The Low FODMAP Diet

What is the FODMAP diet?

The low FODMAP diet is a complex diet which has been shown to be effective in the management of Irritable Bowel Syndrome (IBS)1. It involves the restriction of poorly absorbed, fermentable carbohydrates (collectively known as FODMAPs) for a limited amount of time (usually between 4-6 weeks). During this phase, symptoms tend to settle and a new ‘baseline’ of symptoms is created. This elimination phase is then followed by a reintroduction phase whereby the body is challenged with the previously restricted foods to identify any trigger foods.   

FODMAPs stands for:

Fermentable

Oligosccharides (including Fructans and Galactoligosaccharides found in e.g. Wheat, Rye, Onions, Garlic, legumes …..)

Disaccharides (Lactose found in e.g. milk and yoghurt….)

Monosaccharides (frustose found in e.g. watermelon, sugar snap peas…)

And

Polyols (including Sorbitol, Mannitol, Xylitol found in e.g. apples, plums, chewing gum….)

which are all types of poorly digested/non-digestible carbohydrates naturally found in many different foods. They can also be present in many sports products such as gels and powders.

The evidence and guidelines recommend that trying the low FODMAP diet is best done with the support of a dietitian who can ensure your diet remains balanced throughout the elimination and reintroduction phases and beyond. It is important not to remain on the restriction phase for too long, as following a strict low FOMDAP diet in the long term can negatively affect your good bacteria in the gut. This is why the reintroduction phase is so important.                                                                                                  

Is it only for people with IBS or similar conditions? Or are there benefits for other people?

The majority of the research using the low FODMAP diet has been done in IBS where 60-80% of IBS patients had some improvement in their symptoms. There is growing evidence however, that it can be effective in other conditions such as inflammatory bowel diseases (IBD), including Crohn’s disease and ulcerative colitis, and small intestinal bacterial overgrowth (SIBO) however more research needs to be carried out in these areas. 

Should you get a diagnosis before starting on the FODMAP diet?

IBS symptoms can be different in each person and some of the symptoms of IBS could be indicative of other conditions. It is therefore important to see a health care professional to get a diagnosis first and to rule out other potential health problems such as Coeliac disease, food intolerances or allergies or other gut related conditions. 

[1] Gibson PR, Shepherd SJ. Evidence-based dietary management of functional gastrointestinal symptoms: The FODMAP approach.J Gastroenterol Hepatol. 2010 Feb; 25(2):252-8