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fodmaps diet

FODMAPs stands for Fermentable Oligo-, Di- and Mono-saccharides and Polyols, which means short-chain carbohydrates for us lay people. The basic idea is that because these carbs are not very well absorbed in the small intestine they are prime candidates for fermentation, and that's not what you want happening in the depths of your gut.

This fermentation occurs when the bacteria in the colon find the fodmap carbs. This leads to more gas and more water in the digestive system and that in turn causes intestinal distension and can lead to IBS symptoms.

The acronym was coined by researchers in Australia. The researchers measured the level of water in the intestines by using patients with ileostomies. Gas production was measured using the hydrogen breath test made famous by Dr Mark Pimentel and his small intestinal bacteria overgrowth theory.

What foods must you avoid on a low fodmaps diet?

The most important foods to avoid are wheat, onion and garlic. Although wheat must be avoided, gluten-free products such as bread can be eaten as they are usually made from safe foods such as rice or corn. The complete list of foods that are high in fodmaps is long and quite specific, but it includes the following: apples, pears, milk, onions, garlic, peas, various beans, mushrooms and peaches.

What foods can you eat on a low fodmaps diet?

Foods that are safe include almost all meat (not chorizo or sausages), fish and seafood, dairy, gluten-free or spelt breads, cereals such as cornflakes and rice, parsnip, carrots, cucumber, bananas, oranges, oats, butter and eggs.


Review by Bernadette

I have had IBS-C for 26 years and I first heard about fructose malabsorption in 2005. Fructose is the M in FODMAPS as it is a monosaccharide, a single sugar. It is found in all fruit and some vegetables, honey and high fructose corn syrup. I had a breath test for fructose malabsorption which measured the amount of hydrogen my body produced after eating fructose, and this test was negative.

A few years later (2007) I had a new GP who, after hearing my symptoms of bloating, pain, constipation etc, thought I should have another breath test for fructose malabsorption, but this time one that measured methane, as she thought I might be a methane producer and not a hydrogen producer.

I had a lactulose breath test to check whether I produced methane or hydrogen when fermentation was happening in my gut - nobody can digest lactulose, so it gives a baseline level. You produce both gases naturally, but some people produce more methane than hydrogen, and some more hydrogen than methane, and very high levels of either gas indicate high levels of fermentation.

The lactulose test showed that I was producing too much methane, and so I had another breath test specifically for fructose malabsorption, but this time one that measured my levels of methane after I had ingested fructose. This test was positive.

Interestingly, they say that methane producers are more likely to have constipation than diarrhea as a symptom. I was also tested for lactose intolerance, and that test was positive as well.

At this time I heard of the Royal Prince Alfred Hospital (RPAH) elimination diet from a girl doing the breath test at the same time. This is a very strict, low food chemical diet, where you limit the food chemicals salicylates, amines and glutamates. I had allergy problems as well as bowel symptoms, so I thought this may be more relevant to my allergy and gut problems.

I went to an allergy specialist here in Melbourne who supervises this diet and I found the diet helped my allergy symptoms but not my gut symptoms, although the RPAH diet does help some people with gut symptoms. There is debate over here in Australia as to which is the better diet, the RPAH diet or the low FODMAPs diet. Some dietitians prefer one over the other, and a few are trying both.

After trying the low food chemical diet for six months and still suffering from gut pain, bloating and constipation, I went to a dietitian who specialised in fructose malabsorption. By this time the research had advanced to the FODMAPs diet although the research was new so not all foods had been tested yet. They are slowly testing all the foods against the diet here in Australia.

When I tried the FODMAPs diet I found a definite improvement in my symptoms. After more than 20 years I wasn't in pain and I could see a direct relationship between the foods avoided and my gut reactions. I feel very angry to think of all those specialists who told me my IBS was due to stress.

It is said that onion is the food that most commonly causes symptoms. This is one of the hardest things to avoid in everyday life as a lot of processed foods have onions or onion powder in them, and most restaurants use onions extensively in their cooking. Other vegetables to avoid are garlic, asparagus, sugar snap peas, legumes and lentils.

A few of the fruits to be avoided are apple, pear, watermelon and peaches. You also need to avoid chicory, inulin and pistachio nuts. Testing has just been done on other nuts and it's advised that they are eaten in very small amounts, ie: no more than 12.

I would strongly recommend this diet to all IBS sufferers. As a support group leader I constantly tell our members that 'individual tolerance' is always to be assessed when eating anything, even allowed foods. The quantity of 'allowed' foods is an issue for people with FODMAP sensitivity.

We cannot necessarily eat a large amount of 'allowed' foods, ie: you might manage to eat six blueberries but seven might take you over your individual tolerance level, so you have to learn what that level is with all food by experimentation. And as all IBS sufferers know, some days you can get away with eating things that you suspect you react to and some days you can't.

I hope this helps some of you. I know how awful it is to be in pain day after day and not have any answers. The low FODMAP diet is worth a go.

Review by Joanne

My son now aged 13 was diagnosed with post-infectious IBS three years ago after food poisoning on an island holiday. The first year was very bad with constant pain along with the usual altered bowel function. This resulted in treatment by the chronic pain team at our local kids hospital.

Over the three years he has had every possible test (all normal) and tried every drug. Since that first awful year things have improved and he now gets what I'd call 'flares' of IBS symptoms that last about two or three months interspersed with periods of normality that last about the same time.

J has been on a low fodmpas diet now for about two years and it has made a big difference. It did not solve the problem but it is a factor in the improvement we have seen. Low fodmaps is championed here by a gastroenterologist (we are in New Zealand) and when we did the breath testing J had a huge reaction to the ingestion of the fructose solution. Heaps of gas and a really uncomfortable visibly blown up stomach.

He had no reaction to lactose so he eats dairy no problem. Essentially with the reaction to fructose we cut out/reduce fructose itself and fructans. This means no wheat and nothing from the onion family. Its quite doable really although it makes eating out a bit difficult.

Our gastroenterologist explained that this is not the source of J's problem but that for people who have had a 'gut trauma' these sensitivities often develop and then perpetuate symptoms.

I'd suggest that anyone interested have the hydrogen breath testing as this is quite definitive. This was the first test in dozens that my son actually had a viable abnormal result and there was something associated that we could actually do about it. For anyone with IBS symptoms it would be worth investigating.

Do you suffer from IBS? Have you tried the low fodmaps diet? Please contact Sophie to send in your review.