Probiotics have garnered increasing attention as a potential therapeutic approach for type 2 diabetes mellitus (T2DM). Previous studies have confirmed that Bifidobacterium animalis subsp. lactis MN-Gup (MN-Gup) could stimulate the secretion of glucagon-like peptide-1 (GLP-1) in NCI-H716 cells, but whether MN-Gup has a hypoglycemic effect on T2DM in vivo remains unclear. In this study, a T2DM mouse model was constructed, with a high-fat diet and streptozotocin in mice, to investigate the effect of MN-Gup on diabetes. Then, different doses of MN-Gup (2 × 10⁹ CFU/kg, 1 × 10¹⁰ CFU/kg) were gavaged for 6 weeks to investigate the effect of MN-Gup on glucose metabolism and its potential mechanisms. The results showed that a high-dose of MN-Gup significantly reduced the fasting blood glucose (FBG) levels and homeostasis model assessment-insulin resistance (HOMA-IR) of T2DM mice compared to the other groups. In addition, there were significant increases in the short-chain fatty acids (SCFAs), especially acetate, and GLP-1 levels in the MN-Gup group. MN-Gup increased the relative abundance of Bifidobacterium and decreased the number of Escherichia-Shigella and Staphylococcus. Moreover, the correlation analysis revealed that Bifidobacterium demonstrated a significant positive correlation with GLP-1 and a negative correlation with the incremental AUC. In summary, this study demonstrates that Bifidobacterium animalis subsp. lactis MN-Gup has significant hypoglycemic effects in T2DM mice and can modulate the gut microbiota, promoting the secretion of SCFAs and GLP-1.

Background/Objectives: Current evidence on the diabetes prevention benefit of substituting red meat with white meat remains inconsistent and is predominantly based on Western populations. This research examined whether the benefits of such dietary substitution depend on habitual red meat intake levels. Methods: This prospective analysis included 12,143 adults from the China Health and Nutrition Survey (2004–2015). Dietary intake was assessed by multiple 24 h recalls supplemented by a household food inventory. Incident diabetes was identified via self-report and supplementary biochemical data. Estimates of hazard ratios (HRs) and 95% confidence intervals (CIs) were obtained through Cox proportional hazards modeling. Dose–response relationships were examined using restricted cubic splines. Substitution effects were evaluated within strata defined by baseline red meat intake (<75 vs. ≥75 g/day). Results: During 83,046 person-years of follow-up, 687 incident diabetes cases occurred. U-shaped associations were identified for both red meat (lowest risk at 75 g/day) and white meat (lowest risk at 60 g/day) consumption in relation to diabetes risk (p-nonlinearity < 0.0001). Substitution was not associated with diabetes risk in the low-intake stratum (<75 g/day, p = 0.107). Conversely, in the high-intake stratum (≥75 g/day), replacing 50 g/day of red meat with white meat was associated with a 34% lower diabetes risk (HR: 0.66; 95% CI: 0.51, 0.86; p = 0.002). Conclusions: Meat intake shows a nonlinear association with diabetes risk in Chinese adults. The potential benefit of substituting white meat for red meat is conditional, with a more pronounced effect observed among individuals with high habitual red meat consumption, which may support the development of targeted dietary guidance for this subgroup.