Dietary Therapy for Adults with Crohn’s Disease

H Yanai et al. The Lancet 2021; The Crohn’s disease exclusion diet for induction and maintenance of remission in adults with mild-to-moderate Crohn’s disease (CDED-AD): an open-label, pilot, randomised trial

In this open-label trial of adults with mild-to-moderate biologic naive Crohn’s disease, key findings:

  • At week 6, 13 (68%) of 19 patients in the CDED plus partial enteral nutrition group and 12 (57%) of 21 patients in the CDED group had achieved clinical remission (p=0·4618)
  • Among the 25 patients in remission at week 6, 20 (80%) were in sustained remission at week 24 (12 patients in the CDED plus partial enteral nutrition group and eight in the CDED alone group)
  • 14 (35%) of 40 patients were in endoscopic remission at week 24 (eight patients in the CDED plus partial enteral nutrition group and six in the CDED alone group)

My take: Dietary therapy may be effective option for motivated adult patients with Crohn’s disease.

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Head-to-Head: Nutritional Therapy versus Biological Therapy in Pediatric Crohn’s Disease

The best data to date: D Lee et al. Inflamm Bowel Dis 2015; 21: 1786-93. In this prospective study, the authors studied treatment initiation in children (N=90), comparing partial enteral nutrition (PEN, n=16), exclusive enteral nutrition (EEN, n=22), and anti-TNF therapy (n=52).


  • Clinical response, defined by PCDAI reduction ≤15 or final PCDAI ≤10, was achieved by 64% PEN, 88% EEN, and 84% anti-TNF.
  • Fecal calprotectin ≤250 noted in 14% PEN, 45% EEN, and 62% anti-TNF

Because of the discrepancy between EEN and PEN, the authors speculate that the “efficacy of EEN may be a consequence of elimination of table food rather than providing a uniquely therapeutic method of delivering nutrients.”  They note that “choice of formula has not impacted the efficacy of enteral nutrition.”

More extensive information on this subject: D Lee et al. Gastroenterol 2015; 148: 1087-1106.

Bottomline: Anti-TNF therapy was as effective or more effective than EEN. And, “for patients who prefer treatment with a nutrition-based therapy, EEN seems superior to PEN.”

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“Bacterial Penetration Cycle Hypothesis”

Initially, this blog was titled: “Even More Work for Our IBD Nutritionists?”  If you get to the bottom of this post, you will know why.

A provocative study (Inflamm Bowel Dis 2014; 20: 1353-60) describes the use of partial enteral nutrition (PEN) as effective for induction of remission in children and young adults with Crohn’s disease (CD).  I’m a little wary commenting on this study as many individuals may take a glimmer of information and subject themselves to empiric trials.  In fact, a recent case report (N Engl J Med 2014; 371:668-675) described an adult who without medical advice used fecal transplant therapy (obtained from spouse and infant) to self-treat his ulcerative colitis.  In the case report, this patient ultimately was diagnosed with a secondary cytomegalovirus (CMV) infection and the fecal transplant was not effective.

With regard to the PEN study, the authors treated 47 patients (34 children) with up to 50% of their diet as a polymeric formula (Modulen or Pediasure) along with dietary counseling/changes.  The authors note that CD “may arise from a sequence of events involving changes in the microbiome, intestinal permeability leading to bacterial adherence or penetration of the epithelium, and subsequent stimulation of the adaptive immune response leading to tissue damage.  We have termed this sequence the Bacterial Penetration Cycle Hypothesis.”  Given the compelling improvements noted with exclusive enteral nutrition (EEN), the authors sought to modify the diet after an initial clinical response in two patients who could not adhere to EEN.

Design: Strict diet for 6 weeks with 50% of calories from formula, then less restricted diet for next 6 weeks (25% of calories from formula).  Also, diet required exclusion of gluten, dairy, animal fat, processed meats, products containing emulsifiers, candies, chocolates, gum, packaged snacks, sauces, and canned goods.  A more extensive listing of the foods is given in the appendix (page 1360).  The authors measured the clinical response with PCDAI, Harvey Bradshaw index, and bloodwork (eg. CRP, ESR, albumin, and hemoglobin).

Key finding:

  • 33 (70.2%) achieved a remission on this PEN diet; 78.7% (n=37) had a clinical response.
  • Normalization of CRP occurred in 21 of 30 patients (70%) of those with a clinical remission.

Take home message: A PEN diet needs more study.  I would not advise someone to radically change their diet without the instruction of a qualified nutritionist, unless the individual wants to be another case report of something gone awry.

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