Coeliac disease (pronounced see-lee-ak) is an inflammatory condition characterised by an intolerance to a food protein called gluten, which is found in wheat, oats, barley and rye. This intolerance to gluten causes the body to produce antibodies which damage the lining of the small intestine and makes it difficult for the body to absorb vitamins, minerals and other nutrients from food. Coeliac disease is sometimes referred to as gluten sensitive enteropathy (GSE) or coeliac sprue.
Who gets coeliac disease?
Both genetic and environmental factors play a part in the development of coeliac disease. the condition is hereditary and if one family member suffers from the condition then there is a 10-15% chance that an immediate family member will also have the condition.
The average age of diagnosis of coeliac disease is approximately 40 years but it can occur at any age. It is possible that a major life event such as pregnancy, severe emotional stress, surgery or exposure to a particular virus may activate the condition in genetically pre-disposed individuals. There is also some suggestion that the early introduction of wheat into a child’s diet may induce the condition.
In New Zealand it is estimated that coeliac disease affects up to 1 in 100 of the general population but many of these people will be undiagnosed. New Zealanders of Celtic origin are at greatest risk of developing the condition.
Causes, signs and symptoms
Coeliac disease is caused by an inflammatory response in the small intestine. The exact mechanism of the condition is not understood. However, it is known that when food containing gluten reaches the small intestine the immune system activates in response to a substance called gliadin, which is found in the gluten. The resulting inflammation damages tiny finger-like projections in the small bowel, called villi, the function of which is to absorb nutrients from food.
The villi become inflamed and "flattened". The surface area available for digestion is therefore decreased and fewer digestive enzymes are produced. As a result a person is unable to absorb nutrients from food effectively. The damage is known as gluten sensitive enteropathy (GSE) or villous atrophy. Scarring occurs if the bowel is exposed to dietary gluten over a long period of time.
The sensitivity of individuals to gluten varies greatly. Often the onset of the condition occurs over a long period of time and goes relatively unnoticed.
In children, the symptoms tend to be more dramatic and usually appear soon after the introduction of cereal into the diet. Weight loss, diarrhoea, a swollen abdomen and irritability may become obvious.
In adults, damage to the small intestine may be severe without symptoms being obvious or specific. This may make it difficult for coeliac disease to be identified. The condition is often not suspected until complications, such as nutrient deficiencies, cause other problems.
Symptoms of coeliac disease may include some or all of the following:
- Weight loss
- Indigestion, abdominal pain, bloating and flatulence. This may be general or associated with digestion of particular foods
- Gastrointestinal changes such as bulky fatty bowel motions, sometimes pale and bad smelling
- Diarrhoea or constipation
- Nausea and vomiting
- Anaemia, folate and vitamin B12 deficiencies
- Fatigue and generalised weakness
- Muscle cramps due to low calcium levels
- Slowed growth rate in children
- Blistering, itchy or painful rash - particularly about the knees, elbows, buttocks and back (dermatitis herpetiformis).
Coeliac disease is often difficult to diagnose due to its non-specific symptoms and the long period of onset. Diagnosis is based on three main areas:
The doctor will take note of the symptoms that the person has been experiencing and whether there is a family history of coeliac disease. Any unexplained deficiencies such as a low iron or folate levels in the blood (causing anaemia) may alert the doctor to the possibility of an absorption disorder. A referral to a doctor specialising in digestive system disorders (a gastroenterologist) may then be made.
If coeliac disease is suspected, the person may have blood taken to test for specific antibodies that, if found, are suggestive of coeliac disease when other symptoms are present.
Small bowel biopsy:
In New Zealand the test most commonly used to diagnose coeliac disease is a small bowel biopsy. It is the only test that will conclusively diagnose the condition. The biopsy is taken during a procedure called a gastroscopy. A gastroscopy usually takes less than half an hour and is performed by a specialist. It is performed on a day stay basis using a light sedation. Special preparation to clear out the bowel before the test is needed. During the gastroscopy a small flexible tube called an endoscope is passed down the person’s throat and into the beginning of the small intestine. The endoscope contains a special camera that allows the specialist to view the inside lining of the small intestine on a television monitor. A very small piece of tissue is removed (a biopsy) and sent to a laboratory for viewing under a high powered microscope. A characteristic change in the tissue would confirm that the person was suffering from coeliac disease.
The treatment for coeliac disease is the complete and life-long removal of gluten-containing foods from the diet. This should result in the resolution of the inflammation and the restoration of the inner lining of the small bowel. In some cases medications such as steroids are required to further decrease the body’s abnormal immune response, therefore reducing inflammation. Medications to treat conditions that have developed as a result of coeliac disease, such as anaemia and nutrient deficiencies, may also be required.
A repeat biopsy is sometimes performed three to six months after starting a gluten-free diet to check small intestine recovery.
Studies suggest that if gluten is withdrawn from the diet the bowel lining will return to close to normal in approximately three months. Eating gluten again can result in severe damage to the bowel in as little as three weeks. The amount of gluten eaten, the degree of bowel injury and the severity of symptoms are often not directly related to each other. This means that the person cannot rely on symptoms to gauge the amount of small intestine damage. Therefore strict adherence to a gluten free diet is essential.
If coeliac disease is not effectively treated with a strict gluten-free diet, long term complications can occur. These include:
- An increased risk of developing certain types of bowel cancer (lymphoma and adenocarcinoma)
- Osteoporosis (low bone density)
- Nervous system disorders such as irritability, depression, nerve damage (neuropathy) and seizures
- Missed menstrual periods
- Reduced fertility along with risks to the foetus.
Strategies for dietary management
Because gluten is found in wheat, oats, barley and rye, it is widely consumed in the Western diet but may not always be obvious. It is important to know safe foods to eat and be wary of hidden sources.
Once a diagnosis of coeliac disease is reached a person will usually be referred to a dietician. In New Zealand a person is entitled to be seen by a dietician within the public health system, but may choose to see a dietician privately. Check in the telephone directory for a list of Registered Dieticians (these may also be listed under nutritionists). The dietician can discuss a gluten free diet with the person and their family and provide written information as reference material. It is important that the diet is relevant to the person’s situation, particularly if they have other medical conditions.
Never eat foods known to contain gluten.
Never eat foods with unknown ingredients as they may contain gluten.
Meals should be planned ahead and gluten-free snacks kept available. Many "fast foods" contain gluten so should not be eaten.
Gluten-free food suppliers:
There are many suppliers of gluten free food products and gluten free food is increasingly common on supermarket shelves. Searching the internet provides many links to gluten free food suppliers and outlets. Gluten free apps for smart phones are also available.
It may be useful to find out about eating places that make gluten free meals, or learn to adapt menu choices to rule out the possibility of being served meals containing gluten. It is helpful to educate friends and family about the condition and gluten-free foods, so that meal invitations don’t become difficult.
Pharmac provides a part-subsidy on gluten free flour and pasta. This subsidy is arranged through your GP and is available to people who have been diagnosed with coeliac disease by biopsy and to people diagnosed with dermatitis herpetiformis.
Further information and support
Coeliac New Zealand can provide information and support for people who have coeliac disease. Their website contains information about the condition, treatments, gluten free foods, shopping and dining guides, and many other resources.
Coeliac New Zealand (Inc)
Phone: (09) 414 7467
Auckland Allergy Clinic (Date unknown) Coeliac Disease. Auckland Allergy Clinic. Auckland. http://www.allergyclinic.co.nz/guides/8.html
Coeliac Disease (Information Sheet) 2013. Auckland. Coeliac New Zealand Inc.
Ford-Martin. P, Odle. T (2005) Celiac Disease. The Gale Encyclopedia of Alternative Medicine. Second Edition. Jacqueline L. Longe (Editor). Farmington Hills, MI. Gale Group.
Gastroenterological Society of Australia (2011) Coeliac Disease. (Pamphlet - Fifth Edition). Gastroenterological Society of Australia (GESA).
Last Reviewed – 22 February 2013