In this piece we will discuss Irritable Bowel Syndrome (IBS) and a gluten free diet. A gluten free diet is medically advised for people with coeliac disease. However, people with IBS (who have ruled out coeliac disease) often find that avoiding gluten improves their symptoms.

I’m going to take a look at why this might be the case, and also explore the consequences of cutting gluten out of your diet when it might not be gluten that is causing your issues.

First Up – What Is Gluten?

Gluten is the name given to a group of proteins found in many cereal grains. Gluten helps many foods maintain its shape and is what acts as a glue in most bread type products, giving them their delicious bready texture. Gluten can be found in many foods and often in places you would not expect. Each different type of grain contains different types of gluten – such as gluteins which is found in wheat and secalins which is found in rye.

So, What Foods Contain Gluten?

Gluten is found mainly in wheat, barley and rye. However, gluten can travel in the air – particularly in environments such as kitchens or food processing plants, so cross contamination of other foods with gluten is common. Below is a list of foods which often contain gluten.

Grain Food
Wheat Breads

Many baked goods (e.g. pastries, cookies etc.)




Barley Malt (malted barley flour, malted milk and milkshakes, malt extract, malt syrup, malt flavouring, malt vinegar)


Brewer’s Yeast

Rye Rye Bread

Rye Beer


Triticale Bread



So Why Would Going Gluten Free Help With IBS Symptoms?

Many people with IBS avoid gluten and state that it improves their symptoms. However, the avoidance of gluten itself may not actually be the reason why they are feeling better.

Some studies (here, here and here) have suggested that an increase in the amount of gluten can worsen IBS symptoms.  However in many of these studies the participants tested positive for the coeliac gene – so it is possible that they were experiencing increased symptoms because they in fact had coeliac disease.

For many people with IBS, fermentation in the gut caused by consuming high FODMAP foods leads to digestive symptoms. Following a low FODMAP diet may help reduce symptoms.

Some common high FODMAP foods, e.g. wheat, contain gluten. Therefore, by avoiding gluten you tend to reduce the amount of FODMAPS you are consuming by default, leading to a reduction in symptoms.

Wheat is high in inulin, a type of fructan that is very high in FODMAPs. Fructans are chains of fructose molecules. Short chains of fructose molecules are known as “fructo-oligosaccharides (FOS)”, whereas longer chains are known as “inulin”. It can be tricky to identify fructans as the issue, as inulin, for example, is also found in naturally gluten free foods such a garlic, onion, leeks and beetroot.

For some more reading on FODMAPs, check out our previous blog “Understanding FODMAPs and hydrogen breath testing”.

Non-Coeliac Gluten Sensitivity

Some people who have tested negative for both coeliac disease and for a wheat allergy, and still experience digestive issues after eating gluten, are referred to as “non-coeliac gluten sensitive”.

The cause of this condition is still relatively unknown and could be due to a number of possible reasons such as gluten, other FODMAP containing foods or even amylase-trypsin inhibitors.  Amylase-trypsin inhibitors can trigger small intestine inflammation.

The problem is that gluten containing foods also contain many other components. So at present, we know of this condition, but we can’t be sure that gluten is the cause.

Does Avoiding Gluten Affect My Health?  

Firstly, foods which contain gluten tend to be a good source of fibre and many are also prebiotic (i.e. they promote the growth of good bacteria in your gut). Avoiding such foods can lead to you struggling to meet your recommended 30g fibre per day in the UK and between 25g for women and 38g for men in USA. We know that fibre plays a critical role in our overall health. A high fibre diet has been shown to reduce the risk of a number of serious conditions such as heart disease and diabetes.  Check out previous blogs written by FoodMarble’s Dr Claire Shortt about the important roles that fibre plays in maintaining gut health –

Fibre, Fermentation and FODMAPs

How Fibre Helps Protect Your Gut Health

There is research which suggest that those who follow a gluten free diet have a higher tendency to be obese or over weight.  People who are overweight or obese are more at risk of developing conditions such as cardiovascular disease and diabetes.

In A Nutshell…

It may not be the gluten that is causing your digestive symptoms – it might actually be the FODMAPs!

However, if you find that you have increased symptoms after eating foods containing gluten, it is very important to rule out coeliac disease. Please discuss your symptoms with a doctor or dietitian as they may refer you to get tested for coeliac disease.  

Once other health conditions have been ruled out, tracking the foods that you can and cannot tolerate is key to managing your symptoms. Keeping track of the foods and understanding their FODMAP content is particularly important – especially at the beginning of your IBS journey.

So, What Should I Do?

It’s really important to have as varied a diet as possible, so I would encourage you to try include as many different foods as you can tolerate. If wheat is a problem for you, but you think gluten might be okay, why not try some low FODMAP versions like sourdough bread or spelt bread? Keep an eye on serving sizes (as serving size plays a large part in how FODMAPs may affect you), and monitor your symptoms. You can use your FoodMarble AIRE app and device to keep track of your symptoms and your hydrogen breath tests.

With the FoodMarble AIRE device, you can test your reactions to different FODMAPs, including inulin, using sachets that are available to purchase separately. Check out this blog to follow one of our users as she takes the Inulin FODMAP test – “Aoife takes the inulin challenge”.

You should always discuss with your primary healthcare provider before making any major diet changes, especially if you have been experiencing any new symptoms or a worsening of symptoms.


For some further reading, check out our previous blogs below

High carb vs. high protein: the good, the bad & the ugly

Why is it so difficult to diagnose gastrointestinal disorders?

What is hydrogen breath testing and how does it work?

You’ve been diagnosed with IBS — what does that mean?

FoodMarble is a pocket-sized breath analysis device. It helps people with chronic digestive issues determine the foods that work best with their digestive system. To learn more about FoodMarble, visit

Photo Credits:

Top photo: Ales Krivec on Unsplash

Bottom photo: Fleur Treurniet on Unsplash

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