Allergy or Intolerance – What’s the difference?

According to Allergy UK, the leading national allergy charity, the UK has some of the highest allergy rates in the world.  But what’s the difference between an allergy and an intolerance – and why is it important?

Food Allergy

A food allergy occurs when the immune system mounts a quick and drastic response to protein molecules in a food.  Immune cells called IgE antibodies detect the protein as an invader and trigger the release of massive amounts of histamine and adrenaline, which cause symptoms such as:

  • Hives

  • Difficulty breathing

  • Swollen lips and tongue

  • Itchy mouth and throat

  • Fast heartbeat

  • Vomiting

  • Diarrhoea

Most allergic reactions are mild to moderate, but some can be extreme and cause anaphylaxis – a life-threatening response that requires immediate emergency medical attention.

The 14 most common food allergens are:

  • Peanut

  • Egg

  • Crustaceans

  • Cows’ milk

  • Molluscs

  • Fish

  • Sesame seeds

  • Soya

  • Celery

  • Lupin

  • Cereals containing gluten

  • Mustard

  • Nuts

  • Sulphur dioxide (a preservative often found in dried fruits and wines)

Accurate labelling of menus and food packaging is vital for consumers to be able to purchase foods with confidence, safe in the knowledge that any potential allergens are clearly identified.

Food Intolerance

An intolerance may or may not involve the immune system. When it does, different kinds of antibodies are involved to those seen in food allergy.  Another difference is that food intolerance symptoms don’t always happen immediately.  There may be a delay of several days before the reaction occurs. 

Examples of intolerances that don’t involve the immune system include:

  • Lactose intolerance caused by low levels of the enzyme lactase which breaks down lactose, a milk sugar. Symptoms of cramps, bloating, wind, and diarrhoea, appear fairly quickly after consuming dairy.

  • Histamine intolerance can occur when the body’s ability to breakdown and detoxify histamine is overwhelmed, leading to a build-up of histamine and symptoms such as hives, skin rashes, migraine, and digestive problems.

Food intolerance symptoms can be unpleasant and life-limiting but not usually life-threatening. 

How do immune-mediated intolerances develop?

Approximately 70% of our immune system lives in the gut alongside the gut microbiota – the trillions of bacteria, yeasts, and fungi resident in the digestive tract.  These microbes help to maintain the gut wall, making sure digested nutrients can pass through into the bloodstream, and keeping larger particles out.  If the microbes are affected by stress, infection, or antibiotics, they become unable to maintain the gut wall properly.  Particles can pass through that normally wouldn’t, potentially triggering an immune response and causing intolerance symptoms. 

In recent years there’s been a huge rise in the popularity of foods like kefir, sauerkraut, and kimchi that support numbers of ‘friendly’ gut microbes.  Whether or not these foods can help prevent food intolerances remains to be seen, but they are a helpful way of looking after your digestive and immune health.

New allergen legislation comes into effect in October 2021, requiring businesses to provide full ingredient and allergen labelling on foods that are pre-packed for direct sale. 

Get up to speed with Allergen Checker, the intuitive user-friendly system for organising your product labelling.