is well known in China due to its delicious meat. However, because of large litter size, low birth weight always happens. This experiment used this breed as a model to research bacterial evidence leading to growth restriction and provide a possible solution linked to probiotics. In this experiment, the differences in organs indexes, colonic morphology, short chain fatty acid (SCFA) concentrations, microbiome, and transcriptome were detected between piglets in the standard-birth-weight group (SG) and low-birth-weight group (LG) to find potential evidence leading to low birth weight. We found that LG piglets had a lower liver index (p < 0.05), deeper colonic crypt depth (p < 0.05), fewer goblet cells (p < 0.05), and more inflammatory factor infiltration. In addition, differentially expressed genes (DEGs) were mainly enriched in B-cell immunity and glucose metabolism, and LG piglets had lower concentrations of SCFAs, especially butyrate and isobutyrate (p < 0.05). Finally, most of the significantly differentially abundant microbes were fewer in LG piglets, which affected DEG expressions and SCFA concentrations further resulting in worse energy metabolism and immunity. In conclusion, colonic disrupted microbiota may cause worse glucose metabolism, immunity, and SCFA production in LG piglets, and beneficial microbes colonized in SG piglets may benefit these harmful changes.

Donepezil ameliorates gut barrier disruption in doxorubicin-treated rats

An impact of donepezil against doxorubicin-induced gut barrier disruption and gut dysbiosis has never been investigated. Twenty-four male Wistar rats were divided into three groups. Each group was treated with either vehicle as a control, doxorubicin, or doxorubicin-cotreated with donepezil. Heart rate variability was assessed to reflect the impact of doxorubicin and donepezil. Then, animals were euthanized, and the ileum and its contents were collected in each case to investigate the gut barrier and gut microbiota, respectively. The microbiota-derived endotoxin, trimethylamine N-oxide (TMAO), and short-chain fatty acids (SCFAs) in the serum were determined. An increase in the sympathetic tone, endotoxins, and TMAO levels with disruption of the gut barrier and a decrease in SCFAs levels were observed in doxorubicin-treated rats. Gut microbiota of doxorubicin-treated rats was significantly different from that of the control group. Donepezil treatment significantly decreased the sympathetic tone, restored the gut barrier, and reduced endotoxin and TMAO levels in doxorubicin-treated rats. Nonetheless, donepezil administration did not alter the gut microbiota profile and levels of SCFAs in doxorubicin-treated rats. Doxorubicin impaired the autonomic balance and the gut barrier, and induced gut dysbiosis, resulting in gut toxicity. Donepezil partially improved the doxorubicin-induced gut toxicity through balancing the autonomic disturbance.

Gut microbiota: a superior operator for dietary phytochemicals to improve atherosclerosis

Mounting evidence implicates the gut microbiota as a possible key susceptibility factor for atherosclerosis (AS). The employment of dietary phytochemicals that strive to target the gut microbiota has gained scientific support for treating AS. This study conducted a general overview of the links between the gut microbiota and AS, and summarized available evidence that dietary phytochemicals improve AS via manipulating gut microbiota. Then, the microbial metabolism of several dietary phytochemicals was summarized, along with a discussion on the metabolites formed and the biotransformation pathways involving key gut bacteria and enzymes. This study additionally focused on the anti-atherosclerotic potential of representative metabolites from dietary phytochemicals, and investigated their underlying molecular mechanisms. In summary, microbiota-dependent dietary phytochemical therapy is a promising strategy for AS management, and knowledge of "phytochemical-microbiota-biotransformation" may be a breakthrough in the search for novel anti-atherogenic agents.

Poly(D,l-lactide-co-glycolide) particles are metabolised by the gut microbiome and elevate short chain fatty acids

The production of short chain fatty acids (SCFAs) by the colonic microbiome has numerous benefits for human health, including maintenance of epithelial barrier function, suppression of colitis, and protection against carcinogenesis. Despite the therapeutic potential, there is currently no optimal approach for elevating the colonic microbiome's synthesis of SCFAs. In this study, poly(D,l-lactide-co-glycolide) (PLGA) was investigated for this application, as it was hypothesised that the colonic microbiota would metabolise PLGA to its lactate monomers, which would promote the resident microbiota's synthesis of SCFAs. Two grades of spray dried PLGA, alongside a lactate bolus control, were screened in an advanced model of the human colon, known as the M-SHIME® system. Whilst the high molecular weight (Mw) grade of PLGA was stable in the presence of the microbiota sourced from three healthy humans, the low Mw PLGA (PLGA 2) was found to be metabolised. This microbial degradation led to sustained release of lactate over 48 h and increased concentrations of the SCFAs propionate and butyrate. Further, microbial synthesis of harmful ammonium was significantly reduced compared to untreated controls. Interestingly, both types of PLGA were found to influence the composition of the luminal and mucosal microbiota in a donor-specific manner. An in vitro model of an inflamed colonic epithelium also showed the polymer to affect the expression of pro- and anti-inflammatory markers, such as interleukins 8 and 10. The findings of this study reveal PLGA's sensitivity to enzymatic metabolism in the gut, which could be harnessed for therapeutic elevation of colonic SCFAs.

Butyrate and iso-butyrate: a new perspective on nutrition prevention of gestational diabetes mellitus

BACKGROUND

Dietary imbalance, such as a lower proportion of complex carbohydrates and a higher protein diet, may contribute to gestational diabetes mellitus (GDM) risks through their metabolisms. However, there is a lack of knowledge regarding the association between butyrate, iso-butyrate, and GDM, which are metabolisms of the two primary nutrients above. This study aimed to clarify the association of butyrate and iso-butyrate with GDM.

METHODS

A nested case-control study was conducted based on the Beijing Birth Cohort Study (BBCS) from 2017 to 2018. Totally, 99 singleton women were involved (GDM: n = 49, control: n = 50). All participants provided blood samples twice (in their first and second trimesters). Gas chromatography-mass spectrometry (GC-MS) was used for butyrate and iso-butyrate detection. Unconditional logistic regression and receiver operating characteristic (ROC) curve analysis were used for statistical analysis.

RESULTS

The results showed that butyrate in the first trimester was negatively correlated with GDM (odds ratio (OR): 0.00, 95% confidential interval (CI): 0.00-0.21, P = 0.008), and iso-butyrate in the second trimester was positively related to GDM (OR: 627.68, 95% CI: 40.51-9724.56, P < 0.001). The ratio (butyrate/iso-butyrate) was negatively associated with GDM, both in the first trimester (OR: 0.00, 95%CI: 0.00-0.05, P < 0.001) and in the second trimester (OR: 0.52, 95% CI: 0.34-0.80, P = 0.003). The area under the curve (AUC) using the ratio in the first trimester combined with clinical risk factors achieved 0.89 (95% CI: 0.83-0.95). Iso-butyrate in the second trimester combined with clinical risk factors achieved an AUC of 0.97 (95% CI: 0.92-1.00).

CONCLUSIONS

High iso-butyrate and low butyrate levels may be associated with an increased risk of GDM. As they are produced through dietary nutrient formation by gut microbiota, further studies on the association of dietary intake and butyrate or iso-butyrate concentration in plasma may help find a novel approach to nutritional intervention for GDM.

Gut-Brain Axis Modulation of Metabolic Disorders: Exploring the Intertwined Neurohumoral Pathways and Therapeutic Prospects

A significant rise in metabolic disorders, frequently brought on by lifestyle choices, is alarming. A wide range of preliminary studies indicates the significance of the gut-brain axis, which regulates bidirectional signaling between the gastrointestinal tract and the cognitive system, and is crucial for regulating host metabolism and cognition. Intimate connections between the brain and the gastrointestinal tract provide a network of neurohumoral transmission that can transmit in both directions. The gut-brain axis successfully establishes that the wellness of the brain is always correlated with the extent to which the gut operates. Research on the gut-brain axis has historically concentrated on how psychological health affects how well the gastrointestinal system works. The latest studies, however, revealed that the gut microbiota interacts with the brain via the gut-brain axis to control phenotypic changes in the brain and in behavior. This study addresses the significance of the gut microbiota, the role of the gut-brain axis in management of various metabolic disorders, the hormonal and neural signaling pathways and the therapeutic treatments available. Its objective is to establish the significance of the gut-brain axis in metabolic disorders accurately and examine the link between the two while evaluating the therapeutic strategies to be incorporated in the future.

Comparison of forages’ digestion levels for different in vitro digestion techniques in horses

BACKGROUND

Forages are widely used in horse diets. Different in vitro techniques are being tried to determine the fermentation levels of forages in the horse digestive tract.

OBJECTIVES

This study aimed to evaluate the digestion levels of four dry forages commonly used in horse nutrition: alfalfa herbage, meadow hay, wheat straw, and Italian ryegrass. In vitro total digestion (TDT), in vitro Sunvold-large intestine digestion (SDT) and in vitro Menke-large intestine digestion (MDT) techniques were compared.

METHODS

The study determined in vitro true dry matter digestion (T-DMD), in vitro true organic matter digestion (T-OMD) and in vitro true neutral detergent fibre digestion (T-NDFD). Additionally, concentrations of straight short-chain fatty acids (SCFAs; acetic acid - AA, propionic acid , butyric acid, and valeric acid ) and branched short-chain fatty acids (BSCFA) were assessed.

RESULTS

The highest in vitro T-DMD, T-OMD and T-NDFD values were determined by the in vitro TDT for the four forages (p < 0.05). In vitro T-DMD and T-OMD values of alfalfa herbage were higher than those of Italian ryegrass, meadow hay and wheat straw in the in vitro TDT (p < 0.001). In addition, in vitro T-DMD and T-OMD values of alfalfa herbage in the in vitro SDT were higher than those of meadow hay and wheat straw (p < 0.001). In the in vitro TDT, the molarity of AA, total SCFA and BSCFA in the digestion fluid of alfalfa herbage was higher than those of other forages (p < 0.05).

CONCLUSION

The in vitro total enzymatic + fermentative digestion technique for horse forages revealed higher values than the in vitro fermentative digestion techniques. In general, the higher the non-structural carbohydrate and crude protein contents in the forage, the higher the results of the in vitro TDT compared to the other techniques.

Quantifying Gut Microbial Short-Chain Fatty Acids and Their Isotopomers in Mechanistic Studies Using a Rapid, Readily Expandable LC-MS Platform

Short-chain fatty acids (SCFAs) comprise the largest group of gut microbial fermentation products. While absorption of most nutrients occurs in the small intestine, indigestible dietary components, such as fiber, reach the colon and are processed by the gut microbiome to produce a wide array of metabolites that influence host physiology. Numerous studies have implicated SCFAs as key modulators of host health, such as in regulating irritable bowel syndrome (IBS). However, robust methods are still required for their detection and quantitation to meet the demands of biological studies probing the complex interplay of the gut-host-health paradigm. In this study, a sensitive, rapid-throughput, and readily expandible UHPLC-QqQ-MS platform using 2-PA derivatization was developed for the quantitation of gut-microbially derived SCFAs, related metabolites, and isotopically labeled homologues. The utility of this platform was then demonstrated by investigating the production of SCFAs in cecal contents from mice feeding studies, human fecal bioreactors, and fecal/bacterial fermentations of isotopically labeled dietary carbohydrates. Overall, the workflow proposed in this study serves as an invaluable tool for the rapidly expanding gut-microbiome and precision nutrition research field.

Revisiting multi-omics-based predictors of the plasma triglyceride response to an omega-3 fatty acid supplementation

Background

The aim of the present study was to identify the metabolomic signature of responders and non-responders to an omega-3 fatty acid (n-3 FA) supplementation, and to test the ability of a multi-omics classifier combining genomic, lipidomic, and metabolomic features to discriminate plasma triglyceride (TG) response phenotypes.

Methods

A total of 208 participants of the Fatty Acid Sensor (FAS). Study took 5 g per day of fish oil, providing 1.9-2.2 g eicosapentaenoic acid (EPA) and 1.1 g docosahexaenoic (DHA) daily over a 6-week period, and were further divided into two subgroups: responders and non-responders, according to the change in plasma TG levels after the supplementation. Changes in plasma levels of 6 short-chain fatty acids (SCFA) and 25 bile acids (BA) during the intervention were compared between subgroups using a linear mixed model, and the impact of SCFAs and BAs on the TG response was tested in a mediation analysis. Genotyping was conducted using the Illumina Human Omni-5 Quad BeadChip. Mass spectrometry was used to quantify plasma TG and cholesterol esters levels, as well as plasma SCFA and BA levels. A classifier was developed and tested within the DIABLO framework, which implements a partial least squares-discriminant analysis to multi-omics analysis. Different classifiers were developed by combining data from genomics, lipidomics, and metabolomics.

Results

Plasma levels of none of the SCFAs or BAs measured before and after the n-3 FA supplementation were significantly different between responders and non-responders. SCFAs but not BAs were marginally relevant in the classification of plasma TG responses. A classifier built by adding plasma SCFAs and lipidomic layers to genomic data was able to even the accuracy of 85% shown by the genomic predictor alone.

Conclusion

These results inform on the marginal relevance of SCFA and BA plasma levels as surrogate measures of gut microbiome in the assessment of the interindividual variability observed in the plasma TG response to an n-3 FA supplementation. Genomic data still represent the best predictor of plasma TG response, and the inclusion of metabolomic data added little to the ability to discriminate the plasma TG response phenotypes.

Resveratrol ameliorates intestinal lipid metabolism through the PPAR signaling pathway in high-fat diet-fed red tilapia (Oreochromis niloticus)

Feeding high-fat (HF) diets has been shown to cause hepatic and intestinal impairment in fish species, but the mode of action, especially the pathways involved in the intestine, has not been determined yet. In this study, the effects of resveratrol (RES) supplementation on the intestinal structure, microbial flora, and fat metabolism in red tilapia (Oreochromis niloticus) were determined. The results showed RES maintained the structural integrity of the intestine and significantly increased the number of goblet cells in the midgut. RES significantly induced interferon (IL)-1β, IL-6, IL-10, and tumor necrosis factor (TNF)-α, serumal and fecal trimetlylamine oxide (TMAO) and lipopolysaccharides (LPS), intestinal acetic acid levels. However, the concentrations of bound bile acids increased in HF-fed red tilapia. Atp5fa1 and Pafah1b3 significantly increased, Pmt and Acss2 significantly decreased, respectively, with RES supplementation, which was alleviated and retained at the same level in the selisistat (EX527) group. While for transcriptome and proteomics results, RES was found to promote fatty acid β-oxidation and arachidonic acid metabolism associated with the peroxisome proliferator-activated receptor (PPAR) signaling pathway. The next validation experiment showed some genes related to apoptosis and fatty acid metabolism pathways were altered by RES supplementation. Namely, sn6, loc100702698, new_14481, and prkaa1 were upregulated, while ffrs1, ap3s1, and loc100705861 were downregulated. RES significantly increased Planctomycetes and Verrucomicrobia while decreased Moonvirus, Citrobacter, and Pseudomonas. Akkermansia and Fusobacterium significantly increased and Aeromonas significantly decreased. Thus, unsaturated fatty acid biosynthesis significantly increased and carbohydrate/energy metabolism decreased. To conclude, RES enabled the body to complete fatty acid β-oxidation and arachidonic acid metabolism, whereas the addition of inhibitors increased the expression of the phagosome transcriptome and reduced fatty acid β-oxidative metabolism.

Biomarkers of Metabolic Adaptation to High Dietary Fats in a Mouse Model of Obesity Resistance

Obesity-resistant (non-responder, NR) phenotypes that exhibit reduced susceptibility to developing obesity despite being exposed to high dietary fat are crucial in exploring the metabolic responses that protect against obesity. Although several efforts have been made to study them in mice and humans, the individual protective mechanisms are poorly understood. In this exploratory study, we used a polygenic C57BL/6J mouse model of diet-induced obesity to show that NR mice developed healthier fat/lean body mass ratios (0.43 ± 0.05) versus the obesity-prone (super-responder, SR) phenotypes (0.69 ± 0.07, p < 0.0001) by upregulating gene expression networks that promote the accumulation of type 2a, fast-twitch, oxidative muscle tissues. This was achieved in part by a metabolic adaptation in the form of blood glucose sparing, thus aggravating glucose tolerance. Resistance to obesity in NR mice was associated with 4.9-fold upregulated mitoferrin 1 (Slc25a37), an essential mitochondrial iron importer. SR mice also showed fecal volatile metabolite signatures of enhanced short-chain fatty acid metabolism, including increases in detrimental methyl formate and ethyl propionate, and these effects were reversed in NR mice. Continued research into obesity-resistant phenotypes can offer valuable insights into the underlying mechanisms of obesity and metabolic health, potentially leading to more personalized and effective approaches for managing weight and related health issues.

PNPLA3 Genotype and Dietary Fat Modify Concentrations of Plasma and Fecal Short Chain Fatty Acids and Plasma Branched-Chain Amino Acids

The GG genotype of the Patatin-like phosphatase domain-containing 3 (PNPLA3), dietary fat, short-chain fatty acids (SCFA) and branched-chain amino acids (BCAA) are linked with non-alcoholic fatty liver disease. We studied the impact of the quality of dietary fat on plasma (p) and fecal (f) SCFA and p-BCAA in men homozygous for the PNPLA3 rs738409 variant (I148M). Eighty-eight randomly assigned men (age 67.8 ± 4.3 years, body mass index 27.1 ± 2.5 kg/m2) participated in a 12-week diet intervention. The recommended diet (RD) group followed the National and Nordic nutrition recommendations for fat intake. The average diet (AD) group followed the average fat intake in Finland. The intervention resulted in a decrease in total p-SCFAs and iso-butyric acid in the RD group (p = 0.041 and p = 0.002). Valeric acid (p-VA) increased in participants with the GG genotype regardless of the diet (RD, 3.6 ± 0.6 to 7.0 ± 0.6 µmol/g, p = 0.005 and AD, 3.8 ± 0.3 to 9.7 ± 8.5 µmol/g, p = 0.015). Also, genotype relation to p-VA was seen statistically significantly in the RD group (CC: 3.7 ± 0.4 to 4.2 ± 1.7 µmol/g and GG: 3.6 ± 0.6 to 7.0 ± 0.6 µmol/g, p = 0.0026 for time and p = 0.004 for time and genotype). P-VA, unlike any other SCFA, correlated positively with plasma gamma-glutamyl transferase (r = 0.240, p = 0.025). Total p-BCAAs concentration changed in the AD group comparing PNPLA3 CC and GG genotypes (CC: 612 ± 184 to 532 ± 149 µmol/g and GG: 587 ± 182 to 590 ± 130 µmol/g, p = 0.015 for time). Valine decreased in the RD group (p = 0.009), and leucine decreased in the AD group (p = 0.043). RD decreased total fecal SCFA, acetic acid (f-AA), and butyric acid (f-BA) in those with CC genotype (p = 0.006, 0.013 and 0.005, respectively). Our results suggest that the PNPLA3 genotype modifies the effect of dietary fat modification for p-VA, total f-SCFA, f-AA and f-BA, and total p-BCAA.

The many faces of microbiota-gut-brain axis in autism spectrum disorder

The gut-brain axis is gaining more attention in neurodevelopmental disorders, especially autism spectrum disorder (ASD). Many factors can influence microbiota in early life, including host genetics and perinatal events (infections, mode of birth/delivery, medications, nutritional supply, and environmental stressors). The gut microbiome can influence blood-brain barrier (BBB) permeability, drug bioavailability, and social behaviors. Developing microbiota-based interventions such as probiotics, gastrointestinal (GI) microbiota transplantation, or metabolite supplementation may offer an exciting approach to treating ASD. This review highlights that RNA sequencing, metabolomics, and transcriptomics data are needed to understand how microbial modulators can influence ASD pathophysiology. Due to the substantial clinical heterogeneity of ASD, medical caretakers may be unlikely to develop a broad and effective general gut microbiota modulator. However, dietary modulation followed by administration of microbiota modulators is a promising option for treating ASD-related behavioral and gastrointestinal symptoms. Future work should focus on the accuracy of biomarker tests and developing specific psychobiotic agents tailored towards the gut microbiota seen in ASD patients, which may include developing individualized treatment options.

Dietary isoacids effects on growth, nitrogen, and energy digestibility, and fecal volatile fatty acids and microbial ecology in finishing pigs

Isoacids are branched ketoacids which when fed to ruminants have been shown to enhance the growth of fiber-digesting organisms. Ninety finishing gilts were individually fed dietary treatments consisting of diet type: corn-soybean meal (CSBM), a diet containing 40% distillers dried grains with solubles (DDGS), or a diet containing 40% sugar beet pulp (SBP); in combination with either no feed additive (CNT), the addition of 0.50% isobutyrate (IB), or the addition of a 0.88% mix of isobutyrate, isovalerate, and 2-methylbutyrate (MX). Gilts consumed an average of 2.171 kg/d over the 28-d trial. On d 26, fresh fecal samples were collected for determination of apparent total tract digestibility (ATTD) of gross energy (GE) and nitrogen (N), determination of fecal volatile fatty acids (VFA), and evaluation of microbial ecology. There was no interaction between diet type and isoacid addition, and no main effect of isoacid or diet type on alpha or Shannon microbial diversity measures (P > 0.05). There was no interaction between isoacid addition and diet type, and no main effect of isoacid addition on microbial beta diversity (P > 0.05), but differences were observed in microbial beta diversity due to diet type (P ≤ 0.05). There was no interaction between diet type and isoacid addition observed in fecal VFA concentrations (P > 0.05), with only minor differences in fecal VFA concentrations noted due to isoacid addition (P ≤ 0.05). The interaction between diet type and isoacid addition on ATTD of dietary GE and N (P ≤ 0.01) was large because the addition of IB did not affect the ATTD of GE or N in pigs fed the CSBM diet, but increased ATTD of GE and N in pigs fed diets containing DDGS and decreased the ATTD of GE and N in pigs fed diets containing SBP. In contrast, adding a blend of isoacids (i.e., MX) reduced the ATTD of GE and N, regardless of diet type. There was no interaction between diet type and isoacid addition, and no effect of isoacid addition was observed on pig performance (P > 0.05). Diet type did not affect average daily gain (P > 0.05), but pigs fed diets containing DDGS or SBP consumed less feed (P = 0.01) and exhibited greater GF ratios compared to pigs fed the low-fiber CSBM diet (P ≤ 0.05). In conclusion, there was little to no effect of isoacid addition on microbial ecology, fecal VFA concentrations, ATTD of GE or N, or pig performance, but the improvement in ATTD of GE and N in pigs fed diets containing DDGS when IB was added warrants further investigation.

Rotundic acid alleviates hyperlipidemia in rats by regulating lipid metabolism and gut microbiota

Disturbances in lipid metabolism and dysbiosis of the gut microbiota play an important role in the progression of hyperlipidemia. Previous study indicated that Ilicis Rotundae Cortex possesses anti-hyperlipidemic activity, and rotundic acid (RA) identified as a key active compound to be incorporated into the body. The study aimed to evaluate the anti-hyperlipidemia effects of RA and explored its impact on gut microbiota and lipid metabolism, as well as its possible mechanisms for improving hyperlipidemia. The study methodology included a comprehensive evaluation of the effects of RA on steatosis markers of hyperlipidemia, lipid metabolism, and gut microbiota by assessing biochemical parameters and histopathology, lipidomics, 16S rRNA gene sequencing, and short-chain fatty acid (SCFA) assays. The results showed that RA effectively reduced body weight and the steatosis markers in serum and liver. Moreover, the lipidomic analysis revealed significant changes in plasmatic and hepatic lipid levels, and these were restored by RA. According to the results of 16S rRNA gene sequencing, RA supplementation raised the relative abundance of Bacteroidetes and Proteobacteria while decreasing the relative abundance of Firmicutes. RA significantly boosted the relative abundance of SCFAs by increasing SCFAs-producing bacteria such as Bacteroides, Alloprevotella, Desulfovibrio, etc. In summary, RA could regulate triglyceride metabolism and glycerophospholipid metabolism, restore gut microbiota structure, and increase the relative abundance of SCFAs-producing bacteria to exert its hypolipidemic effects. These findings suggest RA to be a promising therapeutic agent for hyperlipidemia.

Parity modulates impact of BMI and gestational weight gain on gut microbiota in human pregnancy

Dysregulation of maternal adaptations to pregnancy due to high pre-pregnancy BMI (pBMI) or excess gestational weight gain (GWG) is associated with worsened health outcomes for mothers and children. Whether the gut microbiome contributes to these adaptations is unclear. We longitudinally investigated the impact of pBMI and GWG on the pregnant gut microbiome. We show that the gut microbiota of participants with higher pBMI changed less over the course of pregnancy in primiparous but not multiparous participants. This suggests that previous pregnancies may have persistent impacts on maternal adaptations to pregnancy. This ecological memory appears to be passed on to the next generation, as parity modulated the impact of maternal GWG on the infant gut microbiome. This work supports a role of the gut microbiome in maternal adaptations to pregnancy and highlights the need for longitudinal sampling and accounting for parity as key considerations for studies of the microbiome in pregnancy and infants. Understanding how these factors contribute to and shape maternal health is essential for the development of interventions impacting the microbiome, including pre/probiotics.

Green Downstream Processing Method for Xylooligosaccharide Purification and Assessment of Its Prebiotic Properties

Xylooligosaccharides (XOS) obtained from lignocellulosic biomass after autohydrolysis primarily consist of lignin-derived impurities and autogenerated inhibitors like furfural, hydroxymethylfurfural, and acetic acid. In this study, graphene oxide-mediated purification (GOMP), a novel and environmentally friendly downstream processing method, was developed for the purification of XOS from hydrolysate obtained after ozone-assisted autohydrolysis of wheat bran. GOMP resulted in appreciable recovery of total XOS from the hydrolysate (73.87 ± 4.25%, DP2-6) with near complete removal of autogenerated inhibitors (furfural 85.42%, HMF 87.38%, and acetic acid 84.0%). Recovery of XOS by GOMP was higher than the conventional membrane purification technique (44.07 ± 0.92%) and activated charcoal treatment (72.76 ± 0.84%) along with comparatively higher removal of inhibitor compounds. GOMP results in the selective adsorption of inhibitors on the graphene oxide matrix from the XOS-rich hydrolysate, resulting in its purification and concentration. The prebiotic function of the obtained XOS fractions (DP2-4.48%, DP3-39.69%, DP4-36.13%, DP5-8.38%, and DP6-13.10%) was evaluated, indicating the growth stimulation of tested probiotic cultures and differential utilization of XOS oligomers DP3 and DP4 and complete consumption of DP2, DP5, and DP6 along with short-chain fatty acids as a major fermentation product. These findings suggest that GOMP, which employs a common substance (i.e., graphene oxide) used in water treatment, exhibits potential as an efficient and economically viable single-step methodology for XOS purification.

Addition of soluble fiber to standard purified diets is important for gut morphology in mice

Purified diets (PD) increase standardization and repeatability in rodent studies but lead to differences in the phenotype of animals compared to grain-based "chow" diets. PD contain less fiber and are often devoid of soluble fiber, which can impact gut health. Thus, the aim of the present study was to modify the PD AIN93G by addition of soluble fiber, to promote more natural gut development as seen with chow diets. One hundred twenty male C57BL/6J mice were fed over 12 weeks either a chow diet, AIN93G or one of three modified AIN93G with increased fiber content and different ratios of soluble fiber to cellulose. Gut health was assessed through histological and immunohistochemical parameters and gut barrier gene expression. Gut microbiota composition was analyzed and its activity characterized through short chain fatty acid (SCFA) quantification. Feeding AIN93G led to tissue atrophy, a less diverse microbiota and a lower production of SCFA compared to chow diet. The addition of soluble fiber mitigated these effects, leading to intermediate colon and caecum crypt lengths and microbiota composition compared to both control diets. In conclusion, the addition of soluble fibers in PDs seems essential for gut morphology as well as a diverse and functional gut microbiome.

Gut microbiota bridges dietary nutrients and host immunity

Dietary nutrients and the gut microbiota are increasingly recognized to cross-regulate and entrain each other, and thus affect host health and immune-mediated diseases. Here, we systematically review the current understanding linking dietary nutrients to gut microbiota-host immune interactions, emphasizing how this axis might influence host immunity in health and diseases. Of relevance, we highlight that the implications of gut microbiota-targeted dietary intervention could be harnessed in orchestrating a spectrum of immune-associated diseases.

Influence of Brown or Germinated Brown Rice Supplementation on Fecal Short-Chain Fatty Acids and Microbiome in Diet-Induced Insulin-Resistant Mice

Intake of whole grain foods is associated with improving metabolic profile compared to refined grain products, but the underlying mechanism remains unclear. The present study examined the effects of brown rice (BRR) or germinated brown rice (GBR) supplementation on fecal short-chain fatty acids (SCFAs), and relationship with gut microbiota, metabolism and inflammation in high fat (HF)-diet-fed mice. The results demonstrated that an HF diet supplemented with BRR or GBR comparably increased the abundance of fecal isobutyric acid compared to that in mice receiving HF+white rice (WHR) diet (p < 0.01). The abundance of valeric acid in HF+GBR-diet-fed mice was higher than those receiving HF+WHR diet (p < 0.05). The abundances of fecal isobutyric acid negatively correlated with fasting plasma glucose, insulin, cholesterol, triglycerides, tumor necrosis factor-α, plasminogen activator inhibit-1, monocyte chemotactic protein-1 and homeostatic model assessment of insulin resistance (p < 0.01). The abundance of valeric acids negatively correlated with insulin resistance (p < 0.05). The abundances of isobutyric acid positively correlated with Lactobacillus, but negatively correlated with Dubosiella genus bacteria (p < 0.05). The findings demonstrated that the increases in SCFAs in the feces of BRR and GBR-treated mice were associated with improvements in gut microbiome, metabolic and inflammatory profile, which may contribute to the antidiabetic and anti-inflammatory effects of the whole grains in HF-diet-fed mice.

Contribution of the microbiome for better phenotyping of people living with obesity

Obesity has reached epidemic proportion worldwide and in all ages. Available evidence points to a multifactorial pathogenesis involving gene predisposition and environmental factors. Gut microbiota plays a critical role as a major interface between external factors, i.e., diet, lifestyle, toxic chemicals, and internal mechanisms regulating energy and metabolic homeostasis, fat production and storage. A shift in microbiota composition is linked with overweight and obesity, with pathogenic mechanisms involving bacterial products and metabolites (mainly endocannabinoid-related mediators, short-chain fatty acids, bile acids, catabolites of tryptophan, lipopolysaccharides) and subsequent alterations in gut barrier, altered metabolic homeostasis, insulin resistance and chronic, low-grade inflammation. Although animal studies point to the links between an "obesogenic" microbiota and the development of different obesity phenotypes, the translational value of these results in humans is still limited by the heterogeneity among studies, the high variation of gut microbiota over time and the lack of robust longitudinal studies adequately considering inter-individual confounders. Nevertheless, available evidence underscores the existence of several genera predisposing to obesity or, conversely, to lean and metabolically health phenotype (e.g., Akkermansia muciniphila, species from genera Faecalibacterium, Alistipes, Roseburia). Further longitudinal studies using metagenomics, transcriptomics, proteomics, and metabolomics with exact characterization of confounders are needed in this field. Results must confirm that distinct genera and specific microbial-derived metabolites represent effective and precision interventions against overweight and obesity in the long-term.

Metabolic signature of 13C-labeled wheat bran consumption related to gut fermentation in humans: a pilot study

PURPOSE

The aim of this pilot study was to analyze concomitantly the kinetics of production of 13C-labeled gut-derived metabolites from 13C-labeled wheat bran in three biological matrices (breath, plasma, stools), in order to assess differential fermentation profiles among subjects.

METHODS

Six healthy women consumed a controlled breakfast containing 13C-labeled wheat bran biscuits. H2, CH4 and 13CO2, 13CH4 24 h-concentrations in breath were measured, respectively, by gas chromatography (GC) and GC-isotope ratio mass spectrometry (GC-IRMS). Plasma and fecal concentrations of 13C-short-chain fatty acids (linear SCFAs: acetate, propionate, butyrate, valerate; branched SCFAs: isobutyrate, isovalerate) were quantified using GC-combustion-IRMS. Gut microbiota composition was assessed by16S rRNA gene sequencing analysis.

RESULTS

H2 and CH4 24 h-kinetics distinguished two groups in terms of fermentation-related gas excretion: high-CH4 producers vs low-CH4 producers (fasting concentrations: 45.3 ± 13.6 ppm vs 6.5 ± 3.6 ppm). Expired 13CH4 was enhanced and prolonged in high-CH4 producers compared to low-CH4 producers. The proportion of plasma and stool 13C-butyrate tended to be higher in low-CH4 producers, and inversely for 13C-acetate. Plasma branched SCFAs revealed different kinetics of apparition compared to linear SCFAs.

CONCLUSION

This pilot study allowed to consider novel procedures for the development of biomarkers revealing dietary fiber-gut microbiota interactions. The non-invasive assessment of exhaled gas following 13C-labeled fibers ingestion enabled to decipher distinct fermentation profiles: high-CH4 producers vs low-CH4 producers. The isotope labeling permits a specific in vivo characterisation of the dietary fiber impact consumption on microbiota metabolite production.

CLINICAL TRIAL REGISTRATION

The study has been registered under the number NCT03717311 at ClinicalTrials.gov on October 24, 2018.

Effects of different strains fermentation on nutritional functional components and flavor compounds of sweet potato slurry

In this paper, we study the effect of microbial fermentation on the nutrient composition and flavor of sweet potato slurry, different strains of Aspergillus niger, Saccharomyces cerevisiae, Lactobacillus plantarum, Bacillus coagulans, Bacillus subtilis, Lactobacillus acidophilus, and Bifidobacterium brevis were employed to ferment sweet potato slurry. After 48 h of fermentation with different strains (10% inoculation amount), we compared the effects of several strains on the nutritional and functional constituents (protein, soluble dietary fiber, organic acid, soluble sugar, total polyphenol, free amino acid, and sensory characteristics). The results demonstrated that the total sugar level of sweet potato slurry fell significantly after fermentation by various strains, indicating that these strains can utilize the nutritious components of sweet potato slurry for fermentation. The slurry's total protein and phenol concentrations increased significantly, and many strains demonstrated excellent fermentation performance. The pH of the slurry dropped from 6.78 to 3.28 to 5.95 after fermentation. The fermentation broth contained 17 free amino acids, and the change in free amino acid content is closely correlated with the flavor of the sweet potato fermentation slurry. The gas chromatography-mass spectrometry results reveal that microbial fermentation can effectively increase the kinds and concentration of flavor components in sweet potato slurry, enhancing its flavor and flavor profile. The results demonstrated that Aspergillus niger fermentation of sweet potato slurry might greatly enhance protein and total phenolic content, which is crucial in enhancing nutrition. However, Bacillus coagulans fermentation can enhance the concentration of free amino acids in sweet potato slurry by 64.83%, with a significant rise in fresh and sweet amino acids. After fermentation by Bacillus coagulans, the concentration of lactic acid and volatile flavor substances also achieved its highest level, which can considerably enhance its flavor. The above results showed that Aspergillus niger and Bacillus coagulans could be the ideal strains for sweet potato slurry fermentation.

Multiple micronutrient deficiencies alter energy metabolism in host and gut microbiome in an early-life murine model

Introduction

Micronutrients perform a wide range of physiological functions essential for growth and development. However, most people still need to meet the estimated average requirement worldwide. Globally, 2 billion people suffer from micronutrient deficiency, most of which are co-occurring deficiencies in children under age five. Despite decades of research, animal models studying multiple micronutrient deficiencies within the early-life period are lacking, which hinders our complete understanding of the long-term health implications and may contribute to the inefficacy of some nutritional interventions. Evidence supporting the Developmental Origins of Health and Disease (DOHaD) theory demonstrates that early-life nutritional deficiencies carry life-long consequences mediated through various mechanisms such as abnormal metabolic programming, stunting, altered body composition, and the gut microbiome. However, this is largely unexplored in the multiple micronutrient deficient host.

Methods

we developed a preclinical model to examine undernutrition's metabolic and functional impact on the host and gut microbiome early in life. Three-week-old weanling C57BL/6N male mice were fed a low-micronutrient diet deficient in zinc, folate, iron, vitamin A, and vitamin B12 or a control diet for 4-weeks.

Results

Our results showed that early-life multiple micronutrient deficiencies induced stunting, altered body composition, impaired glucose and insulin tolerance, and altered the levels of other micronutrients not depleted in the diet within the host. In addition, functional metagenomics profiling and a carbohydrate fermentation assay showed an increased microbial preference for simple sugars rather than complex ones, suggestive of a less developed microbiome in the low-micronutrient-fed mice. Moreover, we found that a zinc-only deficient diet was not sufficient to induce these phenotypes, further supporting the importance of studying co-occurring deficiencies.

Discussion

Together, these findings highlight a previously unappreciated role of early-life multiple micronutrient deficiencies in shaping the metabolic phenome of the host and gut microbiome through altered glucose energy metabolism, which may have implications for metabolic disease later in life in micronutrient-deficient survivors.

Plasma short-chain fatty acid changes after bariatric surgery in patients with severe obesity

BACKGROUND

Obesity has reached epidemic dimensions in recent decades. Bariatric surgery (BS) is one of the most effective interventions for weight loss and metabolic improvement in patients with obesity. Short-chain fatty acids (SCFA) are gut microbiota-derived metabolites with a key role in body weight control and insulin sensitivity. Although BS is known to induce significant changes in the gut microbiota composition, its impact on the circulating levels of certain metabolites produced by the gut microbiota such as SCFA remains poorly understood.

OBJECTIVE

To determine the impact of BS on the circulating SCFA levels in patients with severe obesity.

SETTING

University hospital.

METHODS

An observational, prospective study was performed on 51 patients undergoing Roux-en-Y gastric bypass. Plasma samples were collected at baseline (1 day before surgery) and at 6 and 12 months after BS. Plasma SCFA levels were determined by liquid chromatography-mass spectrometry.

RESULTS

The results revealed significant changes in the circulating levels of SCFA after BS. A marked increase in propionate, butyrate, isobutyrate, and isovalerate levels and a decrease in acetate, valerate, hexanoate, and heptanoate levels were observed 12 months after BS. Furthermore, the changes in the levels of propionate, butyrate, and isobutyrate negatively correlated with changes in body mass index, while those of isobutyrate correlated negatively with changes in the homeostatic model assessment for insulin resistance index.

CONCLUSION

These results suggest that propionate, butyrate, and isobutyrate levels could be related to weight loss and improved insulin sensitivity in patients with severe obesity after BS.

Maternal microbiota and gestational diabetes: impact on infant health

Gestational diabetes mellitus (GDM) is a common complication of pregnancy that has been associated with an increased risk of obesity and diabetes in the offspring. Pregnancy is accompanied by tightly regulated changes in the endocrine, metabolic, immune, and microbial systems, and deviations from these changes can alter the mother's metabolism resulting in adverse pregnancy outcomes and a negative impact on the health of her infant. Maternal microbiomes are significant drivers of mother and child health outcomes, and many microbial metabolites are likely to influence the host health. This review discusses the current understanding of how the microbiota and microbial metabolites may contribute to the development of GDM and how GDM-associated changes in the maternal microbiome can affect infant's health. We also describe microbiota-based interventions that aim to improve metabolic health and outline future directions for precision medicine research in this emerging field.

Short-Chain Fatty Acids-A Product of the Microbiome and Its Participation in Two-Way Communication on the Microbiome-Host Mammal Line

PURPOSE OF REVIEW

The review aims to describe short-chain fatty acids (SCFAs) as metabolites of bacteria, their complex influence on whole-body metabolism, and alterations in the SCFA profile in obesity and after bariatric surgery (BS).

RECENT FINDINGS

The fecal profile of SCFAs in obese patients differs from that of lean patients, as well as their gut microbiota composition. In obese patients, a lower diversity of bacteria is observed, as well as higher concentrations of SCFAs in stool samples. Obesity is now considered a global epidemic and bariatric surgery (BS) is an effective treatment for severe obesity. BS affects the structure and functioning of the digestive system, and also alters gut microbiota and the concentration of fecal SCFAs. Generally, after BS, SCFA levels are lower but levels of branched short-chain fatty acids (BSCFAs) are elevated, the effect of which is not fully understood. Moreover, changes in the profile of circulating SCFAs are little known and this is an area for further research. Obesity seems to be inherently associated with changes in the SCFA profile. It is necessary to better understand the impact of BS on microbiota and the metabolome in both feces and blood as only a small percentage of SCFAs are excreted. Further research may allow the development of a personalized therapeutic approach to the BS patient in terms of diet and prebiotic intervention.

Gestational diabetes is driven by microbiota-induced inflammation months before diagnosis

OBJECTIVE

Gestational diabetes mellitus (GDM) is a condition in which women without diabetes are diagnosed with glucose intolerance during pregnancy, typically in the second or third trimester. Early diagnosis, along with a better understanding of its pathophysiology during the first trimester of pregnancy, may be effective in reducing incidence and associated short-term and long-term morbidities.

DESIGN

We comprehensively profiled the gut microbiome, metabolome, inflammatory cytokines, nutrition and clinical records of 394 women during the first trimester of pregnancy, before GDM diagnosis. We then built a model that can predict GDM onset weeks before it is typically diagnosed. Further, we demonstrated the role of the microbiome in disease using faecal microbiota transplant (FMT) of first trimester samples from pregnant women across three unique cohorts.

RESULTS

We found elevated levels of proinflammatory cytokines in women who later developed GDM, decreased faecal short-chain fatty acids and altered microbiome. We next confirmed that differences in GDM-associated microbial composition during the first trimester drove inflammation and insulin resistance more than 10 weeks prior to GDM diagnosis using FMT experiments. Following these observations, we used a machine learning approach to predict GDM based on first trimester clinical, microbial and inflammatory markers with high accuracy.

CONCLUSION

GDM onset can be identified in the first trimester of pregnancy, earlier than currently accepted. Furthermore, the gut microbiome appears to play a role in inflammation-induced GDM pathogenesis, with interleukin-6 as a potential contributor to pathogenesis. Potential GDM markers, including microbiota, can serve as targets for early diagnostics and therapeutic intervention leading to prevention.

Monomethyl branched-chain fatty acids: Health effects and biological mechanisms

Branched-chain fatty acids (BCFA) are a group of lipids that are widely present in various organisms; they take part in numerous biochemical processes and affect multiple signaling pathways. However, BCFA are not well explored in terms of their effects on human health. Recently, they have been gaining interest, especially in relation to various human diseases. This review describes the occurrence of BCFA, their dietary sources, their potential health effects, and the current state of knowledge concerning their mechanism(s) of action. Many studies have been conducted so far in cellular and animal models, which reveal potent anti-cancer, lipid lowering, anti-inflammatory and neuroprotective actions. Research in humans is scarce. Therefore, further studies on animals and humans should be performed to confirm and expand these findings, and improve our understanding of the potential relevance of BCFA to human health and disease.

Metabolite interactions between host and microbiota during health and disease: Which feeds the other?

Metabolites produced by the host and microbiota play a crucial role in how human bodies develop and remain healthy. Most of these metabolites are produced by microbiota and hosts in the digestive tract. Metabolites in the gut have important roles in energy metabolism, cellular communication, and host immunity, among other physiological activities. Although numerous host metabolites, such as free fatty acids, amino acids, and vitamins, are found in the intestine, metabolites generated by gut microbiota are equally vital for intestinal homeostasis. Furthermore, microbiota in the gut is the sole source of some metabolites, including short-chain fatty acids (SCFAs). Metabolites produced by microbiota, such as neurotransmitters and hormones, may modulate and significantly affect host metabolism. The gut microbiota is becoming recognized as a second endocrine system. A variety of chronic inflammatory disorders have been linked to aberrant host-microbiota interplays, but the precise mechanisms underpinning these disturbances and how they might lead to diseases remain to be fully elucidated. Microbiome-modulated metabolites are promising targets for new drug discovery due to their endocrine function in various complex disorders. In humans, metabolotherapy for the prevention or treatment of various disorders will be possible if we better understand the metabolic preferences of bacteria and the host in specific tissues and organs. Better disease treatments may be possible with the help of novel complementary therapies that target host or bacterial metabolism. The metabolites, their physiological consequences, and functional mechanisms of the host-microbiota interplays will be highlighted, summarized, and discussed in this overview.

Taiwanese green propolis ameliorates metabolic syndrome via remodeling of white adipose tissue and modulation of gut microbiota in diet-induced obese mice

Excessive energy intake leads to dysbiosis of intestinal microbiota and puts surrounding tissues under oxidative stress and inflammation, contributing to the development of metabolic syndrome. Taiwanese green propolis (TGP) exhibits a broad spectrum of biological activities, including anti-bacterial, anti-inflammatory, and antioxidant properties. However, the benefits of TGP on metabolic syndrome have not been explained in detail. In this study, we examined the preventive effects of TGP on high-fat diet (HFD)-induced obesity. The results showed that TGP supplementation at 1000 ppm improved condition such as hyperlipidemia, fat accumulation, liver steatosis, and whitening of brown adipose tissue (BAT) in mice. In addition, we observed more cold-induced non-shivering thermogenesis by BAT in TGP treatment with 1000 ppm group. At lower dose of 500 ppm, TGP improved glucose intolerance and insulin insensitivity in HFD mice and restructured the composition of gut microbiota to reduce dysbiosis, which involved an increase in the abundance of metabolism-related bacteria such as Lachnospiraceae NK4A136 group and the decrease in Desulfovibrio. The change of dominant microbiota was associated with the homeostasis of blood glucose and lipid. Transcriptome and micro-western array analysis revealed that TGP supplementation at 500 ppm promoted the browning and adipogenesis in white adipose tissue (WAT), blocked inflammation signaling and attenuated reactive oxygen species, contributing to healthy WAT remodeling and offsetting negative metabolic effects of obesity. We concluded that TGP modulated the function of BAT, WAT, and gut microbiota, bringing a balance to the glucose and lipid homeostasis in the body.

Circulating Short-Chain Fatty Acids and Non-Alcoholic Fatty Liver Disease Severity in Patients with Type 2 Diabetes Mellitus

(1) Background: Non-alcoholic fatty liver disease (NAFLD) is a major global health concern. The increasing prevalence of NAFLD has been related to type 2 diabetes mellitus (T2D). However, the relationship between short-chain fatty acids (SCFAs) and NAFLD severity is ambiguous in T2D subjects. This study aimed to explore the association of SCFAs with the severity of NAFLD in T2D patients. (2) Methods: We employed echography to examine the severity of hepatic steatosis. The serum levels of nine SCFAs, namely, formate, acetate, propionate, butyrate, isobutyrate, methylbutyrate, valerate, isovalerate, and methylvalerate, were measured using gas chromatography mass spectrometry. (3) Results: A total of 259 T2D patients was enrolled in this cross-sectional study. Of these participants, 117 with moderate to severe NAFLD had lower levels of formate, isobutyrate, and methylbutyrate than the 142 without NAFLD or with mild NAFLD. Lower circulating levels of isobutyrate and methylbutyrate were associated with an increased severity of NAFLD. A relationship between NAFLD severity and circulating isobutyrate and methylbutyrate levels was found independently of a glycated hemoglobin (HbA1C) level of 7.0%. (4) Conclusion: Circulating levels of isobutyrate and methylbutyrate were significantly and negatively correlated with NAFLD severity in the enrolled T2D patients. SCFAs may be related to NAFLD severity in T2D patients.

Akkermansia muciniphila Cell-Free Supernatant Improves Glucose and Lipid Metabolisms in Caenorhabditis elegans

To explore the mechanism by which Akkermansia muciniphila cell-free supernatant improves glucose and lipid metabolisms in Caenorhabditis elegans, the present study used different dilution concentrations of Akkermansia muciniphila cell-free supernatant as an intervention for with Caenorhabditis elegans under a high-glucose diet. The changes in lifespan, exercise ability, level of free radicals, and characteristic indexes of glucose and lipid metabolisms were studied. Furthermore, the expression of key genes of glucose and lipid metabolisms was detected by qRT-PCR. The results showed that A. muciniphila cell-free supernatant significantly improved the movement ability, prolonged the lifespan, reduced the level of ROS, and alleviated oxidative damage in Caenorhabditis elegans. A. muciniphila cell-free supernatant supported resistance to increases in glucose and triglyceride induced by a high-glucose diet and downregulated the expression of key genes of glucose metabolism, such as gsy-1, pygl-1, pfk-1.1, and pyk-1, while upregulating the expression of key genes of lipid metabolism, such as acs-2, cpt-4, sbp-1, and tph-1, as well as down-regulating the expression of the fat-7 gene to inhibit fatty acid biosynthesis. These findings indicated that A. muciniphila cell-free supernatant, as a postbiotic, has the potential to prevent obesity and improve glucose metabolism disorders and other diseases.

Association of Circulating Branched-Chain Amino Acids with Cardiovascular Diseases: A Mendelian Randomization Study

BACKGROUND

There have been reports linking branched-chain amino acids (BCAAs) to the hazard of various cardiovascular diseases (CVDs); however, the causal role of this relationship is still unclear. We conducted a study using bi-directional two-sample Mendelian randomization (MR) with the aim of investigating the possible causal correlation between BCAAs and 13 types of cardiovascular diseases.

METHODS

The study analyzed data of the largest genome-wide association studies (GWAS) published for the total BCAAs, encompassing isoleucine, leucine, and valine, which were obtained from the UK Biobank, as well as data for 13 cardiovascular endpoints from the MRC-IEU, the FinnGen consortium, and the EBI database. The approach of the primary dissection used became the inverse-variance-weighted (IVW) approach, with additional analyses using the MR-PRESSO global test as well as MR-Egger regression with a view to determining horizontal pleiotropy. Heterogeneity was evaluated by means of Cochran's Q test. The study also conducted logistic regression dissection for the sake of investigating the correlation between cardiovascular events and serum BCAAs in the UK biobank cohort study.

RESULTS

In this study, it was found that individuals with a genetic predisposition to more elevated levels for circulating total BCAAs had a higher hazard of peripheral arterial disease (OR 1.400, 95% CI 1.063, 1.844; p = 0.017) in addition to stroke (OR 1.266, 95% CI 1.012, 1.585; p = 0.039); circulating valine casually increased the risk of intracerebral hemorrhage (OR 1.760, 95% CI 1.116, 2.776; p = 0.015), along with stroke (OR 1.269, 95% CI 1.079, 1.492; p = 0.004); genetically predicted isoleucine showed a positive association with peripheral arterial disease (OR 1.466, 95% CI 1.044, 2.058; p = 0.027), along with cardioembolic stroke (OR 1.547, 95% CI 1.126, 2.124; p = 0.007); furthermore, leucine causally associated with stroke (OR 1.310, 95% CI 1.031, 1.663, p = 0.027). In the UK Biobank cohort study, we detected that total BCAAs (OR: 1.285; 95% CI: 1.009, 1.636), valine (OR: 1.287; 95% CI: 1.009, 1.642), and isoleucine (OR: 1.352; 95% CI: 1.064, 1.718) were independently linked to stroke, but not leucine (OR: 1.146; 95% CI: 0.901, 1.458). No such association was found for BCAAs with peripheral arterial disease and intracerebral hemorrhage in the cohort study.

CONCLUSIONS

In summary, circulating total BCAAs and valine may be causally associated with stroke. The association of BCAAs with other CVD events needs further study.

Industrial and Ruminant Trans-Fatty Acids-Enriched Diets Differentially Modulate the Microbiome and Fecal Metabolites in C57BL/6 Mice

Industrially originated trans-fatty acids (I-tFAs), such as elaidic acid (EA), and ruminant trans-fatty acids (R-tFAs), such as trans-palmitoleic acid (TPA), may have opposite effects on metabolic health. The objective was to compare the effects of consuming 2–3% I-tFA or R-tFA on the gut microbiome and fecal metabolite profile in mice after 7 and 28 days. Forty C57BL/6 mice were assigned to one of the four prepared formulations: lecithin nanovesicles, lecithin nanovesicles with EA or TPA, or water. Fecal samples and animals’ weights were collected on days 0, 7, and 28. Fecal samples were used to determine gut microbiome profiles by 16S rRNA sequencing and metabolite concentrations by GC/MS. At 28 days, TPA intake decreased the abundance of Staphylococcus sp55 but increased Staphylococcus sp119. EA intake also increased the abundance of Staphylococcus sp119 but decreased Ruminococcaceae UCG-014, Lachnospiraceae, and Clostridium sensu stricto 1 at 28 days. Fecal short-chain fatty acids were increased after TPA while decreased after EA after 7 and 28 days. This study shows that TPA and EA modify the abundance of specific microbial taxa and fecal metabolite profiles in distinct ways.

Antimicrobial Peptides Relieve Transportation Stress in Ragdoll Cats by Regulating the Gut Microbiota

Transportation is common in cats and often causes stress and intestinal disorders. Antimicrobial peptides (AMPs) exhibit a broad spectrum of antibacterial activity, and they may have the capacity for antioxidant and immune regulation. The objective of this study was to investigate the effects of dietary supplementation with AMPs on stress response, gut microbiota and metabolites of cats that have undergone transport stress. A total of 14 Ragdoll cats were randomly allocated into 2 treatments: basal diet (CON) and a basal diet supplemented with 0.3% AMPs. After a 6-week feeding period, all cats were transported for 3 h and, then, fed for another week. The results show that the diarrhea rate of cats was markedly reduced by supplementation with AMPs throughout the trial period (p < 0.05). In addition, AMPs significantly reduced serum cortisol and serum amyloid A (p < 0.05) and increased apolipoprotein 1 after transportation (p < 0.05). Moreover, AMPs reduced the level of inflammatory factors in the serum caused by transportation stress, including tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) (p < 0.05). The AMPs enhanced the activities of glutathione peroxidase (p < 0.01) and superoxide dismutase (p < 0.05). Furthermore, cats fed AMPs had higher levels of branched chain fatty acids (BCFAs) and a relative abundance of Blautia and a lower relative abundance of Negativibacillus after transportation (p < 0.05). The serum metabolome analysis further revealed that AMPs markedly regulated lipid metabolism by upregulating cholic acid expression. In conclusion, AMP supplementation alleviated oxidative stress and inflammatory response in transportation by regulating the gut microbiota and metabolites, thereby relieving stress-induced diarrhea and supporting gut and host health in cats.

Virulence Factors of the Gut Microbiome Are Associated with BMI and Metabolic Blood Parameters in Children with Obesity

The development of metabolic diseases is linked to the gut microbiota. A cross-sectional study involving 45 children (6 to 12 years old) was conducted to investigate the relationship between gut microbiota and childhood obesity. Anthropometric and metabolic measurements, food-frequency questionnaires (FFQs), and feces samples were obtained. Using the body mass index (BMI) z-score, we categorized each participant as normal weight (NW), or overweight and obese (OWOB). We determined 2 dietary profiles: one with complex carbohydrates and proteins (pattern 1), and the other with saturated fat and simple carbohydrates (pattern 2). The microbial taxonomic diversity and metabolic capacity were determined using shotgun metagenomics. We found differences between both BMI groups diversity. Taxa contributing to this difference, included Eubacterium sp., Faecalibacterium prausnitzii, Dialister, Monoglobus pectinilyticus, Bifidobacterium pseudocatenulatum, Intestinibacter bartlettii, Bacteroides intestinalis, Bacteroides uniformis, and Methanobrevibacter smithii. Metabolic capacity differences found between NW and OWOB, included the amino acid biosynthesis pathway, the cofactor, carrier, and vitamin biosynthesis pathway, the nucleoside and nucleotide biosynthesis and degradation pathways, the carbohydrate-sugar degradation pathway, and the amine and polyamine biosynthesis pathway. We found significant associations between taxa such as Ruminococcus, Mitsuokella multacida, Klebsiella variicola, and Citrobacter spp., metabolic pathways with the anthropometric, metabolic, and dietary data. We also found the microbiome's lipooligosaccharide (LOS) category as differentially abundant between BMI groups. Metabolic variations emerge during childhood as a result of complex nutritional and microbial interactions, which should be explained in order to prevent metabolic illnesses in adolescence and maturity. IMPORTANCE The alteration of gut microbiome composition has been commonly observed in diseases involving inflammation, such as obesity and metabolic impairment. Inflammatory host response in the gut can be a consequence of dietary driven dysbiosis. This response is conducive to blooms of particular bacterial species, adequate to survive in an inflammatory environment by means of genetical capability of utilizing alternative nutrients. Understanding the genomic and metabolic contribution of microbiota to inflammation, including virulence factor prevalence and functional potential, will contribute to identifying modifiable early life exposures and preventive strategies associated with obesity risk in childhood.

Non-Targeted Metabolomic Profiling Identifies Metabolites with Potential Antimicrobial Activity from an Anaerobic Bacterium Closely Related to Terrisporobacter Species

This work focused on the metabolomic profiling of the conditioned medium (FS03CM) produced by an anaerobic bacterium closely related to Terrisporobacter spp. to identify potential antimicrobial metabolites. The metabolome of the conditioned medium was profiled by two-channel Chemical Isotope Labelling (CIL) LC-MS. The detected metabolites were identified or matched by conducting a library search using different confidence levels. Forty-eight significantly changed metabolites were identified with high confidence after the growth of isolate FS03 in cooked meat glucose starch (CMGS) medium. Some of the secondary metabolites identified with known antimicrobial activities were 4-hydroxyphenyllactate, 3-hydroxyphenylacetic acid, acetic acid, isobutyric acid, valeric acid, and tryptamine. Our findings revealed the presence of different secondary metabolites with previously reported antimicrobial activities and suggested the capability of producing antimicrobial metabolites by the anaerobic bacterium FS03.

Simulated Digestion and Fecal Fermentation Behaviors of Levan and Its Impacts on the Gut Microbiota

Levan is a microbial fructan widely explored in various fields owing to its excellent physical and biochemical properties. However, little is known about its digestion and fermentation characteristics in vitro. This study evaluated the potential prebiotic properties of levan obtained by enzymatic synthesis. Scanning electron microscopy, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy showed that the primary structures of levan remained stable after saliva-gastrointestinal digestion. The microtopography, molecular weight, and functional group of levan were seriously damaged during fecal fermentation. Moreover, the total short-chain fatty acid levels increased significantly, especially for propionic acid, butyric acid, and valeric acid. The 16S rDNA sequencing showed that levan mainly increased the abundance of Firmicutes; in genus levels, certain beneficial bacteria such as Megasphaera and Megamonas genera were remarkably promoted, and the proliferation of harmful genera was inhibited (such as Cedecea and Klebsiella). Overall, this study provided new insights into the potential probiotic mechanism of levan.

Gut Microbial-Derived Short Chain Fatty Acids: Impact on Adipose Tissue Physiology

Obesity is a global public health issue and major risk factor for pathological conditions, including type 2 diabetes, dyslipidemia, coronary artery disease, hepatic steatosis, and certain types of cancer. These metabolic complications result from a combination of genetics and environmental influences, thus contributing to impact whole-body homeostasis. Mechanistic animal and human studies have indicated that an altered gut microbiota can mediate the development of obesity, leading to inflammation beyond the intestine. Moreover, prior research suggests an interaction between gut microbiota and peripheral organs such as adipose tissue via different signaling pathways; yet, to what degree and in exactly what ways this inter-organ crosstalk modulates obesity remains elusive. This review emphasizes the influence of circulating gut-derived short chain fatty acids (SCFAs) i.e., acetate, propionate, and butyrate, on adipose tissue metabolism in the scope of obesity, with an emphasis on adipocyte physiology in vitro and in vivo. Furthermore, we discuss some of the well-established mechanisms via which microbial SCFAs exert a role as a prominent host energy source, hence regulating overall energy balance and health. Collectively, exploring the mechanisms via which SCFAs impact adipose tissue metabolism appears to be a promising avenue to improve metabolic conditions related to obesity.

Recent advances and potentiality of postbiotics in the food industry: Composition, inactivation methods, current applications in metabolic syndrome, and future trends

Postbiotics are defined as "preparation of inanimate microorganisms and/or their components that confers a health benefit on the host". Postbiotics have unique advantages over probiotics, such as stability, safety, and wide application. Although postbiotics are research hotspots, the research on them is still very limited. This review provides comprehensive information on the scope of postbiotics, the preparation methods of inanimate microorganisms, and the application and mechanisms of postbiotics in metabolic syndrome (MetS). Furthermore, the application trends of postbiotics in the food industry are reviewed. It was found that postbiotics mainly include inactivated microorganisms, microbial lysates, cell components, and metabolites. Thermal treatments are the main methods to prepare inanimate microorganisms as postbiotics, while non-thermal treatments, such as ionizing radiation, ultraviolet light, ultrasound, and supercritical CO2, show great potential in postbiotic preparation. Postbiotics could ameliorate MetS through multiple pathways including the modulation of gut microbiota, the enhancement of intestinal barrier, the regulation of inflammation and immunity, and the modulation of hormone homeostasis. Additionally, postbiotics have great potential in the food industry as functional food supplements, food quality improvers, and food preservatives. In addition, the SWOT analyses showed that the development of postbiotics in the food industry exists both opportunities and challenges.