A world-first clinical trial pits the low FODMAP diet against CBT to help fast-track relief from irritable bowel syndrome.
Clinicians may soon have clearer answers for one of gastroenterology’s most frustrating conditions that often goes hand-in-hand with dermatological conditions.
A global research team led by the University of Melbourne has launched the first head-to-head clinical trial comparing two leading but opposite treatments for irritable bowel syndrome (IBS).
The landmark study will evaluate the low FODMAP diet, long considered the gold standard for IBS, against exposure-based cognitive behavioural therapy (CBT), a psychological approach designed to retrain the gut-brain connection.
With up to 20% of Australians affected by IBS, many patients endure years of distressing symptoms and trial-and-error treatments.
The trial aims to pinpoint which therapy works best for which type of patient – a crucial step toward personalised treatment pathways that could dramatically improve quality of life and reduce the burden on healthcare systems.
It follows a recent six-month longitudinal study which found that while the low FODMAP diet helps most patients, around 21% show little to no benefit, highlighting the need for more tailored treatment strategies.
Exposure-based Cognitive Behavioural Therapy (CBT) helps IBS patients gradually reintroduce symptom-inducing foods into their diets, reshaping the gut-brain response through structured psychological exercises.
Alternatively, the low FODMAP diet removes triggering foods from the patients’ meal plans.
Up to 20% of Australians suffer from IBS and for many this chronic gastrointestinal disorder can be debilitating, with common symptoms including abdominal pain, constipation, diarrhoea, bloating and unpredictable bowel movements.
Lead researcher, Associate Professor Jessica Biesiekierski, head of Human Nutrition at the university’s School of Agriculture, Food and Ecosystem Sciences, said that while both treatments were already used in clinical practice with similar success rates, until now no one had directly compared them or identified the factors which determined why patients responded better to one treatment over the other.
“Patients with IBS are often stuck in a frustrating and expensive trial-and-error cycle of appointments, tests, emergency visits, different treatments, medications, as well as invasive procedures trying to find what works,” she said.
“Because there’s no single solution, people can go years without real relief. Our study aims to help fast-track patients to the right treatment, saving time, money, and improving quality of life.”
Professor Biesiekierski told Dermatology Republic this was the first time the two therapies had been directly compared.
“Both the low FODMAP diet and CBT therapy have similar efficacy rates [in IBS treatment] and a very individualised response,” she said.
“So what happens when people don’t respond, or if they are actually more suited to the other [treatment] – how can we identify that really early on? That’s what we are hoping to find out.
“We’re hoping to understand which treatment works best for whom and how. That means we’re looking we’re looking at key predictors, moderators and mediators of response.
“And the only way of doing that is by doing a very large trial and collecting lots of data at regular time points to see essentially what factors or characteristics of that patient group respond best to which of the treatments, or if somebody needs a combination.”
Another exciting prospect of the trial is that it is being conducted remotely, which could also improve access to both treatments for patients in rural and remote parts of Australia.
“We do know that multidisciplinary care in this disorder is also really important, but it’s also about the accessibility,” Professor Biesiekierski told DR.
“Access to a specialised dietitian or a specialised psychologist who has experience in either FODMAP or CBT in IBS, can sometimes be difficult to find. It can be expensive in the private practice field, or you have long wait lists in the public field.
“So this is improving access and giving patients the chance to do this in their own time, from the comfort of their own home.”
She said gold-standard clinician support would be provided remotely to trial participants throughout the program. This would be one-on-one rather than through groups or forums.
The research team is recruiting 200 people across Australia and the US to take part in the free trial, which will be conducted remotely.
Participants will be randomly assigned to receive either the low FODMAP diet or CBT, delivered online over 12 weeks with one-on-one support from a dietitian or psychologist.
The free trial is open to adults aged 18 years and over in Australia and the United States who have been diagnosed with IBS and includes follow-up assessments at three and six months to measure sustained outcomes.
The collaborative trial involves Monash University, Harvard Medical School, Massachusetts General Hospital and the Karolinska Institute.
Specialists and general practitioners are encouraged to refer eligible patients or share the study via professional networks.
Professor Biesiekierski said she hoped the results would be published within 18 months to two years.
“It’s a big study that has taken a long time to set up, so I am very much looking forward to seeing the results,” she said.
For details and screening see here.
