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Food Intolerances vs Food Allergies: What is the difference and how to test for them?


Understanding the difference between food intolerances and food allergies is crucial for managing your health effectively. While both can cause discomfort, they are quite different in nature. This article will help you distinguish between the two, understand the underlying mechanisms, and learn how to test for them.

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What is a Food Allergy?


Food allergies occur when the body's immune system overreacts to a substance (allergen) that it mistakenly identifies as harmful. This exaggerated sensitivity results in an immune response mediated by immunoglobulin E (IgE).


How Does an Allergic Reaction Work?

When someone with a food allergy comes into contact with the allergen, IgE antibodies within their immune system stimulate mast cells to release histamine which is primarily responsible for the symptoms of an allergic reaction. Allergic symptoms include:

  • Hives (itchy, red welts on the skin)

  • Swelling (particularly of the face, lips, tongue, and throat)

  • Rhinitis (runny or stuffy nose)

  • Conjunctivitis (red, itchy, watery eyes)

  • Wheezing (difficulty breathing)

  • Anaphylaxis (a severe, potentially life-threatening reaction)


Characteristics of a Food Allergy

  • Quick-onset: Allergic reactions typically occur immediately, or within an hour of coming into contact with the allergen.

  • Immune Response: Allergic reactions involve the immune system and IgE antibodies.

  • Severity: Can range from mild to severe, with the risk of anaphylaxis.


 

What is a Food Intolerance?


Food intolerances are different from food allergies because they do not involve the immune system. They can lead to a variety of symptoms that can be uncomfortable and can appear similar to an allergic reaction; although there is no risk of anaphylaxis with a food intolerance.


Symptoms of a Food Intolerance

Food intolerances can cause a range of symptoms, which typically develop over a few hours or even days after consuming the offending food. These symptoms can affect the skin, digestive system, and respiratory system:


Skin Symptoms

Digestive Symptoms

Respiratory Symptoms

  • Flushing of the skin

  • Itchy rash

  • Soft tissue swelling

  • Eczema

  • Abdominal pain

  • Diarrhoea

  • Constipation

  • Stomach cramps

  • Bloating

  • Blocked nose

  • Runny nose

  • Itchy nose

  • Sneezing

  • Itchy throat, eyes & ears

  • Postnasal drip

  • Breathing difficulties

  • Wheezing


Characteristics of a Food Intolerance

  • Delayed Onset: Symptoms can appear several hours or even days after consuming the food.

  • No IgE: Does not involve IgE antibodies.



 

Prevalence and Misconceptions


It's common for people to confuse food allergies with food intolerances. Approximately 20% of the population have altered their diet due to a belief that they have a reaction to certain foods. However, the actual number of people with food intolerances is much lower. Food intolerances can also be mistaken for other conditions, such as irritable bowel syndrome (IBS).


 

Testing for Food Allergies and Intolerances


Testing for Food Allergies

If you suspect you have a food allergy, it is crucial to seek professional medical advice.

Reliable tests for diagnosing food allergies include:

  • Specific IgE (Blood) Test: Measures the level of IgE antibodies in response to specific allergens.

  • Skin Prick Test: Involves placing a small amount of the suspected allergen on the skin, then pricking the skin to allow the allergen to enter. If a raised bump (wheal) forms, it indicates an allergic reaction.


Testing for Food Intolerances

There are currently no reliable tests for diagnosing most food intolerances, with the exception of lactose intolerance. For other food intolerances, diagnosis often involves:

  • Elimination Diet: Gradually removing suspected foods from your diet and then reintroducing them to identify which one causes symptoms.

  • Specialist Consultation: Consulting with a specialist who can help rule out food allergies and other conditions before diagnosing an intolerance.

Importance of Professional Guidance

It is vital to consult a doctor before eliminating foods from your diet. An unbalanced diet can lead to further health complications, including nutritional deficiencies. A healthcare professional can provide guidance on how to manage your symptoms while maintaining a healthy and balanced diet.


 

Understanding the difference between food allergies and food intolerances is essential for managing your symptoms and maintaining your overall health. If you suspect you have a food allergy or intolerance, seek professional medical advice to get a proper diagnosis and treatment plan.

At London Allergy Clinic, we offer expert consultations and reliable testing to help you manage your allergies and intolerances effectively. Contact us today to schedule an appointment and take the first step towards better health and well-being.


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