Dietary intervention alters the microbiota and its byproducts improving patient’s outcomes

Inflammatory bowel diseases (IBD) are chronic disorders of the gastrointestinal tract that may be caused by inappropriate inflammatory responses to normal intestinal microbes, collectively called microbiome- in a genetically susceptible host. Several genes involved in the body’s immune response seem to predispose for IBD but genes alone can't explain the sharp rise in IBD incidence. Now we are looking at environmental conditions that can promote the development of the disease. Increasing evidence support that IBD patients exhibit an altered microbiome (harmful bacteria outnumbering the beneficial ones), which can be the lost piece of the puzzle. Given the increasing evidence of the role of diet in shaping the microbiome we aim to understand how diet could restore the microbiome in such a way as to reduce disease activity and improve outcomes for patients suffering with IBD.

Inflammatory bowel diseases (IBD) including Crohn’s disease (CD) and ulcerative colitis (UC) are chronic recurrent inflammatory disorders of the intestinal tract that are of unknown etiology. Evidence supports the notion that this disease is an environmentally initiated and immune mediated chronic inflammatory disorder, which develops in genetically susceptible individuals. It has also been documented that IBD may result from an inappropriate inflammatory response to intestinal microbes in a genetically susceptible host. Recently metabolic profiling studies have further shown that in addition to host endogenous metabolites, bacterial byproducts derived from diverse intestinal bacterial communities also play a critical role in evoking immune responses.

Thus, the gut microbiome plays a fundamental role in the balance between health and disease. The microbiome is distinct for each person and its composition is the result of a combination of initial exposure after birth, life events, host genetics, and diet. Recent evidence has shown that diet is crucial for the dynamics of the gut microbiome. These observations present a possible pathway for dietary manipulations of the microbiome to reduce inflammation in IBD. Surprisingly, there are few dietary guidelines to help patients with inflammatory bowel disease cope with debilitating symptoms that include severe abdominal pain and diarrhea. Therefore, we seek to test the hypothesis that specific dietary patterns may significantly alter the microbiome and improve nutrient absorption, which in turn alters the immune response in such a way as to reduce disease activity and improve outcomes for patients suffering with IBD.

Prior investigation of nutritional approaches to treating IBD have been largely limited to the use of enteral and total parenteral nutrition with the aim of providing bowel rest. Dietary whole food recommendations for the two most common IBD manifestations: UC and CD are poorly developed, even though patients often seek for advice with their diet. Thus, our novel approach of a diet that patients can easily follow and its good for the whole family will prepare clinicians for the complex management of patients. This diet is based on a balance of prebiotic and probiotic foods, fatty acids, beneficial nutrients, and avoidance of adverse foods in a phased approach that, in combination, satisfies nutrient requirements. So far, 100% of patients that completed four weeks on the diet were able to downscale their medication regimen as their IBD symptoms such as bowel urgency and frequency, abdominal pain and bloating, and blood in stools were reduced or eliminated.

Our goal is to understand how this diet intervention alter the microbiome, contributing to improved outcomes for patients in two ways: i) increasing nutrient absorption and adequacy, and ii) lessening the underlying immune and inflammatory response caused by commensal microbes in such a way as to reduce disease activity.

Principal investigators: Beth McCormick, Ph.D.; Ana Maldonado-Contreras, Ph.D.; and Barbara Olendzki, RD MPH