Coeliac Disease explained

What is coeliac disease?

Coeliac disease occurs in people who become sensitive to a particular protein in their diet called gluten. Gluten is found in wheat and other cereals. It is normally a nourishing and quite harmless part of the food we eat. But if you have coeliac disease, gluten causes damage to the lining of your small intestine. This can cause problems with absorption - the process of getting the nutrients and vitamins that we have eaten into the body. Coeliac disease can be diagnosed at any age from infancy to old age, but is most commonly recognised in children and young adults. The treatment, which is usually very successful, is to remove all sources of gluten from the diet.

Why does coeliac disease happen?

 We do not know why people develop coeliac disease but there are lots of theories. Most doctors believe that there is a factor in our genes which determines whether our intestines become sensitive to gluten. In other words, whether we get coeliac disease or not is determined before we are born – and there’s nothing we can do about it. Like many illnesses, coeliac disease can run in families but the specific genes have not been identified. As yet there is no way of testing our genes to see whether you (or your children) will develop the condition.

Your Body

How does gluten damage my intestine?

Although not technically an allergy, it is helpful to think of people who have coeliac disease as being allergic to gluten in the sense that gluten causes no harm to the body unless you have coeliac disease. If we were to look at normal small intestine under the microscope, we would see vast numbers of tiny finger like projections sticking up from the surface (see diagram on page 5). They are called villi and their purpose is to enhance the process of absorption. In coeliac disease, the finger-like villi are shorter and stubbier. In more severe cases, they can barely be seen at all so the lining of the intestine looks quite flat. Doctors call this villous atrophy. We will see later how recognising villous atrophy is the key to making the diagnosis of coeliac disease. If patients with coeliac disease stop eating gluten, their villi grow back again.

How many people are affected?

Over the past few years, it has become clear that coeliac disease is much commoner than we used to think. Recent research has shown that one in 100 people in the UK have this condition. It is known to occur more frequently in certain countries and the world’s highest incidence is in the west of Ireland. Most people who have coeliac disease don't actually know they have it. Although such individuals will have some degree of intestinal damage, they may have no symptoms at all. Because of this, only 1 in 800 people have been diagnosed with coeliac disease in the UK.

What symptoms might I expect with coeliac disease?

Interestingly there is a wide variation in the symptoms that people experience. In children, there may be diarrhoea, vomiting or a failure to gain weight. In adults, the disease comes to medical attention in a wide variety of ways. A common symptom is diarrhoea with bloating or discomfort in the abdomen. Quite often, patients don't have any symptoms that might relate to their guts but coeliac disease is suspected if tests show anaemia or they are found to have thin bones (osteoporosis). Such diseases of the blood and bones may occur because patients cannot absorb iron, calcium and several vitamins from their diet. In other cases, people lose weight for no obvious reason or just feel unwell in a rather vague way. Many patients have mild symptoms for
months or years before seeing a doctor. Only when they are correctly diagnosed and started on treatment do they realise how long they have been unwell.

How is coeliac disease diagnosed?

Having both listened to your medical history and examined you, if the doctor suspects you may have coeliac disease, you will be asked to have some blood tests which will help to find out if you might not be absorbing food properly from your diet. As we have seen, a doctor might consider a diagnosis of coeliac disease in many situations. Fortunately, there is a simple test to look for antibodies in a sample of your blood that can reliably show whether you are likely to have coeliac disease. If the test is negative, it makes it very unlikely that you have coeliac disease. However, a positive blood test does not confirm the diagnosis beyond doubt. So if the result is positive, or in situations where there is still a possibility that you might have coeliac disease, your doctor will advise you to have a further test called endoscopy.