Vitamin D, a crucial fat-soluble vitamin, is primarily synthesized in the skin upon exposure to ultraviolet radiation and is widely recognized as a bone-associated hormone. However, recent scientific advancements have unveiled its intricate association with gut health. The intestinal barrier serves as a vital component, safeguarding the intestinal milieu and maintaining overall homeostasis. Deficiencies in vitamin D have been implicated in altering the gut microbiome composition, compromising the integrity of the intestinal mucosal barrier, and predisposing individuals to various intestinal pathologies. Vitamin D exerts its regulatory function by binding to vitamin D receptors (VDR) present in immune cells, thereby modulating the production of pro-inflammatory cytokines and influencing the intestinal barrier function. Notably, numerous studies have reported lower serum vitamin D levels among patients suffering from intestinal diseases, including inflammatory bowel disease, irritable bowel syndrome, and celiac disease, highlighting the growing significance of vitamin D in gut health maintenance. This comprehensive review delves into the latest advancements in understanding the mechanistic role of vitamin D in modulating the gut microbiome and intestinal barrier function, emphasizing its pivotal role in immune regulation. Furthermore, we consolidate and present relevant findings pertaining to the therapeutic potential of vitamin D in the management of intestinal diseases.
Keywords: IBD; IBS; gut microbiome; intestinal barrier; vitamin D.