Think gluten is causing your symptoms? Here’s what to do next

What is gluten?

Gluten is a protein naturally present in wheat, barley and rye. It’s commonly found in a wide variety of everyday foods, including:

• bread
• pastries
• cakes
• pasta
• pizza bases
• biscuits
• breakfast cereals

Gluten is also often found in less obvious places, such as many processed and packaged foods. It’s often used in these foods as a thickening or stabilising agent. Examples include sausages, soups, sauces and ready meals. Most beers also contain gluten because of the grains used during production.

While oats themselves do not naturally contain gluten, they can be cross contaminated during processing.

What should I do if I think gluten is causing my symptoms?

If you regularly experience gut-based symptoms when eating foods that contain gluten, it’s important to rule out coeliac disease as a possible cause. To do this, you should seek testing before making any dietary changes. This is because tests for coeliac disease are only accurate if you’re still eating gluten during the diagnostic process.

Symptoms of coeliac disease can include:

• diarrhoea
• bloating
• headache
• fatigue
• mouth ulcers

Other longer-term symptoms can include:

• weight loss
• iron-deficiency anaemia
• an itchy, red rash that often shows up on the limbs, back or scalp

Coeliac disease is an autoimmune condition where your body’s immune system mistakenly attacks its own tissues when gluten is consumed. This immune response damages the lining of your small intestine, reducing its ability to absorb essential nutrients effectively. Over time, this can lead to nutritional deficiencies.

It’s important to understand that coeliac disease is not the same as a food allergy or intolerance.

It requires a strict, lifelong gluten-free diet to manage symptoms and prevent further intestinal damage.

How can I test for coeliac disease?

A GP or a gastroenterologist can test you for coeliac disease. You will usually start with a blood test to detect specific antibodies associated with the condition.

To ensure accurate results, you need to include gluten in your diet before and during testing.

If blood test results are positive, you may be referred for an endoscopy. This procedure allows a specialist to look at the lining of your small intestine and, where necessary, take biopsies to confirm the diagnosis.

Gluten sensitivity tests you can buy yourself lack evidence and are not recommended. These include:

• IgG blood testing
• kinesiology
• hair analysis

Relying on results from these tests can lead to unnecessary dietary restriction, increasing the risk of nutritional deficiencies and malnutrition.

What if my coeliac disease test is negative?

If coeliac disease has been excluded, but you still have gut-based symptoms after consuming foods that contain gluten, it’s a good idea to have more investigations.

A gastroenterologist can help to find other causes for your symptoms, such as irritable bowel syndrome (IBS). A registered dietitian can also look at your diet and symptoms and help you to find potential triggers and effective symptom management.

In some cases, the term non-coeliac gluten sensitivity (NCGS) may be used for people who have ongoing symptoms despite negative coeliac testing. This condition isn’t well understood and there are no specific tests for it now, but it’s not thought to cause damage to the small intestine.

Is there a link between gluten and IBS?

Many people with IBS find their symptoms worsen after consuming foods that contain gluten. But current evidence suggests that gluten itself may not always be the main trigger.

In many cases, symptoms are more likely to be related to fermentable carbohydrates known as FODMAPs, particularly fructans. These carbohydrates can contribute to symptoms including:

• bloating
• abdominal discomfort
• altered bowel habits

For this reason, some people with IBS may benefit from a structured trial of a low FODMAP diet rather than adopting a gluten-free diet. This approach involves a temporary elimination phase followed by careful reintroduction to identify specific dietary triggers.

It’s recommended that a low FODMAP diet is undertaken with the support of a registered dietitian. This helps to make sure you get all the nutrients you need and reduce your risk of unnecessary long-term dietary restriction.