Diet as Adjunctive Treatment for Inflammatory Bowel Disease: Review and Update of the Latest Literature

Abstract

PURPOSE OF REVIEW Diet plays an integral role in development of inflammatory bowel disease (IBD) and continues to act as a mediator of intestinal inflammation once disease sets in. Most clinicians provide little dietary guidance to IBD patients, in part due to lack of knowledge in nutrition and lack of available nutritional resources. The purpose of this review is to provide clinicians with a brief summary of the latest evidence behind diets popular among IBD patients, to highlight diets with known efficacy, and to provide guidance that may help busy practitioners. RECENT FINDINGS The latest studies show that exclusive enteral nutrition (EEN) remains the most effective diet for induction of remission in Crohn's disease (CD), either in the form of elemental, semi-elemental, or polymeric formulas. Recent studies also show that EEN can be useful in complicated CD including in enterocutaneous fistulas closure and to optimize nutrition in the pre-operative setting. Although new studies suggest that partial enteral nutrition supplemented with elimination diets may be beneficial in ulcerative colitis (UC) and CD, larger controlled studies are needed to support their use. The autoimmune diet also shows promise but lacks larger studies. Recent uncontrolled clinical studies evaluating the specific carbohydrate diet (SCD) suggest that this diet may improve biochemical markers of inflammation and induce mucosal healing, although larger studies are needed to support its use, especially because the SCD is very restrictive. Short-term use of the low FODMAP diet is appropriate when in the setting of an acute flare up and/or in stricturing disease, but long-term restriction of FODMAPs is not recommended given long-term changes observed in the microbiome. Recent studies suggest that avoidance of processed foods, packaged with preservatives and emulsifiers, may be important in decreasing intestinal inflammation; many of the recent popular diets share a common concept, avoidance of processed foods. In this review of the latest literature, we highlight that dietary studies are still in a rudimentary stage. Large prospective randomized control studies are underway evaluating head to head comparisons on the efficacy of some of these diets. We offer general guiding principles that may help gastroenterologists in the meantime.