Food allergy and intolerance myth buster

There is much in the media about food allergies and intolerances, but what is the difference? And more importantly, how accurate is the information we read? Here we sort fact from fiction.

Do you know the facts?

1) A food intolerance is just a less severe type of allergy

FALSE: Food allergy and food intolerance are quite different things. A food allergy is a reaction produced by the body’s immune system when it encounters a normally harmless substance. This tends to happen relatively quickly, sometimes within minutes, but more likely within 1-2 hours. An intolerance does not usually involve the immune system and is when a foodstuff (such as lactose) causes an unpleasant reaction (such as diarrhoea) and effects are rarely immediate. People who have allergies will have a bad reaction even if they come into contact with a very small amount of the foodstuff they are allergic to, whereas those with an intolerance may still be able to eat that foodstuff in small quantities.

2) If you think you have an allergy or intolerance to a certain food, you should cut it out of your diet

FALSE: Don't cut food groups out of your diet without medical advice, because you could miss out on important nutrients. Consult your GP first, who can refer you for tests to diagnose your symptoms if appropriate.

3) Levels of food allergy are rising

TRUE: It is thought that allergies to food are rising. For instance, the number of children admitted to hospital for food-related anaphylaxis has risen by 700% since 1990. Food allergy is thought to affect 5-8% of young children and 3-4% of adults. It is not known why allergies are rising, but theories include changes in diet and improved levels of hygiene, which leave children’s immune systems underexposed to germs.

4) Most children grow out of their allergy to eggs, milk, wheat and soya

TRUE: It is true that most children will grow out of their allergy to eggs, milk, wheat and soya – generally by about the age of five. It is thought to be as a result of the gut maturing or a change in the immune system’s response to that food.

5) Most people will grow out of allergies to peanuts, seafood, fish and tree nuts

FALSE: An allergy to peanuts, seafood, fish and tree nuts is very rarely lost.

6) You can be allergic to any foodstuff

TRUE: This is true in theory, but in fact just a handful of foods are to blame for 90% of allergic reactions to food in the UK. They are: celery, cereals containing gluten (including wheat, rye, barley and oats), crustaceans (including crabs and prawns), eggs, fish, lupin, milk, molluscs (such as mussels and oysters), mustard, nuts (including brazil nuts, hazelnuts, almonds and walnuts), peanuts (groundnuts or monkey nuts), sesame seeds, soya, sulphur dioxide or sulphites.

7) Symptoms of an allergic reaction will always appear immediately after eating the food that caused it

FALSE: It may be that symptoms of an allergic reaction appear immediately, but it can be several hours before they present themselves. It is also the case that symptoms can be more or less severe on different occasions.

8) Food allergies can be fatal

TRUE: People with allergies can have a reaction called anaphylaxis (pronounced anna-fill-axis), sometimes called anaphylactic shock. Anaphylaxis can be fatal if it isn't treated immediately, usually with an injection of adrenaline (epinephrine). This is why it's extremely important for someone with an allergy to take their medication with them wherever they go.

9) Some people can be allergic to fruit and vegetables

TRUE: This can happen in some people who have hay fever and are sensitive to pollen or in people who are allergic to latex. Symptoms generally include itches or rashes around the mouth and lips, which is why this type of allergy is called oral allergy syndrome. Cooking can destroy the allergens that cause this type of reaction, so a person who has an allergic reaction to raw apples may be able to eat cooked apples. The reverse can also be true, with some cooked vegetables being more allergenic than raw, for example celery or celeriac.

10) A food allergy or intolerance can be easily self-diagnosed

FALSE: It is thought that a much higher number of people will believe that their symptoms are being caused by a food allergy or intolerance than is actually the case. Around 30% believe they are allergic or intolerant to one or more foods, but a Food Standards Agency (FSA) report in 2008 estimated that only 5-8% of children and 1-2% of adults have a food allergy. Some researchers believe that the figure for adults may be slightly higher, at around 3-4%. Always consult with your GP first if you are experiencing symptoms.

11) Food allergies or intolerances can be cured

FALSE: There is currently no cure for food allergy or intolerances. The only way to prevent a reaction is to avoid the food you are sensitive to. Research is under way to see if desensitisation strategies (as are used for hay fever) can also be applied to food allergies, but this is still at an early stage and should not be attempted without close medical supervision. If you think you may have a food allergy or intolerance, it is important to visit your GP before you start cutting out foods. Many children will grow out of their allergies and intolerances as their bodies and immune systems mature

12) Home test kits are recommended for diagnosing food allergies and intolerances

FALSE: The use of commercial allergy testing kits is not recommended. These tests are often of a lower standard than those provided by the NHS or accredited private clinics. Also, allergy tests should be interpreted by a qualified professional who has detailed knowledge of your symptoms and medical history.

13) Allergies and intolerances run in families

TRUE: If you have parents or a sibling with an allergic condition, such as eczema, asthma or a food allergy, you are at a higher risk of developing a food allergy or intolerance. However, you may not develop the same allergy.

14) If you have eczema or asthma you are more likely to develop an allergy or intolerance

TRUE: Children who are born with other allergic conditions, such as asthma or atopic dermatitis (an allergic skin condition), are more likely to develop a food allergy.

15) You are only required to carry medication if your allergy is very severe

FALSE: If you are diagnosed with a food allergy you should carry medication with you at all times, since an allergic reaction can range in severity. Your GP will provide you with two types of medication: antihistamine tablets and/or gels, which can be used to manage the symptoms of a mild to moderate allergic reaction, and adrenaline, which is used to manage the symptoms of anaphylaxis. Adrenaline is normally supplied in a device called an adrenaline auto-injector pen.

16) People who have a food allergy are more likely to develop other food allergies

TRUE: This is known as being ‘atopic’ and refers to a tendency to develop allergies. Being atopic can mean you react to a number of unrelated allergens, for example peanuts and cats. Other people can react to different foods that contain either the same allergen or an allergen with a very similar structure, which means they can cause similar allergic reactions. This is known as allergic cross-reactivity. This means that if someone is allergic to peanuts, they might react to other foods in the legume family such as soya, peas, lentils, lupin and beans.

17) If you have a food allergy or intolerance you may have an allergic reaction to cosmetics

TRUE: If you have an allergy it is important to train yourself to read labels on everything that comes into contact with your body – not just the food that you eat. For instance, some cosmetics may contain nut oils or extracts of fruit or vegetables.

For further information about food allergy and intolerance, try the following useful links:

Health A-Z: Food allergies

Getting tested for allergies

Is it a food allergy or intolerance?

Health A-Z: hay fever

NHS Choices 2012