Allergy and intolerance

What is a food allergy?

Food allergy is an unusual sensitivity to a particular food or food ingredient. For most people the reaction will be mild but in some cases it can cause a life-threatening condition called anaphylaxis which affects the whole body, often within seconds of eating even the smallest amount of the food in question.

The foods most likely to cause anaphylactic reaction are:

  • Peanuts (ground nuts)
  • Tree nuts, including almond, Brazil, cashew, hazelnut, pecan, pistachio and walnut
  • Shellfish/molluscs/crustacea
  • Sesame seeds

Other foods that can cause allergic reactions in some people include eggs, dairy products and soya.

Most people should know the foods to which they are allergic. If you think you may suffer from a food allergy you should consult your doctor.

What is food intolerance?

There are an increasing number of stories in the press or on TV about foods causing unpleasant reactions. In fact, the terms food allergy and intolerance are much misused and apparently misunderstood by the media and the general public. In particular, wheat seems to be the target of unfounded, non-scientifically based claims about it causing intolerance or sensitivity.

This can create a lot of confusion and may lead people to think, wrongly, that they are ‘allergic’ to certain foods including wheat. This can lead people to cut out foods which in fact may be an essential part of a healthy balanced diet. This is not to deny that some people experience unpleasant symptoms after eating certain foods, but if you do you should consult your G.P. rather than self-diagnose.

A report commissioned by the Flour Advisory Bureau on wheat allergy and intolerance ‘Bloating, IBS and a Healthy Diet’ summarises current scientific opinion and research on both food allergy and food intolerance. The report shows that too many people are self diagnosing and could be restricting their diet unnecessarily without proper advice.

What constitutes a wheat allergy?

Food allergy is a reaction to food involving an antibody called IgE (Immunoglobulin E). This causes a range of symptoms usually within 2 hours of eating the foods, which could range from mild to severe. Food allergy occurs because the body treats the proteins present in a particular food, such as wheat, as an invader. When a person with wheat allergy eats wheat the body triggers an immune response – an allergic reaction. This reaction can cause a number of allergic symptoms, eg. Hives/rash, swelling of the lip or tongue, abdominal cramps and itchy runny eyes and nose.

The most severe allergic reaction triggered by food is called anaphylaxis. This can be potentially fatal, but there are however no recorded deaths from allergic reactions to wheat.

How prevalent is wheat allergy/intolerance?

According to recent research, although 20% of us think we have a food allergy or intolerance, less than 2% of the UK population actually has one. Over 98% of the UK population can therefore choose from a wide range of food stuffs to make up a healthy balanced diet without worrying about allergies or intolerances.

The Wheat Hypersensitivity Report, authored by Dr Heather Mackenzie and Dr Carina Venter of the University of Portsmouth reveals that over half of the British population believes that wheat allergy is a common illness and also believe that in 2009, wheat was the most commonly self reported food allergen for both men and women.

However, this new report commissioned by the Flour Advisory Bureau confirmed that wheat allergy is less common than other food allergies such as peanuts and other nuts, eggs and milk. It also highlighted that there is a clear discrepancy between the number of people who report that they have food allergy or intolerance and the numbers whose food allergy/intolerance can be confirmed by a medical diagnosis: self-diagnosis and other diagnostic tests (not conducted by qualified medical professionals) are not reliable.

Parents who believe their child has a food allergy may feel anxious about their health and go to great lengths to ensure their child avoids certain foods. Children are more prone to nutritional problems when foods are excluded from the diet so it’s even more critical that they receive a correct diagnosis.

At present there are no validated tests for diagnosing food intolerance and the diagnosis is through the avoidance of the food for a period of four – six weeks. If the symptoms improve, it is recommended the food should either be introduced at home or during a food challenge, over a period of at least four days.

What is wheat intolerance and how is it different from food allergy?

In contrast with food allergy, food intolerance does not involve the immune system. Unlike food allergy, the symptoms of food intolerance tend to occur after a longer period of time, are usually less severe than food allergy and in most cases require ingestion of larger amounts of food than food allergy. Symptoms associated with food intolerance, such as headache, lethargy, muscle pain and nausea are also associated with many other ailments making diagnosis very difficult.

What is Coeliac disease?

Some people may be intolerant to the gluten protein in wheat flour. This is called Coeliac Disease.

Further information on gluten is available in Factsheet No. 13 – Gluten.

How important is proper diagnosis?

Excluding wheat from the diet without good cause and without appropriate medical advice is undesirable for a number of reasons. Wheat is found in many foods including bread, pastry, pasta, noodles and biscuits, and contains important nutrients, namely: B vitamins (thiamin, riboflavin and niacin), calcium and iron. These foods also contain carbohydrate and fibre, which are essential to a healthy diet.

Wheat should not be excluded without taking appropriate dietary advice on how to continue to maintain a healthy diet. This is especially important for children, who are more prone to nutritional problems when foods are excluded from the diet.

Food allergy is usually investigated via a skin prick test by a medical professional with access to the patient’s clinical history, sometimes in conjunction with a period of eliminating the suspect food.

Finally, if wheat allergy or intolerance has been self-diagnosed there is a chance that the symptoms are in fact due to a different illness, which may remain undiagnosed and untreated.

Bakery products

Some bakery products contain nuts or sesame seeds as an ingredient. These will always be included, by name, in the list of ingredients. Bakeries take all possible steps to avoid inadvertent cross-contamination of products with allergenic ingredients. If there is a risk that a product may contain traces of nuts or seeds, the product wrapper should have a warning note ‘may contain nuts or seeds’.

People who suffer from a food allergy should always check the list of ingredients on the product wrapper carefully.

Food manufacturers keep lists of the foods which contain ingredients likely to cause an allergic reaction and should be able to provide the necessary information for consumers on request. The food wrapper will include a contact address or telephone number for the manufacturer or retailer.

Food safety and hygiene/good manufacturing practice

In plant bakeries, all workers involved in handling ingredients, equipment, utensils, packaging and products are trained in the hazards associated with food allergy. All possible action is taken to ensure there is no inadvertent cross-contamination of products with potentially allergenic ingredients. Controls will include separate storage of ingredients, good handling and hygiene procedures, washing and cleaning down of production plants and the implementation of Good Manufacturing Practice.

With these controls in place it is unlikely that wrapped bread and other wrapped bakery products will contain any unlisted allergenic material.

For more information please download our Factsheet No. 19 – Food Allergies.