King's College London

New research was presented for the first time at the European Crohn’s and Colitis Organisation (ECCO) Conference in Berlin, on Friday 21 February 2025, with a full paper due later this year.

The study, which included 154 participants and is one of the largest ever dietary trials in Crohn’s disease, showed that dietary restriction of emulsifiers, commonly found in ultraprocessed foods, reduce both symptoms and inflammation.

The first clinical trial to test the link between food additive emulsifiers and Crohn’s disease has revealed that a low emulsifier diet could be an effective new treatment.

The trial, known as the ADDapt trial and led by researchers at King’s College London, observed that people with Crohn’s disease were three times more likely to see improvement of their symptoms when cutting out emulsifiers from their diet. Participants also found that their symptoms were twice as likely to go into remission, where their disease symptoms disappeared.

Participants were recruited from 19 different hospitals across the United Kingdom, including the lead clinical site at Barts Health NHS Trust in London. The researchers also worked with scientists at Institut Pasteur in Paris. All participants had active symptoms of Crohn’s disease and were split into two groups and received detailed dietary advice from a dietitian together with some supermarket deliveries of packaged foods and additional snacks for eight weeks.

The control group received supermarket deliveries, such as cereals, condiments and sauces, all of which contained emulsifiers, and the intervention group received similar foods but without any emulsifiers. The researchers also provided them with three snacks per day, including biscuits and flapjacks, that either contained emulsifiers for the control group or were emulsifier-free for the intervention group.

Crohn's disease is a chronic condition where parts of the digestive system become inflamed, causing symptoms such as diarrhoea, severe pain, fatigue, and weight loss. According to the charity Crohn's & Colitis UK there are 200,000 people in the UK living with Crohn's Disease. It is a lifelong condition, so the disease is likely to continue to increase in prevalence as the UK’s population ages.

There is currently no cure for Crohn’s disease but drugs, and sometimes surgery, can give relief from symptoms, but until now there are surprisingly few proven dietary treatments.

A previous study from the same research group at King’s College London has shown that more than 6,000 foods found in UK supermarkets contain emulsifiers. In the UK, there are 63 different types of emulsifiers in the food supply and can be identified by their E number on a food label. They are added to foods to help the oil and water components mix and to give them a smooth texture and increase their shelf life. If a food contains an emulsifier it is classified as an ultraprocessed food.

Emulsifiers have been investigated for many years, but most of the studies so far have been in mice, and not in patients with an inflamed gut. They have been found to change the bacteria in the gut, reduce the mucus that protects the gut and increase the permeability of the gut lining which can lead to ‘leaky gut’.

"For the first time we have shown the benefit of cutting out foods containing emulsifiers for people with the disease and are excited to discover a new treatment that can manage Crohn’s disease.”

Philip Reynolds, a 37-year-old from London and participant in the trial said: “Before the trial I was having to think twice and plan around the condition. I was often uncomfortable and didn’t always feel like I was in control of my Crohn’s."

"As a result, I have made some long-term changes to my diet and lifestyle which have really helped me manage my condition.”

Marianne Radcliffe, Chief Executive of Crohn's & Colitis UK, said: "Being told you have Crohn's Disease is life-changing and one of the things we hear most from members of our community is just how hard the unpredictability is. There's currently no catch-all advice on food and Crohn's but knowing this research could lead to an effective new treatment is really exciting. The challenge now is taking the findings of this study and translating them into everyday life. We welcome anything that empowers people with Crohn's to live better lives."

The trial was independently funded by The Leona M. and Harry B. Helmsley Charitable Trust