Targeting Irritable Bowel Syndrome Through Diet and Mechanism-Based Therapies: A Pathophysiological Approach.

Irritable Bowel Syndrome (IBS) is a prevalent and heterogeneous functional gastrointestinal disorder with a complex and multifactorial pathophysiology. Traditional treatment approaches have focused on symptom relief, often overlooking the underlying biological mechanisms driving the disease. Τhis review summarizes the current evidence linking core pathophysiological pathways of IBS with mechanism- and diet- based therapeutic strategies to guide personalized treatment. Serotonergic signaling, microbial dysbiosis, immune activation, epithelial barrier dysfunction, and bile acid malabsorption interact to shape the diverse phenotypes of IBS, contributing to altered motility, visceral hypersensitivity, and gut-brain axis dysregulation. Increasing evidence supports that targeted dietary and biological interventions including low-FODMAP and Mediterranean low-FODMAP diets, targeted use of probiotics and psychobiotics, and vitamin D supplementation can modulate microbial composition, reduce luminal irritants, support barrier integrity, and attenuate immune system activation. Similarly, pharmacologic therapies including serotonergic receptor modulators, bile acid sequestrants and neuroimmune agents act on specific mechanistic pathways, reflecting a shift from symptom-based to mechanism-driven management. Collectively, these findings highlight that integrating dietary, microbial, neuroimmune, and serotonergic modulation within a unified therapeutic framework can support a more rational and individualized approach to IBS management and long term symptom control.