Authors: Zoe N. Memel, Neha D. Shah, Kendall R. Beck
Journal: Nutrition in Clinical Practice
Year: 2025
Volume: 40
Pages: 1013–1030
DOI: 10.1002/ncp.11307
Study at a glance
- Study type: Invited review
- Number of studies: Multiple randomised controlled trials and systematic reviews examined
- Population studied: Adults with irritable bowel syndrome (IBS)
- Interventions assessed: Low-FODMAP diet, gluten-free diet, lactose-free diet, low-fructose diet, fibre supplements, peppermint oil, other nutraceuticals, physical activity, mindfulness, sleep hygiene
- Focus: Evidence-based dietary, nutraceutical, and lifestyle approaches for managing IBS symptoms
Why was this study done?
Irritable bowel syndrome (IBS) is the most common gastrointestinal disorder, affecting between 4.4% and 4.8% of people in the United States, Canada, and the United Kingdom. It causes recurrent abdominal pain, changes in bowel frequency, and altered stool form.
Between 85% and 90% of IBS patients restrict foods to manage their symptoms, with dairy, wheat, and eggs commonly reported as symptom triggers. The development of IBS is thought to involve several overlapping mechanisms, including an altered balance of gut bacteria, disordered bowel movement patterns, and a heightened sensitivity to pain in the digestive tract.
The authors reviewed current evidence for specific diets, nutritional supplements, and lifestyle interventions to to help patients and their clinicians use these options as a practical part of managing IBS.
How was the study performed?
The authors reviewed published literature on dietary interventions, nutritional supplements, and lifestyle modifications for IBS, examining randomised controlled trials, systematic reviews, and meta-analyses.
The review looked at a range of options: the low-FODMAP, gluten-free, lactose-free and low-fructose diets, fibre supplements, peppermint oil, probiotics and prebiotics, physical activity, mindfulness, and sleep habits. For each one, the authors weighed up how strong the evidence was and how useful it is likely to be in everyday life.
What did the researchers find?
Of all the approaches reviewed, the low-FODMAP diet had the strongest evidence for easing IBS symptoms, with a clear reduction in abdominal pain and bloating after about four weeks. In one trial, 51% of people following the low-FODMAP diet had less abdominal pain, compared with 23% of those given standard healthy-eating advice.
A gentler version of the diet, which cuts out only two of the FODMAP groups (the ones found in foods like wheat, onion, garlic, and pulses) rather than all of them, worked about as well and was easier to stick to, with fewer side effects.
For people who are sensitive to gluten but do not have coeliac disease, cutting out gluten helped their symptoms. In one study, among those who had responded well to a gluten-free, low-FODMAP diet, 46.1% got worse again when gluten was reintroduced, falling to 19% when a stricter definition of “worse” was applied.
When it comes to fibre, the type matters. Soluble fibre, especially psyllium, helped people whose main problem was constipation as well as those whose main problem was diarrhoea. Insoluble fibre such as bran offered no benefit and could actually make symptoms worse.
Enteric-coated peppermint oil (peppermint oil in a capsule designed to release lower down in the gut) noticeably improved abdominal pain and overall symptoms. A pooled analysis of 12 trials, covering 835 people, found it helped symptoms, with no more side effects than a placebo capsule. It is not suitable, though, for people with significant acid reflux or belching, as it can make those worse.
The evidence for probiotics was mixed. The trials varied so much in how they were run that no firm conclusion could be drawn.
Being more physically active improved IBS symptoms along with quality of life, tiredness, low mood, and anxiety. Walking, aerobic exercise, and yoga all showed benefits over roughly 12 to 24 weeks.
A structured mindfulness programme (mindfulness-based stress reduction) significantly eased digestive symptoms. And poor sleep was found to predict more abdominal pain the following day, underlining how much good sleep matters.
What did the authors conclude?
Managing IBS well takes more than medication. Changes to diet and daily habits are a central part of good care. The low-FODMAP diet has the strongest evidence behind it, and works best when a dietitian helps guide it.
Enteric-coated peppermint oil (a capsule that releases lower down in the gut) has enough evidence and a good enough safety record to be used as a helpful add-on for easing symptoms. When it comes to fibre, the soluble kind, such as psyllium, is a better choice than insoluble fibre like bran.
Foods that contain prebiotics and probiotics may be good for the gut, but there is not yet enough evidence to recommend taking them as supplements for everyone.
Because so many different things feed into IBS, the authors suggest that the best way to improve quality of life is to look at the whole person, from eating patterns and cultural food preferences to sleep, activity, and mental wellbeing. Care works best when it is tailored to the individual and, where possible, supported by a dietitian experienced in gut conditions.
Key takeaways
- The low-FODMAP diet has the strongest evidence for easing IBS symptoms. A simpler version that cuts out only certain foods (those high in fructans and galactans, such as wheat, onion, garlic, and pulses) works about as well and is easier to stick to.
- Enteric-coated peppermint oil is a safe and effective add-on for reducing abdominal pain and overall symptoms.
- Soluble fibre such as psyllium can improve IBS symptoms, while insoluble fibre like bran is best avoided as it may make things worse.
- Staying active, practising mindfulness, and sleeping well all help to ease symptoms and improve quality of life.
- There is no one-size-fits-all fix. The most effective approach considers diet, lifestyle, mental health, and a person’s cultural background together.
This Scientific Publication Summary is an objective summary of the published study for personal and educational use. It does not constitute medical advice, endorsement of the intervention, or a recommendation to alter clinical practice.