Paper Title
Evaluation of a Novel Crohn’s-Specific Diet in Children: Effects on Disease Activity and Gut Microbiome

Gut microbiota dysbiosis is important in Crohn's disease (CD) pathogenesis. Whilst exclusive enteral nutrition (EEN) is effective at inducing remission in paediatric CD, partial enteral nutrition (PEN) alongside a solid, free-diet is not. Conversely, PEN accompanied by a specific exclusion diet (SED) has been shown to be effective. Exclusion of certain foods may be associated with altered gut microbiota and promotion of remission. Methods: 13 newly-diagnosed, paediatric CD patients were given a six-week course of EEN. Patients then chose either freediet or SED, which excluded certain foods. Disease activity, nutritional adequacy and anthropometric indices were recorded, and faecal samples collected pre-treatment, during EEN and once established on chosen diet. Microbiome profiling of 16S rRNA gene was carried out using Illumina MiSeq platform. Results: 10/13 patients completed 6-weeks of EEN and 6/10 achieved remission (free-diet n=2; SED n=4). Of the two who chose free-diet, one was in remission and one had relapsed at three months. Of the four who chose SED, one had relapsed, one was in remission and two have not yet reached the three-month endpoint. However, both are in remission at one and two months, respectively. There were changes in microbiota during EEN, including increased Bacteroides and decreased Bifidobacterium. There was a trend towards increased species diversity in SED compared to free-diet. Conclusion: We have shown differences in microbiota between EEN, SED and free-diet samples, although these have not yet reached statistical significance in this interim cohort and conclusions on the clinical effects of SED cannot yet be drawn. Keywords - Crohn's disease, microbiota, specific exclusion diet, exclusive enteral nutrition.