Search Results (1,766)

Microbiome-linked pathologies in humans have significantly increased over recent decades, suggesting that lifestyle changes, particularly those related to diet, have contributed to the disruption of beneficial microbial composition and functions. Specifically, modern processed diets that are low in dietary fiber and high in fat and sugar can lead to the depletion of bacterial taxa over generations and contribute to chronic inflammatory diseases. These pathologies can potentially be prevented by increasing fiber intake, making the promotion of dietary fiber crucial for human health. Despite the recognized importance of fiber integration, there remains a significant gap in the understanding of the use of multiple dietary fibers in food to promote microbiota diversity, as well as which dietary fibers promote specific microbial taxa to restore symbiosis. To address this gap, we conducted an in vitro fermentation study using fecal samples from two individuals. We tested three types of dietary fibers of varying complexity: inulin, pectin, and dextran in a β-glucan–based medium. Samples were collected over a 48 h fermentation period (0–4–8–24–32–48 h) to evaluate temporal shifts in microbial composition and short-chain fatty acid (SCFA) production. Through 16S rRNA gene amplicon sequencing, we found that the introduction of different fibers steered the microbiota of both individuals toward a convergent trajectory by 24–48 h. This result indicated that fiber complexity can reduce inter-individual variation in microbial community structure. Distinct levels of polysaccharide complexity between fiber types modulated specific bacterial taxa, supporting the concept that consuming a diversity of dietary fiber acts on complementary microbial niches. Notably, the observed shifts toward butyrate-associated taxa and reduction of pro-inflammatory lineages with dextran/β-glucan are relevant for pathologies characterized by dysbiosis, such as inflammatory bowel disease (IBD). Together, these results underscore the value of incorporating multiple fibers into food production, including fermented foods, to enhance prebiotic properties, stimulate the growth of fiber-fermenting bacteria, and promote microbial diversity. While these observations derive from a controlled in vitro pilot setting, they support the concept that multi-fiber dietary strategies based on complementary fermentable fibers with prebiotic properties may help shift the microbiome away from a pro-inflammatory state. Accordingly, dietary guidelines and public health approaches aimed at reducing chronic disease risk may benefit from emphasizing the inclusion of composite fiber blends rather than relying solely on single-fiber supplementation. Full article

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by progressive insulin resistance, impaired glucose regulation, and elevated cardiometabolic risk. Despite the availability of pharmacological therapies, long-term glycemic control remains suboptimal in many patients, highlighting the need for effective adjunctive nutritional strategies. Probiotic yogurt containing well-characterized bacterial consortia has been proposed as one such approach, given its potential to modulate gut microbiota composition, increase short-chain fatty acid (SCFA) production, improve intestinal barrier integrity, and attenuate low-grade systemic inflammation. A narrative review was conducted by searching PubMed, Scopus, and Google Scholar databases using terms related to probiotic yogurt, synbiotic yogurt, insulin sensitivity, T2DM, gut microbiota, Lactobacillus, and Bifidobacterium. Priority was given to randomized controlled trials (RCTs), meta-analyses, and systematic reviews, supplemented by mechanistically relevant preclinical studies. The reviewed evidence indicates that probiotic yogurt generally produces more consistent improvements in long-term metabolic markers, particularly glycated hemoglobin (HbA1c) and lipid profile, than in acute fasting glucose responses. Several trials also report reductions in fasting insulin and the homeostatic model assessment of insulin resistance (HOMA-IR), combined with improvement in the quantitative insulin sensitivity check index (QUICKI), particularly when yogurt is enriched with prebiotic substrates such as inulin and konjac glucomannan. Probiotic yogurt formulated with well-selected microbial consortia may serve as a safe complementary intervention for improving insulin sensitivity and overall metabolic control in T2DM patients. Full article

Short-chain fatty acids (SCFAs), acetate, propionate, and butyrate, are typically produced in a 3:1:1 ratio, respectively, via microbial fermentation of non-digestible carbohydrates, and to a lesser degree, from undigested protein. The effects of individual SCFAs on adipocyte function have been described; however, the effects of SCFAs in combination on adipocyte function remain unknown. Mature 3T3-L1 adipocytes were treated with a 1 mM total dose of acetate, propionate, and butyrate combined in a 3:1:1 ratio, respectively, for 24 h ± lipopolysaccharide (LPS, 10 ng/mL) under both normoxic and hypoxic (via the addition of 100 µM cobalt chloride) environmental conditions. In both normoxic and hypoxic LPS-stimulated conditions, SCFAs increased the secretion of adiponectin and reduced the secretion of resistin, interleukin (IL)-6, monocyte chemoattractant protein (MCP)-1/C-C motif chemokine ligand (CCL)2, and RANTES/CCL5, in addition to reducing intracellular protein levels of activated (i.e., the ratio of phosphorylated-to-total) nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) p65 and signal transducer and activator of transcription 3 (STAT3) (p < 0.05). Additionally, SCFA treatment reduced leptin secretion only in LPS-stimulated normoxic environmental conditions compared to control (p < 0.05). In normoxic conditions, SCFA + LPS increased mRNA expression of genes involved in fat storage), fatty acid recycling, and lipolysis, whereas in hypoxic conditions, SCFA + LPS decreased mRNA expression of genes involved in fat storage and triglyceride synthesis (p < 0.05), indicating different effects of SCFAs on adipocyte metabolic function depending on hypoxia status. Collectively, combined SCFAs in a 3:1:1 ratio beneficially modify the adipocyte adipokine secretory profile under both normoxic and hypoxic environmental conditions. Full article

Background: Type 2 diabetes mellitus (T2DM) is associated with altered gut microbiota and reduced short-chain fatty acid production, which may contribute to insulin resistance. However, evidence on fecal Short Chain Fatty Acid (SCFA) profiles in African populations remains limited. This study quantified fecal SCFAs in individuals with and without T2DM using Gas Chromatography–Mass Spectrophotometry (GC-MS) with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) derivatization. Methods: A cross-sectional study included 140 adults (92 non-diabetic and 48 T2DM). Fecal SCFAs were extracted, derivatized using BSTFA, and analysed by GC–MS. Associations between SCFAs, diabetes status, and HbA1c were evaluated using non-parametric statistics. Results: The GC–MS method demonstrated strong linearity (R² = 0.9917–0.9978), acceptable recovery, and reproducibility. Acetic, propionic, butyric, pentanoic, hexanoic, and heptanoic acids were detected, with acetic acid being most abundant in both groups. T2DM participants had higher median SCFA levels, although only butyric acid differed significantly (p = 0.027). HbA1c was significantly higher in the T2DM group (p < 0.001). No significant associations were observed between SCFAs and HbA1c in either group. Age differed significantly between groups, with T2DM participants older than non-diabetic controls. Conclusions: Most fecal SCFA profiles were comparable between individuals with T2DM and healthy controls. However, butyric acid was significantly elevated in the T2DM group, indicating that not all SCFAs exhibited similar patterns between the study groups. These findings suggest that fecal SCFAs alone may not serve as reliable biomarkers of T2DM in this population and highlight the influence of complex host–microbiome–environment interactions suggesting that dietary and microbial factors may outweigh disease status in determining SCFA variability in this cohort setting. Full article

Parkinson’s disease (PD), a debilitating neurodegenerative disorder, is primarily characterized by motor impairments and concurrent gastrointestinal disturbances. Increasing evidence has highlighted the critical role of the microbiota–gut–brain axis (MGBA) in the pathogenesis of PD. This study investigated the neuroprotective potential of sodium hyaluronate (SH) in a mouse model of PD and its underlying mechanisms via the MGBA. In the oral pre-treatment study, three doses (7.5, 15, and 30 mg/kg/day) were evaluated. The results showed that the high dose (SH-H, 30 mg/kg/day) significantly ameliorated motor disorders and gastrointestinal functional disorders. Therefore, SH-H was selected for subsequent mechanistic investigations. Mechanistically, SH-H restored gut microbiota homeostasis, increased fecal short-chain fatty acid (SCFA) levels, and improved the integrity of the intestinal and blood–brain barrier (BBB). Thus, SH reduced the transfer of lipopolysaccharide (LPS) from the intestine to serum and the substantia nigra (SN), suppressing activation of the LPS-TLR4/MyD88/NF-κB signaling pathway. These effects alleviated neuroinflammation, protected dopaminergic neurons, and reduced the aggregation of α-synuclein (α-syn). In summary, SH attenuated PD-related pathological changes by restoring gut microbiota homeostasis and modulating the MGBA, suggesting that SH may represent a potential therapeutic strategy for PD. Full article

Metabolic syndrome (MetS) is a complex and heterogeneous condition characterized by the coexistence of obesity, type 2 diabetes mellitus (T2DM), hypertension, chronic low-grade inflammation, and metabolic dysfunction. Increasing evidence suggests that the gut microbiota plays a central role in the development and progression of MetS by influencing host metabolism, intestinal barrier integrity, immune activation, endocrine signaling, and vascular homeostasis. This narrative review summarizes current evidence regarding gut microbiota alterations across major obesity-related metabolic phenotypes, including obesity alone, obesity complicated by T2DM, and obesity associated with hypertension. Obesity is generally characterized by reduced microbial diversity, depletion of beneficial taxa such as Faecalibacteriumprausnitzii and Akkermansia muciniphila, impaired short-chain fatty acid (SCFA) signaling, increased intestinal permeability, and metabolic endotoxemia. The coexistence of T2DM is associated with a more pronounced depletion of butyrate-producing bacteria, altered bile acid metabolism, impaired incretin signaling, and enhanced inflammatory activation that may contribute to insulin resistance and hyperglycemia. In hypertensive obesity, gut dysbiosis appears to preferentially involve disturbances within the gut–vascular axis, including reduced SCFA-producing taxa, increased trimethylamine N-oxide production, endothelial dysfunction, oxidative stress, and vascular inflammation. Although microbial signatures partially overlap among metabolic phenotypes, functional alterations in microbial metabolites and host–microbiota interactions may better explain disease heterogeneity than isolated taxonomic changes. Current evidence supports the potential role of microbiota-targeted interventions and integrated multi-omics approaches in future precision medicine strategies for cardiometabolic disease prevention and management. Full article

Background/Objectives: Major depressive disorder (MDD) has been increasingly associated with alterations of the gut microbiome through the microbiota–gut–brain axis. However, published findings remain highly heterogeneous, limiting identification of reproducible microbial signatures associated with depression. This systematic review aimed to evaluate reproducible taxonomic and functional gut microbiome alterations in patients with MDD compared with healthy controls. Methods: A systematic literature search was conducted in PubMed/MEDLINE, Scopus, Web of Science Core Collection, and the Cochrane Library for studies published between January 2016 and December 2025. Observational human studies evaluating gut microbiome composition in adults with clinically diagnosed MDD and healthy control groups were included. Methodological quality was assessed using the Newcastle-Ottawa Scale. Due to substantial methodological heterogeneity, findings were synthesized using structured qualitative narrative analysis. Results: Sixteen observational studies were included in the qualitative synthesis. Findings related to alpha diversity were inconsistent across studies, whereas beta diversity alterations demonstrated greater reproducibility across independent cohorts. The most recurrent microbiome pattern involved depletion of short-chain fatty acid (SCFA)-producing bacteria, particularly Faecalibacterium and Roseburia, together with recurrent alterations affecting members of the Ruminococcaceae, Lachnospiraceae, and Clostridia groups. Functional microbiome alterations demonstrated greater consistency than higher-level taxonomic findings and included reduced butyrate synthesis pathways, dysregulated amino acid and tryptophan metabolism, increased lipopolysaccharide biosynthesis, and enrichment of pro-inflammatory microbial signatures. Antidepressant-naïve cohorts generally demonstrated more homogeneous dysbiosis patterns than mixed-treated populations. Conclusions: Current evidence suggests that functional gut microbiome dysregulation may represent a more reproducible biological feature of MDD than isolated taxonomic alterations alone. However, substantial heterogeneity in study design, participant characteristics, sequencing methodologies, and analytical approaches continues to limit clinical translation. Large-scale longitudinal multi-omics studies using standardized methodologies are required to clarify the role of the gut microbiome in depressive disorders and to evaluate the potential utility of microbiome-based biomarkers and interventions in mental health and public health practice. Full article

Human biological matrices such as blood, placenta, lung tissue, and stool have been demonstrated to contain microplastics (MPs) and nanoplastics (NPs), indicating systemic dispersion and long-term environmental exposure. According to novel experimental findings, these xenobiotics may interact with pathways that overlap with the early pathophysiology of insulin resistance and metabolic syndrome, potentially serving as metabolic disruptors. High levels of MP/NP exposure are thought to alter intestinal permeability structurally, which may have an impact on enteroendocrine L-cell environments and the ensuing incretin responses. In animal studies, downstream effects include altered bile acid balance and microbiome remodelling, which is defined by a decrease in taxa that produce short-chain fatty acids (SCFAs). These xenobiotics’ portal translocation provides a plausible mechanism for subclinical hepatic inflammation, which may function in tandem with conventional risk factors to disrupt normal metabolic signalling. We consider the translational theory of “MP drainage” as a conceptual approach to lower intestinal particle bioavailability in order to address these theoretical interactions. Nevertheless, its long-term safety, metabolic advantages, and therapeutic effectiveness are yet unknown and require further confirmation. This perspective provides a framework for creating hypotheses that will direct future experimental and epidemiological studies in environmental metabolic toxicity. Full article

Pediatric sarcopenic obesity (PSO) is an emerging conceptual framework characterized by the coexistence of excess visceral adiposity and impaired skeletal muscle accretion. Evidence suggests that this pathology is driven by systemic meta-inflammation rooted in the gut microbiota–immunometabolism axis. Dysbiosis, particularly the depletion of infant-type Bifidobacterium, compromises the intestinal barrier, potentially causing metabolic endotoxemia. In preclinical models, this triggers a pro-inflammatory, “Warburg-like” glycolytic shift in innate immune cells, releasing cytokines (IL-6, TNF-$\mathsf{\alpha }$) that heavily upregulate the ubiquitin–proteasome system in developing muscle. To address this cascade, we hypothesize that a targeted synbiotic approach utilizing dietary anthocyanins (e.g., cyanidin-3-O-galactoside) and prebiotic galacto-oligosaccharides (GOS) may offer metabolic benefits. This review clarifies the pharmacokinetic distinction between the systemic toxicity of high-dose injected galactose and the safety of dietary galactosides. Preclinical data suggest that ingested galactosides resist upper gastrointestinal digestion and undergo colonic cleavage by commensal $\mathsf{\beta }$-galactosidase, yielding short-chain fatty acids (SCFAs) that support intestinal permeability while releasing bioactive phenolic aglycones. Systemically, these aglycones may attenuate skeletal muscle catabolism by supporting PI3K/Akt signaling. Synthesizing current preclinical and adult-derived evidence, this review highlights the theoretical therapeutic potential of early-life synbiotic interventions as adjunctive therapies to support healthy muscle developmental trajectories in pediatric populations. Full article

Pollen limitation compromises honey bee health and pollination services, and existing pollen substitutes are typically formulated around crude protein content while lacking the long-chain omega-3 fatty acids naturally present in pollen and bee-collected re-sources. To address both protein and fatty acid gaps in current substitutes, this study evaluated marine-protein and insect-larvae-based diets. We assessed how formulations using Asian seabass (Lates calcarifer) and insect larvae affect the nutrition, physiology, longevity, and gut microbiota of Apis mellifera L. Newly emerged bees were fed for 35 days on: sugar syrup (negative control), sugar syrup and natural pollen (positive control), or four experimental diets: seabass-based (SB), or SB supplemented with meal-worm (SBM), or wax moth (SBW), or black soldier fly (SBB). Experimental diets (12.48–15.59% crude protein, vs. 17.24% in natural pollen) while SB supplied eicosapentaenoic acid (39.3–53.3 mg/100 g) and docosahexaenoic acid (37.2–52.3 mg/100 g), and SBB was additionally rich in lauric acid (604.3 mg/100 g). SBB- and SBM-fed bees exhibited the greatest hypopharyngeal gland development (0.123 mm and 0.115 mm, respectively, vs. 0.060 mm in sugar-only controls), with no significant difference from SB alone. All SB-based diets supported significantly greater survival than the sugar-only control (log-rank p < 0.0001) and did not differ significantly from the natural pollen treatment with SBB showing the highest and most consistent day-35 survival (81.1%). All sea-bass-based diets significantly altered the gut microbial community structure, promoting short-chain fatty acid (SCFA)-associated bacteria such as Faecalibacterium prausnitzii and Blautia wexlerae. This enrichment may reflect not only the omega-3 and lauric acid content of the diets but also the presence of substrates that can be utilized by gut microbes, which may exert prebiotic-like effects by favoring SCFA-producing bacteria. These results demonstrate that marine and insect-derived nutrients can supply protein while also providing beneficial lipids and microbially utilizable substrates that promote the enrichment of beneficial SCFA-associated bacteria not typically dominant in the honey bee gut. These enriched diets, particularly SBB, are promising candidates war-ranting further evaluation at the colony and field levels. Full article

Redox homeostasis is essential for intestinal and systemic health and is regulated by antioxidant defense systems and redox-sensitive signaling pathways such as the nuclear factor erythroid 2-related factor 2 (Nrf2) and the nuclear factor ‘kappa-light-chain-enhancer’ of activated B-cells (NF-κB). Disturbances in this balance promote oxidative stress, chronic inflammation, and disease progression. Increasing evidence indicates that microbiota-derived metabolites act as key modulators of redox biology by shaping host gene expression through receptor-mediated signaling, metabolic regulation, and chromatin-associated mechanisms, including histone modifications, DNA methylation, and changes in chromatin accessibility. This review discusses how major classes of microbiota-derived and microbiota-modulated metabolites, including short-chain fatty acids (SCFAs), secondary bile acids, tryptophan-derived metabolites, polyphenol metabolites, hydrogen sulfide, and lipid mediators, influence redox-sensitive signaling and epigenetic regulation. We highlight their effects on intestinal barrier integrity and immune cell function, with particular emphasis on macrophage polarization and T-cell differentiation. Finally, we consider the emerging translational relevance of the microbiota–metabolite–epigenetic axis, while emphasizing that biomarker development and therapeutic applications require further mechanistic validation and clinical studies. Full article

Background: The human microbiota plays a crucial role in maintaining physiological homeostasis and influencing the development of chronic diseases not only in the gut but in the whole body. Material and Methods: This literature review is based on a comprehensive search of the PubMed database covering the period from 2008 to 2026. Approximately 65 key studies were included in the final analysis. Only articles published in English were included. The search included keywords such as microbiota, inflammaging, eubiosis, diet, gut diseases, cardiovascular diseases, diabetes, and osteoporosis. This narrative review explores the composition, development, and functional significance of the gut microbiota across the human lifespan, highlighting its dynamic interaction with environmental factors. Early-life microbial colonization, shaped by factors including delivery mode and breastfeeding, has long-term implications for immune system maturation and disease susceptibility. Results: A balanced gut microbiota (eubiosis) supports host health through metabolic activities, mainly by the production of short-chain fatty acids (SCFAs), which regulate intestinal barrier integrity, immune responses, and systemic inflammation. Contrarily, dysbiosis—characterized by reduced microbial diversity and an overrepresentation of pro-inflammatory species—is associated with chronic low-grade inflammation (inflammaging) and contributes to the pathogenesis of multiple diseases. Age-related changes in microbial composition are shown to activate inflammatory processes and impair immune regulation, thereby increasing disease risk. Therefore, it is important to recognize the role of microbiota alterations in key pathological conditions, including neurodegenerative diseases, cardiovascular diseases, type 2 diabetes mellitus, and osteoporosis. Conclusions: Finally, the potential of microbiome-targeted interventions, such as probiotics, prebiotics, and dietary modulation—in particular the Mediterranean diet is recognized as the most balanced—is discussed as a promising strategy to restore microbial balance and mitigate inflammaging. Further research is needed to better understand the association between microbiota and host health and to optimize therapeutic approaches for aging populations. Full article

The gut microbiome has emerged as a critical determinant of health and disease across virtually all organ systems. In the context of chronic kidney disease (CKD) and renal transplantation, mounting evidence reveals a complex bidirectional relationship between the intestinal microbiota and kidney function—commonly referred to as the gut–kidney axis. Patients with CKD harbor a profoundly altered gut microbial ecosystem characterized by reduced diversity, depletion of beneficial commensal organisms, and expansion of pathobiont taxa capable of generating uremic toxins and pro-inflammatory mediators. These perturbations are further compounded by the uremic milieu itself, dietary restrictions, frequent antibiotic exposure, and the use of immunosuppressive agents following transplantation. The gut–liver–kidney axis adds an additional layer of complexity, linking hepatic metabolism, bile acid signaling, endotoxemia, and systemic immune activation to the progression of renal disease. Gut-derived metabolites—including short-chain fatty acids (SCFAs), bile acids, trimethylamine N-oxide (TMAO), and tryptophan-derived uremic solutes such as indoxyl sulfate and p-cresyl sulfate—serve as molecular mediators of inter-organ crosstalk and have been identified as both biomarkers and therapeutic targets. A growing body of literature supports the diagnostic and prognostic utility of microbiome composition and its metabolic signatures in patients with CKD and those undergoing renal replacement therapy. Therapeutic strategies aimed at restoring microbial homeostasis—encompassing dietary interventions, prebiotics, probiotics, synbiotics, fecal microbiota transplantation (FMT), bile acid–based therapies, and novel pharmacological approaches—hold considerable promise for improving outcomes in CKD and transplant recipients. Importantly, the bidirectional relationship between immunosuppressive drugs and the gut microbiota has emerged as a clinically significant determinant of both microbial ecology and drug pharmacokinetics: each major immunosuppressive agent class—corticosteroids, calcineurin inhibitors, mycophenolate mofetil, and mTOR inhibitors—induces characteristic dysbiotic patterns, while in turn, the microbiota modulates drug bioavailability through enzymatic biotransformation (notably bacterial beta-glucuronidase activity affecting mycophenolic acid enterohepatic recirculation) and modulation of host drug-metabolizing enzymes. This narrative review provides a comprehensive overview of the current understanding of microbiome dysbiosis in the setting of renal disease and transplantation, examines the mechanistic underpinnings of the gut–liver–kidney axis, details the multifaceted impact of dysbiosis on transplant outcomes—including allograft function and rejection, infection, post-transplant diabetes, and cardiovascular complications—and critically appraises the translational potential of microbiome-targeted interventions. We conclude by highlighting ongoing challenges and future directions toward personalized, microbiome-informed clinical care. Full article

Depression and anxiety are increasingly understood to involve systemic biological processes, where chronic stress, immune dysregulation, and vascular dysfunction converge on brain-relevant symptoms. Fermented foods are widely studied as psychobiotic candidates, yet results remain inconsistent because products vary in chemistry, viability, sodium, and biogenic amines, and trials often rely on broad symptom outcomes without exposure verification. A major gap is the lack of a reusable, mechanism-first framework that links what a product delivers to barrier, endothelial, and neurovascular target engagement. As a narrative and conceptual review rather than a systematic review, the article integrates mechanistic evidence into a conceptual framework rather than undertaking quantitative evidence synthesis. It addresses that gap by treating fermented vegetables, dairy, soy, and selected Brazilian cassava ferments and artisanal cheeses as metabolite-engineering platforms mapped onto a tri-barrier remodeling axis from gut epithelium to endothelium and platelets to the blood–brain barrier. We synthesize dosing-resolved metabolite modules, including short-chain fatty acids, tryptophan-derived indoles, bile acids, neuroactive small molecules, and peptide and exopolysaccharide fingerprints, and align them with interpretable readouts for permeability, endotoxemia proxies, endothelial activation, immunothrombosis, and epigenetic aging pace. Here we highlight how this modular framework converts heterogeneous food studies into testable exposure hypotheses, guides comparator design and phenotype stratification, and clarifies why null results can be informative. To maintain a focused scope, the review uses selected fermented-food families as representative test platforms rather than attempting a complete survey of global fermented foods. The emphasis is therefore placed on mechanisms, exposure verification, and trial-design principles that can be transferred to other products. Full article

The mammalian respiratory system stands as a frontline barrier, constantly exposed to environmental insults, balancing defensive immunity with gas exchange. Historically considered sterile, the lung harbors a dynamic, low-biomass microbiome that evolves continuously in response to pulmonary pathologies. Accumulating evidence underscores that respiratory health and structural recovery are not autonomous but are critically integrated with distal microbial systems, especially the intestinal tract, through the gut–lung axis (GLA). This review characterizes the GLA as a bidirectional communication highway fueled by immune pathways, microbial metabolites, and direct microbial translocations. During acute or chronic injuries, such as COVID-19, COPD, asthma, idiopathic pulmonary fibrosis (IPF) and lung cancer, the gut microbiota serves as a remote metabolic “rheostat”. It delivers pivotal signaling molecules, such as short-chain fatty acids (SCFAs) and tryptophan metabolites (indoles), that could shape the local microenvironment in which the respiratory epithelium undergoes functional repair or maladaptive, fibrotic remodeling. Mechanistically, gut-derived butyrate enhances mitochondrial activity in alveolar epithelial cells, while resident progenitors, such as Alveolar Type 2 (AT2) cells, depend on intact mitochondrial fatty acid oxidation for proper regenerative differentiation. Conversely, critical lung illness disrupts this homeostasis via a “pathological circuit,” where severe pulmonary inflammation drives gut permeability, fecal dysbiosis, and the subsequent translocation of pathogen-associated molecular patterns (PAMPs, such as LPS) or gut-associated bacteria back into the pulmonary circulation. This review highlights the systemic nature of lung regeneration, which likely depends heavily on intestinal health through the GLA. Ultimately, leveraging these remote microbial networks through precision postbiotic supplementation, dietary priming, or microbiota transplantation represents a crucial frontier in precision medicine to promote definitive alveolar repair. Full article