The Role of Indigestible Oligosaccharides in Alleviating Human Chronic Diseases by Regulating Gut Microbiota: A Review

The gut has been a focus of chronic disease research. The gut microbiota produces metabolites that act as signaling molecules and substrates, closely influencing host health. Indigestible oli-gosaccharides (NDOs), as a common dietary fiber, play an important role in regulating the structure and function of gut microbiota. Their mechanism of action is mainly attributed to their carbon source as specific probiotics, producing related metabolites, and regulating the gut mi-crobial community. However, due to the selective utilization of oligosaccharides, some factors such as the types and structures of oligosaccharides have different impacts on the composition of microbial populations and the production of metabolites in the colon ecosystem. This review systematically describes the key factors influencing the selective utilization of oligosaccharides in microorganisms and elaborates how oligosaccharides affect the host's immune system, inflam-mation levels and energy metabolism by regulating microbial diversity and metabolic function, which in turn will affect the onset and progress of chronic diseases, especially diabetes, obesity, depression and intestinal inflammatory diseases, constipation. In this review, we re-examine the interaction mechanisms between gut microbiota and its associated metabolites and diseases, and explore new strategies for promoting human health and combating chronic diseases through di-etary interventions.