Effects of Exclusive Enteral Nutrition on the Microbiome in Pediatric Inflammatory Bowel Disease

Exclusive enteral nutrition (EEN) is an effective induction therapy in pediatric Crohn's disease (CD). Compared to corticosteroids, EEN has equivalent rates of clinical remission and significantly higher rates of mucosal healing and weight gain. There is a paucity of literature on the role of EEN in ulcerative colitis (UC). Some have postulated that colonic disease will not respond to EEN, yet two series found no difference in rates of clinical remission between small intestinal and colonic CD. The mechanisms underlying the effectiveness of enteral nutrition in colitis remain unclear. A microbiome-mediated pathogenesis is possible. Two studies have shown how EEN produces profound changes in microbial community structure within as little as 24 hours. These changes correlated with improved disease activity scores. Active inflammatory bowel disease also carries distinct microbial signatures. Baseline differences in taxonomy between IBD phenotypes may account for differences in EEN efficacy between CD and UC.

The purpose of the pilot study is to investigate if EEN can be used for induction of remission of ulcerative colitis, and compare its usage to a) corticosteroids for UC and b) EEN or corticosteroids for Crohn's disease. The goal is to eventually characterize the clinical, biochemical and microbial changes that occur with each. However, given that EEN is a challenging commitment, as a sole source of nutrition for 8 weeks, investigators first have to evaluate feasibility in terms of participant recruitment, compliance and safety of this treatment. Both EEN and corticosteroid treatment require proper compliance to be effective, which can be a significant burden for the patient and his/her family. Investigators will therefore also determine satisfaction with the induction therapies and effect on quality of life. Further, since frequent follow up is being requested, investigators need to assess recruitment and retention rates, as well as compliance with completing bloodwork and providing stool samples. Investigators hypothesize that these induction therapies will be both feasible and safe. However, it is anticipated that, while patients will be satisfied with the treatment, it may have a significant impact on quality of life during those 8 week.

Inclusion criteria

• Children 5-18 years old who have been diagnosed with IBD (confirmed by endoscopy, histology and radiography), and are followed by McMaster Children's Hospital's Division of Pediatric Gastroenterology and Nutrition.
• Patients requiring induction therapy
• Patients already taking 5-aminosalicylic acid (5-ASA) azathioprine, 6-mercaptopurine or anti-TNF (tissue necrosis factor) therapy (e.g. infliximab)

Exclusion criteria

• Patients who are in remission (on maintenance therapy).
• Patients who receive new medical therapies (e.g. antibiotics, probiotics) during the study period