IBS awareness month - Low FODMAP Diet

by Anne Myers-Wright RD/APD

Posted on Apr 6, 07:52 AM No comments.

You may be thinking about trying the Low FODMAP diet. The FODMAP diet has been shown to improve symptoms in 50-80% of patients with IBS but it’s not for everyone. In fact you may not even need to try it at all.

Before starting the Low FODMAP diet, you may need to make some basic “first line” changes to your diet.

This includes drinking enough fluid, eating regular meals, not skipping meals and trying to avoid long gaps between eating. You should also keep your tea and coffee intake to no more than 3 cups per day and reduce your intake of alcohol and fizzy drinks.

Once you have made these “first line” changes, you could be a candidate to start the Low FODMAP diet.

The Low FODMAP Diet

What it is:

The Low FODMAP diet was developed to help people with irritable bowel syndrome (IBS) to control their symptoms. It is essentially an “elimination and challenge protocol” which means you eliminate FODMAPs for a short period of time (until symptoms reduce) and then you “challenge” each FODMAP to see which ones cause you problems. Once you have an idea of your symptom triggers, you can adjust your long term diet.

What it isn’t:

The Low FODMAP diet isn’t a “cure-all” for everyone. It isn’t a long term elimination diet. Staying Low FODMAP long term can cause problems (such as lack of variety in you diet for no reason and changes to your gut bacteria). It is important that you follow the Low FODMAP diet correctly and that you don’t just cut out all FODMAPs long term. It can be potentially damaging to your health to continue the exclusion stage of the diet long term and you may be cutting out foods that you enjoy for no reason.

What are FODMAPs?

FODMAPs are carbohydrates which are poorly absorbed in the small intestine and which are then fermented in the large intestine, or bowel, by gut bacteria.

The term FODMAP stands for:

Oligosaccharides – (e.g. fructans and galacto-oligosaccharides (GOS))
Disaccharides- (e.g. lactose)
Monosaccharides- (e.g. fructose)
Polyols – (e.g. sorbitol, mannitol, xylitol and maltitol)

For some people, eating foods containing FODMAPS can trigger symptoms such as wind, bloating, abdominal pain, diarrhoea or constipation. FODMAPs are found in everyday foods including some dairy products, wheat, other grains, and specific fruits and vegetables. Different types of FODMAPs can be found in different types of food.

How FODMAPs cause IBS symptoms

FODMAPs are poorly absorbed in the small intestine. Because of this, when we eat foods containing FODMAPs, two things can happen:

Water is pulled into the bowel

As they are small and poorly absorbed, FODMAPs drag water into the bowel by osmosis. This extra water stretches the bowel wall and can cause bloating and diarrhoea.

FODMAPs are rapidly fermented in the bowel

FODMAPs that haven’t been absorbed in the small intestine arrive in the large intestine (or bowel), where bacteria use them as an energy source to survive. The bacteria rapidly ferment the FODMAPs and produce gases such as methane, hydrogen and carbon dioxide. This gas production causes an expansion of intestinal contents, stretching the bowel wall. Stretching of the bowel wall is a problem because it causes symptoms such as: bloating, abdominal pain or discomfort, changes in the way the muscles in the bowel wall contract – leading to constipation, diarrhoea or a mixture of both.

As people with IBS have a highly sensitive gut, this ‘stretching’ of the intestinal wall produces sensations of pain and discomfort.

How to follow the Low FODMAP Diet.

The Low FODMAP diet is a 3-stage process You will need to go through each of the three stages to use the diet correctly. The steps are as follows:

Stage 1:4-6 weeks low FODMAP exclusion diet

This phase involves avoiding foods containing FODMAPs for around 4-6 weeks, whilst monitoring symptoms. Four weeks is usually enough time for the majority of people to achieve symptom improvement. Once you have a reduction in symptoms, the reintroduction phase should be started.

Stage 2:Structured reintroduction of FODMAP-containing foods

This stage involves a staged process of re-introducing, or “challenging” foods containing FODMAPs. It is important that you move on to this stage as you will be able to determine which FODMAPs may be triggering your symptoms. The re-introduction phase is a staged, dosed, FODMAP challenge protocol. This means that you will be re-introducing or “challenging” each FODMAP, one at a time, in an effort to discover which ones may trigger your symptoms.

Stage 3:Long-term dietary personalisation

Once you have completed each of the FODMAP “challenges”, you will have a personalised “prescription” with an idea of which FODMAPs trigger your IBS symptoms. You will also know how much of each FODMAP containing food you can tolerate. The aim of this stage is to increase dietary variety and to aim for a balanced dietary intake at the same time as maintaining IBS symptom control

Before starting the Low FODMAP diet, your IBS diagnosis should be confirmed and other conditions should have been ruled out. The Low FODMAP diet should be done with help and support. Our Kings College London and Monash University trained Dietitians offer a 3 package program to help you safely through the process. Please contact us for more information.


Tags: Bloating, Bowel, Challenges, Coffee, Constipation, Elimination, First Line, Fizzy Drinks, Fodmaps, Gut Health, Ibs, Ibs Dietician, Ibs Dietitian, Ibs Symptoms, Ibs Triggers, Pain, Variety

About the author

Anne Myers-Wright

Anne Myers-Wright RD/APD

Anne is a Health Professions Council (HPC) registered dietitian (RD), an Accredited Practicing Dietitian (APD- Australia), a fellow of the Higher Education Academy (FHEA), a member of the British Dietetic Association, The Nutrition Society and of The Dietetics Association of Australia.


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