Published on 1st September 2017


Patients with irritable bowel syndrome (IBS) who follow personalised elimination diets based on food sensitivity testing have fewer symptoms, according to new research published in BMJ Open Gastroenterology.1

IBS affects around 10-20 per cent of people in the UK at any one time. The symptoms – which include chronic abdominal pain, gas, diarrhoea and/or constipation – can be extremely debilitating and have a profound effect on a person’s quality of life.

The research team from Yale University conducted a double-blind, randomised controlled trial – the ’gold standard‘ of scientific testing – of 58 adults with IBS. Blood samples were collected and food sensitivities were identified using a leukocyte activation test (the ALCAT test), which detects immune cell activation after exposure to food extracts. Participants were then randomised to a four-week diet that restricted either “reactive” foods that had been identified by the test results, or “non-reactive” foods. After the trial, participants were asked to rate their symptoms and quality of life.

The research team found that those participants whose diets were guided by the leucocyte activation test did significantly better than those on the sham diet – although both groups did experience improvements.

Statistically significant benefits were observed in global improvement, as well as in symptom severity, in diets where restricted foods had been determined by the test results. While quality of life and adequate relief both improved, statistically significant between-group differences were not observed. 

Roger Deutsch, CEO of Cell Science Systems, the company that developed the ALCAT test, and also funded the study, said: “We are delighted to see such positive results from the Yale study. Seventy per cent to 80 per cent of the immune system is in the gut. What we eat can trigger an immune response that can cause IBS and a host of other inflammatory and dysregulated responses.

“This study will open more discussion about how personalisation of diet can not only prevent and treat many chronic diseases like IBS; but, can be utilised to prevent the associated suffering and increasingly high cost. Implementation of the ALCAT test into routine health care will save billions in health care dollars.”

Nutritional therapist Kate Delmar-Morgan said the study supports the thinking that foods may cause sensitivity reactions in people with IBS, but added that that it is important to look at improving gut health alongside an elimination diet. “After a period without these foods, and with adequate gut support, the patient may possibly be able to return to these foods after a period of time,” she said. She also points out the role of stress in IBS: “In my clinic I’ve also found that stress and anxiety plays a big part in IBS due to the physiological effects of stress and the gut-brain connection.”


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  1. Ali A et al (2017). Efficacy of individualised diets in patients with irritable bowel syndrome: a randomised controlled trial. BMJ Open Gastroenterol, 4(1), e000164.