The Low FODMAP Diet for Irritable Bowel Syndrome (IBS)

3rd September 2018

‘Diagnosis and management of irritable bowel syndrome (IBS) can be frustrating, both for people presenting with IBS symptoms and for clinicians. Both parties need to understand the limitations of current knowledge about IBS and to recognise the chronic nature of the condition.’ Irritable bowel syndrome in adults: diagnosis and management guidelines, National Institute of Health and Care Excellence, 2017

If you have IBS, or you are waiting for a diagnosis, the above statement from NICE (the public organisation tasked with developing clinical guidelines for health and care professionals) might indeed reflect your frustration.

IBS is a functional bowel disorder. People affected experience pain and cramps in their gut, often made worse by eating and improved by visiting the toilet. Despite relieving the pain, toilet trips are no panacea, as those affected also suffer from abnormal bowel movements, with some people experiencing diarrhoea, some people having constipation and a third group enduring both in turns. Bloating and nausea are also common. Symptoms can appear suddenly and many people believe certain foods can trigger a flare up. IBS is immensely frustrating, can be exhausting and decreases quality of life in those affected.

Unfortunately it is also very common, with more than 1 in 20 people affected by IBS. The reason IBS is called a ‘functional’ bowel disorder is because despite people undergoing tests, no physical evidence of disease is found: the problem lies with the function of the gut. This makes IBS harder to diagnose and treat, and underpins some of the frustration that health professionals experience when managing someone with IBS. It has also made it harder to identify its cause – or more likely, causes – though gut infection appears to be a common prelude to the development of IBS in some people.

There is a lack of effective treatments and because people with IBS often blame certain foods for their flare ups, there has been interest in exploring whether diet could be used as a treatment. A group at Monash University, Melbourne, Australia, carried out research that showed that certain food components caused symptoms in susceptible individuals. The team developed a diet that excluded these food components to test whether it helped people with IBS.

The food components excluded in this diet are collectively known as FODMAPs, which stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, And Polyols. The word fermentable means that these food components can end up in the large bowel, where gut bacteria break them down (through the process of fermentation). Saccharides refers to small sugar-like molecules that can come as single units (monosacharides, such as fructose, a sugar found in fruits), as pairs of units (disaccharides, such as lactose, the sugar found in milk and some milk products), or as longer chains of units (oligosaccharides, found in many fibre-rich foods). Polyols are found in some fruit and vegetables, as well as in artificial sweeteners such as xylitol.

The Low FODMAP Diet removes foods that contain high levels of FODMAPs. Research studies have shown that the diet can reduce symptoms in 50-80% of people with IBS.

A Low FODMAP Diet is complex to follow and takes several months to personalise to each person’s needs. People following a Low FODMAP Diet need to be supported by a health professional with the relevant expertise and training on the Low FODMAP Diet, preferably a dietitian. The diet involves 3 stages: Stage 1 restricts high FODMAP foods for 4-8 weeks; Stage 2 reintroduces high FODMAP foods to personal tolerance and usually takes 8-12 weeks; Stage 3 personalises the diet to include well tolerated high FODMAP foods and in the long term achieves a healthy balanced diet without restricting foods unnecessarily.

The aim is not to follow the restriction stage of a Low FODMAP Diet long-term but rather to identify which foods are triggers and exclude those, while following a less restrictive, more nutritionally balanced, and more socially acceptable diet. Avoiding unnecessary restriction is also important as the team at King’s College London have shown that the Low FODMAP Diet changes gut bacteria in ways that are not fully understood at present.

Monash University has produced resources to support the diet, as well as guidance on producing processed foods low in FODMAPs. However, the resources, foods and guidance were more focused on the Australian diet and common foods, and not always relevant to UK diets. In the UK, the teams at King’s College London (a London University) and Guy’s and St Thomas’ Hospitals (a group of London hospitals) have carried out a great deal of research and development work on the Low FODMAP Diet. The work, led by Professor Kevin Whelan, Dr Miranda Lomer and Dr Peter Irving, has helped to clarify who can benefit from the Low FODMAP Diet and adapt the diet to the UK.

Recently Guts UK, in collaboration with Dr Falk Pharma, awarded prizes to recognise exceptional work in the field of gastroenterology. The prize for outstanding work carried out by a dietitian working in gastroenterology went to Dr Miranda Lomer, and her colleagues at King’s College London and Guy’s and St Thomas’ Hospitals, for their work adapting the Low FODMAP Diet for use in the UK. Dr Lomer and her colleagues wanted to test whether the Low FODMAP Diet would be a viable treatment for IBS in the context of a NHS hospital. Their aims were to improve patients’ satisfaction and reduce the need for follow up referrals to gastroenterology departments and dietetic clinics. Dr Lomer and her colleagues showed an improvement at their hospital and have developed an IBS ‘pathway’ that can be transferred to other hospitals across the UK, to provide high quality care and reduce the burden of IBS.

The low FODMAP diet is complex, making patient education challenging in this area. Besides, pre-packed foods are more common in the UK than in Australia and it is also more common to add high FODMAP ingredients to foods in the UK. This makes it harder to work out which foods in the UK are high in FODMAPs (i.e. unsuitable) and which are low (i.e. can be included) in the diet. Dr Lomer and her team developed written and visual patient resources that accounted for differences between the two countries and eventually produced colour-coded resource packs with green and red pages for suitable and unsuitable foods respectively.

They then introduced the Low FODMAP Diet at their hospital and monitored the level of satisfaction among their IBS patients. More than three quarter of patients reported an improvement in their symptoms compared to just over half of patients before the Low FODMAP Diet was introduced.

The team have also conducted a number of clinical trials to show that the diet is effective and contributed to the development of national guidelines informing health professionals, including dietitians, on how to introduce the Low FODMAP Diet into their hospital service. They also created a mobile application (app) called FODMAP by FoodMaestro in collaboration with a software company. The app allows user to scan the barcode of foods to determine if the food product is suitable for their personalised diet. They also developed a successful model for educating people with IBS on the Low FODMAP Diet as a group, rather than in a one-to-one consultation, which helps optimise resources for the hospital dietetic teams. And finally, they have developed an educational programme for dietitians throughout the country, so they can deliver the diet to their patients. This programme has already trained over 1,000 dietitians and it is highly rated.

Keep the research going

Guts UK are delighted that such progress has been made bringing the Low FODMAP Diet to the UK. The team at King’s College London and Guy’s and St Thomas’ Hospitals continue to carry out excellent research and develop additional resources on the diet, as well as explore whether it might be useful in other digestive conditions.

However, more funding needs to be directed to IBS and other functional diseases, as recently highlighted in an article on the medical journal The Lancet:

Despite the prevalence and burden of IBS, funding dedicated to investigating this and other functional gastrointestinal disorders is not keeping pace.” The Lancet, Gastroenterology & Hepatology, online article ‘Unmet needs of people with irritable bowel syndrome’ September 2018.

Guts UK has made research into IBS a priority research area. Please support our work so we can understand more and find treatments that can help bring relief to more people affected by IBS.

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