P840 Dietary interventions rapidly alter metabolomics profile of patients with inflammatory bowel disease after pouch surgery

Abstract

Background: Diet may play a role in the pathophysiology of inflammatory bowel diseases (IBD) via several mechanisms including metabolome alteration. We conducted an interventional cross-over study aiming to evaluate the short-term effect of two dietary regimens, the Mediterranean diet (MED) and the specific carbohydrate diet (SCD) on multiple biomarkers of patients with IBD after pouch surgery. Methods: Two short (one-week) dietary interventions (MED and SCD) were provided to patients. After one washout week, patients were crossed over between diets. Both diets excluded industrialised and processed food. Faecal samples were collected and analysed for metabolomics profiling. Results: Overall 28 patients (male gender: 50%, mean age: 49±13 years, mean pouch age: 12±9 years) were recruited. Of those, 15 had a normal pouch, 12 had pouchitis and 1 - familial adenomatous polyposis. All patients completed both investigated dietary regimens. MED and SCD were isocaloric (Kcal: 1910±575 vs. 1857±614, p = 0.4), however diets differed in their macronutrients composition: MED had higher carbohydrate content and lower protein, fat and saturated fat content compared with SCD (carbohydrate, gr/day: 204±66 vs. 96±48; protein, gr/day: 80±26 vs. 119±45; fat, gr/day: 78±29 vs. 105±40; saturated fat, gr/day: 16±10 vs. 34±14; all p < 0.001). Faecal metabolomics analysis detected a total of 1051 named biochemicals. Both MED and SCD induced significant changes in 182 and 313 metabolites, respectively, including changes in super-pathways associated with carbohydrate, lipid, amino acid, peptide, nucleotide, vitamin and xenobiotics metabolism. MED and SCD had a discordant effect on amino acid metabolism, specifically, branched chain amino acid metabolism was up-regulated in MED and down-regulated in SCD. Both diets affected vitamins and cofactors metabolism, most notably, up-regulation of vitamin A metabolism. Interestingly, both diets up-regulated mono and diacylglycerol and down-regulated endocannabinoids metabolism, however ceramides metabolism was down-regulated in MED and up-regulated in SCD. Hierarchical clustering analysis showed that samples from each study participant tended to be more similar to each other than to other participants. Conclusions: In this cross-over trial, two unindustrialised dietary interventions (MED and SCD) rapidly altered the metabolomic profile of patients with IBD after pouch surgery, despite individual metabolomic signatures. Changes in these metabolites might alter signalling pathways associated with inflammatory responses via autophagy and activation of NLRP3 inflammasome. Thus, personalised dietary intervention may be used to modify inflammation in IBD via altering metabolomics profile.