The article discusses the role of bifidobacteria in promoting intestinal homeostasis and host health throughout the lifespan. Bifidobacteria, which are abundant in the human gut and other warm-blooded animals, have superior colonization and glycan utilization abilities. They internalize complex glycans such as human milk oligosaccharides (HMOs) and plant glycans, which are then degraded into simple structures by extracellular glycosyl hydrolases and transported to cells for fermentation. This glycan utilization introduces cross-feeding activities between bifidobacterial strains and other gut microbiota, influenced by host nutrition and regulating gut homeostasis. The review highlights the glycan utilization strategies of bifidobacteria, focusing on cross-feeding and its potential health benefits. It also emphasizes the impact of cross-feeding on the gut trophic niche of bifidobacteria and host health. The article provides insights into the interactions between microbe-microbe and host-microbe, particularly the cross-feeding relationships between bifidobacteria and other gut bacteria, such as butyrate producers. These interactions help refine the network of gut microbiota interactions during early life and contribute to the stability and maturation of the gut microbiota. The article concludes by discussing the beneficial effects of cross-feeding in early life, such as ameliorating the adverse consequences of cesarean section and antibiotic use, and in adulthood, such as reestablishing gut microbiota structure and improving metabolic status.The article discusses the role of bifidobacteria in promoting intestinal homeostasis and host health throughout the lifespan. Bifidobacteria, which are abundant in the human gut and other warm-blooded animals, have superior colonization and glycan utilization abilities. They internalize complex glycans such as human milk oligosaccharides (HMOs) and plant glycans, which are then degraded into simple structures by extracellular glycosyl hydrolases and transported to cells for fermentation. This glycan utilization introduces cross-feeding activities between bifidobacterial strains and other gut microbiota, influenced by host nutrition and regulating gut homeostasis. The review highlights the glycan utilization strategies of bifidobacteria, focusing on cross-feeding and its potential health benefits. It also emphasizes the impact of cross-feeding on the gut trophic niche of bifidobacteria and host health. The article provides insights into the interactions between microbe-microbe and host-microbe, particularly the cross-feeding relationships between bifidobacteria and other gut bacteria, such as butyrate producers. These interactions help refine the network of gut microbiota interactions during early life and contribute to the stability and maturation of the gut microbiota. The article concludes by discussing the beneficial effects of cross-feeding in early life, such as ameliorating the adverse consequences of cesarean section and antibiotic use, and in adulthood, such as reestablishing gut microbiota structure and improving metabolic status.