Coeliac disease and gluten intolerance

Coeliac disease (pronounced see-lee-ak) is a lifelong condition that affects the digestive system. Symptoms include bloating, diarrhoea, tiredness, and weight loss which result from eating foods that contain a food protein called gluten.

Although there is no cure for coeliac disease, following a strict gluten-free diet can minimise symptoms and development of serious complications.

In New Zealand, coeliac disease may affect 1 in 100 of the general population. However, the rate may be higher because many of these people will be undiagnosed or their condition incorrectly diagnosed as irritable bowel syndrome.

Causes

Coeliac disease is an autoimmune condition, which is where the body’s immune system attacks and damages its own tissues. In people with coeliac disease, eating a food protein called gluten (which is found in wheat, barley, rye, and oats) triggers the immune system to cause damage to the lining of the small intestine (bowel). That damage makes it difficult for the body to absorb vitamins, minerals, and other nutrients from food.

The phrase “gluten intolerance” is used to describe unpleasant symptoms some people have after eating food containing gluten, including diarrhoea, bloating or crampy pain. These people should see their doctor to determine if these gluten intolerance symptoms could be caused by coeliac disease.

Both genetic and environmental factors appear to play a part in the development of coeliac disease.

People who have a family member with coeliac disease are at increased risk of developing the condition. Down’s syndrome is also associated with an increased risk of coeliac disease.

A major life event such as pregnancy, severe emotional stress, surgery or exposure to a particular virus may activate the condition in certain individuals.

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

The average age of diagnosis of coeliac disease is approximately 40 years but it can occur at any age, including during early childhood. Often the onset of the condition occurs over a long period of time and goes relatively unnoticed.

Signs and symptoms

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 (stools), sometimes pale and bad smelling
Abdominal pain
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).

Mainly due the ability to absorb nutrients, children with coeliac disease may also display the following symptoms:

Poor weight and height gains
Delayed puberty
Poor concentration and learning disabilities
Poor muscle co-ordination and seizures.

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 present at elevated levels, may indicate coeliac disease

Small bowel biopsy:
In New Zealand, the test most commonly used to diagnose coeliac disease involves taking a small tissue sample from the small bowel (biopsy) during a procedure called a gastroscopy. This involves a small flexible tube called an endoscope being passed down the person’s throat and into 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 and enables the removal of a small piece of tissue that is sent to a laboratory for viewing under a high-powered microscope.

Treatment

There is no cure for coeliac disease. However, the complete and life-long removal of gluten-containing foods from the diet should resolve the inflammation and restore the inner lining of the small bowel.

Studies suggest that when gluten is withdrawn from the diet the bowel lining will be close to normal in around three months. Eating gluten again can result in severe damage to the bowel in as little as three weeks.

Complications

If coeliac disease is not effectively treated with a strict gluten-free diet, potentially serious 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, including small bowel 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

Gluten is found in wheat, barley, and rye. Oats also contain a gluten-like protein and are often processed in the same places as wheat, barley and rye, causing gluten contamination. There are dozens of foods products that are made using wheat, barley, rye and oats - from breads and cereals to soups and salad dressings.

It is important to know safe foods to eat and be wary of hidden sources of gluten in the diet.

Education:

Once a diagnosis of coeliac disease is reached a person will usually be referred to a dietician, who 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.

The following guidelines will help a person with coeliac disease maintain good health:

Never eat foods known to contain gluten
Never eat foods with unknown ingredients as they may contain gluten
Plan meals ahead of time, and keep gluten-free snacks available
Many "fast foods" contain gluten so should not be eaten
If eating out, use the internet to find restaurants that have gluten-free options
Educate friends and family about the condition and gluten-free foods, so that meal invitations don’t become difficult.

Gluten-free food suppliers:

There are many suppliers of gluten-free food products and gluten-free food is increasingly common on supermarket shelves.

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
Phone: (09) 414 7467
E-mail: admin@coeliac.org.nz
Website: www.coeliac.org.nz

References

Coeliac New Zealand (Date not stated). What is coeliac disease (Web Page). Auckland: Coeliac New Zealand Inc. https://coeliac.org.nz/what-is-coeliac-disease-2/ [Accessed: 10/10/19]
Coeliac UK (2017). Oats (PDF). High Wycombe, Buckinghamshire: Coeliac UK. https://www.coeliac.org.uk/document-library/143-oats/?return=/information-and-support/living-gluten-free/the-gluten-free-diet/about-gluten/oats/
KidsHealth (2019). Coeliac disease (Web Page). Auckland: Starship Foundation and Paediatric Society of New Zealand. https://www.kidshealth.org.nz/coeliac-disease [Accessed: 10/10/19]
Lebwohl B., Sanders D.S., Green P.H.R. (2018). Coeliac disease. Lancet. 2018;391(10115):70-81.
Mayo Clinic (2019). Celiac disease (Web Page). Rochester, NY: Mayo Foundation for Medical Education and Research. https://www.mayoclinic.org/diseases-conditions/celiac-disease/symptoms-causes/syc-20352220 [Accessed: 10/10/19]
NHS (2016). Coeliac disease (Web Page). Redditch: National Health Service (NHS)
England. https://www.nhs.uk/conditions/coeliac-disease/ [Accessed: 10/10/19]
Coeliac New Zealand. Coeliac Disease vs. Gluten Intolerance (Dr Jason Tye-Din). https://coeliac.org.nz/coeliac-disease-vs-gluten-intolerance-dr-jason-tye-din/ [Accessed 4/3/20]

Last Reviewed – March 2020