To answer that, we really need to define what coeliac disease is.
Coeliac disease is a fairly common condition, yet one that's often misunderstood, even by people who live with it. At its core, coeliac disease is an autoimmune condition where the body reacts adversely to a protein called gluten. In people with coeliac disease, the immune system attacks the small intestine's own lining whenever gluten is present, leading to inflammation and an inability to properly absorb nutrients.
Gluten in its natural form is found in three grains – wheat, barley and rye. These grains are extremely common in Western diets, appearing in most bread, beer, cakes, breakfast cereals, and even as a thickener in ready-made meals and sauces.
How Does Coeliac Disease Differ from Wheat Allergy or Wheat Intolerance?
Coeliac disease differs from wheat allergy in both its symptoms and its underlying cause.
Coeliac disease is an autoimmune condition, where the immune system attacks the body's own healthy tissue. As gluten is absorbed into the intestines, the immune system registers both the gluten and the intestinal lining itself as a threat, causing inflammation and symptoms that can include any or all of the following:
- Constipation
- Indigestion
- Flatulence and bloating
- Abdominal pain or discomfort
- Diarrhoea, often with a particularly unpleasant smell
These initial symptoms can lead to secondary symptoms such as:
- Malnutrition and fatigue from poor nutrient absorption
- Rapid weight loss
- Dermatitis herpetiformis – an itchy skin rash
- Speech, balance and coordination problems, such as ataxia
In children, coeliac disease can also cause delayed puberty and slowed growth, as a result of poor nutrient absorption during key developmental years.
Wheat allergy, on the other hand, is a true allergic reaction – not an autoimmune response. Four types of protein found in wheat (albumins, globulins, gliadins and glutenins) can each trigger a reaction.
There are two main types of wheat allergy: the common variety, and a more severe form called exercise-induced anaphylaxis.
The common form of wheat allergy is characterised by:
- Diarrhoea
- Nausea, vomiting and possible stomach cramps
- Difficulty breathing
- Headache
- Nasal congestion
- An itchy skin rash, sometimes with swelling or hives
- Swelling, irritation and itching of the throat and mouth
This can present similarly to so-called "baker's asthma", where a person reacts to inhaled wheat particles rather than wheat that's been eaten, with symptoms nearly identical to asthma.
Exercise-induced anaphylaxis is more serious. It tends to occur only when a susceptible person exercises within a few hours of eating wheat, and if untreated can lead to hospitalisation. This is a medical emergency – if you or someone you're with experiences difficulty breathing, a weak and rapid pulse, nausea or vomiting shortly after eating wheat and exercising, seek emergency medical help immediately.
How Are Coeliac Disease and Wheat Allergy Diagnosed?
Both coeliac disease and wheat allergy need to be formally diagnosed by a doctor – this isn't something to self-diagnose from symptoms alone. Speak to your GP, who may run initial tests themselves or refer you to a specialist.
Diagnosing coeliac disease is a fairly involved process. Your doctor will typically start with blood tests looking for coeliac-specific antibodies. If these suggest coeliac disease is likely, a biopsy – taking a small sample of intestinal tissue – is usually used to confirm the diagnosis. If you think you may have coeliac disease, a coeliac self-test can be a useful first step to discuss with your GP, though it isn't a substitute for formal diagnosis.
Wheat allergy is typically assessed via a skin prick test or an IgE blood test. In a skin prick test, small amounts of wheat protein are introduced just under the skin; redness or swelling developing quickly suggests a likely allergy. Your doctor may also request blood tests or a detailed food history to confirm the diagnosis.
What Foods Should Coeliac Sufferers Avoid?
The obvious answer is wheat – but avoiding it is more involved than it sounds, since gluten appears under many names and in many products. Foods and ingredients containing wheat or gluten include:
- Barley and barley malt
- Bulgur, couscous, cracked wheat, durum, einkorn, emmer, farina and faro
- Fu (a common Asian ingredient)
- Graham flour, kamut, matzo and semolina
- Processed oats (unprocessed oats naturally contain no gluten, but cross-contamination is common)
- Rye, spelt and triticale
- Seitan and wheat starch
- Wheat bran and wheat germ
- Some spice mixes, seasonings and salad dressings
- Veggie burgers not specifically labelled gluten-free
Gluten can also turn up in less obvious places – soy sauce, malt vinegar, sausages (sausage meat is sometimes mixed with wheat rusk), dry roasted nuts, stock cubes, some cornflakes, and even some chocolate. Always check labels, or look specifically for products in the "gluten-free" section. Manufacturing processes can also introduce gluten cross-contamination into foods that wouldn't naturally contain it – this is also why some coeliac sufferers react even to gluten-free oats, due to trace avenin content, despite oats themselves being gluten-free.
Drinks are often assumed to be riskier than they are. Fruit juices, squashes, flavoured waters, fizzy drinks, cider, port, sherry and wine are all naturally gluten-free, and a growing number of dedicated gluten-free beers are now available too.
If you're finding it hard to pin down exactly which foods are causing symptoms, it's worth reading more about gluten intolerance and wheat intolerance, since symptoms can overlap with coeliac disease and wheat allergy but stem from a different underlying cause.
Making Life with Coeliac Disease Easier
Beyond avoiding the foods listed above, it's worth speaking to a dietitian and reading up thoroughly on managing a gluten-free diet day to day.
A thorough clear-out of your kitchen and pantry to remove gluten-containing products is genuinely worthwhile, even if it feels like a big undertaking. If you're cooking for a household that isn't fully gluten-free, keeping gluten-containing and gluten-free foods clearly separated helps avoid cross-contamination – and it's worth wiping down surfaces and shelves before food prep, just in case any trace of gluten remains from previous use.
