INS and diabetes mellitus: This analysis revealed that fruit-intake frequency significantly influences the bidirectional regulation between glucose-related indices (HOMA-IR and insulin level) and microbial vitamin production capacities (vitamin B1: PWY-7357, vitamin B2: PWY-6168, and vitamin B2 group) (Pmediation < 0.05; Figure 3c-d; Table S14), which suggest that fruit-derived proteins and components may decrease diabetes risk through regulation of gut bacterial production of vitamins B1 and B2.