Joel R. Rosh, MD, FAAP, FACG, AGAF

We recognize that diet plays a role in the etiology of Crohn’s disease. Probably the best signal we have for this is the well published experience with exclusive enteral nutrition (EEN), where diet is restricted to just formula with no solid food intake. EEN has been shown to induce steroid-free clinical remission and there is even evidence for mucosal healing with EEN.

However, we also recognize that it’s a very difficult diet to comply with, especially as a maintenance strategy, as most people would prefer to eat food. Even when patients are able to comply with an exclusive enteral nutrition diet for 6 to 8 weeks, there is a paucity of long-term outcome data due to the difficulty continuing such therapy.

The EEN experience has spurred interest into developing an exclusion diet that can achieve similar outcomes. The underlying concept is that EEN works by altering the gut microbiome and, therefore, can an exclusion diet be formulated to achieve that same effect? Currently, we recognize that the chronic inflammation of Crohn’s disease is modulated through an interaction between the host immune system and the gut microbiome. The majority of our most effective therapies are currently focused on the immune system side of that equation. If we were able to alter the gut microbiome with diet and thereby effect the inflammatory process through diet, could we effectively induce and maintain remission in Crohn’s disease?

These investigators looked at exactly that question in pediatric Crohn’s Disease using a Crohn’s Disease Exclusion Diet (CDED), which is a whole-food diet that excludes a variety of agents, including mostly preservatives and emulsifiers and compared a study group that was receiving half their calories by CDED with the other half by formula (Modulen; Nestle Health Science) to a second cohort induced with Modulen alone. Study endpoints included clinical outcomes and dietary compliance.

What the investigators found, not surprisingly, was that the CDED patients had higher rate of tolerance.

Notably, the researchers found relatively high rates of corticosteroid-free remission (75% in the CDED arm; 59% in the EEN only arm).

Something that is important to take away from this study is that researchers were looking at sustained remission at week 12, so as an induction therapy this worked very well.

But this study didn’t look at maintenance.

Also, all the patients were listed as having mild to moderate Crohn’s disease and they were within 3 years of diagnosis, so probably a lot of these were patients who fell out of remission and weren’t necessarily newly diagnosed as we know that the majority — probably more than 80% — of pediatric Crohn’s disease patients are moderate to severe at diagnosis. So, will this diet work for the moderate to severe patient, who is commonly encountered at diagnosis or, is this a therapy best used as an alternative to going back to corticosteroids in a patient who loses response? Clearly this is not the last we will hear of CDED and this remains a very exciting area of clinical and translational research.