Interactions between dietary therapy and gut microbiota in inflammatory bowel disease: a systematic review and meta-analysis

Background: The main risk factor for inflammatory bowel disease (IBD) is a positive family history of 10-25% of patients. Crohn's disease (CD) can affect individuals aged 15 to 40 years and aged 50 to 80 years, more frequently in women. Ulcerative colitis (UC) can start at any age. The pathogenesis of IBD is linked to genetically susceptible individuals, deregulated gut microbiota (GM) (dysbiosis), chronic inflammation, and poor eating patterns. Diet plays an important role in modulating the GM and can be applied as a therapeutic tool to improve the course of the disease. Objective: To carry out a systematic review and meta-analysis on the main interactions between dietary therapy, gut microbiota, and inflammatory bowel disease, to elucidate the main clinical outcomes after nutritional treatment. Methods: This study followed the international model of systematic review and meta-analysis (PRISMA). Clinical studies were included, involving randomized controlled, prospective, and retrospective studies published from 2010 to 2020. Results: It was found 17 randomized controlled clinical studies and other clinical studies on the modulation of diet in the control of IBD. These studies showed reductions in persistent bowel symptoms, improved gut microbiota, reduced markers of inflammation, and improved quality of life, with p<0.05 (95% CI). The studies were homogeneous (I2 = 98.95%), which increases the reliability of the clinical results about 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.