Coeliac disease is an autoimmune condition in which the body reacts abnormally to gluten — a protein found in several common grains. When people with coeliac disease eat gluten, their immune system attacks the lining of the small intestine, causing damage that prevents the body from properly absorbing nutrients.
Gluten is found in three main cereals: wheat, barley and rye. Because of this, it appears in many everyday foods such as bread, pasta, cakes, breakfast cereals and some sauces or ready meals. Most beers also contain barley.
How coeliac disease affects the body
In people with coeliac disease, eating gluten triggers an immune reaction that damages the villi — tiny finger-like projections lining the small intestine. These structures normally help absorb nutrients from food. When they become damaged, the body cannot properly take in essential vitamins and minerals.
As a result, people may develop symptoms related both to digestion and to nutrient deficiencies.
Common symptoms
Symptoms vary widely and can range from digestive discomfort to broader health problems.
Digestive symptoms may include:
- diarrhoea, sometimes with a strong smell
- stomach pain
- bloating and excessive gas
- indigestion
- constipation
Coeliac disease can also cause more general symptoms such as:
- persistent tiredness due to poor nutrient absorption
- unintentional weight loss
- an itchy skin rash known as dermatitis herpetiformis
- fertility problems
- nerve damage (peripheral neuropathy)
- balance or coordination problems (ataxia)
In children, the condition may affect growth. Some children with coeliac disease do not grow at the expected rate or may experience delayed puberty.
What causes coeliac disease?
Coeliac disease is considered an autoimmune disorder, meaning the immune system mistakenly attacks healthy tissue.
In this case, substances within gluten are wrongly identified as a threat. The immune response damages the lining of the small intestine, disrupting nutrient absorption.
Researchers believe the condition develops due to a combination of genetic and environmental factors. It often runs in families, and people with a first-degree relative (parent, sibling or child) with coeliac disease have about a 1 in 10 risk of developing it themselves.
Certain conditions also increase the risk, including type 1 diabetes, autoimmune thyroid disease, Down syndrome and Turner syndrome.
How common is it?
Coeliac disease affects roughly 1 in 100 people worldwide. However, experts believe many cases remain undiagnosed. Some estimates suggest that only around 30% of people with the condition are correctly diagnosed, partly because symptoms can be mild or mistaken for other digestive disorders such as irritable bowel syndrome (IBS).
Reported diagnoses are also more common in women than in men. The condition can develop at any age after gluten is introduced into the diet.
Diagnosis
Routine screening for coeliac disease is not commonly performed. Testing is usually recommended for people who have symptoms or who belong to higher-risk groups, such as those with a family history of the condition.
First-degree relatives of people diagnosed with coeliac disease are often advised to undergo testing as well.
Treatment
There is currently no cure for coeliac disease. The only effective treatment is a strict lifelong gluten-free diet.
Removing gluten from the diet allows the intestine to heal and usually improves symptoms. Even people with mild symptoms are advised to avoid gluten, because continued exposure can lead to long-term health problems.
In recent years, the availability of gluten-free foods has increased significantly, making it easier for people with coeliac disease to maintain a balanced and varied diet.
Possible complications
If coeliac disease is not diagnosed or if gluten continues to be consumed, long-term complications may develop. These can include:
- osteoporosis (weakening of the bones)
- iron-deficiency anaemia
- vitamin B12 or folate deficiency anaemia
More rarely, untreated coeliac disease may be linked to certain cancers, including bowel cancer, or complications during pregnancy such as low birth weight in babies.
Early diagnosis and proper dietary management significantly reduce these risks.
