Description, causes, prevention, treatment and medicines
What is coeliac disease?
Coeliac disease is a condition that affects the small bowel, caused by an abnormal immune response, or sensitivity, to a dietary protein known as gluten. Gluten is found in wheat, rye and barley, and most types of oats. Sensitivity to gluten causes inflammation and damage to the small intestine, and sometimes the damage is so severe that the intestine is unable to absorb essential nutrients, leading to malnutrition.
How common is coeliac disease?
Coeliac disease affects about one per cent of Australians, and has been diagnosed more frequently in recent years. Many people with coeliac disease do not realise they have it.
What are the symptoms?
The symptoms of coeliac disease vary widely from person to person. Some people may have no symptoms at all, while others complain of tiredness or gastrointestinal symptoms. Some of the more common symptoms include:
- tiredness;
- intermittent diarrhoea;
- abdominal pain or cramping;
- indigestion;
- flatulence;
- bloating; and
- weight loss.
Children with coeliac disease may also have slow growth or weight loss, irritability, a swollen abdomen and delayed development.
Some people with coeliac disease will also have conditions relating to the malabsorption of certain nutrients from the diet. A lack of vitamin D can cause osteomalacia — a condition resulting in soft, fragile bones, also known as rickets in children; and low calcium and vitamin D can cause osteoporosis — a loss of bone density that makes bones weak and more prone to fractures. A lack of iron, folate or vitamin B12 can cause anaemia.
What causes coeliac disease?
In people with coeliac disease, the small intestine becomes inflamed when foods containing gluten are consumed. This inflammation damages the lining of the small intestine, which normally has tiny, finger-like projections called villi that are responsible for absorbing nutrients from food. When the villi are damaged, they may flatten out, making it much more difficult for you to absorb nutrients.
The exact cause of coeliac disease is not known. However, there are some factors that can put you at increased risk, including:
- a family history of the disease (if someone in your immediate family is affected, you have about a 10 per cent chance of having coeliac disease);
- being of European descent; and
- having another medical condition that is related to problems with the immune system, such as certain types of thyroid disease, type 1 diabetes, lupus erythematosus, or rheumatoid arthritis.
People of all ages can be affected, but symptoms only appear after gluten has been introduced into the diet. Sometimes a stressful event, such as an infection, injury, or surgery, will trigger symptoms of coeliac disease.
How is coeliac disease diagnosed?
Coeliac disease can be difficult to diagnose because the symptoms are so variable. If your doctor suspects you have this condition, they may suggest some tests for coeliac disease, including blood tests which can be ordered to check for certain antibodies.
Some of the blood tests your doctor might order include:
- anti-tissue transglutaminase antibodies;
- deamidated gliadin peptide IgA and IgG tests (which replace anti-gliadin antibodies in some laboratories); and
- anti-endomysial antibodies (although this test is not commonly used nowadays).
If the blood tests show high levels of antibodies, you will probably be advised to have a biopsy taken of your small intestine to confirm the diagnosis. A biopsy involves taking a small sample of tissue and examining it under a microscope. If you have coeliac disease, there will be evidence of damage to the lining of the small intestine.
To obtain the biopsy, your doctor will perform an endoscopy — a test where an endoscope (a long, thin flexible tube with a camera on the end) is passed down your throat so that your doctor can see inside your stomach and small intestine. A special instrument is passed through the endoscope to take tiny sample(s) of your intestine.
Further blood tests to check for nutritional deficiencies may also be necessary. Your doctor may want to check whether you have a deficiency in iron, folate, vitamin B12, calcium, or vitamin D.
Is there any treatment for coeliac disease?
There is no cure for coeliac disease, but it can be treated with a gluten-free diet. Most people find that once gluten is excluded from their diet, their symptoms improve dramatically because the inflammation in the small intestine resolves quickly, and any damage to its lining can heal. People with coeliac disease need to stick to the gluten-free diet for the rest of their lives to prevent further inflammation.
It’s important to note that you should not have started a gluten-free diet before being tested for coeliac disease, because this can alter your test results and make the diagnosis more difficult.
A dietitian or nutritionist can advise you on how to exclude gluten from your diet and suggest healthy eating alternatives. You will most likely become an expert in reading food labels and knowing which foods are best avoided.
A small number of people who have severely damaged small intestines don’t improve straight away with a gluten-free diet. These people may need medicines to help reduce the inflammation, such as corticosteroids. Some people may also need to be treated for nutritional deficiencies, usually with vitamin and mineral supplements.
What are the main foods that people with coeliac disease should avoid?
Gluten is generally found in foods made from grains such as bread, pasta, cereals, pastry and biscuits. However, it is possible to buy gluten-free alternatives to these foods, which are made from corn, rice, soy or other gluten-free grains.
There are also other food ingredients and food additives that may contain gluten, such as malt flavouring and modified food starch — your dietitian can advise you on what to look for on food labels. In addition, there are some medicines and vitamin supplements that contain gluten, so you will need to check with your doctor or pharmacist before taking any new medicines.