IBS and Coeliac Disease: A guide to understanding & diagnosis

Are you confused about IBS and coeliac disease? Maybe you feel better without gluten in your diet, but you’re not sure whether you’ve been tested for coeliac disease or not.

The cross over between IBS and coeliac disease

Coeliac disease is an autoimmune condition where you react to gluten. It must be treated by a gluten free diet and is not the same as IBS, but the symptoms can be similar.

Unfortunately 1 in 4 people with coeliac disease are misdiagnosed with IBS when they actually have coeliac disease. In one comparison study looking at the typical treatments for IBS, 16% of coeliac patients had a prior IBS diagnosis, and 28% had been given IBS advice in the past, compared to 9% of controls.

This shows that some doctors may assume IBS before ruling out coeliac disease. 

How common is coeliac disease?

Around 1 in 10 people will have IBS in the UK, so it’s statistically more likely that someone would have IBS. But it’s thought around 1 in 100  (1%) of the UK adult population has undiagnosed coeliac disease.

This number rises to 3.3% when you only look at people with IBS. But it could be even higher. In one study 12 out of 105 patients with IBS were found to actually have coeliac disease, and when they adhered to a gluten free diet 11 of those 12 were better. 

That adds up to a lot of people in pain, with terrible digestive symptoms for years and years. In fact, it can take 13 years on average to get diagnosed.

What is coeliac disease?

Coeliac disease is a lifelong inflammatory autoimmune condition affecting the small intestine. If you have it, and you eat gluten it can lead to digestive symptoms like bloating, abdominal pain, gas and diarrhoea.

Exposure to gluten can also lead to systemic whole body symptoms such as brain fog, nutrient deficiencies and fatigue.

If you’ve got coeliac disease and eat gluten your gut cells can attack themselves. Over time this can cause permanent damage to the lining of the gut.

Coeliac disease is not an allergy to gluten, although the immune system is involved.

Issues with untreated coeliac disease

People with coeliac disease must be super strict about gluten contamination. Even ingesting a tiny amount can affect sufferers.

If you imagine a million red marbles, and only 20 of these are blue, it’s a tiny proportion, right. But this is the size of the portion of gluten that can have an impact in the gut of people with coeliac disease. Just 20 parts per million can trigger lasting damage to the gut lining.

A tiny amount of gluten can damage the gut in coeliac disease

That’s like 20 mg of gluten in a kilo of food. It’s not much at all. Which is why people with coeliac disease need to be so strict about contamination.

Managing coeliac disease

Ideally there will be no gluten in the house, but if you live with other people who eat gluten you need to keep your things separate. People with coeliac disease need to have separate butter, jams and spreads so there are no crumbs in their food.

Kitchen drawers should be kept very clean to avoid any crumbs getting cutlery and cooking equipment. And when you’re eating out you need to ensure the restuarant understands how to keep gluten free foods separate. For more support check out Coeliac UK 

Damage to the gut villi

Gluten damage stops key nutrients being absorbed because the tiny villi in the gut lining can become shortened. This can lead to deficiencies in iron, protein, B vitamins and fat soluble nutrients.

When deficiencies become severe they may result in anaemia, joint pain and severe fatigue.

How would you know if you have coeliac disease?

Symptoms of coeliac disease are very similar to IBS, including bloating, abdominal pain, loose stools.

You cannot diagnose coeliac disease by looking at someone or guessing. You need a blood test to look for antibodies, and possibly a biopsy.

Important information about getting your coeliac disease test

NICE guidelines state an IBS diagnosis should include ruling out other conditions including coeliac disease. This is because the symptoms are so similar.

This can be an issue because not everyone goes to their doctor about IBS. On the other hand some people go, but they don’t eat enough gluten in the run up to the blood test.

Testing for coeliac disease only works if you’ve been eating gluten daily for 6 weeks prior to the test. If you don’t eat gluten in the run up to the test, you may not have enough antibodies to show up in the blood. This could lead to a false negative result.

Don’t give up gluten before you’ve had a coeliac disease test

Before you trial a gluten free diet for IBS it’s worth getting a blood test to check for antibodies.

Is there another way to test for coeliac disease?

Maybe you’ve already trialled a gluten free diet, and feel worried about eating bread and pasta again daily. You might be concerned the symptoms will come back, and it’s not worth the risk.

There is a test to look for the genes which all people with coeliac disease have.

Genetic testing for coeliac disease

People with coeliac disease will have one or more copy of the following genes:

• HLA DQ 2.5
• HLA DQ8
• HLA DQ2.2 

If you have the genes it doesn’t mean you have coeliac disease, but you won’t have coeliac disease if you don’t have the genes. Actually around 40% of the population might carry these genes and be ok. 

I recommend everyone with IBS ask their GP to be tested for celiac disease as part of the process of diagnosing IBS, in line with the NICE guidelines.

Don’t give up gluten until you’ve already had this test or it won’t be valid.

You can have both coeliac disease and IBS

Unfortunately, some people don’t feel better even when they have well managed coeliac disease. You may have IBS as well, or other conditions such as SIBO. Up to around 30% of people with coeliac disease continue to get symptoms. 

This could be down to other health conditions. You may benefit from working with a specialist nutrition professional to improve your diet. 

For more information

If you’re struggling with IBS alongside coeliac disease then please get in touch about working with me in the 3 month Gut Reset.