Food allergies and intolerances

We explain the difference between a food allergy and a food intolerance, and highlight the 14 most common food allergens

Bread roll with sesame seeds ontop

What is a food allergy?

A food allergy is when the body’s immune system mistakenly reacts to specific foods.. The food the body reacts to is known as the allergen. Most allergic reactions to food are mild, but some can be very serious. 

If someone is allergic to something, simply taking it off their plate isn’t enough. Even a tiny trace of the food someone is allergic to can be serious. The only way people can deal with a food allergy is to not eat the foods that make them ill.

You can be allergic to any food but certain foods are responsible for most food allergies. In the UK, food businesses must tell you if they use any of 14 key allergens in the food and drink they make. This may be provided on a label, verbally or written on a menu.

Food allergy symptoms

Food allergies normally causes symptoms within a few minutes of eating the food or being in contact with the substance. 

The symptoms of a food allergy differ from person to person. Find more information on some common symptoms from NHS inform:

Important: anaphylaxis can be a life-threatening condition. Seek medical advice immediately if you think someone is having an anaphylactic reaction. 

The difference between a food allergy and food intolerance

A table with milk, dairy and eggs on it

A food allergy involves a reaction in the immune system. Food allergies normally causes symptoms within a few minutes of eating the food or being in contact with the allergen. 

Food intolerances are more common and are caused by the body being unable to digest certain substances e.g. lactose. They're not the same as food allergies, as most do not involve the immune system. 

Food intolerances can make someone feel very ill and affect their long-term health. Symptoms of a food intolerance usually appear more slowly than those of a food allergy, and may not be felt until several hours after eating the food. Symptoms can last for hours, even into the next day.

Important: If you think you, or someone close to you, has a food allergy, it’s important to get a proper diagnosis. Don’t cut food groups out of your diet without medical advice, because you could miss out on important nutrients.

14 key allergens

There are 14 food allergens which, by law, must be highlighted on food labels in the UK, or through information such as menus, chalkboard, shelf label or spoken when used as ingredients in a food product or meal. 

When used in foods that aren’t in packaging, information must be available before buying them, such as on a menu, chalkboard, shelf label or verbally.

While there are 14 allergens that must be highlighted, it’s important to remember that people can be allergic to any food.

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