The Effect of Diet on Disease Activity and Symptoms in Patients With Ulcerative Colitis

Few studies have found a single dietary factor as being protective or detrimental against inflammatory bowel disease (IBD), therefore novel diet approaches for the prevention and treatment of IBD are urgently needed. The Mediterranean Diet Pattern (MDP) is associated with improvements in health status and inflammatory markers in healthy individuals and rodent models of colitis. Reductions in inflammatory biomarkers and a "normalization" of the gut microbiota have been shown in patients with Crohn's disease following a MDP. To date, no studies have examined the effect of MDP on disease activity, inflammatory markers or the effects on the microbiome in ulcerative colitis (UC).

This study will examine the effects of a MDP taken by patients with UC on 1) symptoms, clinical and quality of life endpoints and 2) on gut microbiome and fecal immune biomarkers. One hundred subjects and two subjects with UC will be randomly allocated to follow a MDP for 12 weeks or their usual diet (controls). Upon initiation, throughout and completion of each diet, symptoms, clinical and quality of life endpoints will be monitored. Fecal samples will be collected to assess pH, short-chain fatty acid concentrations, bacterial abundance and diversity.

Inclusion criteria

• Ulcerative Colitis in clinical remission (partial Mayo score 0-1)
• Taking oral 5-ASA, methotrexate, azathioprine or 6-mecaptopurine as long as there have been no changes in dosage for 2 months prior to the start of the study
• Generally healthy besides having UC
• Agree not to use any dietary supplements, herbal treatments, prebiotics, probiotics or diet therapies within three weeks of the onset of the trial or during the study

Exclusion criteria

• Using prednisone (or steroid equivalent) or biologics (i.e., infliximab, adalimumab, vedolizumab) at the time of enrollment
• Using antibiotics two weeks prior to or anytime during the study period
• Pregnancy, lactation or desire to become pregnant during the study period because we do not know if or how an unborn baby/fetus could be harmed
• History of colectomy or extensive colonic resection or disease is limited to the rectum
• Significant chronic disorders such as severe cardiac disease, significant renal failure, severe pulmonary disease (need for oxygen)
• Active gastrointestinal infection (e.g., C. difficile infection)
• Severe psychiatric disorder
• Unable or unwilling to consent
• Unable to comply with study requirements
• Presence of alcohol or drug abuse