Coeliac disease (pronounced SEE-lee-ak) is a significant medical condition that can cause serious problems if it is not diagnosed and treated properly. It affects the small intestine – the part of the digestive system responsible for absorbing nutrients.
If you have coeliac disease, eating gluten – a protein found in wheat, rye, barley, triticale (a hybrid of rye and wheat) and oats – causes damage to the lining of your small intestine. It also causes inflammation in other parts of your body.
The component of gluten that causes problems for people with coeliac disease is the prolamin fraction. There are different prolamin fractions in different the grains:
- gliadin in wheat
- secalin in rye
- hordein in barley
- avenin in oats.
Coeliac disease affects approximately one in 70 Australians. It is treated by following a lifelong gluten-free diet
. This means avoiding all gluten-containing foods. This allows the lining of the small intestine to recover. Even small amounts of gluten can cause harm to someone with coeliac disease. If coeliac disease is left untreated, problems that can develop include: malnutrition, osteoporosis, depression and infertility. Untreated coeliac disease can also lead to a small (but real) increased risk of certain forms of cancer, such as lymphoma of the small bowel.
Damage to the small intestine from coeliac disease
The normal lining of the small intestine (also called the small bowel) is covered with tiny, finger-like projections called villi. The cells on villi break down and absorb nutrients in food. If you have coeliac disease, the mucosa (lining) of your small intestine is damaged. This causes inflammation of the villi, referred to as villous atrophy. As a result of this inflammation, the surface area of your small intestine, which enables the absorption of nutrients and minerals, is seriously reduced. This can lead to nutritional deficiencies.
What are the symptoms of coeliac disease?
The symptoms of coeliac disease can range from severe to minor or atypical, and may even go undetected. Some symptoms can be wrongly confused with irritable bowel syndrome or a sensitivity to wheat or other food, while other symptoms may be put down to stress or getting older.
The most common symptoms of coeliac disease in adults include:
- bloating and flatulence
- diarrhoea or constipation
- fatigue, weakness and lethargy
- nausea and vomiting
- stomach cramps
- weight loss – although weight gain is also possible.
The most common symptoms of coeliac disease in children include:
- abdominal pain, bloating and flatulence
- bulky, foul-smelling bowel motions (poo)
- chronic anaemia
- diarrhoea or constipation
- nausea and vomiting
- weight loss or poor weight gain in older children
- delayed growth or delayed puberty
What are the risk factors for coeliac disease?
Around 50% of people in Australia are born with a genetic predisposition to develop coeliac disease. This means that they have one or both of the ‘coeliac genes’ (HLA-DQ2 and HLA-DQ8).
One in 40 of these people may develop coeliac disease – if something triggers one or both of these genes to be expressed. Yet, many people who carry the genes will never get coeliac disease. Environmental factors play an important role in triggering coeliac disease.
If you are diagnosed with coeliac disease, your first-degree relatives (brother, sister, parent or child) have an increased risk (10 per cent chance) of also having the condition. Therefore it is recommended that first degree relatives of someone diagnosed with coeliac disease be screened (tested) for the disease.
Often, people with coeliac disease will have no other family members who have been diagnosed with the condition, either in their immediate family or in other generations.
How is coeliac disease diagnosed?
As the symptoms of other conditions can closely mimic coeliac disease, correct diagnosis can only be made by showing that the lining of the person's bowel is damaged.
Your doctor will do special blood tests (coeliac serology and IgA) for your initial screening. If the results are positive, your doctor will refer you to a gastroenterologist. This specialist will confirm the diagnosis by performing a gastroscopy – a procedure that allows tiny samples (biopsies) to be taken from your small intestine. This procedure occurs while you are under sedation and involves a slender instrument (an endoscope) being passed through your mouth into your small intestine.
Do not try to self-diagnose coeliac disease. If the blood tests and endoscopy are to be accurate, it’s important that you do not put yourself on a gluten-free diet beforehand. These tests are dependent on a normal gluten intake.
How is coeliac disease treated?
At present there is no cure for coeliac disease. If you have coeliac disease the only treatment is a strict, lifelong gluten-free diet. That means avoiding all foods that contain gluten. To do this, it is important to:
- know which ingredients contain gluten
- read the labels of all packaged or prepared foods
- avoid eating gluten-free foods that have been contaminated with gluten (known as cross-contamination).
How to follow a gluten-free diet
If you are newly diagnosed with coeliac disease you may find it challenging to discover tasty substitutes for all the foods you can no longer eat. The list of forbidden foods may seem very long, but be reassured – you can still enjoy a nutritious, balanced, delicious diet with a wide range of foods. You can do this by:
- eating naturally gluten-free foods, such as fresh fruits and vegetables, fresh, unprocessed meat and fish, eggs, nuts, seeds, legumes, most dairy foods, fats, oils and alternative grains (such as corn, rice, quinoa, sorghum, buckwheat and soy)
- choosing products that are labelled as gluten free
- choosing products that have the Coeliac Australia Endorsement Logo (a crossed grain in a circle) – these have been produced under strict conditions and have been tested for detectable gluten and found to have none
- selecting products that are gluten free by ingredient – to do this safely you need to be very familiar with which ingredients are gluten free and which are not.
Avoid foods that contain gluten
It is easier to identify some gluten-containing foods than others.
Foods that have a gluten-containing grain as one of their main ingredients may be easier to identify and avoid. For example:
- breakfast cereals
- foods crumbed or battered with wheaten breadcrumbs or batter
- wheat-based noodles
- couscous, semolina, burghul
However, many other kinds of prepared and commercial foods contain gluten, so it is important to read the labels of the products you buy, and do your research before eating out.
Just some of the other foods and drinks that can contain gluten include:
- wheaten corn flour
- soy sauce
- yeast extract spread (such as Vegemite)
- malted drinks (such as Milo, Ovaltine or malted milk)
- sausages, hamburgers, crumbed and marinaded meats
- barbequed chicken
- ice cream
- custard powder
- icing sugar mixture
- baking powder
So, if you have coeliac disease, you need to become 'ingredient aware'. An accredited practising dietitian can give you advice about how to follow a gluten-free diet.
If you join Coeliac Australia you will receive information and advice about following a gluten-free diet, including an ‘ingredient list booklet’ which shows you which ingredients you need to avoid, as well as other benefits.
A note on oats
The current tests for gluten in food can measure the gluten in wheat (gliadin), barley (hordein), and rye (secalin) but not oats (avenin), as it is a slightly different protein. Accordingly, the Australian Food Standards Code prohibits the use of a ‘gluten free’ claim on oat-containing products.
The Australian food standard differs to the regulations in Europe and the USA, where oats can be marketed as ‘gluten free’. More accurately, these ‘gluten free’ oats are the equivalent of oats labelled ‘wheat free’ in Australia - where there is no measurable contamination with wheat, rye or barley. For this reason, you will find products in these parts of the world that are labelled ‘gluten free’ but contain oats.
Evidence shows that uncontaminated oats are well tolerated by most people with coeliac disease. However, in some people with coeliac disease, oat consumption can trigger a potentially harmful immune response. Please note that the absence of symptoms when consuming oats does not necessarily indicate they are safe – bowel damage can still occur despite the absence of symptoms.
It is recommended that individuals who wish to consume oats as part of their gluten free diet do so under medical supervision to ensure appropriate review and safety. Undertaking a gastroscopy and small bowel biopsy before and after three months of regular uncontaminated oat consumption can help guide whether an individual with coeliac disease can safely consume oats.
Avoid cross-contamination with gluten
As well as choosing gluten-free foods, it is important to avoid cross contaminating those foods with gluten when preparing, cooking and serving. It only takes a very small amount of gluten to damage your small intestine if you have coeliac disease.
Steps you can take to avoid cross-contamination include:
- Store gluten-free products in separate, sealed, labelled containers.
- Make sure that all cooking utensils, appliances and surfaces used for preparing gluten-free food are clean and free of gluten.
- Use a clean pot with clean water to cook gluten-free pasta, and strain it with a clean strainer.
- If cooking both gluten-containing and gluten-free pots of food side by side, protect the gluten-free pot from contamination from the other pot. For example, avoid using the same utensils for stirring or serving.
- Avoid using spreads and condiments that may contain crumbs or other sources of contamination. You could have your own, labelled, gluten-free-only condiments in a separate part of the fridge, or you could establish a ‘single-dip’ policy for shared condiments.
- Use clean oil when deep frying at home (or fry your gluten free item first), and avoid eating food that has been deep fried in oil that has also been used to cook foods that are crumbed or battered.
- Wash your hands after handling gluten-containing foods.
Food labelling and gluten
All packaged foods have an ingredient list printed on the label.
The product ingredient label may not list 'gluten' as a component. However, under mandatory labelling standards, all ingredients and food additives derived from wheat, rye, barley, triticale or oats must be declared on food labels in Australia. Processing aids must also be declared if they are present in the final product.
There is an Australian Food Standard for foods labelled 'gluten free'. When these foods are tested, there must be 'no detectable gluten'. Currently, this test is sensitive to 0.0003 per cent (three parts per million), which is the lowest amount that can be detected (also known as the limit of detection).
Medications and gluten
Gluten may also be present in some medications. Where this is the case, it must say ‘contains gluten’ or ‘contains wheat’ on the label. If you are diagnosed with coeliac disease, ask your GP (doctor) and pharmacist about making sure that any medicines you are taking orally are gluten free.
Where to get help