Editorial: Inflammatory Bowel Disease and Dietary Emulsifiers—A Conundrum That Continues. Authors' Reply

Editors,

We currently work in a clinical environment where expert IBD organisations and clinicians recommend that patients with Crohn's disease avoid emulsifiers. Unfortunately, these recommendations are based upon preclinical data that have not been translated to human real-world food intake. We have questioned the wisdom of providing non-evidence-based recommendations that demonise food components, just as we did for gluten in patients with self-reported non-coeliac gluten sensitivity [1]. Hence, we undertook a randomised double-blinded study in patients with active ileal Crohn's disease providing diets differing only in the emulsifier content (natural and synthetic) as found in the food supply—an interrogation of IBD recommendations that deter ingestion of dietary emulsifiers [2]. The results showed no evidence of a difference in objective and symptomatic outcomes according to the dietary emulsifier content.

We concur with some of the limitations raised by Gold et al. in their editorial on that report [3]. First, 4 weeks may not have been long enough to see the impacts of emulsifiers. Yet, in 4 weeks we saw significant clinical and objective benefits of both diets. Intestinal inflammation in Crohn's disease can respond quickly to therapy. Exclusive enteral nutrition (EEN) reduces inflammation in two weeks [4] and ustekinumab can reduce bowel wall thickness on intestinal ultrasound by 9.6% in 5 weeks [5]. We saw reduction of 34% and 15% on bowel wall thickness on the high and low emulsifier diets, respectively, in 4 weeks. Second, we recognise the small sample size was exacerbated by the withdrawal of 20%, mostly within days of the dietary intervention due to intolerable symptoms and, incidentally, greater systemic inflammation (higher serum C-reactive protein). However, this withdrawal rate was modest in comparison to other dietary trials, such as the landmark Crohn's Disease Exclusion Diet with partial enteral nutrition compared with EEN, where 34% of 40 participants withdrew [6].

Scepticism around the dietary quality of prospectively designed and prepared diets used in the study was somewhat surprising, especially as the diets were matched for all components and met healthy eating guidelines. Dietary quality may be a mechanism for the improvement in outcomes, but is not a confounder between the two intervention diets. Likewise, adherence was high when all meals were provided (supported by food diaries) and these diets underwent pre-trial evaluation for adherence, tolerance and blinding [7].

We strongly disagree that the study was limited by the lack of objective outcomes that directly reflect intestinal inflammation. Gastrointestinal ultrasound is validated for this purpose [8] and is more practical and, particularly for a transmural disease, more relevant than mucosal healing.

We urge clinicians to stop demonising dietary emulsifiers, based on preclinical and epidemiological data, as unnecessary dietary restriction can be harmful. Counselling patients to avoid all labelled emulsifiers in the food supply as a way to reduce intestinal inflammation remains an emotive action that is currently not based upon evidence, remembering for now that our best dietary evidence to induce mucosal healing in Crohn's disease is EEN, a 100% ultra-processed food diet which contains emulsifiers [9, 10].

Jessica A. Fitzpatrick: conceptualization, writing – original draft, writing – review and editing. Peter R. Gibson: conceptualization, writing – review and editing. Emma P. Halmos: conceptualization, writing – review and editing.

J.A.F.: speaker honoraria Mindset Health Pty Ltd. and Pepsi Co. P.R.G.: consultant or advisory board member for Anatara, Atmo Biosciences, Topas, and Comvita; research grants for investigator-driven studies from Mindset Health; and speaker honoraria from Dr. Falk Pharma and Mindset Health Pty Ltd. Shareholder in Atmo Biosciences. E.P.H.: received research grants from Mindset Health Pty Ltd. and Gastroenterological Society of Australia IBD Clinical Project award. She has received honoraria or consulted for Ferring, Janssen, Abbvie, Takeda, Shire, Sandoz, and Dr. Falk Pharma.

This article is linked to Fitzpatrick et al papers. To view these articles, visit https://doi.org/10.1111/apt.70041 and https://doi.org/10.1111/apt.70112.