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Food allergies and intolerances

Food allergies

A food allergy occurs when a person's immune system reacts to allergens that are harmless to other people. Most food allergies are caused by peanuts, tree nuts, milk, eggs, sesame seeds, fish and shellfish, soy, lupin and wheat. These must be declared whenever they are present in food as ingredients (or as components of food additives or processing aids), however small the amounts present. Read more about the requirements on the allergen labelling page.

Food intolerances

Adverse reactions to foods occur in a small proportion of the population. These reactions are not the same as allergies, but may include:

  • rashes and swelling of the skin, asthma, and stuffy or runny nose
  • irritable bowel symptoms, colic, bloating, and diarrhoea
  • migraines, headaches, lethargy, and irritability.

If you think you or your child has a food intolerance, it is important to seek advice from a medical practitioner since all of the symptoms you may be experiencing can also be caused by other disorders.

Both added ingredients, including food additives and processing aids, and naturally occurring food components, such as salicylates, lactose and gluten may be involved in food intolerance.

It may help to keep a food diary and note carefully any symptoms that may be related to food. To properly diagnose a food intolerance, the usual practice is to eliminate all suspect foods from the diet and then reintroduce them one by one, to see which food or component(s) of the food causes the reaction. This should only be done under medical supervision, since some of the reactions - such as asthma - can be serious.

More information

Page last updated 6 December 2023