Taxonomic diversity of fecal microbiota associated with different metabolic phenotypes in residents of Arkhangelsk, Northwestern Russia

The study assessed the taxonomic diversity and composition of gut microbiota in Arkhangelsk residents, Northwestern Russia, with varying metabolic statuses. A population-based cross-sectional "Know Your Heart" study (2015–2017, participants aged 35–69 years) included a health examination and gut microbiota analysis (n = 685). Participants were divided into four metabolic phenotypes: metabolically healthy non-obese (MHN), metabolically unhealthy non-obese (MUN), metabolically healthy obese (MHO), and metabolically unhealthy obese (MUO). Analyses were performed using RStudio software (version 4.2.0) with the vegan and phyloseq packages (version 1.42.0) for microbiota analysis. The sample was distributed across phenotypes as follows: MHN (47.7%), MUN (22.6%), MHO (10.4%), and MUO (19.3%). Beta-diversity analysis revealed significant differences in overall microbiome composition between MUO and MHN participants, while alpha-diversity did not differ significantly across phenotypes. The MHN group was characterized by a higher abundance of beneficial commensals such as Christensenellaceae R-7 group, Ruminococcaceae UCG-005, and Eubacterium xylanophilum group, which are taxa previously associated with metabolic health and longevity. In contrast, the MUO group showed an increased abundance of Streptococcus salivarius and Negativibacillus, taxa whose potential roles in metabolic health warrant further investigation. Blautia spp. emerged as a major hub in the microbiota of obese participants, consistent with its reported association with visceral fat. In conclusion, gut microbial composition differed across metabolic phenotypes, with the most notable taxonomic differences observed between MHN and MUO participants. Several taxa associated with metabolic health were enriched in the MHN group, whereas other taxa were more abundant in the MUO group. These findings suggest that distinct gut microbial signatures are associated with obesity and metabolic dysfunction, although the cross-sectional design precludes causal inference.