Rationale: Ulcerative colitis (UC) patients respond differently to treatments/interventions (e.g. diet/fecal microbiota transplantation), but the reason for this individual specificity remains unknown. The investigators hypothesize that the baseline fecal microbiota composition determines the efficacy of a treatment/intervention, and potential responders, i.e. patients showing symptoms improvement after treatment, can be predicted based on fecal microbiota composition.~Objective: The primary objective is to validate the prediction that prebiotics intervention boosts butyrate production and thereby induces a higher response (lower mean Patient Simple Clinical Colitis Activity Index (P-SCCAI) score) in mild UC patients with low intestinal Bacteroidetes levels (predicted responders), but not in those with high intestinal Bacteroidetes levels (predicted non-responders) at T = 8 weeks. The secondary objectives are to study the effects of prebiotics intervention on disease activity over time (T = 0, 4, 8, 12 and 60 weeks), mucosal inflammation, gastro-intestinal (GI) complaints, stool consistency, stool frequency, fecal microbiota composition, fecal short-chain fatty acids concentrations, quality of life, number of participants with increased or decreased medication use, and incidence of adverse events in mild UC patients.~Study design: This study is a four-arm double-blind randomized placebo-controlled parallel trial. It consists of a screening stage in which mild UC patients will be assigned to be predicted responders or predicted non-responders based on fecal Bacteroidetes levels. Afterwards the predicted responders and non-responders will be assigned to either the prebiotics group (arm 1 and 3) or placebo group (arm 2 and 4).~Study population: Adult subjects aged 18-65 years and body mass index 18-30 kg/m2 with mild UC defined by P-SCCAI (3-5 points in a 19-point scale), with at least one relapse in the last two years.~Intervention: An 8-week intervention period with four parallel arms: 1) predicted responders with prebiotics treatment (acacia gum, partially hydrolyzed guar gum, and resistant starch), 2) predicted responders with placebo (maltodextrin and corn starch), 3) predicted non-responders with prebiotics treatment, 4) predicted non-responders with placebo, during which the study participants consume the respective supplement (3 grams, twice daily).~Main study parameters/endpoints: The main parameter is the response (mean P-SCCAI score) between arms at T = 8 weeks. The secondary parameters are the disease activity over time at T = 0, 4, 8, 12, and 60 weeks, mucosal inflammation (fecal calprotectin), gastro-intestinal (GI) complaints, stool consistency, stool frequency, fecal microbiota composition, fecal short-chain fatty acids concentrations, health-related quality of life, number of participants with increased or decreased medication use, and incidence of adverse events.
A double-blind randomized placebo-controlled parallel trial with two intervention arms and two placebo arms and a period of eight intervention weeks to validate the prediction that prebiotics could induce a higher response in mild UC patients with certain fecal microbiome signatures.