Coeliac disease (gluten intolerance)

 

Coeliac disease (pronounced see-lee-ak) is a lifelong condition that affects the digestive system. It is the result of 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 that 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.

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, or their condition may be incorrectly diagnosed as irritable bowel syndrome.

Both genetic (inherited) 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.

Individuals with autoimmune conditions such as rheumatoid arthritis, diabetes mellitus , and sarcoidosis, have a higher incidence of coeliac disease.

Coeliac disease is caused by an inflammatory response in the small intestine (bowel). 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 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 of coeliac disease tend to be more dramatic than in adults 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 (usually resulting from iron deficiency)
• Folate and vitamin B12 deficiencies
• Fatigue and generalised weakness
• Muscle cramps due to low calcium levels
• Blistering, itchy or painful rash - particularly about the knees, elbows, buttocks and back (dermatitis herpetiformis).

Diagnosis

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:

Medical history:
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 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.

Blood tests:
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 performed by a specialist on a day-stay basis using a light sedation. 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.

Treatment

Unfortunately, there is no cure for coeliac disease. The only 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 corticosteroids 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.

Complications

If coeliac disease is not effectively treated with a strict gluten-free diet, long term complications can occur. These include:

• Malnutrition (damage to the small bowel reduces its ability to absorb nutrients)
• Slow growth and short stature in children due to malnutrition
• An increased risk of developing certain types of cancer 
• Osteoporosis (low bone density due to calcium and vitamin D deficiency)
• 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.

Education:
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.

Gluten foods:
Never eat foods known to contain gluten.

Unknown foods:
Never eat foods with unknown ingredients as they may contain gluten.

Planning:
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.

Dining out:
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 subsidy:
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 provides 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)
Post: P.O. Box 302717 North Harbour, Auckland 0632
Phone: (09) 414 7467
E-mail: admin@coeliac.org.nz
Website: www.coeliac.org.nz

References

Auckland Allergy Clinic (Date unknown). Coeliac disease (Web Page). Auckland: Auckland Allergy Clinic. http://www.allergyclinic.co.nz/coeliac_disease.aspx [Accessed: 27/02/17]
Coeliac New Zealand (Date unknown). What is coeliac disease (Web Page). Auckland: Coeliac New Zealand Inc. http://www.coeliac.org.nz/coeliac-disease/what-is-coeliac-disease [Accessed: 27/02/17]
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.
Digestive Health Foundation (2012). Coeliac disease. (Pamphlet PDF - Sixth Edition). Mudgrave, VIC: Gastroenterological Society of Australia (GESA). http://membes.gesa.org.au/membes/files/Consumer%20Information/Coeliac%20Disease.pdf
Mayo Clinic (2016). Celiac disease (Web Page). Rochester, NY: Mayo Foundation for Medical Education and Research. http://www.mayoclinic.org/diseases-conditions/celiac-disease/home/ovc-20214625 [Accessed: 27/02/17]


Last Reviewed – February 2017