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Food allergy testing - 6 food intolerance symptoms

12 Aug 2021 • 2 min read


In recent years, food allergies and intolerances in the UK have become much more widespread. Although more common in children, they can affect anyone at some point in their lives.

But how can you tell if you have a food allergy? We tackle the symptoms and triggers of food allergies along with the differences between an allergy and an intolerance.

What is a food allergy?

Food allergies strike when the body mistakes a substance in certain foods for something harmful. Mistaking the substance as a threat, the immune system responds by releasing chemicals to attack the allergens.

Symptoms usually appear within a few minutes of eating the food.

What are the most common food allergy symptoms?

Although allergic reactions are often mild, they can be very serious. Symptoms can affect different areas of the body and people can react in different ways.1

Some common symptoms include:

  1. Skin rashes or hives
  2. Itching – possibly in the mouth, throat or ears
  3. Vomiting
  4. Diarrhea
  5. Swelling – commonly of the face, around the eyes, lips tongue and the roof of the mouth

Many people with food allergies also experience coughing, wheezing and a blocked or runny nose.

In rare cases, foods like peanuts can cause severe reactions called anaphylaxis which can be life-threatening if they are not treated straight away.

What are the most common food allergies?

Any food can cause an allergic reaction, but the most commonly found food allergens according to the NHS include:2

  1. Nuts
  2. Eggs
  3. Cow’s milk
  4. Shellfish
  5. Soya
  6. Fruits such as citrus fruits and kiwis

What is a food intolerance?

Food intolerances may take some time to diagnose.

While food intolerances are not life threatening they often can make the sufferer feel unwell, which can have an impact on working and social life.

Continual symptoms can also affect you psychologically as it may feel like it takes a long time for symptoms to improve.3

Although a food intolerance can cause discomfort and some problematic symptoms, the immune system is not involved.

Reactions to intolerances normally take longer than allergies, with symptoms like diarrhoea taking hours or days to appear.

Unlike allergies which are a reaction to even small amounts of food, most people with an intolerance are able to eat larger quantities of the problem causing food without even knowing that there is an issue.

What are the most common food intolerance symptoms?

Symptoms of intolerances can vary greatly for each person and can take longer to diagnose. The symptoms caused by these reactions are usually gut symptoms, such as

  1. Bloating
  2. Diarrhoea
  3. Constipation
  4. IBS
  5. Skin problems such as eczema and joint pain
  6. Migraines

What's the difference between an allergy and an intolerance?

At first glance, allergies and intolerances may seem very similar, but these two conditions are actually quite different.

Food allergies are often in response to specific foods, whilst intolerances can be triggered by many different foods. Although food intolerances can cause discomfort, unlike food allergies they are never life threatening.

Food intolerances are much more common than food allergies with less severe symptoms that come on several hours after eating and last longer.

How are food allergies treated?

If you suspect you have a food allergy, make an appointment with your GP who may refer you to an allergy clinic for testing.

Once you find out what you are allergic to, the best way of preventing a reaction is to avoid it. There are no cures for food allergies but, you can control and treat symptoms in the following ways:

  1. Antihistamines – typically available over-the-counter or via prescription, they are often used to relieve the symptoms of many allergic reactions.
  2. Adrenaline injections and auto-injector pens – commonly used to treat severe allergic symptoms, like anaphylaxis. Auto-injector pens contain an adrenaline dose for use in emergencies.
  3. Check food labels – make sure you read pre-packed food or drink labels in case they contain ingredients that trigger your allergies.
  4. Inform staff when you eat out – if you’re eating at a restaurant, let staff know about your allergies to avoid eating any food you are allergic to.

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The advice in this article is for information only and should not replace medical care. Please check with your GP or healthcare professional before trying any supplements, treatments or remedies. Food supplements must not be used as a substitute for a varied and balanced diet and a healthy lifestyle.

Last updated: 12 August 2021



Author: Donia HilalNutritionist

Joined Holland & Barrett: Jan 2018

Bsc in Nutrition, Registered Associate Nutritionist and Certification in Pre and Post Natal Nutrition

Donia started her career as a freelance nutritionist, later she joined Nestle as their Market Nutritionist to help support their healthier product range, before joining the team at Holland & Barrett in January 2018.

Donia has over 6 years experience as a Nutritionist and also works with clients on a one to one basis to support their goals which include weight loss, prenatal and postnatal nutrition and children’s health.

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