Evaluation of the gastric microbiota based on body mass index using 16S rRNA gene sequencing

Alpha diversity (Gini-Simpson index) was significantly lower in the combined overweight/obese group than that in the normal group (<i>P</i>=0.049). Beta diversity analysis revealed clear group separation (Bray-Curtis, <i>P</i>=0.005; unweighted UniFrac, <i>P</i>=0.004). Significant species differences between the groups were observed; specifically, the abundances of <i>Muribaculum gordoncarteri</i>, <i>Turicibacter bilis</i>, and <i>Duncaniella dubosii</i>, were significantly reduced in the overweight/obese group. Functional predictions showed differential enrichment of pathways related to fatty acid, amino acid, vitamin, and carbohydrate metabolism across BMI categories. These findings suggest that alterations in the gastric microbiota may be linked to obesity and metabolic dysregulation.