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. In a person with coeliac disease, the lining of the small intestine is damaged by gluten, which is a protein in wheat, rye, barley, triticale (a hybrid of rye and wheat) and oats. It also causes inflammation in other parts of the body.
Malnutrition, osteoporosis, depression, infertility and a small (but real) increased risk of certain forms of cancer, such as lymphoma of the small bowel, are just some of the problems that can develop if coeliac disease is left untreated. Coeliac disease affects approximately one in 70 Australians.Even small amounts of gluten can cause harm to someone with coeliac disease. The only treatment is to avoid all gluten-containing foods. This allows the bowel lining to recover. This strict attention to diet must be lifelong.
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. In a person with coeliac disease, the mucosa (lining) of the small intestine is damaged. This causes inflammation of the villi, referred to as villous atrophy. The surface area, which enables the absorption of nutrients and minerals, is seriously reduced and this can lead to nutritional deficiencies.
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 in adults include:
- bloating and flatulence
- diarrhoea or constipation
- fatigue, weakness and lethargy
- nausea and vomiting
- stomach cramps
- weight loss – although weight gain is possible.
The most common symptoms in children include:
- abdominal pain, bloating and flatulence
- bulky, foul-smelling bowel motions
- chronic anaemia
- diarrhoea or constipation
- nausea and vomiting
- weight loss or poor weight gain in older children
- delayed growth or delayed puberty
Risk factors for coeliac disease
People are born with a genetic predisposition to develop coeliac disease. They inherit a particular genetic make-up (HLA type), with the genes DQ2 and DQ8 being identified as the 'coeliac genes'. One in 40 people with one or both of these genes will develop coeliac disease (many people who carry the genes will never get coeliac disease). Other genes and environmental factors also play a role.
In many cases, the condition will not have been diagnosed in other generations. However, a first-degree relative (brother, sister, parent or child) of a person with coeliac disease has about a 10 per cent chance of also having the condition.
Diagnosis of coeliac disease
Since 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.
Doctors will do special blood tests (coeliac serology and IgA) for an 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, you must not put yourself on a gluten free diet beforehand. These tests are dependent on a normal gluten intake.
A gluten free diet and coeliac disease
The component of gluten that causes problems for people with coeliac disease is the prolamin fraction. The type of prolamin fraction depends on the grain, for instance:
- gliadin in wheat
- secalin in rye
- hordein in barley
- avenin in oats
A person with coeliac disease should avoid all foods that contain gluten. It is important to read the labels of all packaged or prepared foods.
Obvious foods that contain gluten include:
- breakfast cereals
- foods crumbed or battered with wheaten breadcrumbs or batter
but there is also a whole range of ingredients in prepared and commercial foods that can come from a gluten source. A person with coeliac disease must become 'ingredient aware'. A dietitian can give valuable guidance to suit your needs.
The challenge for many people newly diagnosed with coeliac disease is to find tasty substitutes for all the foods they can no longer eat. The list of forbidden foods may seem very long, but a person with coeliac disease can still enjoy a nutritious, balanced diet with a wide range of foods by experimenting with alternative grains.
Food labelling and gluten
All packaged foods have an ingredient list printed on the label. There are four main types of suitable gluten free foods, which include:
- foods that are naturally gluten free, such as fresh fruit and vegetables and fresh, unprocessed meats
- foods carrying the Coeliac Australia Endorsement logo
- foods labelled 'gluten free'
- foods made for the general market that are gluten free by ingredient.
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. 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 foods are tested using the prescribed test, there must be 'no detectable gluten'. Currently, this test is sensitive to 0.0003 per cent (three parts per million).
Where to get help
- Your doctor
- Dietitians Association of Australia Tel. 1800 812 942
- Coeliac Australia Tel. 1300 458 836
Things to remember
- Coeliac disease is an autoimmune disease where the immune system reacts abnormally to gluten.
- Correct diagnosis can only be made by gastroscopy.
- For people with coeliac disease, even small amounts of gluten can damage the lining of the small intestine (bowel), which prevents the proper absorption of food nutrients.
- Damage can occur to the small intestine even when there are no symptoms.
- There is no cure, but coeliac disease can be managed by a lifelong gluten free diet.
- A person with coeliac disease can still have a nutritious, balanced and varied diet.
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