Food allergy or intolerance?

Food allergy or intolerance?

If you suspect that you’re suffering from either a food allergy or a food intolerance, it could be a distressing time for you, especially if your symptoms are affecting your quality of life.

It’s useful to understand the difference between a food allergy versus a food intolerance, as these are two separate conditions. So, let’s get started!


What Is The Difference Between A Food Allergy And A Food Intolerance?

A food intolerance and a food allergy are often thought to be variations of the same thing, and are usually thrown around in the same conversation. However, the biological processes behind them, and how they affect you, are very different.

In fact, in one of our polls (which surveyed 1,000 respondents*) we found that the majority of those questioned were unable to differentiate between the two conditions and many respondents assumed they were the same thing.

A food allergy is when the body’s immune system believes that it’s being ‘invaded’ and produces IgE (Immunoglobulin E) antibodies to fight off the food or drink ingredient that it mistakenly considers to be harmful.

In the case of a food allergy, reactions can range from mild to severe, and may affect one or more systems in the body, such as the digestive system, respiratory system or the skin.


food allergy vs food intolerance infographic


However, in severe cases the immune system triggers a response throughout the whole body, resulting in a systematic reaction (anaphylaxis) which is potentially fatal and would need immediate medical attention.

But what about a food intolerance?

Alarmingly, in the same poll studying 1,000 respondents*, 64% thought that a food intolerance can trigger anaphylaxis, which is not the case.

food intolerance is often a delayed biological reaction which, although uncomfortable and unpleasant, is not life-threatening.

A food intolerance is often caused by a difficulty digesting certain foods, with symptoms emerging hours or days later. Depending on the type of food intolerance, the immune system can sometimes identify food protein particles as ‘foreign’ when they enter the bloodstream, and so it produces IgG antibodies to ‘attack’ the food in question.

Breaking Down The Science

You’ve most likely caught onto the fact that a food allergy produces IgE antibodies.

On the other hand, food intolerances take different forms, such as lactose intolerance and celiac disease. In this case, we’ll look at IgG-mediated intolerances.

Here at YorkTest, we define food sensitivity as a food-specific IgG reaction. There are four subtypes of IgG: IgG1 is the most prevalent, making up around 60-70% of your total IgG, followed by IgG2 (20-30%), and IgG3 (5-8%). IgG4 only makes up 1-4% of the IgG antibodies present.

However, not all food sensitivity tests that you see online are created equal. Therefore, it’s important to find a reliable provider. Our food sensitivity programs analyze all four antibodies, so your whole IgG profile is fully covered.


What Are The Symptoms Of A Food Allergy?

Food allergy symptoms can vary from mild to severe, usually appearing from 30 minutes to two hours after coming into contact with the food. The most common food allergy signs and symptoms include:

  • Itching or tingling in the mouth
  • Swelling of the lips, face, tongue, throat or other parts of the body
  • Wheezing, shortness of breath or nasal congestion
  • Hives, eczema or itching
  • Nausea or vomiting, abdominal pain, diarrhoea
  • Fainting, feeling lightheaded or dizzy
  • Hay fever-like symptoms, such as sneezing or itchy eyes
  • Difficulty swallowing


In severe cases, the immune system may trigger a response throughout the whole body, causing anaphylaxis. The symptoms of anaphylaxis include:

  • Swollen tongue or a ‘lump in the throat’ sensation
  • Breathing difficulties
  • A sudden drop in blood pressure
  • Tight chest
  • Trouble swallowing or speaking
  • Feeling dizzy or faint
  • Rapid pulse
  • Loss of consciousness


Anaphylaxis is a medical emergency and anyone experiencing these symptoms needs immediate assistance.


Do I Have A Food Allergy?

You may experience minor symptoms but, in some cases, if you consume the culprit food once again it could lead to anaphylaxis. The way your body responds to a food allergy can be unpredictable.

If you suspect a food allergy, your first port of call is to see your doctor. They can then refer you to a specialist and carry out certain tests, like a skin prick test.

Be cautious when it comes to commercial tests on the Internet that claim they test for food allergies. If you haven’t consumed the culprit food for quite some time, the test may say that you have no reaction to it. This may cause serious consequences if you then eat the trigger food.

How Long Does a Food Allergy Reaction Last?

The duration of an allergic reaction to food can vary greatly depending on the severity of the allergy, the amount of allergen that was consumed, and the sensitivity of the person affected. Mild reactions may last just a few minutes or up to an hour, causing symptoms like an itchy mouth, hives, or digestive distress. Moderate reactions can last 1-2 hours and may include symptoms like swelling of the lips, face, tongue and throat, cramping, vomiting, and diarrhea. Severe reactions or anaphylaxis can persist for many hours. They are classed as medical emergencies and require epinephrine and a trip to the emergency room.

Even after treatment, some symptoms like fatigue, rashes, and gastrointestinal issues may persist for up to 24 hours. You should consult your doctor if you have any questions about the typical duration of your food allergy symptoms.

What Are The Symptoms Of A Food Intolerance?

Symptoms can vary greatly from person to person and range from uncomfortable to debilitating.

Common symptoms of a food intolerance include:

  • Abdominal pain or cramping
  • Gas and bloating
  • Vomiting
  • Tiredness
  • Headaches and migraines
  • Skin issues, such as acne, eczema, psoriasis or urticaria
  • Constipation or diarrhoea
  • Anxiety or depression
  • Respiratory issues, such as rhinitis and sinusitis
  • Joint pain, swelling, fibromyalgia and arthritis


The above symptoms can take hours or up to 3 days to appear. Therefore, it can be difficult to pinpoint your reaction, especially if a person has more than one food trigger.

Do I Have A Food Intolerance?

Food intolerances are much more common when in comparison to food allergies. They can occur at any point in your life and their symptoms can be distressing, especially if they affect your day-to-day life. If you suspect you may have a food intolerance, there are ways to test for it: such as an elimination diet or a food intolerance test. Getting tested can help to determine which foods may be causing your adverse reactions so you can modify your diet accordingly.

How Common Are Food Allergies And Food Intolerances?

Food intolerances are estimated to affect 45% of the UK population, whereas a food allergy affects approximately 2% of the adult population.

It can be assumed that food intolerances have increased over the years, with speculation that changes in agriculture practices, antibiotic usage and environmental pollution could be responsible.
Delayed onset food intolerances can be measured through a YorkTest program. We have over 40 years’ experience in diagnostic testing and test your IgG reactions to over 200 food and drink reactions, including cow’s milk, wheat, gluten, eggs and several wine types, such as Merlot and Shiraz.

The good news is that sometimes people can tolerate their food intolerances after a period of elimination.

† yorktest define Food Intolerance as a food-specific IgG reaction.
Our information is intended to provide nutritional advice for dietary optimisation. yorktest do not claim to treat or cure symptoms and recommend that you discuss any medical concerns you have with a GP before undertaking a yorktest programme.
*OnePoll surveying 1,000 UK respondents