Wheat allergy, wheat intolerance and Coeliac Disease are all associated with eating foods containing wheat.
To complicate matters further, wheat may also trigger or worsen symptoms in some, but not all, people with irritable bowel syndrome (IBS).
Wheat allergy
Around 90% of food allergies are caused by just eight foods, one of them wheat. A wheat allergy occurs when the body’s immune system over-reacts to a substance - usually a protein - present in wheat.
In people with an allergy, the immune system responds to the food allergen by producing IgE antibodies and releasing histamine and other chemicals from specialised cells.
Within minutes of eating the culprit food – including wheat - symptoms such as wheezing, itchy or swollen mouth or throat, runny nose, red and itchy skin rash and watery eyes can develop. Eating tiny amounts of the food can trigger a severe, and potentially fatal allergic reaction. Fortunately, food allergies are relatively rare as only around 2% of people have them.
Allergy symptoms differ from those of a wheat intolerance (see below). Wheat allergy can be diagnosed using standard blood and skin prick allergy tests, but diagnosing a wheat intolerance is more difficult.
Wheat intolerance
The symptoms of a food intolerance, including wheat are much more varied and can include stomach pain, bloating, nausea, wind, diarrhoea/constipation, joint and muscle pain, headache and more.
Unlike a wheat allergy, a wheat intolerance does not involve the immune system - in fact, little is known about the underlying mechanisms behind food intolerances, including wheat. It also means standard blood and skin tests used to diagnose a wheat allergies will be negative for wheat intolerance.
With wheat intolerance, it may take hours or even days for symptoms to develop after eating food containing wheat. People with wheat intolerance may be able to eat small amounts of the offending foods, but larger amounts can cause them to feel unwell.
Coeliac Disease
People who have Coeliac Disease cannot eat wheat either. Confusingly, it is often referred to as “gluten intolerance,” but Coeliac Disease is actually an autoimmune condition.
Eating any amount of gluten - the sticky substance found in wheat, rye, barley and oats – triggers the body’s immune system to turn on itself.
Antibodies produced against a protein in gluten result in the lining of the gut becoming inflamed, leading to problems absorbing nutrients from food.
Some of the symptoms of Coeliac Disease - bloating, stomach pain, nausea, diarrhoea, excessive wind, heartburn, indigestion, and/or constipation - are also similar to those of a wheat intolerance and IBS.
If they are not diagnosed and put on a strict gluten-free diet, people with Coeliac Disease can face serious health problems later in life.
In the UK alone, an estimated 500,000 people have Coeliac Disease and don’t know it. Fortunately, there are blood tests to diagnose the condition and some can even be bought over the counter.
Under some circumstances, these blood tests can give “false negative” results, so if you think you could have Coeliac Disease, it’s essential you contact your GP.
How do you know if you have a wheat intolerance?
There are no specific tests to diagnose wheat intolerance. Because of this, and the wide range of symptoms, some doctors remain sceptical whether wheat intolerance is a stand alone medical condition.
Be that as it may, if you're having problems eating foods containing wheat or wheat products you need to get checked out by a doctor. At the very least, they can rule out other medical conditions with similar symptoms. You can also ask to be referred to a registered dietician.
Food diary
Before you visit your GP, keep a food diary for a couple of weeks. Note down all the foods you eat and the time you eat them. Then note down your symptoms, how severe they are and the time they first appear. This will help your doctor or dietician to find a pattern. Although you may link your symptoms to eating wheat based foods, there are many other substances in foods which can be the cause.
Elimination Diet
The only way to identify a food intolerance, including wheat, is by an elimination diet. The suspect foods are removed from your diet for a period of time. Any effect this has on your symptoms is recorded. Foods are then re-introduced one at a time to identify exactly which food or food component is the cause of the symptoms.
This is not as easy as it sounds and is best done with the help of a dietician. Some suspect ingredients lurk in foods where you least expect them. And foods which are guaranteed to be gluten-free may not be wheat-free. They're not the same thing.
You should never exclude an entire food group from your diet as it can leave your body deprived of essential nutrients, and may even make you feel worse. A dietician can advise you on what extra nutrients you need during the test period to keep your diet balanced and help you find an answer.
