At least one in every 100 people in the UK is thought to have coeliac disease, an autoimmune disease where your immune system mistakenly attacks healthy tissue.
If you have coeliac disease, your immune system incorrectly sees the gluten present in the food you’ve eaten as a threat, triggering an immune response that produces antibodies and causes inflammation. This subsequently damages the lining of your gut, and over time this can prevent your gut from properly absorbing certain nutrients. Gluten is found in wheat, barley and rye.
It is important to note that coeliac disease is different to gluten sensitivity. Coeliac disease has a clearly defined immune response that causes your body to produce specific antibodies that result in damage to your gut lining known as villous atrophy. Gluten sensitivity and other food intolerances don’t trigger the production of specific antibodies or cause damage to the gut lining.
Although current estimates suggest one in 100 people in the UK have coeliac disease, this may be an underestimate as some individuals are likely undiagnosed due to very mild symptoms or have no symptoms at all.
Coeliac disease is slightly more common in women. It is also more likely if you have a family history of the disease with over 40 different genes implicated. If you have a first-degree relative with coeliac disease (ie a parent, sibling or child), your risk of developing the condition increases by 10%.
Your risk of developing coeliac disease is also greater if you have autoimmune thyroid disease, Down's syndrome, Turner syndrome or type 1 diabetes.
Symptoms can develop at any age but most often develop in babies aged eight to 12 months when they are first introduced to gluten-containing food or much later in adulthood at around 40 to 60 years of age.
As coeliac disease prevents you from properly absorbing certain nutrients, common symptoms include changes in your bowel habits, notably diarrhoea and greasy, frothy stools. You may also experience abdominal pain, bloating, constipation, flatulence and vomiting.
In addition to gut symptoms, you may feel extremely tired (fatigue) due to anaemia, unintentionally lose weight, experience tingling and numbness in your hands and feet, and develop swelling in your limbs.
Around 10% of people with coeliac disease will also develop a painful rash called dermatitis herpetiformis. In some cases, this may be the first noticeable symptom that triggers an individual to see their GP and results in a diagnosis of coeliac disease.
The range and severity of symptoms varies from one person to the next. Some individuals do not have any noticeable symptoms of coeliac disease, while others develop severe symptoms after only eating a small amount of gluten.
Coeliac disease is treated by following a gluten-free diet for life. Trace amounts of gluten, within the range of 10–100 milligrams per day, can usually be tolerated by most individuals with coeliac disease. However, for some, even trace amounts, such as the amount that may be found in oats, can trigger symptoms.
In very rare cases, individuals with coeliac disease can present with damage to their gut lining despite following a gluten-free diet — this is called refractory coeliac disease.
Symptoms usually improve after several weeks of following a gluten-free diet but existing damage to your gut can take up to two years to heal. If you have been diagnosed with coeliac disease but don’t have any gut symptoms, you should still follow a gluten-free diet to avoid long-term complications of the disease as your gut may still not be absorbing enough nutrients.
Once you are on a gluten-free diet, you will need to have annual reviews to check your weight, symptoms, and vitamin and nutrient levels (eg levels of calcium, iron, vitamin B12 and vitamin D).
Your doctor will also recommend that you receive the pneumococcal vaccine and a booster every five years. This is because coeliac disease increases your risk of infection with the bacteria that cause pneumonia.
Left untreated, coeliac disease can lead to anaemia, intestinal lymphoma (a type of small bowel cancer), osteoporosis (brittle bones) and an increased risk of bone fractures. In women, untreated coeliac disease can lead to infertility and complications during pregnancy.
Following a gluten-free diet significantly reduces the risk of all of the above complications. However, osteoporosis remains an ongoing risk due to the loss of bone density that occurs before diagnosis — up to 75% of individuals have a reduced bone density when diagnosed with the disease. Bone density can be increased by following a gluten-free diet; however, this will still need to be monitored via DEXA bone scans.
Currently, if you have no symptoms of coeliac disease but have a first-degree relative with the condition, you should be offered a blood test to screen for the condition. Discussions into the benefits of broader screening for certain at-risk groups, such as those with type 1 diabetes or Down’s syndrome, are ongoing.
Although the only effective treatment today is a strict gluten-free diet, research continues into the potential benefits of non-dietary therapies. This includes immunotherapy, gluten-degrading enzymes and medication to regulate the tight junctions between cells lining the gut. There is hope that these therapies will help people with coeliac disease tolerate more gluten in their diet.
Dr Jamal Hayat is a Consultant Gastroenterologist at Spire St Anthony's Hospital and at St George's University Hospitals NHS Trust, specialising in gastroenterology, colonoscopy, endoscopy, gastrointestinal cancer and inflammatory bowel disease. He holds an MD research degree in the use of advanced diagnostic techniques in upper gastrointestinal disease (GI) and continues to participate in multinational research studies. Dr Hayat also runs the GI Physiology lab at St George's Hospital, investigating patients with indigestion and swallowing disorders.
If you're concerned about symptoms you're experiencing or require further information on the subject, talk to a GP or see an expert consultant at your local Spire hospital.