The diet rapidly and differentially affects the gut microbiota and host lipid mediators in a healthy population

Microbial micronutrient sharing, gut redox balance and keystone taxa as a basis for a new perspective to solutions targeting health from the gut

In health, the gut microbiome functions as a stable ecosystem maintaining overall balance and ensuring its own survival against environmental stressors through complex microbial interaction. This balance and protection from stressors is maintained through interactions both within the bacterial ecosystem as well as with its host. As a consequence, the gut microbiome plays a critical role in various physiological processes including maintaining the structure and function of the gut barrier, educating the gut immune system, and modulating the gut motor, digestive/absorptive, as well as neuroendocrine system all of which are crucial for human health and disease pathogenesis. Pre- and probiotics, widely available and clinically established, offer various health benefits primarily by beneficially modulating the gut microbiome. However, their clinical outcomes can vary significantly due to differences in host physiology, diets, individual microbiome compositions, and other environmental factors. This perspective paper highlights emerging scientific insights into the importance of microbial micronutrient sharing, gut redox balance, keystone species, and the gut barrier in maintaining a diverse and functional microbial ecosystem, and their relevance to human health. We propose a novel approach that targets microbial ecosystems and keystone taxa performance by supplying microbial micronutrients in the form of colon-delivered vitamins, and precision prebiotics [e.g. human milk oligosaccharides (HMOs) or synthetic glycans] as components of precisely tailored ingredient combinations to optimize human health. Such a strategy may effectively support and stabilize microbial ecosystems, providing a more robust and consistent approach across various individuals and environmental conditions, thus, overcoming the limitations of current single biotic solutions.

Branched- Chain Fatty Acids and Obesity: A Narrative Review

Branched- chain fatty acids (BCFAs) are a category of saturated fatty acids that are commonly present in various organisms and play a crucial role in a variety of metabolic reactions, including anticancer, lipid-lowering, anti-inflammatory, and neuroprotective actions. Currently, there is growing interest in the relationship between BCFAs and obesity. Branched- chain fatty acids regulate the gene expression of related enzymes by activating PPARα and sterol regulatory element-binding protein-1c, thereby reducing triglyceride synthesis in the body. Additionally, BCFAs reduce inflammation by decreasing the expression of pro-inflammatory factors in obesity such as cyclooxygenase-2, interleukin-6, and lipoxygenase-15 genes. Branched- chain fatty acids can also expedite the conversion of branched chain amino acids to BCFAs to regulate obesity-induced insulin resistance. In this article we provide a comprehensive review of research progress on how BCFAs affect obesity from the perspectives of lipid metabolism, inflammation, and insulin resistance.

ITIH4 alleviates OVA-induced asthma by regulating lung-gut microbiota

BACKGROUND

Inter-alpha-trypsin inhibitor heavy chain 4 (ITIH4), a Type 2 acute phase protein, is critical for resolving inflammation and promoting tissue repair. While its role in chronic respiratory diseases is recognized, its effects on asthma remain unclear. This study investigated the effects of ITIH4 on the modulation of lung and gut microbiota, the attenuation of allergic inflammation, and the improvement of respiratory outcomes in an asthma mouse model.

METHODS

Six-week-old male Balb/c mice were divided into five groups: control, ITIH4, ovalbumin (OVA), and two OVA + ITIH4 treatment groups at different doses. Lung function and oxygen saturation were measured, and bronchoalveolar lavage fluid (BALF) was analyzed for white blood cell counts and cytokines. Lung and gut microbiota were profiled using 16 S rRNA gene sequencing, and short-chain fatty acids (SCFAs) were measured using gas chromatography-mass spectrometry (GC-MS). Proteomic profiling of intestinal tissues was conducted to identify ITIH4-associated signaling pathways.

RESULTS

ITIH4 administration significantly mitigated OVA-induced asthma symptoms by reducing weight loss, airway resistance, and tissue damping (p < 0.05). Histological analysis showed decreased airway wall thickening and lung injury scores (p < 0.05). ITIH4 also lowered BALF eosinophils and lymphocytes, IgE, and Th2 cytokines (IL-4, IL-5, and IL-13) (p < 0.05). ITIH4 treatment modulated microbiome composition, enriching Gram-positive taxa (Nocardioidaceae and Acholeplasmataceae) and depleting Gram-negative Helicobacteraceae (p < 0.05). SCFAs correlated with microbiome alterations, notably reduced 4-methylpentanoic acid levels (p < 0.05). Proteomic analysis revealed a dose-dependent activation of granzyme A signaling and suppression of metabolic and solute transport pathways.

CONCLUSIONS

ITIH4 ameliorates asthma symptoms by modulating lung and gut microbiota, dampening Th2-driven inflammation, and restoring mucosal immune balance. These findings support ITIH4 as a potential candidate for microbiome-targeted asthma therapy.

Alcohol-induced bone loss driven by dysregulated spatial distribution of gut microbiota and PGD2-IL17 pathway-mediated osteoclast activation

Introduction

Alcohol-induced damage to bone microstructure leads to alcoholic osteoporosis (AOP). While prior studies have demonstrated alcohol's negative impact on bone density, the mechanisms by which alcohol induces osteoporosis through immune pathways, gut microbiota dysbiosis, and metabolic alterations remain insufficiently characterized. Given that alcohol is primarily absorbed in the upper gastrointestinal tract, in this research, we aimed to elucidate the role of spatial distribution disorders in gut microbiota and metabolites in the pathogenesis of alcohol-induced osteoporosis. We further sought to evaluate the potential of microbiota supplementation and targeted immunosuppressants as therapeutic strategies for related bone diseases.

Methods

An osteoporosis model using mice was established using alcohol drinking bottles, and bone loss was validated using micro-computed tomography. Segmented intestinal samples and fecal samples were analyzed using 16S rRNA sequencing and metabolomics. Mechanistic studies were conducted by supplementing R. intestinalis, prostaglandin D2 (PGD2), and its specific immune inhibitor, ramatroban. Analytical methods included tartrate-resistant acid phosphatase staining, flow cytometry, and enzyme-linked immunosorbent assay.

Results

Alcohol disrupted the spatial complexity of intestinal segments and fecal microbiota in mice, causing metabolic dysregulation and ultimately leading to elevated PGD2 levels. This, in turn, triggered Th17/Treg immune imbalance and osteoclast activation, resulting in bone loss. Supplementation with the probiotic R. intestinalis or inhibition of PGD2 significantly improved bone density and alleviate inflammation.

Conclusion

This study demonstrates that alcohol-induced elevation of PGD2 is a key pathogenic factor in AOP. PGD2 accelerates bone loss by promoting osteoclast formation through the activation of Th17 cells. Furthermore, this study highlights the importance of investigating the spatial distribution of gut microbiota and metabolites, providing potential targets and novel strategies for the precise treatment of AOP and other diseases associated with external stimuli.

Gellan gum-sialoglycan conjugates: a mucin mimic for alleviating inflammation in Caco-2 cells and modulating gut microbiota in the elderly

The sialylation of intestinal mucins plays a crucial role in maintaining intestinal homeostasis and shaping the gut microbiota. This study aims to develop a mucin-like polymer to modulate the intestinal microbiota in the elderly individuals. We synthesized functionalized conjugates using sialic acid monomer, 3'-sialyllactose, and Gellan gum, resulting in a series of GG-sialoglycan conjugates with diverse glycan chain lengths and terminal structures. The sialic acid contents of GG-EDA-Sia, GG-EDA-SL, GG-HAD-Sia, and GG-HAD-SL were 28.48 %, 29.78 %, 23.45 and 41.58 %, respectively. These conjugates exhibited anti-digestion effects. In addition, they demonstrated favorable biocompatibility and exhibited notable anti-inflammatory properties. In vitro fermentation experiments using fecal bacteria from elderly individuals revealed that GG-sialoglycan conjugates enhanced the proliferation of beneficial bacteria such as Lactobacillus, Bifidobacterium, and Blautia, while simultaneously suppressing pathogens like Escherichia-Shigella. It is worth noting that GG-sialoglycan conjugates containing 3'-sialyllactose exhibited superior prebiotic activity compared to those with sialic acid monomer. In summary, our findings strongly support the promising potential of functional sialic acid-based macromolecular glycan conjugates as a novel strategy to improve aging-related intestinal health.

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

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

CiLi (Rosa roxburghii Tratt.) polyphenols improve colitis via gut microbiota-lipid mediator-immunity axis

Dysbiosis of gut microbiome is one of the most important factors leading to inflammatory bowel disease (IBD). Intake of phytochemicals from fruits and vegetables is an effective way to improve IBD, but how these bioactivators regulate gut microbiota to exert healthy effects remains unclear. Here, we found that pretreatment with CiLi juice, particularly its polyphenol component, alleviated dextran sulfate sodium (DSS)-induced colitis while preserving intestinal barrier integrity. CiLi polyphenols (CL_PP) reduced inflammation and oxidative stress in colon tissue and enriched fecal short-chain fatty acids. Importantly, CL_PP significantly regulated the gut microbiome diversity, increasing beneficial bacteria (e.g., Clostridia_UCG-014, f_Muribaculaceae and Ileibacterium_valens) while decreasing harmful bacteria (Escherichia-Shigella and Romboutsia). Multiomics analysis revealed that CL_PP upregulated bioactive lipid metabolites, particularly those derived from polyunsaturated fatty acids (e.g., resolvin D2, prostaglandin A1, and glycerophosphocholine) related gene expressions (Pltp, Alox15 and Pld4). Additionally, CL-PP downregulated the oxidative stress markers (oxidized glutathione and glutathione peroxidase 3), and immune cell markers (CD8 and CD68). Fecal microbiota transplantation confirmed that the fecal microbiota from CL_PP-treated mice exhibited anti-colitis effects. These effects were diminished in antibiotic-treated mice, underscoring the importance of the gut microbiota in mediating the CL_PP's anti-inflammatory benefits. This study suggests that CL_PP is a potential modulator of gut microbiome dysbiosis for the prevention and treatment of colitis.

Trimethylamine N-Oxide Plasma Levels Following Red Meat and Cod Fish Intake: A Pilot Crossover Trial in Hemodialysis Patients

SCOPE

The uremic toxin trimethylamine N-oxide (TMAO) accumulates in patients with chronic kidney disease (CKD) and is associated with its progression, cardiovascular disease, and other complications. The gut microbiota produces TMAO from substrates mainly found in red meat, eggs, and dairy. However, some saltwater fish also contain high levels of TMAO. Although fish consumption is generally linked to beneficial effects, its effects on CKD patients require further research.

METHODS AND RESULTS

This study compares the effect of red meat and cod fish intake on TMAO plasma levels in CKD patients undergoing hemodialysis (HD). Participants received a single animal protein source (red meat vs. cod fish) for lunch and dinner for four consecutive days (each intervention), with a 2-week washout period in between. TMAO plasma levels were analyzed using LC-MS/MS. All 14 patients concluded the red meat intervention, while one refused to participate in the fish intervention. No significant difference in TMAO plasma levels was found post-red meat (p = 0.21) or fish intervention (p = 0.91), as well as between groups (p = 0.43).

CONCLUSION

In this study, 4 days of red meat and cod fish intake did not significantly impact TMAO levels in HD patients, while other factors may be associated with their circulating levels.

The Pathogenesis of Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBDs) are relapsing, remitting inflammatory diseases of the intestinal tract. Familial aggregation and genome-wide association studies revealed susceptibility variants that point toward a combination of innate immune and adaptive immune dysregulation that in concert with environmental factors, such as our microbiome, can initiate and perpetuate inflammation. Innate immune perturbations include functional abnormalities in the intestinal barrier, endoplasmic reticulum stress, and abnormal recognition of microbes. Adaptive immune changes include dysregulation of cytokines, regulatory T cells, and leukocyte migration. IBD is linked with an abnormal wound-healing response leading to fibrosis. This article summarizes key pathogenic mechanisms in the pathogenesis of IBDs.

Symphony of the gut microbiota and endocannabinoidome: a molecular and functional perspective

This review examines the impact of interactions between the gut microbiota and the endocannabinoidome (eCBome) on health and disease, highlighting their significance for physiological and pathological processes. We identify key research gaps and challenges to advance the field. The review discusses the role of dietary patterns and physical activity in regulating these interactions. It also explores the complex nature of these interactions in conditions such as inflammatory bowel disease (IBD), depression, anxiety, Alzheimer's disease (AD), and metabolic disorders. This analysis evaluates their contributions to disease onset and progression, and examines the molecular mechanisms and signaling pathways involved. From this, we provide forward-looking perspectives on future research directions, advocating for a more nuanced understanding of the gut microbiota-eCBome axis. We anticipate that future research will integrate gut microbiota-endocannabinoidome interactions into therapeutic strategies for a broad range of diseases.

The role of the intestinal microbiome in cognitive decline in patients with kidney disease

Cognitive decline is frequently seen in patients with chronic kidney disease (CKD). The causes of cognitive decline in these patients are likely to be multifactorial, including vascular disease, uraemic toxins, blood-brain barrier leakage, and metabolic and endocrine changes. Gut dysbiosis is common in patients with CKD and contributes to the increase in uraemic toxins. However, the gut microbiome modulates local and systemic levels of several metabolites such as short-chain fatty acids or derivatives of tryptophan metabolism, neurotransmitters, endocannabinoid-like mediators, bile acids, hormones such as glucagon-like peptide 1 (GLP1) or cholecystokinin (CCK). These factors can affect gut function, immunity, autonomic nervous system activity and various aspects of brain function. Key areas include blood-brain barrier integrity, nerve myelination and survival/proliferation, appetite, metabolism and thermoregulation, mood, anxiety and depression, stress and local inflammation. Alterations in the composition of the gut microbiota and the production of biologically active metabolites in patients with CKD are well documented and are favoured by low-fiber diets, elevated urea levels, sedentary lifestyles, slow stool transit times and polypharmacy. In turn, dysbiosis can modulate brain function and cognitive processes, as discussed in this review. Thus, the gut microbiome may contribute to alterations in cognition in patients with CKD and may be a target for therapeutic interventions using diet, prebiotics and probiotics.

Structural Characterization of Dendrobium officinale Polysaccharides and Their Regulation Effect on Intestinal Microbiota During In Vitro Fermentation

Polysaccharides derived from Dendrobium officinale have been demonstrated to exhibit metabolic regulatory properties. However, the correlation between their structure and function, particularly their mechanism of action through gut microbiota, remains underexplored. This study systematically elucidates the structural characteristics of Dendrobium officinale polysaccharide (DOP) from the Guizhou (GZ) and Zhejiang (ZJ) provinces of China using nuclear magnetic resonance (NMR) and a series of chromatographic analyses, revealing their unique molecular features. Additionally, the metabolic regulatory activities were assessed through α-glucosidase inhibitory assay and in vitro intestinal flora activity assay. The findings include the following: (1) both DOP-GZ and DOP-ZJ predominantly consist of glycosidic linkages of β-1,4-Manp and β-1,4-Glcp; (2) zhe monosaccharide composition ratios of mannose to glucose are 2.51:1 for DOP-GZ and 2.66:1 for DOP-ZJ, with molecular weights of 356 kDa and 544 kDa, respectively, indicating significant structural differences between DOPs from different sources; (3) treatment with DOP-GZ and DOP-ZJ led to alterations in the α-diversity indices and Firmicutes-to-Bacteroidota ratios; (4) more importantly, DOP-GZ and DOP-ZJ significantly increase the abundance of beneficial bacteria (e.g., g_Proteobacteria_unclassified) while suppressing the growth of pathogenic bacteria (e.g., f_Enterobacteriaceae_unclassified), with statistically significant results. These findings not only uncover a novel mechanism by which DOPs regulate metabolism through gut microbiota but also provide a crucial theoretical basis for the application of DOPs in functional foods and pharmaceutical development.

Cardiometabolic benefits of a non-industrialized-type diet are linked to gut microbiome modulation

Industrialization adversely affects the gut microbiome and predisposes individuals to chronic non-communicable diseases. We tested a microbiome restoration strategy comprising a diet that recapitulated key characteristics of non-industrialized dietary patterns (restore diet) and a bacterium rarely found in industrialized microbiomes (Limosilactobacillus reuteri) in a randomized controlled feeding trial in healthy Canadian adults. The restore diet, despite reducing gut microbiome diversity, enhanced the persistence of L. reuteri strain from rural Papua New Guinea (PB-W1) and redressed several microbiome features altered by industrialization. The diet also beneficially altered microbiota-derived plasma metabolites implicated in the etiology of chronic non-communicable diseases. Considerable cardiometabolic benefits were observed independently of L. reuteri administration, several of which could be accurately predicted by baseline and diet-responsive microbiome features. The findings suggest that a dietary intervention targeted toward restoring the gut microbiome can improve host-microbiome interactions that likely underpin chronic pathologies, which can guide dietary recommendations and the development of therapeutic and nutritional strategies.

Understanding dysbiosis and resilience in the human gut microbiome: biomarkers, interventions, and challenges

The healthy gut microbiome is important in maintaining health and preventing various chronic and metabolic diseases through interactions with the host via different gut-organ axes, such as the gut-brain, gut-liver, gut-immune, and gut-lung axes. The human gut microbiome is relatively stable, yet can be influenced by numerous factors, such as diet, infections, chronic diseases, and medications which may disrupt its composition and function. Therefore, microbial resilience is suggested as one of the key characteristics of a healthy gut microbiome in humans. However, our understanding of its definition and indicators remains unclear due to insufficient experimental data. Here, we review the impact of key drivers including intrinsic and extrinsic factors such as diet and antibiotics on the human gut microbiome. Additionally, we discuss the concept of a resilient gut microbiome and highlight potential biomarkers including diversity indices and some bacterial taxa as recovery-associated bacteria, resistance genes, antimicrobial peptides, and functional flexibility. These biomarkers can facilitate the identification and prediction of healthy and resilient microbiomes, particularly in precision medicine, through diagnostic tools or machine learning approaches especially after antimicrobial medications that may cause stable dysbiosis. Furthermore, we review current nutrition intervention strategies to maximize microbial resilience, the challenges in investigating microbiome resilience, and future directions in this field of research.

Divergent effects of monomethyl branched-chain fatty acids on energy metabolism and insulin signaling in human myotubes

Branched-chain fatty acids (BCFAs) are predominantly saturated fatty acids with one or more methyl branches on the carbon chain, typically found in dairy products and measured in micromolar concentrations in human plasma. The biological function of BCFAs in humans remains ill-defined, but a relationship between circulating BCFAs and cardiometabolic health has been suggested. The objective of this study was to evaluate the impact of BCFAs on energy metabolism in human myotubes. The results revealed distinct effects of BCFAs. 12-Methyltetradecanoic acid (12-MTD) increased glucose uptake and glycogen synthesis, while 13-methyltetradecanoic acid (13-MTD), 14-methylhexadecanoic acid (14-MHD), and 15-methylhexadecanoic acid (15-MHD) increased oleic acid uptake and 13-MTD and 15-MHD oleic acid oxidation, indicating a more general stimulatory effect on fatty acid than glucose metabolism. Interestingly, the same BCFAs, 13-MTD, 14-MHD, and 15-MHD, appeared to reduce insulin-stimulated glycogen synthesis. Insulin-stimulated phosphorylation of IRS1 was not apparent after exposure to 12-MTD, 13-MTD, and 15-MHD, whereas insulin-stimulated phosphorylation of Akt was unchanged by BCFAs. Incorporation of [14C]leucine into lipids was affected, as 13-MTD increased the total lipid content, and 12-MTD altered the distribution of lipid classes. Metabolic flux analysis indicated that 14-MHD stimulated extracellular acidification. The effects of BCFAs might involve increased mRNA expression of pyruvate dehydrogenase kinase 4. In conclusion, the study demonstrates that different BCFAs have distinct effects on energy metabolism in myotubes, 12-MTD mainly affect glucose metabolism, while 13-MTD, 14-MHD, and 15-MHD modulated oleic acid metabolism. These data suggest that some BCFAs might have therapeutic applications by improving energy metabolism.

How to Study the Effects of Dietary Lipids on the Small Intestinal Microbiome? Methodological Design and Evaluation of the Human HealThy fAt, haPpy mIcRobiome (TAPIR) Proof-of-Concept Study

Background

Emerging evidence highlights the importance of the small intestinal microbiota in digestion and metabolism, underscoring the challenging need for human studies beyond fecal analyses.

Objective

The TAPIR (acronym of "healthy fat, happy microbiome") proof-of-concept study was primarily designed to confirm the interaction between the small intestinal microbiota and dietary lipids in healthy adults with a challenge test. We also aimed to assess the impact of a plant-based mild-ketogenic preconditioning diet on microbiome composition and function. Here, we comprehensively describe our extensive study protocol and evaluate the study execution.

Methods

Participants consumed an 8-day preconditioning diet, followed by a high-fat shake challenge test on day 9. During this test, fasting and postprandial small intestinal aspirates were collected every 20 min via a naso-intestinal catheter, and blood samples were collected hourly. Participants ingested small intestine aspiration capsules before (day 0), on day 6 of the preconditioning diet, and during the challenge test. Dietary compliance, capsule retrieval, sample collection, stool pattern, and gastrointestinal complaints were monitored to evaluate study execution.

Results

Twenty adults with a mean age of 48 y (19-88 y) and a mean body mass index (BMI) of 24.3 kg/m2 (19.5-30 kg/m2) consumed a preconditioning diet with a 96% compliance. There were no significant changes in gastrointestinal complaints and stool patterns during the study. Mean aspiration capsule retrieval rate was 94.7%, with mean sample weights per timepoint between 84.2 and 95.4 mg and median transit times between 32.8 and 49.3 h. The average success rate of aspirate collection by catheter was 49%, varying significantly between time points.

Conclusion

The dietary intervention was successful and well-tolerated. We sampled in the small intestine with capsules and catheters, each with its own (dis)advantages. The comprehensive description and evaluation of our study execution offer practical insights supporting future study designs in food-microbe interactions in the small intestine.The trial is registered at clinicaltrials.gov as NCT06064266.

Dietary Guidance, Sensory, Health and Safety Considerations When Choosing Low and No-Calorie Sweeteners

The growing global focus on the adverse health conditions associated with excessive sugar consumption has prompted health and policy organizations as well as the public to take a more mindful approach to health and wellness. In response, food and beverage companies have proactively innovated and reformulated their product portfolios to incorporate low and no-calorie sweeteners (LNCSs) as viable alternatives to sugar. LNCSs offer an effective and safe approach to delivering sweetness to foods and beverages and reducing calories and sugar intake while contributing to the enjoyment of eating. The objective of this paper is to enhance the understanding of LNCSs segmentation and definitions, dietary consumption and reduction guidance, front-of-package labeling, taste and sensory perception and physiology, metabolic efficacy and impact, as well as the overall safety of LNCSs and sugar.

Fecal microbiota and genetics in pediatric-onset orofacial granulomatosis and Crohn´s disease

Orofacial granulomatosis (OFG) is a rare chronic inflammatory condition. It is under debate, whether it is a condition of its own or merely a subtype of Crohn's disease (CD). We aimed to search for markers characteristic of patients with pediatric-onset OFG compared to patients with pediatric-onset CD. We recruited young patients with OFG (with or without CD, n = 29), CD (n = 24), and healthy controls (n = 20). All participants provided a fecal sample for microbiota and calprotectin analyses and saliva for DNA analysis of genes associated with OFG and kept a 3-day food diary. Oral disease activity was evaluated using The Oral Disease Activity Score by an otorhinolaryngologist and a dentist. We observed decreased relative abundance in class Clostridia and increased relative abundances of classes Actinobacteria and Bacilli in the feces of patients with OFG when compared to patients with CD and healthy controls. The relative abundances of Bifidobacterium adolescentis increased and Faecalibacterium prausnitzii decreased along with the increase in the Oral Disease Activity Score. We found the NOD2 gene rs8057341 allele A to be enriched in patients with OFG compared to patients with CD. These findings support the theory that OFG is a distinct disease phenotype.

The Human Fecal Endocannabinoidome Mediator Profile Is Mainly Defined by the Fecal Microbiota and Diet

CONTEXT

The endocannabinoid system and its extension, the endocannabinoidome (eCBome), are involved in numerous biological processes, notably energy homeostasis, across virtually all tissues. While the circulating eCBome mediator profile is associated with dietary intakes and metabolic status, an important knowledge gap resides in the identification of the precise determinants of these mediators in the gut lumen.

OBJECTIVE

We aimed at establishing the profile of eCBome mediators in human feces and investigating their association with circulating eCBome mediators, dietary intakes, metabolic status, and gut microbiota composition.

METHODS

N-acyl-ethanolamines (NAEs) and 2-monoacyl-glycerols (2-MAGs) were profiled by liquid chromatography coupled to tandem mass spectrometry in plasma and feces of a cross-sectional cohort (n = 195) and a short-term dietary intervention trial (n = 21) with comprehensive dietary intakes and gut microbiota measures.

RESULTS

Six NAEs and 7 2-MAGs were identified in fecal samples, but some, especially omega-3-derived mediators, were undetectable in the majority of samples. Fecal NAEs, and to a lower extent 2-MAGs, were positively albeit weakly correlated with the circulating levels of eCBome mediators. Fecal 2-arachidonoyl-glycerol, N-palmitoyl-ethanolamine, and N-docosahexaenoyl-ethanolamine levels were positively associated with visceral adiposity and with some parameters of the metabolic profile. Dietary intakes of foods rich in fibers were associated with lower fecal levels of several eCBome mediators, while intakes of unsaturated fatty acids were associated with fecal 2-oleoyl-glycerol and 2-linoleoyl-glycerol. Interestingly, gut microbiota diversity and composition were a strong correlate of the fecal eCBome profile.

CONCLUSION

The fecal eCBome profile is associated with gut microbiota composition and dietary intakes, more than with the circulating profile. These results strengthen the hypothesis of an interrelation between the gut microbiome and eCBome signaling involved in the regulation of numerous host biological processes.

Dietary index for gut microbiota is associated with stroke among US adults

Aims: Emerging evidence underscores the diet-microbiota-gut-brain axis as vital to brain health. The dietary index for gut microbiota (DI-GM), quantifying diet quality linked to gut microbiota diversity, reflects healthier gut microbiota with higher scores. Therefore, this study was designed to explore the unclear association between DI-GM and stroke. Methods: A cross-sectional analysis was conducted using data from 48 677 participants aged ≥20 years in the National Health and Nutrition Examination Survey (NHANES). Demographic and dietary data were collected, and multivariable weighted logistic regression analysis was performed to evaluate the association between the DI-GM and stroke. Additionally, restricted cubic spline (RCS), subgroup analyses, and receiver operating characteristic (ROC) curve were conducted. Results: In participants aged ≥20 years, the odds ratio (OR) was 0.96 (95% CI: 0.92-1.00, P = 0.075) in the crude model, but after adjustment, the OR was 0.93 (95% CI: 0.89-0.98, P = 0.003), while higher beneficial to gut microbiota scores were consistently associated with lower stroke prevalence with ORs of 0.87 (95% CI: 0.83-0.90, P < 0.001) in the crude model and 0.88 (95% CI: 0.83-0.93, P < 0.001) after adjustment. Among participants aged 20-29 years, no significant association was observed. For those aged ≥30 years, higher DI-GM and beneficial to gut microbiota scores were associated with lower stroke prevalence, with DI-GM showing ORs of 0.93 (95% CI: 0.89-0.97, P < 0.001) in the crude model and 0.93 (95% CI: 0.89-0.98, P = 0.003) after adjustment, and beneficial to gut microbiota scores showing ORs of 0.82 (95% CI: 0.79-0.86, P < 0.001) in the crude model and 0.88 (95% CI: 0.83-0.93, P < 0.001) after adjustment. RCS indicated a linear relationship between DI-GM and stroke. Conclusion: The DI-GM was inversely and linearly associated with stroke prevalence, particularly in adults aged 30 years and above.

Detection of colorectal-cancer-associated bacterial taxa in fecal samples using next-generation sequencing and 19 newly established qPCR assays

We have previously identified increased levels of distinct bacterial taxa within mucosal biopsies from colorectal cancer (CRC) patients. Following prior research, the aim of this study was to investigate the detection of the same CRC-associated bacteria in fecal samples and to evaluate the suitability of fecal samples as a non-invasive material for the detection of CRC-associated bacteria. Next-generation sequencing (NGS) of the 16S ribosomal RNA (rRNA) V4 region was performed to evaluate the detection of the CRC-associated bacteria in the fecal microbiota of cancer patients, patients with adenomatous polyp and healthy controls. Furthermore, 19 novel species-specific quantitative PCR (qPCR) assays were established to detect the CRC-associated bacteria. Approximately, 75% of the bacterial taxa identified in biopsies were reflected in fecal samples. NGS failed to detect low-abundance CRC-associated taxa in fecal samples, whereas qPCR exhibited high sensitivity and specificity in identifying all targeted taxa. Comparison of fecal microbial composition between the different patient groups showed enrichment of Fusobacterium nucleatum, Parvimonas micra, and Gemella morbillorum in cancer patients. Our findings suggest that low-abundance mucosa-associated bacteria can be detected in fecal samples using sensitive qPCR assays.

Macronutrient balance determines the human gut microbiome eubiosis: insights from in vitro gastrointestinal digestion and fermentation of eight pulse species

The interactions between macronutrients, the human gut microbiome, and their metabolites (short-chain fatty acids) were comprehensively investigated via an in vitro digestion and fermentation model subjected to eight pulse species. 16S rRNA sequencing and taxonomic analysis of pulse digesta fermented for up to 24 h revealed an increase in the relative abundance of gut health-detrimental genera represented by Escherichia-Shigella in kidney bean, soybean, cowpea, chickpea, and black bean samples. In contrast, the relative abundance of health-positive genera, including Bacteroides, Eubacterium, and Akkermansia, was elevated in red bean, mung bean, and Heunguseul. At the same time, the proportion of the pathogenic Escherichia-Shigella decreased. Concurrently, these three species exhibited an increase in microbial diversity as evidenced by the calculation of α-diversity (Shannon index) and β-diversity (Bray-Curtis distance). Despite the lower nutrient contents in the three pulses, represented by carbohydrates, amino acids, and fatty acids, network analysis revealed that the nutrient contents in the pulse digesta possess complex positive or negative correlations with a variety of bacteria, as well as their metabolites. These correlations were more pronounced in red bean, mung bean, and Heunguseul than in the other pulses. It was postulated that the overall potential to nourish gut environments in these species was due to the balance of their nutritional components. The linear regression analysis demonstrated that there was a negative association between carbohydrate and amino acid contents and the increase in Shannon indices. Furthermore, the ratio of carbohydrates to fatty acids and amino acids to fatty acids displayed negative correlations with the diversity increase. The ratio of carbohydrates to amino acids showed a weak positive correlation. It is noteworthy that a diet comprising foods with a balanced nutritional profile supports the growth of beneficial gut microbes, thereby promoting microbial eubiosis. Consistent work on different ingredients is essential for precise insight into the interplay between food and the human microbiome in complex dietary patterns.

The impact of the Mediterranean diet on alleviating depressive symptoms in adults: a systematic review and meta-analysis of randomized controlled trials

CONTEXT

High adherence to the Mediterranean diet (MD) has been associated with a reduced risk of depression in prospective cohort studies, but whether MD interventions are effective among adults with depression is uncertain.

OBJECTIVE

This study aimed to synthesize findings on the effects of MD interventions on the severity of depressive symptoms in adults with depression.

DATA SOURCES

PubMed, Cochrane CENTRAL, PsycINFO, Scopus, and Web of Science were systematically searched from database inception to March 2023. The Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines and the Cochrane recommendations were followed. We included randomized controlled trials (RCTs) comparing outcomes after MD interventions with outcomes for control conditions in adults with depressive disorders or depressive symptoms.

DATA EXTRACTION

Two authors extracted the data independently. The Sidik-Jonkman estimator, the I2 metric, and the prediction interval were used to estimate between-study heterogeneity. To determine the risk of bias and the certainty of evidence from RCTs, we used the Cochrane Collaboration's Risk of Bias 2 and Grades of Recommendation, Assessment, Development, and Evaluation tools, respectively.

DATA ANALYSIS

In total, 1507 participants (mean age range: 22.0 years-53.3 years) with depression were initially included in the 5 RCTs of this review. Compared with control conditions, MD interventions significantly reduced depressive symptoms among young and middle-aged adults with major depression or mild to moderate depressive symptoms (standardized mean difference: -0.53; 95% confidence interval: -0.90 to -0.16; I2 = 87.1%). The prediction interval ranged from -1.86 to 0.81. The overall risk of bias was within the range of "some concerns" to "high," while the certainty of evidence was low.

CONCLUSION

MD interventions appear to have substantial potential for alleviating depressive symptoms in people experiencing major or mild depression. However, to establish robust recommendations, there remains a need for high-quality, large-scale, and long-term RCTs.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42022341895.

Constant light and high fat diet alter daily patterns of activity, feed intake and fecal corticosterone levels in pregnant and lactating female ICR mice

The prevalence of constant light exposure and high-fat diet in modern society raises concerns regarding their impact on maternal and offspring health outcomes. In rodents, exposure to maternal high-fat diet or continuous light negatively program metabolic and stress response outcomes of offspring. A 2x3 factorial study was conducted to investigate the impact of diet (control-CON, 10% fat, or high fat-HF, 60% fat) and exposure to different lighting conditions: regular 12-hour light-dark cycles (LD), continuous dim light (L5), or continuous bright light (L100) on female ICR mice daily patterns of time in and out of the nest, feed intake, and fecal corticosterone levels during gestation and lactation. Our previous analysis of these mice found HF diet decreased number of pups born, but increased litter growth rate to postnatal (PN) d12. Whereas continuous light increased gestation length and tended to increase PN litter growth. Here we report that patterns of grams of feed intake, an indicator of feeding activity, were affected by light, diet, period of the day (day versus night) and physiological state (gestation and lactation), with significant interactions among all these variables (P<0.05). HF diet and light treatment increased fecal corticosterone output (P<0.05) during lactation. Dams exhibited significant 12 h and 24 h rhythms of activity out of the nest in the first 48 h postnatal, with time outside of the nest greater in the second 24 h period. L100 treatment and HF diet attenuated rhythms and shifted phase of rhythms relative to LD and CON, respectively (P<0.05). Alterations in behavior affect maternal physiology, including level and timing of release of corticosteroids. Elevated fecal corticosterone levels due to high-fat diet and continuous light may have potential implications on maternal-offspring health, and potentially underlie some of the adverse effects of modern lifestyle factors on maternal and offspring health.

Changes in social environment impact primate gut microbiota composition

BACKGROUND

The gut microbiota (GM) has proven to be essential for both physical health and mental wellbeing, yet the forces that ultimately shape its composition remain opaque. One critical force known to affect the GM is the social environment. Prior work in humans and free-ranging non-human primates has shown that cohabitation and frequent social interaction can lead to changes in GM composition. However, it is difficult to assess the direction of causation in these studies, and interpretations are complicated by the influence of uncontrolled but correlated factors, such as shared diet.

RESULTS

We performed a 15-month longitudinal investigation wherein we disentangled the impacts of diet and social living conditions on GM composition in a captive cohort of 13 male cynomolgus macaques. The animals were in single housing for the first 3 months of the study initially with a variable diet. After baseline data collection they were placed on a controlled diet for the remainder of the study. Following this diet shift the animals were moved to paired housing for 6 months, enabling enhanced social interaction, and then subsequently returned to single housing at the end of our study. This structured sequencing of diet and housing changes allowed us to assess their distinct impacts on GM composition. We found that the early dietary adjustments led to GM changes in both alpha and beta diversity, whereas changes in social living conditions only altered beta diversity. With respect to the latter, we found that two particular bacterial families - Lactobacillaceae and Clostridiaceae - demonstrated significant shifts in abundance during the transition from single housing to paired housing, which was distinct from the shifts we observed based on a change in diet. Conversely, we found that other bacteria previously associated with sociality were not altered based on changes in social living conditions but rather only by changes in diet.

CONCLUSIONS

Together, these findings decouple the influences that diet and social living have on GM composition and reconcile previous observations in the human and animal literatures. Moreover, the results indicate biological alterations of the gut that may, in part, mediate the relationship between sociality and wellbeing.

The interplay between diet and the gut microbiome: implications for health and disease

Diet has a pivotal role in shaping the composition, function and diversity of the gut microbiome, with various diets having a profound impact on the stability, functionality and diversity of the microbial community within our gut. Understanding the profound impact of varied diets on the microbiome is crucial, as it will enable us not only to make well-informed dietary decisions for better metabolic and intestinal health, but also to prevent and slow the onset of specific diet-related diseases that stem from suboptimal diets. In this Review, we explore how geographical location affects the gut microbiome and how different diets shape its composition and function. We examine the mechanisms by which whole dietary regimes, such as the Mediterranean diet, high-fibre diet, plant-based diet, high-protein diet, ketogenic diet and Western diet, influence the gut microbiome. Furthermore, we underscore the need for exhaustive studies to better understand the causal relationship between diet, host and microorganisms for the development of precision nutrition and microbiome-based therapies.

Gymnemic acid alleviates gut barrier disruption and lipid dysmetabolism via regulating gut microbiota in HFD hamsters

Gut microbiota dysbiosis and gut barrier disruption are key events associated with high-fat diet (HFD)-induced systemic metabolic disorders. Gymnemic acid (GA) has been reported to have an important role in alleviating HFD-induced disorders of glycolipid metabolism, but its regulatory role in HFD-induced disorders of the gut microbiota and gut barrier function has not been elucidated. Here we showed that GA intervention in HFD-induced hamsters increased the relative abundance of short-chain fatty acid (SCFA)-producing microbes including Lactobacillus (P<.05) and Lachnoclostridium (P<.01) in the gut, and reduced the relative abundance of lipopolysaccharide (LPS)-producing microbes including Enterococcus (P<.05) and Bacteroides (P<.05), subsequently improving HFD-induced intestinal barrier dysfunction and systemic inflammation. Specifically, GA intervention reduced mRNA expression of inflammatory cytokines, including IL-1β, IL-6, and TNF-α (P<.01), increased mRNA expression of antioxidant-related genes, including Nfe2l2, Ho-1, and Nqo1 (P<.01), and increased mRNA expression of intestinal tight junction proteins, including Occludin and Claudin-1 (P<.01), thereby improving gut barrier function of HFD hamsters. This ameliorative effect of GA on the gut of HFD hamsters may further promote lipid metabolic balance in liver and adipose tissue by regulating the Toll-like receptor 4 (TLR4)-nuclear factor-κB (NF-κB) signaling pathway. Taken together, these results systematically revealed the important role of GA in regulating HFD-induced gut microbiota disturbance and gut barrier function impairment, providing a potential clinical theoretical basis for targeted treatment of HFD-induced microbiota dysbiosis.

Holistic Evaluation of the Gut Microbiota through Data Envelopment Analysis: A Cross-Sectional Study

Background

The gut microbiome plays a crucial role in human health, but maintaining a healthy gut microbiome remains challenging. Current approaches often focus on individual components rather than providing a holistic assessment.

Objectives

To introduce and evaluate a novel approach using data envelopment analysis (DEA) for assessing gut microbiota efficiency and identifying potential targets for personalized interventions.

Methods

We conducted a cross-sectional analysis of 577 participants from the Kanagawa "ME-BYO" Prospective Cohort Study. Lifestyle factors and gut microbiota composition were assessed. DEA was employed to calculate an efficiency score for each participant, incorporating multiple inputs (lifestyle factors) and outputs (gut microbiotas). This score represents how efficiently an individual's lifestyle factors contribute to their gut microbiota composition. Tobit regression analysis was used to assess associations between efficiency scores and demographic and health-related factors.

Results

The mean efficiency score was 0.86, with 14.2% of participants classified as efficient. Efficiency scores showed positive correlations with alcohol intake and Faith's phylogenetic diversity. Tobit regression analysis revealed significant associations between efficiency scores and sex, fat intake, and yogurt consumption. DEA identified specific targets for improving gut microbiota composition in inefficient individuals.

Conclusions

This study demonstrates the potential of DEA as a tool for evaluating gut microbiota efficiency and providing personalized recommendations for microbiota optimization. This approach could lead to more effective strategies for optimizing gut health across diverse populations.

Research on preventive effect of Akkermansia muciniphilaAKK PROBIO on acute gouty arthritis in mice

In mice with acute gouty arthritis, this study intends to examine the mechanism of action of Akkermansia muciniphila AKK PROBIO. We developed a mouse model of acute gouty arthritis using sodium urate. The efficiency and mechanism of AKK PROBIO in preventing acute gouty arthritis in mice were then determined by examining the degree of foot swelling, pain threshold, blood biochemical indicators, histological alterations, and messenger RNA (mRNA) expression changes. The results of the animal experiment showed that AKK PROBIO can lessen mouse foot edema severity and increase pain threshold. AKK PROBIO can enhance the enzyme activity of superoxide dismutase (SOD) and the level of glutathione (GSH) in the ankle joint tissues of mice with acute arthritis while decreasing the enzyme activity of myeloperoxidase (MPO) and the level of malondialdehyde (MDA). Interleukin 6 (IL-6), interleukin 10 (IL-10), interleukin 1 beta (IL-1β), and tumor necrosis factor-alpha (TNF-α) levels are all reduced by AKK PROBIO in the blood of mice with acute arthritis. Results from histopathology showed that AKK PROBIO reduced tissue damage in the mouse ankle and foot joints. In the tissues of the ankle joints of mice with acute arthritis, the results of the quantitative polymerase chain reaction (qPCR) and Western blot experiments suggested that AKK PROBIO may inhibit the mRNA and protein expression of extracellular signal-regulated kinase 1/2 (ERK1/2), cyclooxygenase-2 (COX-2), and prostaglandin E2 (PGE2) in the tissues. AKK PROBIO can also regulate gut microbiota, inhibit harmful bacteria, and enhance valeric acid in the intestine, isobutyric acid, and isovaleric acid. Therefore, it is evident that AKK PROBIO prevents acute gouty arthritis better than glucosamine sulfate. It is a strain that has probiotic potential.

Impact of a legumes diet on the human gut microbiome articulated with fecal and plasma metabolomes: A pilot study

BACKGROUND & AIMS

Legumes intake is known to be associated with several health benefits the origins of which is still a matter of debate. This paper addresses a pilot small cohort to probe for metabolic aspects of the interplay between legumes intake, human metabolism and gut microbiota.

METHODS

Untargeted nuclear magnetic resonance (NMR) metabolomics of blood plasma and fecal extracts was carried out, in tandem with qPCR analysis of feces, to assess the impact of an 8-week pilot legumes diet intervention on the fecal and plasma metabolomes and gut microbiota of 19 subjects.

RESULTS

While the high inter-individual variability hindered the detection of statistically significant changes in the gut microbiome, increased fecal glucose and decreased threonine levels were noted. Correlation analysis between the microbiome and fecal metabolome lead to putative hypotheses regarding the metabolic activities of prevalent bacteria groups (Clostridium leptum subgroup, Roseburia spp., and Faecalibacterium prausnitzii). These included elevated fecal glucose as a preferential energy source, the involvement of valerate/isovalerate and reduced protein degradation in gut microbiota. Plasma metabolomics advanced mannose and betaine as potential markers of legume intake and unveiled a decrease in formate and ketone bodies, the latter suggesting improved energy utilization through legume carbohydrates. Amino acid metabolism was also apparently affected, as suggested by lowered urea, histidine and threonine levels.

CONCLUSIONS

Despite the high inter-individual gut microbiome variability characterizing the small cohort addressed, combination of microbiological measurements and untargeted metabolomics unveiled several metabolic effects putatively related to legumes intake. If confirmed in larger cohorts, our findings will support the inclusion of legumes in diets and contribute valuable new insight into the origins of associated health benefits.

A systematic framework for understanding the microbiome in human health and disease: from basic principles to clinical translation

The human microbiome is a complex and dynamic system that plays important roles in human health and disease. However, there remain limitations and theoretical gaps in our current understanding of the intricate relationship between microbes and humans. In this narrative review, we integrate the knowledge and insights from various fields, including anatomy, physiology, immunology, histology, genetics, and evolution, to propose a systematic framework. It introduces key concepts such as the 'innate and adaptive genomes', which enhance genetic and evolutionary comprehension of the human genome. The 'germ-free syndrome' challenges the traditional 'microbes as pathogens' view, advocating for the necessity of microbes for health. The 'slave tissue' concept underscores the symbiotic intricacies between human tissues and their microbial counterparts, highlighting the dynamic health implications of microbial interactions. 'Acquired microbial immunity' positions the microbiome as an adjunct to human immune systems, providing a rationale for probiotic therapies and prudent antibiotic use. The 'homeostatic reprogramming hypothesis' integrates the microbiome into the internal environment theory, potentially explaining the change in homeostatic indicators post-industrialization. The 'cell-microbe co-ecology model' elucidates the symbiotic regulation affecting cellular balance, while the 'meta-host model' broadens the host definition to include symbiotic microbes. The 'health-illness conversion model' encapsulates the innate and adaptive genomes' interplay and dysbiosis patterns. The aim here is to provide a more focused and coherent understanding of microbiome and highlight future research avenues that could lead to a more effective and efficient healthcare system.

Modifiable risk factors for mild cognitive impairment among cognitively normal community-dwelling older adults: A systematic review and meta-analysis

Although numerous studies have investigated modifiable risk factors for mild cognitive impairment (MCI) among community-dwelling seniors, no meta-analysis has summarized these findings. Five databases were searched from January 1, 2000, to December 30, 2023. The protocol was registered with PROSPERO. Data were extracted and reported following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Relevant meta-analyses of modifiable risk factors were performed. The evidence of each factor was assessed by the GRADE for cohort studies. Of 16,651 citations, 87 studies involving 225,584 community-dwelling seniors were included. Fourteen meta-analyses involving 20 studies with 44,199 participants were performed. The analyses revealed low-to-moderate-quality evidence supporting that diabetes, 2 or more comorbidities, anxiety, apathy, depressive symptoms, and physical frailty were risk factors for incident MCI in older adults. Conversely, hypertension, agitation, and irritability might not be risk factors. Additionally, moderate-quality evidence supports the protective effect of engaging in cognitive-demanding activities on the onset of MCI. Collectively, this study constitutes the first extensive compilation of evidence regarding the various risk factors for the development of MCI in older adults. Our findings hold significant potential to guide the formulation of prevention and management strategies to either prevent or potentially reverse the onset of MCI.

A thorough investigation into the correlation between migraines and the gut microbiome: an in-depth analysis using Mendelian randomization studies

Objective

A growing body of evidence underscores a significant association between neurological disorders, particularly migraines, and the gut microbiota. However, a research gap persists in understanding the cause-and-effect dynamics between these elements. Therefore, we employed robust methodologies aimed at thoroughly exploring the causal relationship between the gut microbiome and migraines.

Methods

Employing bidirectional Two Sample Mendelian Randomization (TSMR) analysis, we investigated the causal association between the composition of the gut microbiota and migraines. Data summarizing the relationship between gut microbiota and migraines were extracted from one or more genome-wide association studies. The TSMR analysis employed five methods to assess the correlation between the gut microbiota and migraines, with the inverse variance-weighted method serving as the primary approach for analyzing causal links. Sensitivity analyses were applied to address horizontal pleiotropy and heterogeneity. Simultaneously, a meta-analysis was performed to strengthen the robustness of the findings. Additionally, a reverse TSMR was carried out to explore potential occurrences of reverse causal relationships.

Results

The ongoing TSMR analysis identified a collection of 14 bacterial taxa connected to migraines. Among these, 8 taxa exhibited a protective effect, while 5 taxa had a detrimental impact, and 1 taxon maintained a neutral relationship. The reverse Mendelian randomization analysis highlighted stable outcomes for only one bacterial taxonomic group.

Conclusion

The study confirms a causal relationship between the gut microbiota and migraines, offering a new perspective for migraine research. Strategically targeting specific bacterial taxa with dysregulation may be effective in both preventing and treating migraines, thus opening new avenues for therapeutic strategies.

Nourishing the gut: the impact of diet on host-gut microbiota interaction

PURPOSE OF REVIEW

Understanding the spectrum of drivers that influence the gut microbiome (GM) remains a crucial field of investigation. Among these factors, diet has received particular attention, as it could explain up to 20% of the variability in GM composition between individuals. This review focuses on the complex relationships between different dietary patterns and GM in humans, based on recent findings.

RECENT FINDINGS

Current evidence underscores the multifaceted impact of diet on GM richness, diversity, and overall composition. Key contributing factors encompass dietary habits, nutritional interventions, food quality and variety, macronutrient distribution, timing of feeding, and selective exclusion of certain foods.

SUMMARY

The intricate interplay between diet and GM is of fundamental importance in shaping the interaction between the host and the environment. Further understanding the causal impact of diet on GM has promising potential for the advancement of strategies to promote health and mitigate cardio-metabolic disease risks through dietary interventions.

GRAPHICAL ABSTRACT

http://links.lww.com/COCN/A21.

Obesity-associated inflammation countered by a Mediterranean diet: the role of gut-derived metabolites

The prevalence of obesity has increased dramatically worldwide and has become a critical public health priority. Obesity is associated with many co-morbid conditions, including hypertension, diabetes, and cardiovascular disease. Although the physiology of obesity is complex, a healthy diet and sufficient exercise are two elements known to be critical to combating this condition. Years of research on the Mediterranean diet, which is high in fresh fruits and vegetables, nuts, fish, and olive oil, have demonstrated a reduction in numerous non-communicable chronic diseases associated with this diet. There is strong evidence to support an anti-inflammatory effect of the diet, and inflammation is a key driver of obesity. Changes in diet alter the gut microbiota which are intricately intertwined with human physiology, as gut microbiota-derived metabolites play a key role in biological pathways throughout the body. This review will summarize recent published studies that examine the potential role of gut metabolites, including short-chain fatty acids, bile acids, trimethylamine-N-oxide, and lipopolysaccharide, in modulating inflammation after consumption of a Mediterranean-like diet. These metabolites modulate pathways of inflammation through the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, toll-like receptor 4 signaling, and macrophage driven effects in adipocytes, among other mechanisms.

Ultra-Processed Foods: A Narrative Review of the Impact on the Human Gut Microbiome and Variations in Classification Methods

Ultra-processed foods (UPFs) are foods that are industrially processed and are often pre-packaged, convenient, energy-dense, and nutrient-poor. UPFs are widespread in the current Western diet and their proposed contribution to non-communicable diseases such as obesity and cardiovascular disease is supported by numerous studies. UPFs are hypothesized to affect the body in multiple ways, including by inducing changes in the gut microbiome. This review summarizes the available research on the effect of UPFs on the gut microbiome. We also review current usage of the NOVA food classification system in randomized controlled trials and observational studies and how its implementation effects UPF research. Despite some differences in methodology between studies, results often associate UPF consumption with a number of negative health consequences. There are attempts to standardize a UPF classification system; however, reaching and implementing a consensus is difficult. Future studies focusing on the mechanisms by which UPFs effect the body, including through the microbiome and metabolome, will be essential to refine our understanding of the effects of UPFs on human health.

Effect of 1-year lifestyle intervention with energy-reduced Mediterranean diet and physical activity promotion on the gut metabolome and microbiota: a randomized clinical trial

BACKGROUND

The health benefits of the Mediterranean diet (MedDiet) have been linked to the presence of beneficial gut microbes and related metabolites. However, its impact on the fecal metabolome remains poorly understood.

OBJECTIVES

Our goal was to investigate the weight-loss effects of a 1-y lifestyle intervention based on an energy-reduced MedDiet coupled with physical activity (intervention group), compared with an ad libitum MedDiet (control group), on fecal metabolites, fecal microbiota, and their potential association with cardiovascular disease risk factors.

METHODS

A total of 400 participants (200 from each study group), aged 55-75 y, and at high cardiovascular disease risk, were included. Dietary and lifestyle information, anthropometric measurements, blood biochemical parameters, and stool samples were collected at baseline and after 1 y of follow-up. Liquid chromatography-tandem mass spectrometry was used to profile endogenous fecal metabolites, and 16S amplicon sequencing was employed to profile the fecal microbiota.

RESULTS

Compared with the control group, the intervention group exhibited greater weight loss and improvement in various cardiovascular disease risk factors. We identified intervention effects on 4 stool metabolites and subnetworks primarily composed of bile acids, ceramides, and sphingosines, fatty acids, carnitines, nucleotides, and metabolites of purine and the Krebs cycle. Some of these were associated with changes in several cardiovascular disease risk factors. In addition, we observed a reduction in the abundance of the genera Eubacterium hallii group and Dorea, and an increase in alpha diversity in the intervention group after 1 y of follow-up. Changes in the intervention-related microbiota profiles were also associated with alterations in different fecal metabolite subnetworks and some cardiovascular disease risk factors.

CONCLUSIONS

An intervention based on an energy-reduced MedDiet and physical activity promotion, compared with an ad libitum MedDiet, was associated with improvements in cardiometabolic risk factors, potentially through modulation of the fecal microbiota and metabolome. This trial was registered at https://www.isrctn.com/ as ISRCTN89898870 (https://doi.org/10.1186/ISRCTN89898870).

Exome-Based Amino Acid Optimization: A Dietary Strategy to Satisfy Human Nutritional Demands and Enhance Muscle Strength in Breast Tumor Mice Undergoing Chemotherapy

Breast cancer patients undergoing chemotherapy often experience muscle wasting and weakness, which impact their quality of life. A potential solution lies in customizing amino acid compositions based on exome-derived formulations (ExAAs). The study hypothesized that tailoring dietary amino acids using ExAAs could enhance muscle health. Theoretical amino acid requirements were calculated from the genome's exome region, and a breast cancer mouse model undergoing paclitaxel treatment was established. The mice were supplemented with a cancer-specific nutritional formula (QJS), and the effects of QJS and amino acid-adjusted QJS (adjQJS) were compared. Both formulations improved the nutritional status without compromising tumor growth. Notably, adjQJS significantly enhanced muscle strength compared to QJS (1.51 ± 0.25 vs. 1.30 ± 0.08 fold change, p < 0.05). Transcriptome analysis revealed alterations in complement and coagulation cascades, with an observed upregulation of C3 gene expression in adjQJS. Immune regulation also changed, showing a decrease in B cells and an increase in monocytes in skeletal muscle with adjQJS. Importantly, adjQJS resulted in a notable increase in Alistipes abundance compared to QJS (10.19 ± 0.04% vs. 5.03 ± 1.75%). This study highlights the potential of ExAAs as valuable guide for optimizing amino acid composition in diets for breast cancer patients undergoing chemotherapy.

Past, present, and future of microbiome-based therapies

Technological advances in studying the human microbiome in depth have enabled the identification of microbial signatures associated with health and disease. This confirms the crucial role of microbiota in maintaining homeostasis and the host health status. Nowadays, there are several ways to modulate the microbiota composition to effectively improve host health; therefore, the development of therapeutic treatments based on the gut microbiota is experiencing rapid growth. In this review, we summarize the influence of the gut microbiota on the development of infectious disease and cancer, which are two of the main targets of microbiome-based therapies currently being developed. We analyze the two-way interaction between the gut microbiota and traditional drugs in order to emphasize the influence of gut microbial composition on drug effectivity and treatment response. We explore the different strategies currently available for modulating this ecosystem to our benefit, ranging from 1st generation intervention strategies to more complex 2nd generation microbiome-based therapies and their regulatory framework. Lastly, we finish with a quick overview of what we believe is the future of these strategies, that is 3rd generation microbiome-based therapies developed with the use of artificial intelligence (AI) algorithms.

Alterations in the diversity, composition and function of the gut microbiota in Uyghur individuals with sarcopenia

BACKGROUND

Research on the gut microbiota has emerged as a new direction for understanding pathophysiologic changes in diseases associated with aging, such as sarcopenia. Several studies have shown that there are differences in the gut microbiota between individuals with sarcopenia and without sarcopenia. However, these differences are not consistent across regions and ethnic groups, and additional research is needed.

METHODS

In this study, we collected fresh fecal samples from 31 Uyghur individuals with sarcopenia and 31 healthy controls. We used 16S rRNA sequencing to obtain fecal base sequences and analyzed the diversity, composition and function of the gut microbiota.

RESULTS

There was no significant difference in alpha diversity between the sarcopenia group and the healthy control group (P > 0.05). There was a significant difference in beta diversity between the groups (P < 0.05). In the sarcopenia group, the abundances of Alloprevotella, un_f_Prevotellaceae, Anaerovibrio, Prevotellaceae_NK3B31_group, Mitsuokella, Prevotella and Allisonella were lower than those in the heathy control group, and the abundances of Flavobacteriales, Flavobacteriaceae, Catenibacterium, Romboutsia, Erysipelotrichaceae_UCG-003, GCA-900066575, Lachnospiraceae_FCS020_group, and un_f_Flavobacteriaceae were higher than those in the heathy control group. Linear discriminant analysis effect size (LEfSe) revealed that the microbial species in the control group that were significantly different from those in the sarcopenia group were concentrated in the genus Alloprevotella, while the species in the sarcopenia group were concentrated in the genus Catenibacterium. Functional prediction analysis revealed that D-alanine, glycine, serine, and threonine metabolism and transcription machinery, among others, were enriched in the sarcopenia group, which indicated that metabolic pathways related to amino acid metabolism and nutrient transport may be regulated to varying degrees in the pathophysiological context of sarcopenia.

CONCLUSIONS

There were significant differences in the composition and function of the gut microbiota between Xinjiang Uyghur sarcopenia individuals and healthy individuals. These findings might aid in the development of probiotics or microbial-based therapies for sarcopenia in Uyhur individuals.

Safety, feasibility, and impact on the gut microbiome of kefir administration in critically ill adults

BACKGROUND

Dysbiosis of the gut microbiome is frequent in the intensive care unit (ICU), potentially leading to a heightened risk of nosocomial infections. Enhancing the gut microbiome has been proposed as a strategic approach to mitigate potential adverse outcomes. While prior research on select probiotic supplements has not successfully shown to improve gut microbial diversity, fermented foods offer a promising alternative. In this open-label phase I safety and feasibility study, we examined the safety and feasibility of kefir as an initial step towards utilizing fermented foods to mitigate gut dysbiosis in critically ill patients.

METHODS

We administered kefir in escalating doses (60 mL, followed by 120 mL after 12 h, then 240 mL daily) to 54 critically ill patients with an intact gastrointestinal tract. To evaluate kefir's safety, we monitored for gastrointestinal symptoms. Feasibility was determined by whether patients received a minimum of 75% of their assigned kefir doses. To assess changes in the gut microbiome composition following kefir administration, we collected two stool samples from 13 patients: one within 72 h of admission to the ICU and another at least 72 h after the first stool sample.

RESULTS

After administering kefir, none of the 54 critically ill patients exhibited signs of kefir-related bacteremia. No side effects like bloating, vomiting, or aspiration were noted, except for diarrhea in two patients concurrently on laxatives. Out of the 393 kefir doses prescribed for all participants, 359 (91%) were successfully administered. We were able to collect an initial stool sample from 29 (54%) patients and a follow-up sample from 13 (24%) patients. Analysis of the 26 paired samples revealed no increase in gut microbial α-diversity between the two timepoints. However, there was a significant improvement in the Gut Microbiome Wellness Index (GMWI) by the second timepoint (P = 0.034, one-sided Wilcoxon signed-rank test); this finding supports our hypothesis that kefir administration can improve gut health in critically ill patients. Additionally, the known microbial species in kefir were found to exhibit varying levels of engraftment in patients' guts.

CONCLUSIONS

Providing kefir to critically ill individuals is safe and feasible. Our findings warrant a larger evaluation of kefir's safety, tolerability, and impact on gut microbiome dysbiosis in patients admitted to the ICU.

TRIAL REGISTRATION

NCT05416814; trial registered on June 13, 2022.

Between Dysbiosis, Maternal Immune Activation and Autism: Is There a Common Pathway?

Autism spectrum disorder (ASD) is a neuropsychiatric condition characterized by impaired social interactions and repetitive stereotyped behaviors. Growing evidence highlights an important role of the gut-brain-microbiome axis in the pathogenesis of ASD. Research indicates an abnormal composition of the gut microbiome and the potential involvement of bacterial molecules in neuroinflammation and brain development disruptions. Concurrently, attention is directed towards the role of short-chain fatty acids (SCFAs) and impaired intestinal tightness. This comprehensive review emphasizes the potential impact of maternal gut microbiota changes on the development of autism in children, especially considering maternal immune activation (MIA). The following paper evaluates the impact of the birth route on the colonization of the child with bacteria in the first weeks of life. Furthermore, it explores the role of pro-inflammatory cytokines, such as IL-6 and IL-17a and mother's obesity as potentially environmental factors of ASD. The purpose of this review is to advance our understanding of ASD pathogenesis, while also searching for the positive implications of the latest therapies, such as probiotics, prebiotics or fecal microbiota transplantation, targeting the gut microbiota and reducing inflammation. This review aims to provide valuable insights that could instruct future studies and treatments for individuals affected by ASD.

Gut microbiota dysbiosis and intestinal barrier impairment in diarrhea caused by cold drink and high-fat diet

Cold drink and high-fat diet (CDHFD) are common diet patterns. However, the potential risks remain unclear. We investigated the effects of CDHFD in adult mice and explored the mechanisms of action. Twenty adult male mice were randomly divided into control and model groups, and the control group was fed a normal diet, whereas the model group was fed CDHFD for 28 days. We found that mice in the model group developed diarrhea symptoms accompanied by fatigue and weakness. Analysis of the intestinal flora revealed that the model group had a lower diversity and richness of microorganism species in the gut than the control group. Furthermore, the characteristic analysis indicated that CDHFD downregulated specific bacteria, such as norank_f_Muribaculaceae, Muribaculum, and Odoribacter, which are known to be associated with the systemic inflammatory response and mucosal barrier function. Blood tests showed that immune cells and inflammatory cytokines were significantly elevated in the model group, along with increased LPS induced by CDHFD. Pathological investigations demonstrated that CDHFD damages the intestinal mucosa while affecting the expression of tight junction proteins, including ZO-1, Claudin-1, Claudin-2, and Occludin, which may be attributed to the activation of the TRAF6/IκB/p65 signaling pathway. In conclusion, impaired gut microbial and mechanical barrier function is responsible for CDHFD-induced diarrhea. In this study, we constructed a model of diet-induced diarrhea by simulating human dietary patterns, evaluated the long-term effects of CDHFD on human intestinal barriers and immune systems, and revealed its mechanism of action based on chronic inflammation. This study validated the model's fit to provide an effective screening model for drug or functional food development.

Effect of a Probiotic Beverage Enriched with Cricket Proteins on the Gut Microbiota: Composition of Gut and Correlation with Nutritional Parameters

The health and balance of the gut microbiota are known to be linked to diet composition and source, with fermented products and dietary proteins potentially providing an exceptional advantage for the gut. The purpose of this study was to evaluate the effect of protein hydrolysis, using a probiotic beverage enriched with either cricket protein (CP) or cricket protein hydrolysates (CP.Hs), on the composition of the gut microbiota of rats. Taxonomic characterization of the gut microbiota in fecal samples was carried out after a 14-day nutritional study to identify modifications induced by a CP- and CP.H-enriched fermented probiotic product. The results showed no significant differences (p > 0.05) in the diversity and richness of the gut microbiota among the groups fed with casein (positive control), CP-enriched, and fermented CP.H-enriched probiotic beverages; however, the overall composition of the microbiota was altered, with significant modifications in the relative abundance of several bacterial families and genera. In addition, fermented CP.H-enriched probiotic beverages could be related to the decrease in the number of potential pathogens such as Enterococcaceae. The association of gut microbiota with the nutritional parameters was determined and the results showed that digestibility and the protein efficiency ratio (PER) were highly associated with the abundance of several taxa.

A modified Mediterranean-style diet enhances brain function via specific gut-microbiome-brain mechanisms

Alzheimer's disease (AD) is a debilitating brain disorder with rapidly mounting prevalence worldwide, yet no proven AD cure has been discovered. Using a multi-omics approach in a transgenic AD mouse model, the current study demonstrated the efficacy of a modified Mediterranean-ketogenic diet (MkD) on AD-related neurocognitive pathophysiology and underlying mechanisms related to the gut-microbiome-brain axis. The findings revealed that MkD induces profound shifts in the gut microbiome community and microbial metabolites. Most notably, MkD promoted growth of the Lactobacillus population, resulting in increased bacteria-derived lactate production. We discovered elevated levels of microbiome- and diet-derived metabolites in the serum as well, signaling their influence on the brain. Importantly, these changes in serum metabolites upregulated specific receptors that have neuroprotective effects and induced alternations in neuroinflammatory-associated pathway profiles in hippocampus. Additionally, these metabolites displayed strong favorable co-regulation relationship with gut-brain integrity and inflammatory markers, as well as neurobehavioral outcomes. The findings underscore the ameliorative effects of MkD on AD-related neurological function and the underlying gut-brain communication via modulation of the gut microbiome-metabolome arrays.

Characterizing Gut Microbiota in Older Chinese Adults with Cognitive Impairment: A Cross-Sectional Study

Background

Cognitive impairment is a clinical manifestation that occurs in the course of dementia like Alzheimer's disease. The association between cognitive impairment and gut microbiota is unclear.

Objective

We aimed to identify gut microbiota characteristics and key gut microbiota biomarkers associated with cognitive impairment in a relatively large cohort of older adults in China.

Methods

A total of 229 adults aged ≥60 years from Shenzhen, China were recruited into this cross-sectional study. Participants were divided into cognitive impairment (CI) and no cognitive impairment (NCI) groups according to the results of the Mini-Mental State Examination. Diversity analysis and network analysis were used to characterize the gut microbiota between the two groups. The linear discriminant analysis effect size method and machine learning approaches were sequentially performed to identify gut microbiota biomarkers. The relationship between biomarkers and lifestyle factors was explored using Transformation-based redundancy analysis (tb-RDA).

Results

A total of 74 CI participants and 131 NCI participants were included in the analysis. The CI group demonstrated lower α-diversity compared to the NCI group (Shannon: 2.798 versus 3.152, p < 0.001). The density of the gut microbiota interaction network was lower in the CI group (0.074) compared to the NCI group (0.081). Megamonas, Blautia, Pseudomonas, Stenotrophomonas, and Veillonella were key biomarkers for CI. The tb-RDA revealed that increased fruit intake and exercise contribute to a higher abundance of Megamonas, Blautia, and Veillonella.

Conclusions

We identified a significantly reduced abundance of certain beneficial gut microbiota in older Chinese adults with cognitive impairment.

Effect of low-and non-calorie sweeteners on the gut microbiota: A review of clinical trials and cross-sectional studies

Use of non-nutritive sweeteners (NNSs) has increased worldwide in recent decades. However, evidence from preclinical studies shows that sweetener consumption may induce glucose intolerance through changes in the gut microbiota, which raises public health concerns. As studies conducted on humans are lacking, the aim of this review was to gather and summarize the current evidence on the effects of NNSs on human gut microbiota. Only clinical trials and cross-sectional studies were included in the review. Regarding NNSs (i.e, saccharin, sucralose, aspartame, and stevia), only two of five clinical trials showed significant changes in gut microbiota composition after the intervention protocol. These studies concluded that saccharin and sucralose impair glycemic tolerance. In three of the four cross-sectional studies an association between NNSs and the microbial composition was observed. All three clinical trials on polyols (i.e, xylitol) showed prebiotic effects on gut microbiota, but these studies had multiple limitations (publication date, dosage, duration) that jeopardize their validity. The microbial response to NNSs consumption could be strongly mediated by the gut microbial composition at baseline. Further studies in which the potential personalized microbial response to NNSs consumption is acknowledged, and that include longer intervention protocols, larger cohorts, and more realistic sweetener dosage are needed to broaden these findings.

The interplay between the microbiota, diet and T regulatory cells in the preservation of the gut barrier in inflammatory bowel disease

Inflammatory bowel disease (IBD) is becoming more common in the Western world due to changes in diet-related microbial dysbiosis, genetics and lifestyle. Incidences of gut permeability can predate IBD and continued gut barrier disruptions increase the exposure of bacterial antigens to the immune system thereby perpetuating chronic inflammation. Currently, most of the approved IBD therapies target individual pro-inflammatory cytokines and pathways. However, they fail in approximately 50% of patients due to their inability to overcome the redundant pro inflammatory immune responses. There is increasing interest in the therapeutic potential of T regulatory cells (Tregs) in inflammatory conditions due to their widespread capability to dampen inflammation, promote tolerance of intestinal bacteria, facilitate healing of the mucosal barrier and ability to be engineered for more targeted therapy. Intestinal Treg populations are inherently shaped by dietary molecules and gut microbiota-derived metabolites. Thus, understanding how these molecules influence Treg-mediated preservation of the intestinal barrier will provide insights into immune tolerance-mediated mucosal homeostasis. This review comprehensively explores the interplay between diet, gut microbiota, and immune system in influencing the intestinal barrier function to attenuate the progression of colitis.

Variations in the Relative Abundance of Gut Bacteria Correlate with Lipid Profiles in Healthy Adults

The gut microbiome is a versatile system regulating numerous aspects of host metabolism. Among other traits, variations in the composition of gut microbial communities are related to blood lipid patterns and hyperlipidaemia, yet inconsistent association patterns exist. This study aims to assess the relationships between the composition of the gut microbiome and variations in lipid profiles among healthy adults. This study used data and samples from 23 adult participants of a previously conducted dietary intervention study. Circulating lipid measurements and whole-metagenome sequences of the gut microbiome were derived from 180 blood and faecal samples collected from eight visits distributed across an 11-week study. Lipid-related variables explained approximately 4.5% of the variation in gut microbiome compositions, with higher effects observed for total cholesterol and high-density lipoproteins. Species from the genera Odoribacter, Anaerostipes, and Parabacteroides correlated with increased serum lipid levels, whereas probiotic species like Akkermansia muciniphila were more abundant among participants with healthier blood lipid profiles. An inverse correlation with serum cholesterol was also observed for Massilistercora timonensis, a player in regulating lipid turnover. The observed correlation patterns add to the growing evidence supporting the role of the gut microbiome as an essential regulator of host lipid metabolism.

Dys-R Questionnaire: A Novel Screening Tool for Dysbiosis Linked to Impaired Gut Microbiota Richness

Practical and affordable tools to screen intestinal dysbiosis are needed to support clinical decision making. Our study aimed to design a new subjective screening tool for the risk of intestinal dysbiosis from a previously described nonvalidated questionnaire (DYS/FQM) and based on subjective and objective data. A total of 219 individuals comprised the chronic diseases (CD; n = 167) and healthy control (HC; 52 subjects) groups. Sociodemographic, anthropometric, body composition, lifestyle, past history, intestinal health, and dietary data were collected. The gut microbiota (GM) profile was assessed from fecal samples using the 16S rRNA sequencing. Scores for the new tool (Dys-R Questionnaire) were assigned using discrete optimization techniques. The association between Dys-R scores and dysbiosis risk was assessed through correlation, simple linear models, sensitivity, specificity, as well as positive and negative predictive values. We found significant differences in the Chao1 Index between CD and HC groups (adjusted p-value = 0.029), highlighting lower GM richness as the primary marker for intestinal dysbiosis. DYS/FQM showed poor performance in identifying poor GM richness. Dys-R exhibited a 42% sensitivity, 82% specificity, 79% positive predictive value (PPV), and 55% negative predictive value (NPV) to identify poor GM richness. The new Dys-R questionnaire showed good performance in ruling out dysbiosis.