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What is a food allergy?

You have a food allergy if your immune system overreacts to a particular protein (an ‘allergen’) in food. Peanuts, nuts, eggs and milk contain some of the most common allergens. Symptoms of an allergic reaction usually come on quickly and may include breathing difficulty, vomiting, swelling and collapse.

What is a food intolerance?

You may have a food intolerance if you find a particular type of food often brings on unpleasant symptoms. These may include an upset stomach, rash, headache or other discomfort. However, they do not involve the immune system and usually take a few hours to appear. Examples include lactose intolerance (when you cannot digest milk properly); migraine brought on by red wine; or gluten intolerance (which is different from coeliac disease – see below).

The term allergen is generally used for any foods or food products that causes allergies or intolerances.

What is coeliac disease?

Coeliac disease is triggered by gluten. It is not an allergy or intolerance but an autoimmune disease where your immune system produces antibodies that attack the lining of the gut. This means you cannot absorb food properly, resulting in malnutrition and symptoms that range from pain and diarrhoea to fatigue and nerve damage. You cannot cure coeliac disease but you can stay healthy by keeping to a gluten-free diet. Gluten occurs naturally in wheat, barley and rye but can easily contaminate other cereals and other foodstuffs, such as oats, during processing or packaging.

Most common symptoms of an allergic reaction:

• Coughing
• Dry itchy throat and tongue
• Wheezing and breathlessness
• Runny nose
• Itchy eyes
• Flushing of the skin
• Abdominal pain, nausea and vomiting
• A red or raised rash anywhere on the body
• Swelling, especially of the face, lips, tongue and throat
• Changes in heart rate
• Feeling bloated

In a severe reaction, these symptoms get rapidly worse and can lead to anaphylactic shock. Symptoms of anaphylactic shock (anaphylaxis) include:

• Intense fear
• A rapid fall in blood pressure
• Rapid heartbeat
• Breathlessness from severe asthma
• Collapse and unconsciousness
• Swelling of the throat and mouth

Anaphylaxis is a medical emergency. Seek urgent medical treatment if the person has difficulty in swallowing or breathing or suddenly feels weak.

Food intolerance / coeliac disease

• Symptoms of food intolerance or coeliac disease may include:
• Stomach pain, nausea or diarrhoea
• Wind or bloating
• Headache
• Flushing or skin rash
• Wheezing

Symptoms are usually not immediate and tend to be less severe than those associated with an allergic reaction.

Allergenic foods:

Which foods are associated with food allergy and food intolerance?

These are the 14 foods listed in EU legislation concerning the provision of information to consumers:

• Celery
• Cereals containing gluten (specifically wheat, rye, barley, oats, spelt, kamut)
• Crustaceans (e.g. prawns, crabs, lobsters)
• Eggs
• Fish
• Lupin
• Molluscs (e.g. mussels, oysters)
• Mustard
• Nuts (specifically almonds, hazelnuts, walnuts, cashews, pecan nuts, Brazil nuts, pistachio nuts, macadamia nuts)
• Peanuts
• Sesame seeds
• Soybeans
• Sulphur dioxide and sulphites

These foods are easy to identify when they are sold separately. However, they may be less obvious as ingredients in a food product or menu item. Under EU legislation, if any of the 14 allergens are used as ingredients in pre-packed food products, they must be highlighted on the product label. This obligation has been extended to non-pre-packed foods such as menu items in a restaurant. In the Republic of Ireland, this allergen ingredients information must be provided in writing while in Northern Ireland it can be provided verbally.

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