Evidence from clinical studies of the nutrological modulation of the gut microbiota in inflammatory bowel diseases: a systematic review

Introduction: The main risk factor for inflammatory bowel disease (IBD) is a positive family history in 10-25% of patients. Crohn's disease (CD) can affect individuals from 15 to 40 years old and from 50 to 80 years old, more frequently in women. Ulcerative colitis (UC) can start at any age. The pathogenesis of IBD is linked to genetically susceptible individuals, dysregulated gut microbiota (dysbiosis), chronic inflammation, and poor dietary patterns. Diet plays an important role in modulating the gut microbiota and can be applied as a therapeutic tool to improve the course of the disease. Objective: To carry out a systematic review of the main interactions between dietary therapy, gut microbiota, and inflammatory bowel disease, to elucidate the main clinical outcomes after nutrological treatment. Methods: The present study followed the international model of systematic review (PRISMA). Clinical studies were included, involving randomized controlled, prospective, and retrospective studies published from 2010 to 2022. Results: It was founded 87 studies on diet modulation in the control of IBD. These studies showed reductions in persistent intestinal symptoms, improvement of gut microbiota, reduction of inflammation markers, and improvement in quality of life, with p<0.05 (95% CI). The studies were homogeneous (X2 = 98.9%), which increases the reliability of the clinical results on the dietary importance in the modulation of IBD. Conclusion: The important role of diet modulation in the control and even in the remission of IBD was evidenced.