Coeliac Disease: An Overview

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Published: 16 May 2021

More than just a gluten-free diet, coeliac disease is a serious and life-long autoimmune condition that if not properly managed can have devastating effects on a person's physical and mental health, and lead to other life-threatening complications.

What is Coeliac Disease?

Coeliac disease is a chronic autoimmune condition affecting about 1 in 70 Australians. It is characterised by an abnormal immune response to gluten, a protein that is found in wheat, rye, oats, triticale and barley (Better Health Channel 2019).

Gluten contains a component known as a prolamin fraction, which is responsible for triggering the abnormal immune response. Different grains each have a different prolamin fraction:

  • Gliadin (wheat)
  • Secalin (rye)
  • Hordein (barley)
  • Avenin (oats).

(Better Health Channel 2019)

When a person living with coeliac disease eats even a tiny amount of gluten, it triggers an immune response that damages the villi - tiny, finger-like projections that increase the surface area of the small intestine (Better Health Channel 2019; Lab Tests Online Australasia 2017).

The villi are responsible for breaking down and absorbing nutrients, vitamins, minerals, fluids, and electrolytes from food. However, in someone with coeliac disease, exposure to gluten triggers the production of autoantibodies that target the villi. This causes the villi to become inflamed and flattened in a process known as villous atrophy, greatly reducing the surface area of the small intestine that is able to absorb nutrients (Lab Tests Online Australasia 2017; Healthy WA 2018).

Damage from this immune response may result in various symptoms that impair health and quality of life (Healthy WA 2018).

coeliac disease villi
Coeliac disease causes the villi to become inflamed and flattened, impairing the absorption of nutrients.

What Causes Coeliac Disease?

Almost every person who develops coeliac disease has one or both of two particular genes: HLA DQ2 and HLA DQ8 (Healthdirect 2020).

This genetic predisposition is common, with more than 40% of people being born with HLA DQ2 and/or HLA DQ8 ( (Lab Tests Online Australasia 2017). Despite that, only about 1 in 40 people will actually develop coeliac disease (Better Health Channel 2019).

In order for coeliac disease to develop, it appears that HLA DQ2 and/or HLA DQ8 must be triggered by an environmental factor such as diet or a previous gastrointestinal infection. Coeliac disease can develop at any age (Healthdirect 2020).

Coeliac disease is a hereditary disease. While the inheritance pattern is unknown, first-degree relatives (parents, children and siblings) of someone with coeliac disease have a 10% chance of developing the condition themselves (MedlinePlus 2019; Better Health Channel 2019).

Comorbidities that appear to increase the risk of developing coeliac disease include:

  • Type 1 diabetes
  • Ulcerative colitis
  • Certain neurological disorders (e.g. epilepsy)
  • Thyroid disease
  • Down syndrome.

(Healthdirect 2020)

Interestingly, coeliac disease appears to be more common in people of European descent (Lab Tests Online Australasia 2017).

Symptoms of Coeliac Disease

The symptoms of coeliac disease can range from minor, to severe, to unnoticeable in some cases. Coeliac disease is often underdiagnosed and symptoms may be misinterpreted as irritable bowel syndrome, food sensitivity, stress or age (Better Health Channel 2019; Healthdirect 2020).

Potential symptoms include:

  • Diarrhoea or constipation
  • Fatty stools
  • Nausea and vomiting
  • Flatulence
  • Abdominal pain and discomfort
  • Nutritional deficiencies such as anaemia or iron deficiency
  • Weight loss or gain
  • Persistent fatigue
  • Irritability
  • Failure to thrive, developmental delay or delayed puberty (in children) Pain and stiffness in bones or joints
  • Dental problems, including swelling of the mouth or tongue and recurring mouth ulcers
  • Dermatitis herpetiformis (an Itchy, blistery skin rash)
  • Bruising easily.

(Healthdirect 2020; Lab Tests Online Australasia 2017)

coeliac disease symptoms abdominal pain

How is Coeliac Disease Diagnosed?

A person experiencing any of the following is encouraged to be screened for coeliac disease:

  • Early osteoporosis
  • Infertility with no known explanation
  • Family history of coeliac disease
  • Liver disease
  • Autoimmune disease (e.g. type 1 diabetes, autoimmune thyroid condition).

(Healthdirect 2020)

The diagnosis of coeliac disease may involve autoantibody testing, particularly in symptomatic patients. Potential tests include:

  • Anti-tissue Transglutaminase (anti-tTG) Antibodies, IgA (generally the first test performed)
  • Anti-tTG, IgG
  • Deamidated Gliadin Peptide (DGP) Antibodies, IgA
  • Anti-Gliadin Antibodies (AGA), IgG and IgA
  • Anti-Endomysial Antibodies (EMA), IgA
  • Anti-Reticulin Antibodies (ARA), IgA
  • Anti-Actin IgA (F-actin).

(Lab Tests Online Australasia 2017)

Diagnosis should be confirmed via a biopsy of the small intestine in order to determine whether there is any damage to the villi (Lab Tests Online Australasia 2017). This is performed using gastroscopy (Healthdirect 2020).

Genetic tests to detect a genetic predisposition for coeliac disease may be performed if there is uncertainty about the patient’s diagnosis, however, they cannot diagnose coeliac disease on their own as HLA DQ2 and/or HLA DQ8 are found in half of the population. Despite this, they may be useful in ruling out coeliac disease as a potential diagnosis (Lab Tests Online Australasia 2017; Healthdirect 2020).

Once coeliac disease has been diagnosed, some people may undergo additional testing in order to determine the severity and extent of the condition, such as:

  • Full blood count to detect anaemia
  • Faecal calprotectin to measure intestinal inflammation
  • E/LFTs to evaluate electrolyte, protein and calcium levels, along with kidney and liver status
  • Vitamin D, B12 and folate testing to identify any vitamin deficiencies
  • Iron, iron-binding capacity or transferrin, and ferritin to identify iron deficiency
  • Stool fat testing to assess for malabsorption.

(Lab Tests Online Australasia 2017)

Complications of Coeliac Disease

Coeliac disease can have serious complications if not managed properly. These may include:

  • Osteoporosis
  • Infertility and miscarriage
  • Malnutrition
  • Depression
  • Chronic poor health
  • Dental issues
  • Lactose intolerance
  • Liver disease
  • Nervous system problems (e.g. seizures, peripheral neuropathy)
  • Increased risk of certain cancers (rarely), for example, lymphoma of the small intestine.

(Healthdirect 2020; Better Health Channel 2019; Mayo Clinic 2020; Healthy WA 2018)

These complications can generally be avoided if coeliac disease is diagnosed and treated early (Healthdirect 2020).

How is Coeliac Disease Treated?

While there is no cure for coeliac disease, symptoms can be managed by consuming a strict gluten-free diet, which will allow the small intestine to heal and stay healthy. This diet must be a lifelong commitment (Healthdirect 2020).

Foods to Avoid

coeliac disease gluten free diet supermarket

An essential component of maintaining a gluten-free diet is knowing what foods to avoid. Some are obvious, but there are many foods containing gluten that you might not expect.

The following foods contain gluten and should be avoided by people living with coeliac disease (apart from gluten-free alternatives):

  • Bread
  • Cereal
  • Porridge
  • Cake
  • Biscuits
  • Pizza
  • Pasta
  • Wheaten breadcrumbs or batter
  • Pastry
  • Wheat-based noodles
  • Couscous, semolina and burghul
  • Stuffing.

(Better Health Channel 2019)

The following foods may contain gluten, and therefore, people living with coeliac disease should research and read food labels before consuming them:

  • Cornflour
  • Soy sauce
  • Vegemite
  • Stock
  • Gravy
  • Soup
  • Malt drinks
  • Sauce
  • Dressing
  • Sausages and hamburgers
  • Crumbed and marinated meats
  • Smallgoods (e.g. salami)
  • Barbequed chicken
  • Confectionary
  • Ice cream
  • Custard powder
  • Icing sugar mixture
  • Baking powder
  • Beer.

(Better Health Channel 2019)

Some medicines may contain gluten. This should be stated on the label (Better Health Channel 2019).

Can Coeliac Disease be Prevented?

There is no way to prevent coeliac disease. The best way to avoid complications is through early diagnosis and strict adherence to a gluten-free diet (Healthdirect 2020).

Additional Resources


References

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