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Update on the Low FODMAP Diet for IBS
The low FODMAP diet for IBS was created by researchers at Monash University in Australia in the 2000s. Since that time many scientific studies have been published on this subject. I will examine the current findings in this article.
Irritable Bowel Syndrome (IBS) – Diagnosis
Irritable bowel syndrome (IBS) is defined by the Rome IV criterion, which states that a person may have IBS if they experience recurrent abdominal pain at least once a week on average for the past three months, and if this pain is associated with at least two of the following criteria:
- Defecation;
- A change in stool frequency;
- change in the shape or appearance of the stools.
Before concluding a diagnosis of IBS, it is important to rule out celiac disease via an antibody test, and to refer patients for further examination if they have any red flag indicators. These include unintentional and unexplained weight loss, rectal bleeding, a family history of bowel or ovarian cancer, a change in bowel habits towards softer or more frequent stools persisting for more than six weeks in a person over 60 years of age, abdominal or rectal mass, anemia, or elevated markers of inflammatory bowel disease.
The Low FODMAP diet for IBS
The low FODMAP diet represents a therapeutic avenue for people who suffer from IBS. However, before attempting this diet, it is first recommended to adopt healthy lifestyle habits such as those described by the National Institute for Health and Care Excellence (NICE) and the British Dietetic Association. These include adequate hydration, adequate dietary fiber intake, a regular meal schedule, chewing well, as well as reducing consumption of coffee, alcohol, and sparkling drinks.
What are FODMAPs?
FODMAPs refers to certain short-chain carbohydrates that can be poorly digested and thus cause digestive symptoms in people with IBS. The acronym stands for:
Fermentable: These are fermentable carbohydrates
Oligosaccharides: Includes fructans and galacto-oligosaccharides (GOS)
Disaccharides: This is lactose
Monosaccharides: This is fructose (when it is found in excess of glucose)
And
Polyols: Includes sorbitol and mannitol
Thus, there are 5 families of FODMAPs: fructans, GOS, lactose, fructose, and polyols. These different types of carbohydrates are found in a variety of foods. For a list of the main foods in each family, please refer to
FODMAPs can cause digestive symptoms via several mechanisms. First, they are poorly absorbed by the small intestine and then fermented by bacteria in the colon, which can result in digestive symptoms, including excessive gas production and bloating. Their presence in the colon also creates a need for water and can lead to diarrhea. It is important to understand that ingesting foods that are high in FODMAPs causes symptoms only if their digestion causes an abnormal or excessive intestinal response. It should be noted that more recent studies suggest that the contribution of FODMAPs to the pathophysiology of IBS is much more complex than previously thought. Indeed, studies in rodents suggest that a high-FODMAP diet may increase intestinal permeability, visceral sensitivity, and mast cell activation.
A Three Phase Approach
The low FODMAP diet was created by researchers at Monash University in Australia in the 2000s. It is a temporary approach aimed at establishing an individual’s tolerance to different families of FODMAPs in order to control digestive symptoms without sacrificing balance and food variety. The low FODMAP diet has three phases: elimination, reintroduction, and personalization.
The first phase, which lasts two to six weeks, involves eliminating high-FODMAP foods from the diet in order to achieve a marked decrease in gastrointestinal symptoms. In the event that there is no improvement in symptoms at the end of the first phase, it is recommended to discontinue the low FODMAP diet and to try alternative approaches.
The second phase aims to reintroduce each of the FODMAP families in order to measure an individual’s tolerance. Specifically, according to Monash University’s protocol, tests are performed by increasing amounts of a food containing a single family of FODMAPs to assess whether this family triggers gastrointestinal symptoms. It is important to maintain a low FODMAP diet during this phase to avoid distorting the results of the reintroduction tests.
The third phase consists of reintegrating the tolerated foods, depending on the results obtained in the reintroduction phase. Since an individual’s tolerance can vary in the long term, it may be useful to repeat some tests in the future to re-evaluate one’s tolerance.
The low FODMAP diet has been shown to be effective in reducing the severity of gastrointestinal symptoms of IBS and improving the quality of life of people with IBS in at least 50% of cases. In the studies that have been done, despite the restrictions imposed by the low-FODMAP diet, no dietary deficiencies were observed in people with IBS who followed this diet along with personalized support from a Registered Dietitian.
The Low FODMAP Diet, Not Only for IBS
The low FODMAP diet may also sometimes be recommended for conditions other than IBS, such as for people with inflammatory bowel disease (IBD), or for athletes who have exertional digestive symptoms.
A significant proportion of people with IBD (ulcerative colitis and Crohn’s disease) have gastrointestinal symptoms, even if their disease is in remission. A few short-term studies have shown that a low FODMAP diet can help reduce digestive symptoms in people with IBD and improve their quality of life.
More than 50% of endurance athletes suffer from digestive symptoms during an endurance event such as a marathon or triathlon. During prolonged and intense exercise, the rate of digestion is reduced, which can lead to carbohydrate malabsorption. In addition, there is less oxygen available to the gastrointestinal system, which can create damage and inflammation in the intestines. A high FODMAP intake can cause symptoms during exercise in some individuals who generally tolerate these types of sugars well when at rest. A few studies have observed a significant decrease in symptoms in endurance athletes who have followed a low-FODMAP diet for a short time. In some cases, it may therefore be useful to adopt a low FODMAP diet before prolonged and intense sports activity. On the other hand, there are several other factors to consider to help limit digestive disorders during exercise. Indeed, it is important to ensure optimal hydration and train your intestines to tolerate carbohydrates during exercise.
Other considerations
It is not recommended to follow a low FODMAP diet in the long term, as it is too restrictive. People are generally not intolerant to all families of FODMAPs. The purpose of the diet is to identify problematic foods so that all other foods can be reintroduced and unnecessary restrictions can be avoided. Some studies suggest that following a long-term low FODMAP diet can alter the gut microbiota. However, according to a recent meta-analysis of studies including 403 participants, the effects of a low FODMAP diet on the colon microbiota of people with IBS appear to be specific to bifidobacteria, with no consistent impact on other measures of microbiota health, including diversity, fecal short-chain fatty acid concentrations, and fecal pH. Nevertheless, to optimize one’s health, diet variety is essential.
Adherence to the low FODMAP diet is a major obstacle for many people. A more targeted, less restrictive approach, called the
The Canadian and American gastroenterology associations recommend that people who want to follow the low FODMAP diet be accompanied by a Registered Dietitian specialized in gastrointestinal diseases and who are familiar with the FODMAP approach, given the complexity of this dietary approach. Too often, people obtain a list of high-FODMAP foods to avoid, but don’t know that they only need to restrict these foods temporarily and reintroduce them afterwards, or don’t know how to do the reintroduction tests. However, not everyone has access to a Registered Dietitian who specializes in the low FODMAP diet.
FODMAP Wizard
To address this, we have created a ‘FODMAP Wizard’ in the form of a mobile app, for people who need to follow the FODMAP protocol but cannot access – or cannot afford – a Registered Dietitian who has been trained in this protocol.
The Wizard guides users step-by-step through the three phases of the protocol. Each step is explained in detail through video clips recorded by expert Registered Dietitians. In addition, users have access at all times to a peer support group moderated by Registered Dietitians, where they can find reliable answers to their questions about protocol and diet. The Wizard has an adaptive algorithm that determines the quantities of reintroduction tests based on user-reported symptoms. Following the instructions, the Wizard automatically generates a personalized table showing the amount that can be freely consumed for hundreds of foods, as well as recipes suitable for one’s individual tolerances as determined by the Wizard for each user.
The Wizard was the subject of an independent clinical study conducted by the University of Montreal Hospital Research Centre (CRCHUM), which demonstrated its effectiveness.
Conclusion
In conclusion, the low FODMAP diet has been shown to be clinically relevant for people with IBS, as it can greatly help reduce their digestive symptoms and improve their quality of life.
Sources
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Author
Kathryn holds a Bachelor Degree in Nutrition as well as a Bachelor and a Master Degree in Kinesiology, all from Laval University. She is a Registered Dietitian and active member of the Ordre professionnel des Diététistes Nutritionnistes du Québec (ODNQ) and of the American Academy of Nutrition and Dietetics. She holds the Monash University's certification for the FODMAP diet and IBS, and has considerable clinical experience in that area. She is also an accomplished athlete, having ran track and cross-country at a national level. Kathryn specializes in sports nutrition, weight loss, diabetes, as well as heart and gastrointestinal health.
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