Intestinal stem cells (ISCs) are essential for maintaining the intestinal epithelium, which serves as a barrier against pathogens and regulates immune responses. ISCs reside in crypts and continuously replenish the intestinal lining, balancing self-renewal and differentiation through signaling pathways like Wnt. Recent research highlights the role of ISCs in mucosal homeostasis and how their function is influenced by the niche environment. Key regulators include Lgr5, which promotes Wnt signaling, and TRIM27, which stabilizes β-catenin. Vitamin D receptor (Vdr) expression is also crucial for ISC function. The ISC niche includes Paneth cells, fibroblasts, and immune cells that provide growth factors and signals necessary for ISC maintenance. Aging reduces ISC regenerative capacity, leading to impaired mucosal homeostasis, while diet and the microbiome significantly impact ISC function and intestinal health. High-fat diets can enhance ISC self-renewal but also promote tumorigenesis. The gut microbiome plays a critical role in shaping mucosal homeostasis, with aging and environmental factors altering microbial composition and function. Understanding these factors is essential for developing strategies to improve gut regeneration and prevent diseases. Future research should explore the interplay of aging, diet, and the microbiome to enhance intestinal health.Intestinal stem cells (ISCs) are essential for maintaining the intestinal epithelium, which serves as a barrier against pathogens and regulates immune responses. ISCs reside in crypts and continuously replenish the intestinal lining, balancing self-renewal and differentiation through signaling pathways like Wnt. Recent research highlights the role of ISCs in mucosal homeostasis and how their function is influenced by the niche environment. Key regulators include Lgr5, which promotes Wnt signaling, and TRIM27, which stabilizes β-catenin. Vitamin D receptor (Vdr) expression is also crucial for ISC function. The ISC niche includes Paneth cells, fibroblasts, and immune cells that provide growth factors and signals necessary for ISC maintenance. Aging reduces ISC regenerative capacity, leading to impaired mucosal homeostasis, while diet and the microbiome significantly impact ISC function and intestinal health. High-fat diets can enhance ISC self-renewal but also promote tumorigenesis. The gut microbiome plays a critical role in shaping mucosal homeostasis, with aging and environmental factors altering microbial composition and function. Understanding these factors is essential for developing strategies to improve gut regeneration and prevent diseases. Future research should explore the interplay of aging, diet, and the microbiome to enhance intestinal health.