Studiendatenbank

The human gut microbiome and its relationship with both physiological and pathological functions have long intrigued researchers. One of the most fascinating and important areas within this domain is cognitive function. Given that a substantial number of studies, especially interventional ones, have been conducted on animal models, the findings of which are not fully generalizable to humans and may therefore be misinterpreted, the purpose of this study is to synthesize evidence from the most recent human research. Current evidence indicates that the gut microbiota is linked to cognitive function in both healthy and diseased states, with numerous studies suggesting a potential causal relationship between the two. Although the majority of these studies associate changes in cognitive function with differences in the composition of the gut microbiota, some findings also indicate an inverse relationship.

Obesity in older adults is a known risk factor for Alzheimer's disease and related dementias, potentially driven by metabolic dysfunction, inflammation and gut dysbiosis. The gut-brain axis, influenced by diet and the gut microbiome, is increasingly recognized as a contributor to neurodegeneration. In this sub-analysis of a 10-week randomized dietary education intervention (NCT06121986), we examined how obesity modulates gut microbiome, metabolome, and cognitive responses in 31 adults aged 55-85, with or without mild cognitive impairment. Participants received education on either a Mediterranean Diet or a Modified Mediterranean-Ketogenic Diet. Analyses were stratified by baseline obesity (BMI ≥30 kg/m²). Individuals with obesity exhibited lower microbial alpha-diversity, higher <i>Bacteroides</i>, and lower <i>Akkermansia</i> and <i>Christensenellaceae_R-7_group</i>, along with poorer memory and executive function. Only in the obese group did fat loss correlate with improvements in episodic memory and cognitive flexibility. In contrast, increased fat mass was associated with improved memory in non-obese participants. Gains in skeletal muscle mass predicted cognitive improvement in adults aged ≥73. Changes in gut (acetate, propionate, lactate) and plasma (acetate, pyruvate, citric acid) metabolites were linked to cognitive and body composition outcomes. These exploratory findings highlight the gut-muscle-brain axis as a modifiable target to enhance cognitive health in aging po

Osteoporosis, a global health challenge characterized by reduced bone mineral density (BMD) and increased fracture risk, is closely linked to interactions between dietary patterns and gut microbiota (GM). Recent advances in GM research highlight the gut-bone axis as a pivotal focus in osteoporosis studies, revealing that variations in dietary habits and nutrient intake differentially modulate GM composition and metabolic activity, thereby influencing skeletal health. This review synthesizes current evidence on the interplay between dietary practices, GM, and bone health, aiming to identify preventive and therapeutic strategies for osteoporosis management. Collectively, these findings underscore the potential of dietary interventions targeting GM modulation as a novel therapeutic approach, advocating for personalized nutritional strategies to improve skeletal health in high-risk populations.

<b>Background/Objectives:</b> The gut microbiome is a critical regulator of host metabolism, immunity, and the gut-brain axis. Exercise is a promising non-pharmacological modulator of microbial ecology, yet human evidence remains heterogeneous and the translational gap persists. This narrative review synthesizes mechanisms, human and animal evidence, and future directions for the exercise-gut microbiome axis. <b>Methods:</b> PubMed, Scopus, Web of Science, and SID were searched for articles published between January 2000 and February 2025. Keywords included exercise, physical activity, gut microbiome, gut microbiota, short-chain fatty acids, and gut-muscle axis. From 218 initial records, 89 original studies (47 human, 42 animal) met inclusion criteria and were critically appraised. <b>Results:</b> Exercise modulates the gut microbiome via splanchnic hypoperfusion, hyperthermia, altered transit time, and immune-mediated barrier regulation. Moderate-intensity continuous training consistently increases alpha diversity and enriches butyrate-producing taxa (<i>Faecalibacterium prausnitzii</i>, <i>Roseburia hominis</i>) and mucin-degrading <i>Akkermansia muciniphila</i>. High-intensity interval training transiently increases intestinal permeability in untrained individuals but, following adaptation, stimulates butyrate production via lactate cross-feeding metabolism-a recent breakthrough. Effects are transient and reversible upon detraining. Animal models establish causality throug

Recent advances in microbiome research have highlighted that age-related physiological changes are closely shaped by shifts in the gut microbial community rather than by the passage of time alone. Aging is frequently accompanied by a decline in microbial diversity and the loss of short-chain fatty acid-producing taxa, changes that weaken the intestinal barrier and contribute to the persistent low-grade inflammation described as inflammaging. These alterations intersect with immune and metabolic pathways linked to immunosenescence, cellular senescence, and mitochondrial function. In contrast, microbial ecosystems enriched with butyrate-producing and polyamine-generating species have been associated with more stable epithelial integrity, improved metabolic flexibility, and balanced immune activity. Emerging findings also indicate that the gut microbiota communicates with peripheral organs through the gut-skin, gut-muscle, and gut-brain axes, influencing tissue-specific aging processes. Evidence from animal models and human studies shows that dietary modulation, probiotics, and other microbiota-directed approaches can partially restore microbial functions relevant to aging, although responses vary considerably across individuals. Interest is also growing in postbiotic strategies, including microbial metabolites and vesicle-based components, which may offer targeted effects without requiring colonization. By integrating these mechanistic and translational insights, this review ou

The gut microbiota changes throughout life, potentially influencing health and triggering physiological disorders. Frailty syndrome (FS) is an age-related condition that reduces quality of life and increases hospitalization and mortality risks, making early detection and prevention essential in older populations. This study analyzed 16S rRNA gene and metagenomics sequencing of fecal samples from 203 older adults (FS: n = 64, non-FS (NFS): n = 139) to assess the role of gut microbiota in FS and related comorbidities, such as sarcopenia and impaired lower extremity function (ILEF) or anthropometric variables. Consistent taxonomic patterns were observed: Eggerthella, Parabacteroides, and Erysipelatoclostridium were significantly abundant in FS, while Christensenellaceae R-7 group, Erysipelotrichaceae UCG-003, and Hungatella were enriched in NFS. Christensenellaceae R-7 group was also associated with better mobility. Metagenomics analysis identified 680 KEGG functions differing between groups, categorized into 28 metabolic pathways. FS individuals had overrepresented biotin metabolism, antimicrobial resistance, and energy production, but underrepresented ribosomal and protein synthesis and sporulation pathways. Resistome analysis found the tetM/tetO (K18220) gene most abundant, alongside tetracycline, β-lactam, and macrolide resistance, primarily mediated by antibiotic efflux and transporters. These findings highlight distinct microbial and functional signatures associated with F

<b>Background</b>: The human gut microbiota plays a pivotal role in maintaining health throughout the lifespan, and age-related alterations in its composition and diversity have been implicated in numerous chronic and neurodegenerative conditions. However, the combined effects of aging, dementia, and shared living environments on gut microbial communities remain incompletely understood. <b>Methods</b>: This study included 56 older adults residing in a nursing home, of whom 29 had been diagnosed with dementia. Gut microbiota composition was characterized by 16S ribosomal RNA (rRNA) gene sequencing. Microbial diversity was assessed using alpha- and beta-diversity metrics, and differences in amplicon sequence variants (ASVs)/features were determined. Analyses adopted some covariates as potential confounders variables including age, sex, frailty status, drug use, and time spent in the nursing home. <b>Results</b>: Alpha diversity was significantly higher in older adults compared with younger, while beta-diversity analyses revealed distinct microbial community structures between age groups. In older individuals, <i>Bacteroidota</i> and <i>Proteobacteria</i> were the most abundant phyla, whereas <i>Firmicutes</i> and <i>Actinobacteriota</i> declined with advancing age. Notably, older adults exhibited an increased relative abundance of <i>Euryarchaeota</i>, a phylum encompassing <i>Archaea</i>, predominantly methanogens involved in anaerobic carbon dioxide reduction to methane. In s

Age-related alterations in the gut microbiota contribute to chronic low-grade inflammation, immune dysregulation, metabolic dysfunction, frailty, sarcopenia, and cognitive decline. Dietary polyphenols and fermentable fiber modulate microbial composition and metabolism, promoting the production of bioactive metabolites, including short-chain fatty acids, secondary bile acids, indole derivatives, and urolithins, which regulate intestinal barrier integrity, immune homeostasis, mitochondrial function, and gut-organ communication. This narrative review critically synthesizes evidence from experimental studies, observational cohorts, randomized controlled trials, systematic reviews, and meta-analyses to examine microbiota-mediated mechanisms linking these dietary components to healthy aging within the geroscience framework. Although mechanistic evidence is compelling, translation into clinically meaningful aging outcomes remains limited because most intervention studies are small and heterogeneous and primarily rely on surrogate biomarkers. Current evidence supports polyphenol- and fiber-rich dietary patterns as biologically plausible strategies for promoting healthy aging through modulation of the gut microbiota; however, establishing causal relationships will require standardized microbiome methodologies, validated microbiome-derived biomarkers, integrated multi-omics approaches, and adequately powered longitudinal studies and randomized controlled trials.

The Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet has emerged as a promising dietary pattern associated with reduced Alzheimer's disease (AD) risk, supported by growing evidence that both diet and the gut microbiota are modifiable contributors to disease development and progression. Observational studies have linked higher MIND diet adherence to lower AD incidence and slower cognitive decline, with certain comparative analyses reporting stronger associations with cognitive outcomes than those observed for the parent Mediterranean or DASH diets. Developed specifically to support cognitive health, the MIND diet emphasizes leafy green vegetables, berries, and olive oil while restricting butter, cheese, fried foods, sweets, and red meat. While these features suggest a biologically plausible basis for neuroprotection, the underlying mechanisms remain incompletely defined. The microbiota-gut-brain axis offers a potential mechanistic framework, as diet is a major determinant of gut microbiota composition and microbiota-derived metabolites that may influence brain function and AD-related pathways. However, direct evidence characterizing MIND diet-specific effects on the gut microbiota remains limited, with most mechanistic insights derived from related dietary patterns or individual dietary components. Accordingly, this review synthesizes evidence from these related dietary patterns and key MIND components to propose a conceptual framework linking the MIND d

Gut microbiota (GM) plays a crucial role in maintaining health through metabolic, endocrine and immune functions. With ageing, shifts in GM composition, characterised by increased pathogenic and decreased health-promoting bacteria, contribute to dysbiosis, which is linked to several age-related diseases. Given the global trend of increasing sedentary behaviour (SB) and declining physical activity (PA) among older adults, this study aims to explore the relationships between GM and two critical indicators of healthy ageing, movement behaviours and physical function. Cross-sectional study assesses the GM composition, PA levels and physical function of 101 healthy, community-dwelling older adults aged 65-85 years. Participants undertook anthropometric measures and functional tests, wore an accelerometer for 7 days and provided a faecal sample which was analysed using 16s rRNA sequencing. All the results were adjusted for key covariates such as diet, age and activity levels. Key findings include positive associations of <i>Prevotella copri</i> with moderate-to-vigorous PA, physical function and negative associations with SB, while <i>Roseburia</i> species were linked to better mobility and strength measures. Conversely, potentially pathogenic taxa like <i>Bilophila wadsworthia</i> and <i>Eggerthella</i> were negatively associated with PA and handgrip strength, underscoring their possible detrimental roles in muscle function and healthy ageing. This cross-sectional study highlights

Aging is a complex biological process characterized by progressive functional decline at molecular, cellular, and systemic levels, accompanied by increased susceptibility to chronic diseases. Accumulating evidence indicates that the gut microbiota plays a critical role in shaping aging trajectories and age-related health outcomes. This review systematically summarizes current research progress on the relationship between gut microbiota and aging. We first describe the characteristic alterations of the gut microbiota during aging, including reduced microbial diversity, shifts in core bacterial taxa, and profound changes in microbial metabolite profiles such as short-chain fatty acids, bile acid derivatives, and tryptophan metabolites. We then discuss the mechanistic links between gut microbiota dysbiosis and age-related functional decline, focusing on immunosenescence and inflammaging, gut barrier dysfunction, metabolic disorders and oxidative stress, as well as endocrine and neuroendocrine regulation through gut-organ axes. In addition, major internal and external factors influencing gut microbiota composition in the elderly, including diet, medication use, lifestyle, host immunity, and living environment, are reviewed. Finally, we summarize current and emerging gut microbiota-targeted anti-aging intervention strategies, such as dietary modulation, probiotics, prebiotics, postbiotics, fecal microbiota transplantation, and natural product-based approaches, and discuss future r

Population ageing has intensified interest in biological mechanisms that influence healthspan and susceptibility to age-related diseases. Among these mechanisms, the gut microbiota has emerged as an important modulator of immune, metabolic, and neurophysiological processes involved in ageing. This narrative review critically synthesises current evidence regarding age-related alterations in gut microbiota composition and function, their relationship with inflammaging and the hallmarks of ageing, and the potential role of microbiota-targeted interventions in promoting healthy ageing. A comprehensive narrative literature search was conducted using PubMed, Scopus, and Web of Science, focusing primarily on human observational studies, longitudinal cohorts, mechanistic investigations, and interventional trials published in peer-reviewed journals between 2010 and 2025. Priority was given to studies examining older adults, frailty, longevity, and microbiota-mediated mechanisms relevant to ageing biology. Current evidence suggests that ageing is frequently associated with reduced microbial diversity, depletion of beneficial short-chain fatty acid-producing taxa, altered intestinal barrier integrity, and increased abundance of pro-inflammatory microorganisms. These alterations are linked to inflammaging and may contribute to neurodegenerative, cardiovascular, metabolic, musculoskeletal, and joint diseases, including osteoporosis, sarcopenia, rheumatoid arthritis, and osteoarthritis. Ho

<h4>Introduction</h4>Preserving physical function is a central goal of ageing research, yet the dietary factors that precede early motor limitation remain incompletely defined.<h4>Methods</h4>Here we examined whether dietary fiber density was associated with incident gross motor limitation in the 2013 Health Care and Nutrition Study linked to the Health and Retirement Study. Among 5,388 adults aged 50 years or older who were free of gross motor limitation at baseline, 2,018 developed incident limitation during biennial follow-up through 2022.<h4>Results</h4>In the fully adjusted modified Poisson model, each 1-s.d. increment in fiber density was associated with a risk ratio of 0.86 (95% CI, 0.82 to 0.90), and the highest versus lowest quartile had a risk ratio of 0.72 (95% CI, 0.64 to 0.81). Augmented inverse probability weighting estimated a 9.0 percentage-point lower absolute risk in the highest versus lowest quartile. Estimates were unchanged after multiple imputation for missing covariates. In Fine-Gray models treating death as a competing event, the subdistribution hazard ratio was 0.82 per 1-s.d. increment (95% CI, 0.77 to 0.87). Results were also consistent across alternative exposure and outcome definitions, interval-aware models, diet-pattern adjustment and secondary functional outcomes.<h4>Conclusion</h4>Higher fiber density was consistently associated with lower functional-limitation risk, but it may index a broader constellation of dietary and lifestyle factors; ca

With rising life expectancy and global population aging, cognitive decline has become a major and growing public health challenge. Advances in nutritional neuroscience highlight the gut microbiota-immune-brain axis as a key biological pathway through which diet may influence cognitive function during aging. The gut microbiota, a metabolically active ecosystem, responds dynamically to habitual dietary patterns and produces bioactive metabolites capable of modulating immune signaling, neuroinflammation, and neuronal function. Diets rich in microbiota-modulating foods (e.g., dietary fiber, polyphenols, prebiotics, and probiotics) promote beneficial microbial communities. These communities support short-chain fatty acid production, maintain intestinal barrier integrity, and regulate systemic immune responses, processes increasingly associated with cognitive resilience in aging populations. In contrast, Western-style dietary patterns characterized by high intakes of saturated fats and refined sugars are linked to microbial dysbiosis, impaired gut barrier function, metabolic endotoxemia, and chronic low-grade inflammation, which may contribute to neuroinflammatory pathways involved in cognitive decline. This narrative review synthesizes evidence from observational studies, dietary intervention trials, and mechanistic animal models to examine how diet-driven alterations in gut microbiota composition and microbial metabolites interact with and modulate immune pathways to influence br

Population aging, the rising burden of chronic non-communicable diseases, and environmental degradation are increasingly recognized as interconnected global challenges, underscoring the need for integrated strategies that simultaneously promote human and planetary health. The Planetary Health Diet (PHD), originally proposed to address these challenges, has emerged as a promising dietary framework for supporting healthy aging. Although its health benefits are increasingly supported by epidemiological and clinical evidence, the biological mechanisms underlying these effects remain incompletely understood. This narrative review synthesizes evidence on the interplay among the PHD, the gut microbiome, and biological aging, with emphasis on microbiome-mediated pathways connecting sustainable nutrition with healthspan. Adherence to PHD-consistent dietary patterns is associated with greater microbial diversity and functional capacity, increased production of bioactive microbial metabolites, and more favorable intestinal barrier, immune, and metabolic profiles. These adaptations may modulate several hallmarks of aging and contribute to the preservation of physiological resilience. Evidence from prospective cohort studies, randomized controlled trials, and systematic reviews further indicates that dietary patterns consistent with the PHD are associated with lower risks of cardiometabolic diseases, frailty, cognitive decline, and premature mortality. By integrating findings from nutriti

<b>Background</b>: Gut microbiota plays a key role in the aging process, with age-related microbial shifts contributing to chronic inflammation, metabolic dysfunction, frailty, and cognitive decline. Despite growing interest, an integrated synthesis of how diet and lifestyle modifications influence gut microbiota remains limited. This overview of reviews summarizes the current evidence on how dietary and lifestyle interventions shape microbial composition and affect aging outcomes. <b>Methods</b>: Following the PRISMA guidelines, we searched PubMed and Scopus for English-language reviews (January 2023-October 2025) including human adults aged ≥ 18 years, evaluating dietary or lifestyle interventions, and reporting gut microbiota with healthy-aging outcomes. Quality of the reviews was appraised using the SANRA tool. <b>Results</b>: Mediterranean and plant-based diets, calorie restriction, and microbiota-targeted approaches such as probiotics, prebiotics, symbiotics, and fecal microbiota transplantation were associated with increases in short-chain fatty acid-producing bacteria, including <i>Faecalibacterium</i>, <i>Bifidobacterium</i>, <i>Lactobacillus</i>, and <i>Akkermansia muciniphila</i>, while reducing pro-inflammatory taxa. These changes were linked to improved metabolic and immune function, reduced inflammaging, lower frailty, and greater physical resilience. Cognitive benefits included decreased neuroinflammation and a lower risk of Alzheimer's and Parkinson's diseases