Gluten and Coeliac Disease: Symptoms, Testing and a Gluten-Free Diet

What is gluten and where is it found?

Gluten refers to a group of proteins found in wheat, rye, barley and their hybrids. Spelt, a type of wheat, and triticale also contain gluten. Common sources include bread, pastries, pasta, semolina, breadcrumbs and barley malt.

For processed foods, check the specific ingredients and packaging information. The product name alone is not enough.

Coeliac disease, allergy and sensitivity are different

Similar symptoms can have different causes. Feeling better after avoiding wheat does not, by itself, confirm coeliac disease.

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What symptoms may occur?

Coeliac disease may involve bloating, abdominal pain, diarrhoea, constipation or unintended weight loss. Sometimes tiredness, iron-deficiency anaemia, mouth ulcers or reduced bone density are more prominent. In children, slowed growth may also prompt testing.

A very itchy, blistering rash called dermatitis herpetiformis can be a skin manifestation. Some people have only mild symptoms or no obvious symptoms at all. Symptoms alone cannot establish the diagnosis.

What does testing involve?

Your doctor considers symptoms, diet, family history and test results. Blood tests usually include tTG-IgA antibodies and total IgA. Other appropriate tests are used if IgA levels are deficient.

Depending on the circumstances, an upper gastrointestinal endoscopy with samples from the small intestinal lining may follow. A specialist decides whether a biopsy is needed and what comes next; children have specific diagnostic criteria.

HLA-DQ2/DQ8 genetic testing: a positive result does not confirm coeliac disease on its own. The absence of relevant variants makes it very unlikely.

When should you discuss testing?

Discuss persistent digestive symptoms, unexplained anaemia, weight loss or growth problems with your doctor. Testing may also be considered for close relatives of someone with coeliac disease and people with certain associated conditions, such as type 1 diabetes or autoimmune thyroid disease.

Coeliac disease can become apparent at different ages. Your doctor decides whether testing or repeat testing is appropriate.

A gluten-free diet after a confirmed diagnosis

Confirmed coeliac disease requires strict, lifelong avoidance of gluten. Simply reducing intake according to whether you notice symptoms after meals is not enough. A qualified dietitian experienced in coeliac disease can help plan a balanced diet.

Naturally gluten-free foods include rice, buckwheat, maize, quinoa, potatoes, pulses, fruit, vegetables, eggs and unprocessed meat or fish. Always check the ingredients of prepared products.

Oats: choose only products labelled gluten-free and discuss their suitability individually. Tolerance varies. A gluten-free label also says nothing about the amount of sugar, fat or fibre in a product.

Be aware of gluten cross-contact

Gluten-free food can become contaminated during production, storage or preparation. Examples include crumbs in a toaster or butter, shared frying oil used for breaded foods, and flour on work surfaces.

Separate storage, clean utensils and checking preparation methods in restaurants help reduce cross-contact. Gluten-free ingredients alone do not guarantee a gluten-free finished meal.

Vitamins, minerals and bacterial cultures

Supplement needs vary from person to person. Depending on your health, your doctor may check a full blood count, iron and ferritin, folate, vitamins B12 and D or other markers. Nutrient supplementation should reflect an identified need.

Food supplements, bacterial cultures and digestive enzymes do not replace a gluten-free diet for coeliac disease. They are not a reason to consume gluten. Check every product's ingredients, allergens and suitability for your circumstances.

If symptoms persist

Discuss ongoing symptoms with a gastroenterologist. Assessment may include unintended gluten intake and other possible causes, such as lactose intolerance or irritable bowel syndrome. Avoid excluding further food groups without professional guidance.

Normal antibody levels while following a gluten-free diet do not mean that confirmed coeliac disease has disappeared. Regular follow-up remains important.

Frequently asked questions