What are Food Allergies & Intolerances?

What is a Food Allergy?

A food allergy occurs when the immune system reacts abnormally to certain foods that are eaten. Even though allergy reactions are frequently modest, they can be extremely dangerous.1 There are various types of food allergies, which are discussed below. 

Non-IgE Mediated Allergic Reaction

A non-IgE-mediated food allergy is another form of allergic reaction. This allergy can take a long time to reveal its symptoms, sometimes up to several days.4

A non-IgE0 mediated response is caused by a reaction involving immune system components other than IgE antibodies; the immune system produces antibodies called immunoglobulin E (IgE).4

If you have an allergy, your immune system overreacts to an allergen by creating Immunoglobulin E (IgE) antibodies. Antibodies migrate to cells that produce chemicals, resulting in an allergic reaction.4 

Non-IgE Mediated types of allergies also present themselves with the usual allergic reaction symptoms. However, you may also notice the following:1

  • Itchy, dry, cracked red skin, also known as atopic eczema  
  • Hives, but not always a raised rash 
  • Constipation 
  • In babies, excessive crying for no apparent reason (not hungry/tired etc.)


A severe allergic reaction is called Anaphylaxis, whereby the symptoms might have abrupt and severe symptoms that worsen quickly. 

Anaphylaxis symptoms:1 

  • Tight Chest 
  • Difficulty Breathing
  • Collapsing 
  • Swollen Tongue 
  • Speech difficulties 

Anaphylaxis is considered a medical emergency, if it is not treated quickly, there can be severe consequences, so if you are experiencing these symptoms, you need to call 999 for an ambulance or get to your local A&E as soon as possible. 

Causes of Allergies 

Allergies - Your immune system misinterprets normal proteins in particular foods as a threat, resulting in a food allergy. The immune system emits a variety of compounds that cause an allergic reaction to happen. Most allergic reaction symptoms are caused by histamine (a substance in some body cells).

Histamine causes the following - 

  1. Causes tiny blood vessels to enlarge and the skin around them to turn red and expand 
  2. It causes itching by affecting the skin's nerves. 
  3. increases the quantity of mucus generated in the lining of your nose, causing itching and burning.1 

Treatment for Allergies 

Two types of medications can be used to help reduce the symptoms of food allergies. 

Antihistamines - These are used to treat a mild to moderate allergic reaction.1 Antihistamines operate by inhibiting the effects of histamine, the chemical that causes many allergic reaction symptoms.

Many antihistamines are available without a prescription from your pharmacist; store up in case of an emergency. Antihistamines that do not cause drowsiness are favoured.

Adrenaline - these are used to treat more severe allergic reactions.1 

Adrenaline narrows blood vessels to offset the effects of low blood pressure and opens the airways to help with breathing problems.

What is a Food Intolerance?

Food intolerance is the inability to digest certain foods, resulting in unpleasant bodily reactions. In recent years the amount of people who believe in having a food intolerance has increased considerably.

The causes of this could be due to various reasons, such as environmental pollution and dietary changes, which can affect the strength of our immune system.3

In many cases, people who believe they have a food intolerance are mistaken, and the symptoms are caused by something else.2 

Key Difference - Food intolerances are not life-threatening and do not involve the immune system, whereas food allergies affect the immune system and can have significant health consequences.

Symptoms of a food allergy will usually appear straight away. The most common symptoms are:1 

  • Hives, itchy red rash 
  • Feeling dizzy 
  • Nausea/Vomiting  
  • Difficulty swallowing
  • Abdominal Pain 
  • Diarrhoea 
  • Swelling of the body or face
  • Shortness of breath
  • Wheezing
  • Hay Fever-like symptoms  
    These symptoms usually appear a few hours after the food has been consumed. It's tough to tell if you have a food intolerance because the symptoms are similar to many other illnesses.

    People who have a food intolerance commonly suffer the following symptoms:2 

    • Abdominal Pain 
    • Bloating 
    • Wind 
    • Diarrhoea 

    Causes of Food Intolerances

    Intolerances - The cause of food intolerance is simply the fact that your body cannot digest that particular food. It's not always evident why someone is intolerant to specific foods. The culprit may be a food ingredient, chemical, or pollutant, such as:2 

    1. MSG 
    2. Alcohol 
    3. Caffeine 
    4. Histamine in foods, e.g. mushrooms 
    5. Artificial sweeteners
    6. Artificial colours, preservatives
    7. Food infected with poisons, viruses, germs, or parasites 

    Treatment for Food Intolerances

    Food intolerances are slightly harder to manage; you will have to undergo a process of elimination to determine precisely what it is you are intolerant to. Unless, of course, this is apparent.

    One way to determine the food/foods you are intolerant of is by keeping a food diary, noting precisely what foods you are eating and then the symptoms that may follow.

    Once you've figured out which foods might be causing your symptoms, try eliminating them from your diet one at a time to see how it affects you.

    You can try eliminating the suspicious food from your diet for 2 to 6 weeks to see if your symptoms improve during this change. To observe whether symptoms reappear, reintroduce the food. You may discover that you can tolerate a particular threshold and only have symptoms if you exceed it.2 

    How Does our Gut Health Link to Food Intolerances? 

    One strategy to maintain proper immune function in the gut appears to be through diet. Certain bacteria have been shown to assist in maintaining the gut barrier and mucosal layer, protecting against loss of tolerance, and have been found to positively influence the immune system.5

    Food components interact with the gut flora, which may influence the intensity of food sensitivity. Certain bacteria in the gut, for example, have been shown to break down the gluten protein, which can either enhance or decrease its toxicity in celiac disease.

    Certain Lactobacillus strains seen in healthy people can break down gluten into small molecules called peptides, reducing the immunological response. This raises the possibility of reducing the toxicity of gluten in people with celiac disease by increasing or decreasing particular types of bacteria in the gut.5

    Numerous studies have supported the evidence that having a healthy gut microbiome can reduce the risk of food intolerances. Here is an example of such a study - Mechanisms by which gut microorganisms influence food sensitivities

    Final Thoughts 

    In conclusion, there is a clear difference between food allergies and food intolerances. They are managed differently and present very different symptoms.

    Whilst your gut health may not be related to allergies, it can influence food intolerances. Check out our Gut Care probiotic daily supplement that can help boost healthy bacteria in your microbiome!

    References → 1

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