Bifidobacteria play a crucial role in maintaining intestinal homeostasis through cross-feeding interactions with other gut microbiota. These bacteria utilize complex glycans, such as human milk oligosaccharides (HMOs) and plant glycans, which are transported into the gut and broken down by extracellular enzymes. This process allows bifidobacteria to share metabolites with other microbes, promoting gut adaptation and health. Different bifidobacterial species have distinct glycan utilization strategies, which influence their colonization and dominance in the gut. For example, B. infantis primarily internalizes HMOs, while B. longum metabolizes arabinoxylan. Cross-feeding between bifidobacteria and other microbes, such as butyrate producers, enhances the availability of substrates and supports the growth of beneficial bacteria. This interaction is essential for maintaining gut homeostasis, especially in infants, where bifidobacteria dominate the gut microbiota. In adulthood, the relative abundance of bifidobacteria decreases, but they continue to play a role in gut health through cross-feeding with other bacteria. The ability of bifidobacteria to utilize various glycans and their cross-feeding relationships with other gut microbes are key factors in their ecological success and contribution to host health. Understanding these interactions can lead to the development of synbiotic strategies that promote a balanced gut microbiota and improve overall health.Bifidobacteria play a crucial role in maintaining intestinal homeostasis through cross-feeding interactions with other gut microbiota. These bacteria utilize complex glycans, such as human milk oligosaccharides (HMOs) and plant glycans, which are transported into the gut and broken down by extracellular enzymes. This process allows bifidobacteria to share metabolites with other microbes, promoting gut adaptation and health. Different bifidobacterial species have distinct glycan utilization strategies, which influence their colonization and dominance in the gut. For example, B. infantis primarily internalizes HMOs, while B. longum metabolizes arabinoxylan. Cross-feeding between bifidobacteria and other microbes, such as butyrate producers, enhances the availability of substrates and supports the growth of beneficial bacteria. This interaction is essential for maintaining gut homeostasis, especially in infants, where bifidobacteria dominate the gut microbiota. In adulthood, the relative abundance of bifidobacteria decreases, but they continue to play a role in gut health through cross-feeding with other bacteria. The ability of bifidobacteria to utilize various glycans and their cross-feeding relationships with other gut microbes are key factors in their ecological success and contribution to host health. Understanding these interactions can lead to the development of synbiotic strategies that promote a balanced gut microbiota and improve overall health.