Coeliac Disease

What is coeliac disease?

Coeliac disease is a chronic autoimmune condition where the immune system reacts abnormally to gluten — a protein found in wheat, rye, barley, and oats. This immune reaction causes inflammation and damage to the lining of the small intestine, reducing the absorption of important nutrients and leading to a range of symptoms. It is not the same as a food allergy or intolerance.

What are the symptoms of coeliac disease?

Symptoms vary from person to person and can affect both the digestive system and other parts of the body. Common symptoms include:

  • Bloating, abdominal pain, cramping

  • Diarrhoea or constipation

  • Fatigue or low energy

  • Iron-deficiency anaemia

  • Unexplained weight loss

  • Nausea or vomiting

Other symptoms may include:

  • Skin rash (dermatitis herpetiformis)

  • Osteoporosis or fragility fractures

  • Mouth ulcers

  • Headaches

  • Joint or bone pain

  • Fertility issues or delayed growth in children

Some people have mild symptoms or be well (asymptomatic) despite the presence of intestinal damage.

What causes coeliac disease?

Coeliac disease is caused by an abnormal immune response to gluten that leads to damage of the small bowel lining. More specifically, the villi — tiny finger-like projections that absorb nutrients — become inflamed and later flattened. This reduces the surface area for absorption, causing digestive symptoms and nutritional deficiencies. It occurs in people with a genetic predisposition. Most people with coeliac disease have certain genes (HLA-DQ2 or HLA-DQ8), but not everyone with these genes will develop the condition. Environmental factors also play a role. The condition often runs in families. First-degree relatives (parents, siblings, children) of someone with coeliac disease have about a 10% chance of also having the condition. Coeliac disease is also more common in people with other autoimmune diseases, such as type 1 diabetes, autoimmune thyroid disease, and inflammatory bowel disease.

What are the complications of untreated coeliac disease?

If not diagnosed and treated, coeliac disease can lead to:

  • Nutrient deficiencies (especially iron, calcium, vitamin D, folate)

  • Osteoporosis (thinning of the bones)

  • Infertility or pregnancy complications

  • Delayed growth and puberty in children

  • Increased risk of gut cancers, especially small bowel lymphoma

How is coeliac disease diagnosed?

Accurate diagnosis requires that you continue eating gluten (at least one slice of bread per day) for 6–8 weeks prior to testing. Otherwise, the results may be inaccurate and need to be repeated.

Testing includes:

  • Blood tests: To check for coeliac-specific antibodies

  • Gastroscopy with duodenal biopsies: A thin tube with a camera is passed through the mouth to the small intestine to look for damage and take small tissue samples for confirmation

How is coeliac disease treated?

The only treatment is a strict, lifelong gluten-free diet, which allows the small intestine to heal and helps prevent complications.

Treatment includes:

  • Complete avoidance of foods containing wheat, barley, rye, and most oats (unless certified gluten-free)

  • Reading labels carefully and being aware of hidden gluten in foods and medications

  • Working with a dietitian experienced in coeliac disease

  • Monitoring symptoms and blood markers annually to track improvement

  • Follow-up gastroscopy after 12 months on a gluten-free diet to confirm healing

  • Annual review with GP or specialist to monitor symptoms, nutrient levels and coeliac antibodies

  • Bone density scans every 5 years (or more frequently if needed) to monitor for osteoporosis

Reliable information and support are available through organisations like Coeliac Australia, which help individuals stay informed and up-to-date with safe dietary practices.