Like many Western countries it’s estimated that around 1 to 2 percent of New Zealanders have coeliac disease. Here, we explain what coeliac disease is, how to know if you have it and where to go for help.
What is coeliac disease?
Coeliac disease is an autoimmune disease that causes damage to the bowel wall because gluten is not digested normally. It is an adverse reaction in the body’s digestive system to gliadin, which is part of the plant protein called gluten, naturally found in wheat and a range of grasses, including rye, barley and oats.
In people with coeliac disease, eating these grains results in damage to the villi (finger-like projections important in the small intestine for digesting and absorbing nutrients) and inflammation of the tissues. The effects of this damage occur a few hours after eating the offending food. As a result of this damage, the absorption of almost all nutrients appears to be affected in some way.
Who does it affect?
Coeliac disease occurs in people with a genetic susceptibility but only develops through the interplay of environmental factors. While around 30 percent of the population may carry the genes implicated in the disease, and all of us will have been exposed to gluten-containing foods, only one percent of people go on to develop coeliac disease. Exactly why that is, remains unknown. Coeliac disease can occur at any age and once diagnosed, people have it forever.
While it’s thought the prevalence of coeliac disease is similar in men and women, studies have found higher rates of diagnosis in women. This may be due to women experiencing more symptoms as well as women getting more regular health checks.
Once thought to be more common in people of European descent, as diets have changed around the world, we now know that coeliac disease also affects people from the Middle East, Asia, South America and North Africa.
Signs of coeliac disease
Coeliac disease can be tricky to diagnose as it is usually not tested for until several other possibilities have been eliminated. Blood tests are used to screen for coeliac disease but a biopsy is needed to confirm the damage to the lining of the small intestine due to the disease. When a diagnosis is uncertain, gene testing may also be used to help with a diagnosis. Coeliac disease may not be diagnosed until the gut wall has been damaged by malabsorption over many years, often resulting in changed bowel motions such as bulky stools and abdominal discomfort. Prior to these symptoms people may be lacking in energy and experience frequent headaches.
In infants and children the symptoms are more easily identified, as after eating gluten they become more tired and lethargic, with changes in bowel motions that may have a very strong smell. Older children do not grow as predicted and can have various mineral deficiencies (low iron is common), abdominal pain or discomfort and more frequent, softer bowel motions. For adults symptoms are less clear as diarrhoea, unexplained weight loss, bone pain, mild gastric upsets, abdominal distention, tiredness, irritation and other symptoms could easily be put down to the stresses and strains of modern life. And, while gastrointestinal symptoms are a common symptom, in fact less than 50 percent of adults with coeliac disease experience these. Researchers have suggested that anaemia and osteoporosis may be two other important presentations to look for in adults, especially in those with a family history of coeliac disease. Dermatitis herpetiformis, an intensely itchy, blistering rash, has also been associated with coeliac disease in a small number of people.
Coeliac disease vs. gluten sensitivity – is there a difference?
Non-coeliac gluten sensitivity (NCGS), also referred to as gluten sensitivity or gluten intolerance, is characterised by intestinal and other symptoms related to eating gluten-containing cereals in people who don’t have coeliac disease or wheat allergy. Whether the culprit is gluten, another protein in cereals or another compound altogether, is still being investigated. One 2018 randomised, double blind, placebo-controlled crossover study of 59 people with self-reported NCGS, found fructans induced symptoms, rather than gluten. Fructans are found in foods such as onion, garlic and wheat. It is likely different people are sensitive to different compounds found in food.
If you think you are gluten intolerant it’s better not to eliminate gluten from your diet before coeliac disease has been investigated and ruled out. You will need to be eating gluten-containing foods for four to eight weeks before you can be reliably tested for coeliac disease.
Wheat allergy, is a different condition, being an immune system response specifically to wheat. People with this allergy only need to avoid wheat, and most children with wheat allergies will outgrow them.
What are the health problems associated with coeliac disease?
A frequent health problem experienced by people who with coeliac disease is anaemia due to poor absorption. There are various types of anaemia due to a deficiency of iron, vitamin B12, folate or vitamin B6 and there may be only minor symptoms in adults. A well-controlled gluten-free diet, the use of appropriate supplements and improved dietary intake providing plenty of these nutrients is recommended, with blood tests to monitor progress. As the gut heals with a gluten-free diet, absorption of nutrients will improve.
A big concern for people with coeliac disease as they age is bone health. Osteomalacia (weakening and softening of bone) results from the impaired absorption of vitamin D, and osteoporosis can occur due to impaired calcium absorption. People with osteoporosis appear to be 10 times more likely to have coeliac disease. Muscle cramps, due to poor absorption of calcium and magnesium are other possible health problems.
Supplements that people with coeliac disease may need
Because of the damage to the small intestine and the reduction in nutrient absorption that occurs, some vitamin and mineral supplementation may be necessary to correct a deficiency or to improve intake. The most likely nutrients include iron, vitamin D, calcium and vitamin B12. The need for these can be confirmed with a blood test or bone scans. If gluten is introduced to the diet accidentally and the gut lining is damaged, this may also be a time when additional nutrient support may be necessary. Talk to you GP or dietitian before using vitamin and mineral supplements as they can interact with medications and with each other.
Lactose is the carbohydrate found in milk. An intolerance can sometimes occur due to coeliac disease, particularly where there is damage to the intestinal lining of the digestive system. A lactose-free diet is used in conjunction with the gluten-free diet, and once healing of the lining has occurred (due to removing gluten) the lactose intolerance disappears. This is because the enzymes needed to digest the milk sugar are found in the lining of the small intestine, which the gluten has damaged. Symptoms of abdominal distension, gas production and changes in bowel function are further aggravated by the undigested lactose. Foods containing lactose include all milk products, as well as ice cream, yoghurt and foods where milk or milk solids are added as an ingredient. Hard cheeses (cheddar) have almost no lactose. Calcium-enriched soy milk, rice milk and almond milk can be used to replace the milk in beverages, on breakfast cereal and in cooking.
Where to get help
If you think you may have coeliac disease, you should contact your local doctor and if necessary a referral to a specialist will be arranged. Proper diagnosis is very important. Remember: its important not to start a gluten-free diet before a diagnosis.
Once diagnosed, a visit to a dietitian is often recommended. They will give you practical advice to help you adapt your diet.
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