What is coeliac disease?

Coeliac disease is an allergic response to the molecule gluten, which is found in wheat, rye and barley. If you have coeliac disease and you eat foods containing gluten your small intestine can react and become inflamed very quickly, leading to severe diarrhoea, pain, and, in the long-term, malnutrition. Avoiding gluten in the diet can be an effective treatment for coeliac disease but is not always easy.

Coeliac disease: an allergic reaction in the gut

The small intestine is largely responsible for digesting and extracting nutrients from the food that we eat. Many thousands of different molecules cross from the intestines into the blood without causing damage. The immune system, which identifies invading pathogens and attacks and destroys them, does not recognise food as harmful in the same way. Sometimes, though, things can go wrong.

When the immune system reacts to a molecule that should pass through without causing a problem, this can lead to an allergic response. Allergies often lead to swelling and inflammation in the area of the body where the allergen comes into close contact with body tissues. For example hay-fever, which is an allergy to pollen, causes inflammation in the nose when the pollen is inhaled.

People with coeliac disease, which is also known as celiac disease or celiac sprue, have an allergic response to the protein gluten. If gluten gets into their small intestine, the immune system becomes fully activated, causing local inflammation, soreness and pain. This sets off the typical symptoms of coeliac disease.

What foods upset someone with coeliac disease?

Any food that contains gluten, no matter how little, can trigger the inflammation that occurs in coeliac disease. Sources of gluten can be hard to avoid as they include:

  • Wheat: this means that gluten is present in flour, bread, cakes, pasta, biscuits, and pastries.
  • Rye:  gluten is therefore in rye breads.
  • Barley: so gluten is found in a lot of breakfast cereals.

Many processed foods contain wheat, rye or barley in small amounts as flour made from the grains are commonly used as thickening agents in sauces and gravies. Coping with coeliac disease often means getting used to reading ingredient labelling very carefully.

Coeliac disease causes unpleasant symptoms

Coeliac disease is more common than many people think. It’s estimated that 1% of the population is affected by this distressing condition. That means that across Europe there are 3 million people trying to cope with coeliac disease.

This type of food allergy is most common among Europeans and people of European descent. Coeliac disease is usually first noticed when wheat is first eaten when babies are weaned, so from the age of 8 to 12 months. For reasons that are less clear, a first diagnosis of coeliac disease is also common in people between the ages of 30 and 40.

Some experts believe that many cases of coeliac disease go undetected as the symptoms can vary so much from one person to another. Some people have no symptoms at all.

The main symptoms of coeliac disease in children and adults include:

  • Diarrhoea, which can result in not enough nutrients or fats being absorbed.
  • Excessive flatulence and grumbling of the stomach.
  • Stomach pain that can be very severe.
  • Tiredness and mental clouding.
  • A feeling of weakness and wasting of the muscles.
  • Failure to grow (in children with coeliac disease).
  • Around 10% of people also develop a rash that affects the skin of the elbows, knees, shoulders, and scalp.

Most of us get some of these symptoms from time to time and if the coeliac disease is fairly mild, it can be explained away.

For people who are more seriously affected, perhaps the most concerning outcome of coeliac disease is the malnutrition that occurs as a result of frequent diarrhoea. This can make you feel weak and tired, you tend to lose weight, and you can develop anaemia. Vitamin deficiencies are also common in people diagnosed with coeliac disease.