Inclusion Criteria:

• - Patients with Ulcerative colitis (UC) with confirmed diagnosis by histology and endoscopy.

• - Currently in clinical remission defined as total Mayo score of ≤ 2 and endoscopic score of 0 or 1) who have experienced at least one flare in the past 18 months.

• - On stable doses of oral 5-ASA for 2 weeks and/or a stable doses of azathioprine and/or anti-tumor necrosis factor (anti-TNF) biologics for 2 months - Colonic involvement of >15 cm from the anal verge.

• - Ability to give valid informed consent - For females of child bearing potential, a negative pregnancy test and an agreement to use appropriate birth control over the study period.

Exclusion Criteria:

• - Crohn's disease, indetermined colitis or infectious colitis.

• - Active UC, (total Mayo score of ≥ 3) - Taking prednisone (or steroid equivalent) within 1 month of enrollment - Used topical 5-ASA or steroids within 2 weeks of enrollment - Using immunosuppressive treatments of 6-mercaptopurine or methotrexate - Used antibiotics within 2 months - Used anti-diarreal agents with the previous 3 days - Pregnancy or lactation - Significant chronic disorders such as severe cardiac disease, significant renal failure, severe pulmonary disease (need for oxygen) - Active gastrointestinal infection - Severe psychiatric disorder - Not able to consent to the study.

Objectives: Based on the efficacy of inulin plus FOS shown in experimental colitis as well as their ability to improve active human UC the investigators propose double-blind placebo controlled study using Synergy1, a 1:1 FOS/ inulin mixture, in patients in clinical remission of UC. The specific aims of this study are as follow: 1. To determine if β-fructans are effective in maintaining clinical remission in UC patients. 2. To examine the mechanisms of action of β-fructans on the intestinal microbiota composition and function and host immune response of these patients. It is hypothesized that β-fructans will prolong remission in UC patients with inactive disease maintained on standard drug therapy and that the prebiotics beneficial effect is associated with enhanced colonic energy homeostasis as a result of specific stimulation of butyrate- and/ or other SCFA-producing microorganisms combined with improved host mucosal energy and inflammation regulation. The proposed trial Trial Design: A double blind placebo controlled clinical trial Intervention and duration of treatment: All patients in the treatment group will receive chicory-derived β-fructans inulin plus FOS (1:1) ("Synergy1") for 6 months. Synergy1 will be administered as 7.5 gram dose twice a day as a pre-packaged powder added to meals and provided by Beneo-Orafti. This 15 gram daily prebiotic dose was found to be most effective in treating mild to moderately active UC in the investigator's previous pilot study. Patients in the placebo group will receive non-fermentable maltodextrin with a similar appearance, dosage and frequency as β-fructans. Patients that completed the 6 months treatment period will be monitored for disease related symptoms for additional 6 months. Co-Intervention: Participants will continue at standard maintenance therapy for the duration of the trial. Participants will be asked to maintain their regular diet. This will be confirmed by having subjects complete the Food Frequency Questionnaire and assessing dietary intake at 0 and 6 months of the study, or at relapse, using online system. Compliance will be assessed by counts of study agent packages and by metabolomic analysis of participants serum and urine. Specimen Samples: Fecal samples will be collected for fecal calprotectin (FC) and microbiota analysis at 0, 1, 3, 6 and 12 months, or at relapse. Colon biopsies will be collected between 15-20 cm from the anus for host mucosal response (4 biopsies), microbiota studies (4 biopsies) and histology (2 biopsies) at the start, and at 6 months, or at relapse. Urine and blood/serum will be collected for metabolomics analysis at 0, 1, 3 and 6 month of treatment, or at relapse. Colonic luminal washes will be collected at the start and at 6 months or at relapse during the sigmoidoscopy exam. Sample Size: Ninety patients, 45 in each arm, will be needed to detect a difference of 30 % in the proportion of UC patients with clinical recurrence by 6 months with a power of 80% using a two-sided p=0.05 level test. An anticipated dropout rate for this trial will be 10%, based on previous maintenance trials, therefore the overall sample size for this trial will be 100 patients. Outcomes: Primary Outcome: The proportion of patients with relapse over 6 months. Relapse is defined as an increase of Mayo score of 3 or more with an endoscopy grade equal to or more than 2, and rectal bleeding for at least 3 days. The relapse rate in the prebiotic-treated group at 6 month will be compared to the relapse rate in the placebo group. Secondary outcomes: 1) Time to relapse. 2) Patient compliance and tolerability. Compliance will be assessed as a ratio of packages (used) divided by the total packages dispensed over 6 months. Tolerability will be assessed by a validated questionnaire by Casellas et al on adverse effects such as bloating and flatulence, compliance by package, pill counting and metabolomic analysis at 3 and 6 months, or at relapse. 3) Intestinal inflammation (measured by fecal calprotectin) at baseline and months 1, 3 and 6, or at relapse. 4) Microscopic inflammation scores (0 and 6 months, or at relapse) Basic science parameters: 1) Colonic biopsies for cytokine measurement, butyrate transporters and oxidation pathway and Mucin 2 (MUC2) mRNA expression analysis, histological assessment and characterization and quantification of the mucosa-associated microbiota; 2) Stool and urine for assessment of fecal calprotectin concentrations, the luminal microbiota and its metabolic products using pyrosequencing, quantitative PCR (qPCR) and gas chromatography (GC) and nuclear magnetic resonance (NMR); 3) Blood/serum for metabolomic analysis with GC and NMR; 4) colonic luminal wastes for assessing the Immunoglobulin G (IgG) associated microbiota.

Arms

Interventions