What is a food allergy?

The term allergy is used to describe a response, within the body, to a substance, which is not necessarily harmful in itself, but results in an immune response.

This can cause a reaction and symptoms in certain people. These reactions can vary in severity from inconvenience, a great deal of misery, to the most severe which can be fatal.

An allergy is everything from a runny nose, itchy eyes and palate to skin rash. It aggravates the sense of smell, sight, tastes and touch causing irritation, extreme disability and sometimes fatality. It occurs when the body's immune system overreacts to normally harmless substances.

An allergic person's immune system believes allergens to be damaging and so produces a special type of antibody (IgE) to attack the invading material. This leads other blood cells to release further chemicals (including histamine) which together cause the symptoms of an allergic reaction.

Food allergies and food allergens (those foods that cause allergic reactions), are widespread and affects approximately one in four of the population in the UK at some time in their lives. Each year the numbers are increasing by 5% with as many as half of all those affected being children.

What causes an Allergy?

Allergic reactions are caused by substances in the environment known as allergens. Unfortunately almost any food can be an allergen for someone. So it is important to be very careful.

Allergens contain proteins, which is often part of the food we eat. Allergens and allergies are not just caused by foods. There are many forms of allergies and the most common allergens are:

  • Pollen from trees and grasses, which cause hay fever
  • House dust mite
  • Moulds
  • Pets such as cats and dogs
  • Insects like wasps and bees
  • Industrial and household chemicals, medicines
  • Foods
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How to recognise if you have an allergy

The most common symptoms of allergy include asthma, gastro-intestinal symptoms (nausea, vomiting, and diarhhoea), eczema, urticaria (hives), rhinorrhea (heavy discharge from the nose), and angio-oedema (swelling of the blood vessels). Other more long-term symptoms include can depression, anxiety, fatigue, migraine, sleeplessness and hyperactivity in children.