The Role of Diet- and Microbial-Based Therapies in IBD

Some dietary strategies, probiotics, supplements, and alternative therapies may have utility in helping induce and maintain remission of ulcerative colitis (UC) and Crohn disease (CD), Kerri Glassner, DO, explained during her presentation at the September 26 Advances in Inflammatory Bowel Disease (AIBD) virtual regional meeting.

Dr Glassner is gastroenterologist at Houston Methodist Hospital in Houston, Texas.

“Many patients view diet as a crucial component in management of their IBD,” she said. However, between 50% and 69% of patients with IBD report not receiving any information about diet from their gastroenterologists.

Dr Glassner presented the case of a 31-year-old woman with recently diagnosed UC. This patient underwent colonoscopy for symptoms of hematochezia and diarrhea, and was diagnosed with mild Mayo 1 pancolitis; biopsies were consistent with UC but findings were negative for cytomegalovirus. After beginning treatment on mesalamine, 4.8 g daily, and experiencing improvement in her symptoms, the patient returned for follow-up with several questions:

• What kind of diet should I follow?
• Are there any supplements I can take to help?
• Should I be taking probiotics?
• I read online about fecal transplant; can I have one?

Dr Glassner reviewed several dietary programs and the existing evidence for their efficacy in helping reduce the symptoms of inflammatory bowel disease (IBD). She noted that research has found that exclusive enteral nutrition (EEN)—in which 100% of nutrition is delivered through liquid formulations orally or via feeding tube for 6 to 8 weeks—is as efficacious as corticosteroids for inducing remission in pediatric CD. Pediatric patients using EEN were 4.5 times more likely to achieve mucosal healing than corticosteroids in one meta-analysis, she added, while 3 meta-analyses reported an “overall combined remission rate of 73% for EEN in pediatric CD.” 

However, Dr Glassner stated, studies of EEN in adults have found the diet inferior to corticosteroids in inducing remission, possibly due to issues with adherence and tolerability.

For adult patients with IBD, studies of the Crohn Disease Exclusion Diet (CDED) have found that at week 12, the CDED group was more likely to be in remission than the EEN group.

The CDED diet eliminates animal fats, dairy, wheat, red meat, emulsifiers, maltodextrin, and carrageenan, she explained. The CDED plus partial enteral nutrition (PEN) dietary plan was superior to EEN in sustaining remission at 12 weeks

“Fecal calprotectin improved significantly in the CDED+PEN group at 6 and 12 weeks vs EEN, where an increase in fecal calprotectin was seen from week 6 to week 12 after reintroduction of solid food diet,” Dr Glassner stated.

The CD-TREAT Diet, she explained, is an “individualized food-based diet with similar composition to EEN on gut microbiome, inflammation, and clinical response.” This plan is “easier to adhere to,” Dr Glassner said, and appears to induce similar microbiome effects to EEN. “In children receiving CD-TREAT, 80% had a clinical response and 60% entered remission, and their calprotectin significantly decreased.” The CD-TREAT Diet excludes gluten, lactose, and alcohol and matches EEN in macronutrients, vitamins, minerals, and fiber.

First described in 1924 by Dr Sidney Haas, the specific carbohydrate diet (SCD) gained fame as the “banana diet” for children with celiac disease. It eliminates most grains, sugars (except honey), processed and canned foods, and milk. No randomized clinical trials have been conducted to assess the efficacy of the SCD, but some surveys and retrospective analyses have shown reduction in fecal calprotectin, remission of symptoms, and improved laboratory markers, Dr Glassner said.

The low FODMAP diet has demonstrated some benefit “in quiescent IBD with ongoing IBS-type symptoms,” Dr Glassner said. A randomized control trial of 52 such patients found that those on the low FODMAP diet were “more likely to have adequate relief of symptoms and higher health-related quality of life scores” than those in the control diet group after 4 weeks. Another study showed similar results after 6 weeks on this diet. 

Studies have shown some contradictory results in terms of the protective effects of reducing meat consumption on flares of Crohn disease, Dr Glassner noted. In general, dietary guidance for Crohn disease calls for increasing fruits and vegetables while reducing saturated fats, artificial sweeteners, maltodextrin, and emulsifiers. For patients ulcerative colitis, dietary guidelines include increasing consumption of healthy fats, such as fatty fish, while avoiding saturated fats, red meats, dairy, and artificial sweeteners.

Among popular supplements, curcumin has shown some effectiveness as an adjunctive agent in mild to moderate UC for induction and maintenance of remission. “There is some evidence to support use of curcumin in primary prevention and maintenance of remission for pouchitis,” Dr Glassner said. 

Probiotics can alter the mucosal immune system, improve barrier function, and increase bacterial diversity, but they have not been found to be effective in the treatment of CD. However, they “may have some benefit in the maintenance of remission of mild to moderate UC,” she said. However, outcomes have varied in studies. There is some evidence to support the use of a probiotic VSL#3 in patients with pouchitis to maintain remission in UC. 

Dr Glassner noted that more patients are asking about the possibility of fecal microbiota transplants (FMT). She explained that a clinical trial comparing anaerobically prepared donor FMT with autologous FMT showed that the anaerobic FMT resulted in 32% of participants achieving steroid-free remission of UC at week 8, compared with 9% of those who received autologous FMT. Using anaerobic processing may preserve some beneficial anarobic microbiota, she said.

—Rebecca Mashaw

Reference:

Glassner K DO. Eastern versus western medicine: role of diet and microbial based therapies. Talk presented at: Advances in Inflammatory Bowel Disease 2020 regional meeting; September 26, 2020; virtual.