Associations between Yogurt Consumption, Gut Microbiota Composition, and Glucose Dynamics: A Single-Arm 84-Day...

Although yogurt consumption has been associated with favorable metabolic outcomes, its effect on continuous glucose dynamics and gut microbiota composition remains unclear.

This study aims to evaluate the effects of daily yogurt intake on glucose dynamics and gut microbiota composition in healthy adults, and to examine baseline host factors associated with interindividual variability in glycemic response.

This single-arm, 84-d intervention study involved 303 Japanese adults without a prior diabetes diagnosis consuming 200 g of plain yogurt daily at breakfast. Continuous glucose monitoring (CGM) was used to assess mean glucose levels, standard deviation (SD), and an autocorrelation-based index (AC_Var). Fecal samples were collected at baseline and postintervention for 16S rRNA gene sequencing. Associations between baseline clinical, microbial, and genetic characteristics and changes in the CGM-derived measures were evaluated. Differential abundance analysis was used to identify microbial taxa altered by the intervention.

Mean glucose levels decreased progressively, with a reduction of 4.06 mg/dL [95% confidence interval (CI): 2.97 mg/dL, 5.14 mg/dL] by the final period. Significant decreases were also observed in SD (-0.86 mg/dL; 95% CI: -1.32 mg/dL, -0.41 mg/dL) and AC_Var (-0.0059; 95% CI: -0.010, -0.0017). Several baseline gut bacterial genera, including Gemmiger, Veillonella, Alistipes, and Butyricicoccus, were significantly associated with changes in the CGM-derived measures. After the intervention, increases were observed in the genera Blautia, Faecalibacterium, and Coprococcus, as well as in the phylum Firmicutes, whereas decreases were noted in Prevotella, Oscillospira, and the phylum Bacteroidetes.

Daily yogurt consumption was associated with improvements in glucose dynamics and significant remodeling of the gut microbiota. Baseline microbiota profiles were linked to interindividual differences in glycemic response. These findings suggest the potential role of the gut microbiome in modulating the metabolic effects of yogurt and underscore the value of personalized dietary strategies.