The Crohn’s disease exclusion diet (CDED), with or without partial enteral nutrition (PEN), effectively induced and maintained remission in adults with mild to moderate, biologic-naive CD, a randomized Israeli pilot study found.
The authors, led by Henit Yanai, MD, MBA, chief of the IBD Center at Rabin Medical Center in Petah Tikva, Israel, also suggested that dietary monotherapy might lead to durable endoscopic remission.
The study, published in The Lancet Gastroenterology & Hepatology, found about 60% of patients on CDED achieved clinical remission by week 6 without adding medications.
Furthermore, 80% of patients in remission at week 6 maintained clinical remission at week 24 on dietary monotherapy alone, allowing more than 50% of the intention-to-treat (ITT) population to achieve sustained remission at 6 months.
Dietary therapy resulted in a significant and progressive reduction in inflammatory markers such as C-reactive protein and fecal calprotectin. The benefit extended to mucosal healing, with 35% of the ITT population achieving endoscopic remission at 24 weeks.
Dr. Yanai explained the clinical context in which her group designed the study. “There were preliminary data regarding the efficacy of the dietary strategy for the induction of remission of mild CD in the pediatric population,” she said in an interview. “Additionally, there was an anecdotal experience in adults who reported benefits. Facing this and the lack of attractive alternatives for mild CD, we decided to examine the effectiveness of this therapeutic strategy in adults.”
Given the costs and side effects of medical treatment, interest in dietary monotherapy for IBD has been growing. As Dr. Yanai said, the CDED, a whole-foods regimen, plus PEN, has been found to help children with CD.
The CDED excludes proinflammatory food components associated with intestinal microbial dysbiosis, altered innate immunity, and impaired gut barrier function.
It involves increased consumption of fruits and vegetables, high-quality lean protein, complex carbohydrates, healthy oils, and fiber, while decreasing intake of inflammation-driving components such as animal and saturated vegetable fats, wheat, and dairy, as well as food additives such as emulsifiers, maltodextrin, and sulfites.
“The realization that exclusive enteral nutrition, which is based on liquid formulas, is effective for inducting remission in children PEN, which is a combination of liquid formulas and food, was less effective, led to the hypothesis that the mechanism might be the exclusion of dietary components that may lead to inflammation,” Dr. Yanai said. This theory, she added, derived from animal models showing that specific dietary components potentially drive inflammation.
The only current guideline-recommended nutritional therapy for remission induction is exclusive enteral nutrition (EEN) in pediatric CD.
The open-label pilot trial led by Dr. Yanai, conducted at three medical centers, enrolled biologic-naive adults ages 18-55 with uncomplicated mild to moderate CD, with a disease duration of no more than 5 years. They had active disease on imaging and elevated C-reactive protein or fecal calprotectin.
During the period January 2017 to May 2020, eligible patients were randomly assigned 1 to 1 to CDED plus PEN enteral (n = 20) or CDED alone (n = 24) for 24 weeks. The primary endpoint was clinical remission, defined as a Harvey–Bradshaw Index score of less than 5 at week 6, an outcome was assessed in the ITT population, which consisted of those who used dietary therapy for at least 48 hours.
At week 6, 13 (68%) of 19 remaining patients in the CDED-plus-PEN group and 12 (57%) of 21 patients in the CDED-alone group had achieved clinical remission (P = .4618).
Among the 25 patients in remission 6 weeks out, 20 (80%) remained in sustained remission at week 24: 12 in the CDED-plus-PEN group and 8 in the CDED-alone group.
Moreover, 14 (35%) of 40 patients were in endoscopic remission at week 24: 8 on CDED plus PEN and 6 on CDED alone.
“CDED with or without partial enteral nutrition was effective for induction and maintenance of remission in adults with mild to moderate biologic-naive Crohn’s disease and might lead to endoscopic remission,” the authors wrote, adding that CDED for mild to moderate active disease should be assessed in a powered randomized controlled trial.
Compliance and adherence are obstacles to dietary therapies. Data for adults using exclusive enteral nutrition are conflicting, with poor compliance postulated to drive an inadequate response in some studies.
“Like every dietary treatment, adherence is challenging,” Dr. Yanai said. “However, when patients feel that it helps them, they have more incentive to follow the diet in the long run, and also once they quit and fare worse, they can go back and follow the first stage of CDED.”
She and her colleagues stressed the need for adequately powered randomized trials and recommended that the personalization of therapeutic diets in the future should take into account the need to deliver energy tailored to the nutritional and therapeutic goals of the patient.