People with Crohn's or colitis in a Belgian study ate more emulsifiers than healthy volunteers, but not more ultra-processed food

Emulsifiers such as lecithins, polysorbates, carboxymethylcellulose and carrageenan are added to many packaged foods to stop ingredients separating and to give a smooth texture. They have drawn attention in inflammatory bowel disease (IBD), the group of conditions that includes Crohn's disease and ulcerative colitis, because animal studies suggest some of them can disturb the gut lining and its bacteria. Whether people with IBD actually eat more of them, and whether it matters for their illness, is much less clear.

A team at University Hospitals Leuven and KU Leuven in Belgium set out to test both questions. Their study, published online on 17 October in the Journal of the Academy of Nutrition and Dietetics, analysed 186 adults: 65 healthy volunteers recruited for a separate diet study between November 2022 and April 2023, and 121 patients (59 with Crohn's disease and 62 with ulcerative colitis) recruited at the hospital's infusion unit between September 2023 and April 2024. Everyone filled in a food frequency questionnaire. Patients also completed two 24-hour dietary recalls and the healthy volunteers two food records, and the researchers then followed the patients for a year.

The researchers had expected the patients to eat more of both ultra-processed food and emulsifiers. Only the second part held. Ultra-processed food servings did not differ between the groups. Emulsifier intake did: it averaged 5.64 servings in the healthy volunteers, 8.50 in people with ulcerative colitis and 9.02 in people with Crohn's disease, and the gap stayed after adjusting for age, sex, disease activity, energy and fibre intake.

Over the year of follow-up, the team counted hospital stays, surgery and emergency visits linked to IBD. When patients were split into higher and lower consumers, the higher groups had more of these events, with a hazard ratio of 4.85 for emulsifiers, though the 95% confidence interval ran from 1.05 to 22.47, a sign of how few events there were. Counting ultra-processed food servings as a continuous number was also linked with more events. But once age, sex, disease activity, energy and fibre were taken into account together, neither ultra-processed food nor emulsifiers remained an independent predictor. The study cannot say whether emulsifiers worsen IBD, or whether people with the disease simply eat differently, for example choosing softer, smoother foods. The authors call for larger studies.