Coeliac disease
Coeliac disease is an autoimmune disease that is triggered by gluten. It causes damage to the lining of the gut, making it harder to digest and absorb food. It can also affect many other parts of the body, including the brain, nervous system, bones and skin. It is a genetic condition and is lifelong and irreversible. Around one in 50 people in Ireland has coeliac disease, but many are undiagnosed. Up to 75 per cent of people with coeliac disease do not know that they have it.
Coeliac disease can cause many symptoms. People often think of diarrhoea, stomach pain and nausea, but coeliac disease can present in many other ways. It is worth remembering that up to 40 per cent of people with coeliac disease do not have any gut symptoms at all.
Who should be tested for coeliac disease?
Anyone with symptoms of coeliac disease should be tested, even if the symptoms are mild. People who have recurrent headaches or migraines, osteoporosis, low iron, infertility, low folate or low vitamin B12 should also be tested. People with a family history of coeliac disease are at higher risk of developing the condition and should also be tested. Around one in 50 people in the general population has coeliac disease, but this increases to one in ten for first-degree relatives, including parents, siblings and children.
People with Down’s syndrome, Turner syndrome, an underactive thyroid or type 1 diabetes are also at higher risk of developing coeliac disease and should be tested.
You must be eating gluten to be tested for coeliac disease
The test for coeliac disease does not work if you have already started to avoid gluten. You must be eating gluten for at least six weeks before having a coeliac test. If you think you are reacting to gluten, speak to your GP and get tested before cutting out any foods.
Coeliac disease and the gluten-free diet
The diet for coeliac disease is a strict gluten-free diet. This is because people with coeliac disease must avoid all gluten at all times. There are no days off, no exceptions and no crumbs. Even a very small amount of gluten can cause damage, even if symptoms do not appear straight away. Some people become unwell after consuming even a tiny amount of gluten, while others may eat small amounts for some time before feeling unwell. This does not mean that one person has a milder form of coeliac disease. The internal damage is the same, regardless of symptoms. Continuing to eat gluten increases the risk of osteoporosis, fertility problems and other health conditions. This is why everyone with coeliac disease must avoid all gluten at all times.
What foods contain gluten?
Gluten is found in wheat, rye, barley and standard oats. A small number of people with coeliac disease also react to pure gluten-free oats, so they are best introduced carefully under the guidance of a dietitian. Spelt, semolina and couscous are all forms of wheat and contain gluten.
Common sources of gluten include bread, pasta, cakes, noodles and breakfast cereals. It also turns up in foods you might not expect, such as stock cubes, sauces, soups and sausages, anywhere flour or barley malt is used as an ingredient. Always read labels carefully. Under Irish and EU law, gluten-containing cereals must be highlighted in the ingredients list. The Coeliac Society of Ireland publishes an up-to-date list of safe gluten-free foods each year.
Look for the Crossed Grain symbol
The Crossed Grain symbol is the international trademark used by coeliac societies, including the Coeliac Society of Ireland, to mark products that have been independently certified as gluten-free. Products carrying the symbol have been tested to confirm that they contain less than 20 parts per million of gluten and follow strict manufacturing controls to prevent cross-contamination. When in doubt, the symbol is the most reliable visual shortcut to look for.
Gluten and cross-contamination
Cross-contamination occurs when gluten-free food comes into contact with food containing gluten. This alone is enough to cause damage. Examples include a crumb in butter, sandwiches placed on a shared plate, stirring gluten-free sauce with the same spoon as regular sauce, or cooking chips in oil that has previously been used for foods such as chicken nuggets. These are common ways that people with coeliac disease can accidentally consume gluten.
Avoiding cross-contamination
- Use a separate toaster or toaster bags if sharing a toaster.
- Keep separate butter, jam, marmalade and similar items. Anything that has a knife dipped into it can contain crumbs.
- If frying food, use fresh, clean oil. Deep-fat fryers used for foods such as chicken nuggets or onion rings will contain gluten, and the oil must be replaced before cooking gluten-free foods.
- Use separate chopping boards and store gluten-free food away from gluten-containing foods, especially bread.
- Do not allow gluten-free food to touch foods containing gluten.
Cross-contamination in foods you buy
If a product states that it may contain gluten, or may contain wheat, barley, oats or rye, people with coeliac disease must avoid it. This warning is only used when there is a genuine risk of gluten contamination.
Coeliac disease and nutrition
There are a few nutrients that are particularly important to keep an eye on if you have coeliac disease, partly because absorption may have been compromised before diagnosis and some can be harder to get on a gluten-free diet.
Vitamin D
People with coeliac disease are at increased risk of osteoporosis. This may be due to poor absorption of vitamin D or calcium, but gluten can also directly damage bone health. People with coeliac disease should take a vitamin D supplement during the winter months. The HSE recommends 15 micrograms daily for adults from October to March. Some health professionals recommend year-round supplementation. Discuss this with your dietitian or GP, as needs vary.
Calcium
Calcium is essential for bone health alongside vitamin D. Dairy foods such as milk, yoghurt and cheese are good sources. Calcium-fortified plant-based milks are also suitable. Always check labels, as not all plant-based milks contain added calcium.
Fibre
Getting enough fibre on a gluten-free diet can be challenging. Many people move from diarrhoea to constipation after starting a strict gluten-free diet. Fibre-rich gluten-free foods include:
- Fruit and vegetables
- Nuts and seeds
- Beans and lentils
- Brown rice, potatoes with skins and quinoa
Shopping or cooking for someone with coeliac disease
A coeliac diagnosis affects the whole household. If you are the one doing the shopping or cooking for a family member with coeliac disease, such as a partner, parent, child or housemate, a few things are particularly worth knowing:
- Most of the meals you already make can be made gluten-free with small swaps. Fresh meat, fish, eggs, fruit, vegetables, rice and potatoes are all naturally gluten-free. A roast dinner with potatoes, vegetables and gluten-free gravy is easier than you might think.
- Cross-contamination is the biggest day-to-day risk. The advice about separate toasters, butter, chopping boards and oil applies to anyone cooking in the same kitchen. Read the cross-contamination section above carefully.
- Read labels every time, even on products you have bought before. Manufacturers reformulate, and a product that was gluten-free last month might not be this month.
- Do not try to estimate that “a tiny amount won’t hurt”. Even crumbs do real damage. Trust the person with the diagnosis when they ask careful questions about ingredients.
Getting the right support after a diagnosis
Being diagnosed with coeliac disease can feel overwhelming. The lifelong nature of the diet, careful label reading and social adjustments can feel like a lot to take on, particularly in the first few months. The good news is that the gut heals once gluten is removed, symptoms usually improve significantly, and shopping and cooking become routine more quickly than most people expect.
The only treatment for coeliac disease is a strict gluten-free diet. Working with a CORU-registered dietitian at diagnosis, after six months and after one year is important. Remember to have your coeliac blood tests checked annually with your doctor.