Older adults living in rural areas of southern Portugal exhibited greater gut microbiome diversity than their urban counterparts, according to research assessing intestinal microbiota and metabolic profiles. Although overall alpha-diversity showed no significant differences when comparing older, middle-aged, and younger cohorts, rural older individuals demonstrated the highest diversity within the older demographic.
The investigation, conducted in the Algarve region of southern Portugal, characterized the intestinal microbiome and examined fecal metabolite measures among older residents across rural and urban environments. Researchers sought to evaluate how geographic residence settings align with alterations in microbial composition and metabolic activity during aging.
Microbial profiles were determined using 16S rRNA gene sequencing on the Oxford Nanopore platform to calculate diversity indices. Alongside sequencing, the research team quantified fecal metabolic markers, specifically determining fecal total bile acids and short-chain fatty acids across the study groups.
Beyond exhibiting the highest diversity among older participants, rural older adults displayed the highest absolute frequency of beneficial bacterial taxa, including Blautia luti and Faecalibacterium duncaniae. Analysis also identified distinct bacterial markers characterizing each evaluated age group, with the rural older group presenting the greatest number of specific markers.
Metabolic evaluations demonstrated that fecal total bile acid levels remained comparable between rural and urban older individuals, with no statistically significant difference detected (p > 0.05). In contrast, fecal short-chain fatty acid measurements revealed that urban older individuals had significantly higher acetate levels than rural older individuals (p = 0.039).
Fecal lactate concentrations were significantly elevated in the older cohort compared to the young and middle-aged groups (p < 0.001). Furthermore, older individuals with lower functional status exhibited higher lactate levels than younger and middle-aged participants, leading the authors to conclude that rural-urban residency associates with distinct microbial and metabolic patterns that may have implications for functionality and future microbiota-diet strategies.
The investigation centers on the understanding that the human intestinal microbiome mirrors the distinctive characteristics of different geographic locations and human lifestyles. As adults age, their gut microbial communities experience compositional alterations that are potentially linked to their specific living settings and environments. To evaluate these dynamics in a defined regional population, the researchers set out to characterize the intestinal microbiome and systematically examine the metabolite profile of older adult residents living in rural and urban areas of the Algarve region in southern Portugal.
To evaluate the intestinal microbial architecture, the researchers performed 16S ribosomal RNA sequencing using the Oxford Nanopore sequencing system. In addition to genomic sequencing, the experimental protocol incorporated targeted biochemical profiling of fecal metabolites.
When evaluating community diversity indices across the broader study population, the researchers found no statistically significant differences in alpha-diversity when comparing older people, middle-aged individuals, and young groups. However, when evaluating residency within the older population, geographic setting was associated with clear variation. Older individuals residing in rural areas exhibited the highest microbial diversity in comparison with their urban older peers. In addition, rural older individuals demonstrated the highest absolute frequency of beneficial bacterial members, notably including Blautia luti and Faecalibacterium duncaniae. Analysis across the study cohorts also identified specific bacterial markers for each evaluated age group, with the rural older participants displaying the greatest total number of distinct bacterial markers.
The biochemical assessments revealed distinct patterns among fecal metabolites across geographic and age groups. Total bile acid content remained statistically similar between rural and urban older individuals, showing no significant difference between the two residential settings (p > 0.05). In contrast, short-chain fatty acid analysis showed that acetate levels were significantly higher among urban older individuals compared to rural older individuals (p = 0.039). Furthermore, fecal lactate concentrations were significantly elevated in the older cohort relative to the middle-aged and young cohorts (p < 0.001). Within the older group, individuals categorized as less functional displayed higher fecal lactate levels when compared directly to the middle-aged and young cohorts.
The researchers noted that these findings regarding residential associations and metabolic shifts may help guide future microbiota-diet-based strategies designed to support healthy aging.
Subject of Research: Gut microbiome diversity and metabolite variations between rural and urban older adults in Portugal
Article Title: The gut microbiome of old people in a Portuguese population is associated with Rural-Urban residence: impact on the metabolic profile and functionality
Article References: Matos, J., Silva, N., Pestana, D., Rajado, A., Alfa Score Consortium*, Andrade, R., Nóbrega, C., Bragança, J., Araújo, I., Apolónio, J., Calado, S. M., Carraco, G., Esteves, F., Brito, D., Trindade, M., Matos, C. A., Marques, N., Marreiros, A., Nzwalo, H., … Faleiro, M. L. (2026). The gut microbiome of old people in a Portuguese population is associated with Rural-Urban residence: impact on the metabolic profile and functionality. Aging Clinical and Experimental Research. https://doi.org/10.1007/s40520-026-03503-3
Image Credits: AI Generated
DOI: 10.1007/s40520-026-03503-3
Keywords: gut microbiome, aging, rural living, urban living, microbial diversity, metabolites, short-chain fatty acids, Oxford Nanopore, microbiome, people, Portuguese, population
