Irritable Bowel Syndrome & Low FODMAP Diet

Irritable bowel syndrome or ‘IBS’ is a functional gastrointestinal (gut) disorder that affects the colon, commonly known as the large bowel or large intestine. IBS is thought to affect approximately 10-20% of the population and is twice as common in women than men.

Over recent years the dietary treatment for IBS has developed. Like most other areas of nutrition or medicine this change has been in line with new and emerging research.

One area of particular interest has been that of the low FODMAP diet. In the 1980-90’s researchers became interested in the role of poorly absorbed short chain carbohydrates (particularly lactose, fructose and sorbitol) in influencing IBS symptoms. With time and research, they also realised that other groups of carbohydrates – mainly fructans and GOS were also causing problems because of their chain length. The group name for these carbohydrates is now known by the acronym FODMAPs.

  • Fermentable
  • Oligo-saccharide (found in fructans and GOS)
  • Di-saccharide (found in lactose)
  • Mono- saccharide (found fructose) and
  • Polyols (found in sugar alcohols e.g. sorbitol)

The first trial confirming the role of FODMAPs in managing gastrointestinal symptoms was not published until 2006 by a team of Australian researchers at the Monash university in Australia. Since this publication, research has also taken place in the UK at Kings College London, where subsequent studies and trials have taken place showing similar results.   

The low FODMAP diet is now considered one of the most effective and evidence based dietary therapies for the management of IBS.


What do FODMAPs do?

In simple terms, FODMAPs are different types of carbohydrates (sugars) which are found both naturally and as additives in the food we eat.  Some of these FODMAPs do not get absorbed in our small intestine and so they travel along our gut to our large intestine where they act as a food source for the bacteria that live there. The bacteria in our gut then ferment these FODMAPs causing symptoms for some people living with IBS.


What does the low FODMAP diet involve?

Low FODMAP education is given in two phases. 

Phase 1  

This phase involves the restriction of FODMAPs from the diet for approximately 6- 8 weeks.

It is acknowledged that this is a complex diet, therefore your dietitian will provide you with the relevant advice and support that you need to restrict these FODMAPs. This restriction is only temporary and not a lifetime diet! Your dietitian will also ensure that your overall diet remains varied and balanced.  

Remember, it is very important that you adhere to the diet as strictly as possible to achieve the best possible results.

Phase 2

After you have completed phase 1 of the diet you will be asked to book back in to see your dietitian who will reassess both your diet and symptoms.

If you have noted a symptom improvement you will then receive education on how to start the reintroduction phase of the diet. This is a gradual approach whereby you will be asked to reintroduce specific foods over a 3-day period. It is this reintroduction of FODMAPs that will help to identify the type and amount of FODMAPs which can be tolerated in the longer term. Not all FODMAPs will trigger symptoms (it is mainly the FODMAPS which do not absorb that will trigger symptoms) hence this phase of the diet is important to establish what FODMAP is causing the problem.

Does it work?

Research has shown that the low FODMAP diet improves ‘gut symptoms’ for about 70% of people with IBS. A small number of people may not see a symptom improvement. This can be for a variety of reasons and if this occurs it is something that needs to be explored on an individual level.


Frequently asked questions

Does the low FODMAP diet cure IBS?

No. There is no known cure for IBS. The low FODMAP diet is one approach to help you self-manage IBS as it allows you to identify ‘problem foods’ or ‘triggers’ and so avoid these. 


I have symptoms which I think may be IBS – would I benefit from the low FODMAP diet?

The diet is specifically designed for people with a functional gut disorder or a confirmed diagnosis of IBS. If you are unsure, please speak with your GP or give us a call and speak with our dietitian who may be able to assist further. It is important for us to have a clear diagnosis and rule out any other possible cause of gut symptoms as the management plan for each gastrointestinal condition does vary.


Who should I see for a low FODMAP diet?

As the low FODMAP diet is quite complex, it is important that you receive good quality, evidence-based advice about how to follow the diet and the different stages.

A CORU registered dietitian, with experience in educating people on the low FODMAP diet, will help you to follow it carefully while ensuring your diet remains healthy and balanced.

Ask your GP or gastroenterologist to refer you to a registered dietitian who is trained in the low FODMAP approach.  Or give us a call!


What do we offer at Strive Clinic Galway?

Consultations are offered on a 1:1 basis. The total package costs €195.  


What does the package include?

Initial consultation: 60-75 minutes

Includes: a full dietary and symptom assessment, education on how to implement the low FODMAP diet and booklets with information to help you follow the diet accurately.

Phone consultation: 15 minutes

Includes: a midway review of progress, any additional support needed and the opportunity to ask questions!

Follow up consultation: 45 minutes

Includes: a dietary and symptom review, education on the reintroduction phase of the diet and additional booklets with information to help support you with the reintroduction phase.

Further appointments or supermarket visits are also available if requested for an additional fee.

Please note: Coeliac Disease must be ruled out in advance of a consultation as the symptoms of Coeliac Disease can mimic those of IBS.

If you wish to be tested, please request a coeliac screen from your own GP prior to booking an appointment with our dietitian. Remember you will need to be following a gluten diet at the time of your coeliac screen in order to get a more accurate result.