Gut microbiota and aging: current understanding and future perspectives.

Aging is a complex biological process characterized by progressive functional decline at molecular, cellular, and systemic levels, accompanied by increased susceptibility to chronic diseases. Accumulating evidence indicates that the gut microbiota plays a critical role in shaping aging trajectories and age-related health outcomes. This review systematically summarizes current research progress on the relationship between gut microbiota and aging. We first describe the characteristic alterations of the gut microbiota during aging, including reduced microbial diversity, shifts in core bacterial taxa, and profound changes in microbial metabolite profiles such as short-chain fatty acids, bile acid derivatives, and tryptophan metabolites. We then discuss the mechanistic links between gut microbiota dysbiosis and age-related functional decline, focusing on immunosenescence and inflammaging, gut barrier dysfunction, metabolic disorders and oxidative stress, as well as endocrine and neuroendocrine regulation through gut-organ axes. In addition, major internal and external factors influencing gut microbiota composition in the elderly, including diet, medication use, lifestyle, host immunity, and living environment, are reviewed. Finally, we summarize current and emerging gut microbiota-targeted anti-aging intervention strategies, such as dietary modulation, probiotics, prebiotics, postbiotics, fecal microbiota transplantation, and natural product-based approaches, and discuss future research directions and clinical translation challenges. Overall, this review highlights the gut microbiota as a key modifiable factor in aging biology and underscores its potential as a promising target for promoting healthy aging.