Everything you need to know about food intolerance testing

What is a food intolerance?

A food intolerance is an aversion to certain types of foods or ingredients, which your body has difficulty digesting.  

Reactions to food intolerance are not usually serious or emergencies, but they can lead to feeling uncomfortable, tired, or unwell for anything from several hours to a couple of days. Symptoms most often occur a few hours after consuming the ingredient or food that you have an intolerance towards. 

Causes of food intolerance

Food intolerance is caused by your digestive system being unable to break down a certain type of ingredient or food. This happens when your gut is sensitive to an ingredient and has trouble digesting it, often failing to produce enough of the enzyme needed to break down a particular type of food.  

It’s important to be aware that food intolerance, unlike food allergy, cannot cause a serious allergic reaction. This is because an allergic reaction is triggered by an immune system overreaction, rather than difficulty digesting. 

It isn’t known why some people develop food intolerances of different sensitivities, but conditions like inflammatory bowel disease (IBD), Crohn’s disease, ulcerative colitis, and coeliac disease can make you more prone to food intolerance. 

Lactose intolerance is the most common form of food intolerance and is caused by the body underproducing the enzyme lactase, which helps to digest lactose. 

You can be intolerant to any type of food or individual ingredient, with some of the other most common intolerances including: 

• Alcohol, found in beer, wine, and spirits 

• Caffeine, found in coffee, tea, and caffeinated soft drinks 

• Gluten (barley, rye, and wheat), found in bread and pasta 

• Histamine, found in alcohol, cheese, and cured meat 

• Monosodium glutamate (MSG), found in processed food 

• Salicylates, found in certain fruits, vegetables, herbs, and spices 

• Sulphites, found in alcohol, soft drinks, and pickled food 

Common symptoms of food intolerance

Food intolerance can lead to a range of symptoms, which usually appear a couple of hours after eating the ingredient you’re intolerant towards. 

These can vary in intensity, and range from uncomfortable or unpleasant to painful, but are not usually serious and should normally subside after a few days. 

The most common symptoms of food intolerance are: 

• Diarrhoea 

• Bloating of the stomach and tummy pain 

• Excess gas (flatulence)  

• Headache 

• Tiredness, fatigue, or exhaustion  

• Constipation 

• Joint pain 

• Rashes 

In contrast, a food allergy reaction can cause swelling of the lips, throat, and face, itchy skin, tightness of the throat or struggling to breathe, and fainting. If you think you or someone you’re with is having an allergic reaction, you should call 999. 

Testing for food intolerance

What is a food intolerance test? There are several different methods to test for food intolerance, based on the intolerance you are looking to identify.  

They include: 

• Blood test: Providing a blood sample allows testing for IgG antibodies to identify food sensitivities across a wide range of ingredients. 

• Breath test: This measures hydrogen gas levels in the breath and is used to test for lactose intolerance.  

• Diet test: This process involves working with a health professional to cut out and reintroduce certain food types you think you might be intolerant to and measuring symptom changes. 

The difference between IgG and IgG4-only testing

Food intolerance blood tests measure the antibody immunoglobulin (IgG), which is a major part our immune systems. There are four IgG subtypes, IgG1-4, which each perform a slightly different function: 

• IgG1: 60-70% of total IgG, fights viral infections 

• IgG2: 20-30% of total IgG, fights certain bacterial infections 

• IgG3: 5-8% of total IgG, fights viral infections 

• IgG4: 1-4% of total IgG, fights parasitic infections 

Meaningful food intolerance test results can only be achieved by testing all four of these IgG subtypes. IgG4-only tests are available, but IgG1, IgG2, and IgG3 can all trigger inflammation and contribute to food intolerance symptoms, which is why a more comprehensive test is recommended. The YorkTest Premium Food Intolerance Test provides a thorough analysis of food sensitivity and intolerance. 

By testing all four subtypes of immunoglobulin, you may be able to measure a wider breadth of reactions and identify any intolerances to over 200 food and drink ingredients. 

Why gut health matters

Identifying food intolerance and reducing its symptoms can contribute to better gut health, which plays a key role in digestion, well-being, immunity, and weight management.  

Around 70% of your immune system cells are located in your gut, interacting with an ecosystem of trillions of microorganisms. Together, they train your immune system to distinguish between helpful and harmful entities and regulate inflammation. 

Keeping a healthily balanced gut may help to maintain a resilient immune system and balanced “immune load” (the burden of the immune system). This may help maximise digestion, improve mood and mental health, and support weight management by regulating appetite, fat storage, and blood sugar.

How testing helps you take control of your gut health

Testing for food intolerance helps empower you to make conscious lifestyle and dietary choices to improve your gut health. Identifying the triggers of food intolerance means you can cut out the food or ingredients that your body struggles to digest.  

There are many factors that affect gut health, including exercise, sleep quality, stress levels, medication, ageing, genetics, and environment, but a key consideration is diet. Understanding your body and its food intolerances is an important step towards maintaining a diet that is beneficial to your gut health. 

What to do after receiving your test results

Once you have tested for food intolerance with the YorkTest Premium Food Intolerance Test, you will receive a bespoke analysis of up to 200 food and drink ingredients within a week of returning your blood sample for laboratory testing. 

You will receive traffic light results to your secure account that are easy to read and understand, with additional support provided by a trained nutritional therapist. They will help you interpret your results and adjust your diet in line with the test findings, so that you can take proactive steps to reduce the symptoms of food intolerance and promote great gut health.  

FAQs

What’s the difference between a food intolerance and food allergy? 

A food intolerance is a response to your digestive system being unable to digest certain types of food or ingredients. It is usually not serious, and symptoms including diarrhoea, bloating, and stomach pain can last from a few hours to a couple of days, normally starting several hours after eating the food you’re intolerant to. 

A food allergy, on the other hand, is an immune system reaction to certain foods or ingredients. An allergic reaction can occur immediately after consuming the food you’re allergic to and can be extremely serious. Symptoms include dizziness, itchy skin, swelling of the lips and face, and trouble breathing.  

What is food intolerance testing? 

Food intolerance testing is a way to confirm which food or drink ingredients your digestive system has an intolerance towards. A blood test can establish a list of ingredients, while a breath test can be used to diagnose lactose intolerance. You can also test for food intolerance by removing and reinstating certain ingredients from your diet and measuring the results.  
 
There is limited evidence supporting IgG antibody testing for food intolerances, and the NHS does not recommend its use. This information is for general education only and not medical advice. 

What makes the YorkTest Premium Food Intolerance Test different from other tests? 

The YorkTest Premium Food Intolerance Test is a comprehensive test that may assess intolerance to 200 different food and drink ingredients. What sets it apart from other tests is that it measures all four subtypes of immunoglobulin (IgG) for a food-specific reaction, whereas many other tests only measure IgG4. 

Is the YorkTest Premium Food Intolerance Test accurate? 

YorkTest’s products have a 98% reproducibility rate. This means that two independent results from the same person will be identical 98% of the time. In addition, 82% of YorkTest customers reported that it had a positive impact on their health and well-being. 

How do you take a food intolerance test? 

To take a food intolerance blood test, follow the simple instructions in the test to collect 2-3 drops of blood and post your sample to a laboratory for testing. For the YorkTest Premium Food Intolerance Test, you will receive results online within a week that are easy to read and understand, followed by a consultation with a nutritional therapist.