How can sourdough help people with IBS digest bread?

IBS, FODMAPs and sourdough

The discomfort of irritable bowel syndrome (IBS) is all too familiar for many people. The NHS reports that 1 in 5 people will experience symptoms of IBS at some point in their life. While there is no cure for IBS, many people find that they can alleviate the symptoms by altering their diet. But diets to control symptoms generally involve excluding individual foods or whole food groups, which means care needs to be taken to ensure a healthy balanced diet is still maintained. The importance of a varied diet is especially clear as we learn more about the influence of a diverse gut microbiota on our physical and mental health.

So how can Sourdough Help with IBS?

Research at Monash University in Australia has shown that a low FODMAP diet can help in managing IBS symptoms. FODMAPs (fermentable oligo-, di- and monosaccharides, and polyols) are a group of short chain carbohydrates which have been found to aggravate the gut. The diet, which should only be used under the supervision of a qualified dietician, removes potential trigger foods for IBS symptoms for a period of time, before slowly reintroducing certain foods, and is now used as an effective therapy.

Bread is one of the foods that are often implicated in triggering IBS symptoms, but not all breads are equal in this respect. There is much anecdotal evidence that sourdough is less likely to cause dietary discomfort when eaten in moderation. This appears to be due to the long fermentation associated with sourdough, which can reduce the FODMAP levels by up to 90%. Modern yeasted bread, made with additives which allow rapid processing, is a high FODMAP food. But traditionally made sourdough, given a long fermentation, especially if it’s made with whole wheat or spelt flour, is low FODMAP.

Increasing The positive gut Microbes

It’s more than just breaking down the FODMAP’s ; a 2014 study compared the effects of different fermentation processes on the gut bacteria. They used in vitro trials to investigate the effects of three different breads, one sourdough and two yeasted on the gut microbiota of IBS sufferers and healthy subjects. These trials showed that sourdough bread that has been fermented for at least 8 hours resulted in significant differences in bacterial populations, with increased the numbers of bifidobacterium, a gut bacteria found in much higher numbers in the faeces of healthy individuals than IBS patients. In addition, a 15 hour fermented sourdough produced significantly lower gas levels when compared to two different yeasted breads. The study concludes that ‘sourdough products may be advantageous for patients suffering from IBS.’

One thing that is pointed out in many articles about sourdough and IBS, is the importance of ensuring that it really is genuine sourdough. Artisan bakers have led a resurgence in interest in traditionally made breads, but this has resulted in some bakeries using the word ‘sourdough’ as a marketing tool. Not all breads labelled as sourdough have been made using the long, slow fermentation needed to get the beneficial effects. So, get to know your local baker, always check the ingredients on the label or, even better, start making sourdough at home, so that you can enjoy real bread as part of your diet again.

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All reasonable care is taken when writing about health aspects of bread, but the information it contains is not intended to take the place of treatment by a qualified medical practitioner. You must seek professional advice if you are in any doubt about any medical condition. Any application of the ideas and information contained on this website is at the reader's sole discretion and risk.

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About Dr Vanessa Kimbell

Dr Vanessa Kimbell is acknowledged as one of the world’s foremost authorities on bread and human health — the first person to hold a doctorate in Baking as Lifestyle Medicine and Preventative Healthcare, and the pioneer who, long before gut health became a mainstream concern, first identified the crucial role bread plays in the gut microbiome and mental wellbeing. A fourth-generation baker of Italian descent, she has been baking sourdough since the age of 11, served her traditional apprenticeship in the Dordogne, and is a time-served, French-trained qualified baker who has worked alongside some of the world’s greatest bakers including Richard Hart and Gabriele Bonci. She has spent four decades asking the questions the food industry preferred no one asked: why was industrial mono bread slowly harming us, and what would it take to make bread that genuinely nourishes?

The answer became her life’s work. As founder and Course Director of The Sourdough School in Northamptonshire — a world-renowned centre of research and education — she has taught bakers from over 84 countries, integrated the BALM (Baking as Lifestyle Medicine) Protocol into NHS clinical practice at Bethlem Royal Hospital, and developed Proven Bread: the first bread built on clinical evidence, personalised to the individual through nutrigenetics and gut microbiome assessment. She delivered the Royal College of General Practitioners‘ approved course in the Nutrition of Bread, has been a regular contributor to BBC Radio 4’s Food Programme for many years, and collaborates with leading scientists and clinicians including Professor Tim Spector — who credits her with teaching people to make the healthiest bread in the world — and Professor David Veale. Named the Sourdough Queen by The Telegraph in 2013, her influence reaches far beyond the classroom — from artisan bakers and healthcare professionals to the world’s leading food scientists and multinational food corporations.

A bestselling international author of five books, her sixth — Proven — publishes in November 2026.

More information about Vanessa can be found at
The Sourdough School,
The Sourdough Club,
on Instagram at @SourdoughClub,
@SourdoughSchool and
@vanessakimbell,
on Facebook and
LinkedIn.