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What is food intolerance?

If you’re new to yorktest, I’m sure you’re eager to find out all about food sensitivities. After all, approximately 45% of the UK population suffer from a food intolerance* – that’s nearly half of the population! The good news is that you don’t have to be a science whizz to understand information on food intolerance or how this plays an effect on the body.

A food intolerancecan occur when your body has difficulty digesting certain foods. When this occurs over time, large food particles (proteins) may enter the blood stream.

Test for food intolerances

Common intolerances

As individuals, our reactions to foods and drinks vary a great deal. An ingredient which may cause problems for one person could be completely acceptable for another. At yorktest, we like to refer to this as our ‘food fingerprint’. The most common food intolerances include:

Interestingly, our recent customer survey date shows that 64% of yorktest customers have between 2 and 8 food reactions.

Understanding your own personal food and drink intolerances, and the effects they could have on your health and wellbeing, is important to ensure you make the best possible choices for your diet.

Test for food intolerances
food intolerance fructose

What causes food intolerance?

When food particles enter the bloodstream, the immune system can sometimes identify these food protein particles as “foreign” and produces IgG antibodies to “attack” the food in question. This response is your immune system’s natural defence mechanism to ward off harmful invaders in the body which can create inflammation.

This inflammation could trigger bothersome symptoms, which may persist or develop in the body if they are neglected. Imagine if you stopped brushing your teeth twice a day. The more foods and drinks you consume, the more bacteria lands on your teeth. Through this neglection, over time you may see a build-up of plaque, bad breath and discolouration which may lead to problems, such as tooth decay. Food intolerance can build up in the same way and could create further problems as the root cause hasn’t been addressed.

Can you develop a food intolerance?

Yes, you can develop a food intolerance at any point in your life. However, it is often very challenging to pinpoint exactly what foods and drinks you’re reacting to.

Food intolerance testing is not something that is currently offered on the NHS. Instead, people are encouraged to eliminate certain foods one-by-one to identify an intolerance, especially ones you suspect are causing a reaction. However, this can often be an exhaustive process and not knowing where to start can be daunting.

If you’re keen to find out if there’s something you’re reacting to in your diet, then we’re here to help. At yorktest Laboratories, a leading provider in IgG food intolerance testing (you’ll find out more on this soon), we offer a fast-track way to identify what foods and drinks work for and against your body and give you a starting point for an elimination diet. We analyse your IgG reactions to up to 208 food and drink ingredients and offer post-test aftercare through nutritional consultations, relevant content material and ongoing guidance from our Customer Care team.

Once a food intolerance sufferer understands their dietary requirements, and has a period of elimination of the offending food or foods, there is evidence that the food culprits can be reintroduced into the diet in small doses at a later date. Many people are able to reintroduce foods back in to their diet once their immune system has ‘reset’.

Symptoms of a food intolerance

It’s important to discuss any symptoms you may have with your GP, so they can refer you for further tests to rule out any underlying conditions. If you are still suffering thereafter, it is at this point where you may wish to take a closer look at your diet.

There are misconceptions about food intolerance, and unfortunately some underestimate how uncomfortable and painful symptoms can be, simply writing it off as another, irrelevant niggle of the middle class! It’s sad to hear this as we know that dealing with chronic pain can be extremely draining both emotionally and physically. If you’ve been checked out by your doctor and think that changing your diet might help you then understanding your food intolerance can sometimes provide a first step to feeling better.

Can you test for a food intolerance?

In short, yes. There are several ways in which food intolerance can manifest itself, including coeliac disease and lactose intolerance. The majority of food intolerance sufferers though aren’t given a medical “label” and testing isn’t offered on the NHS.

For those who think they might have a food intolerance, the gold standard approach is to try an elimination diet, removing one food at a time to see if symptoms ease. However, the elimination diet is difficult to do without any prior knowledge about which combination of foods could be causing a reaction.

A food intolerance test carried out by taking a blood test can measure food-specific IgG antibodies which shows foods your body has an IgG antibody reaction to. Many use this approach to define their elimination diet, rather than starting with no knowledge.

What is IgG?

Immunoglobulin (IgG) is a type of antibody. Antibodies are major components of the immune system. In normal human blood IgG1 is the most prevalent making up 60-70% of the total IgG, followed by IgG2 (20-30%) and IgG3 (5-8%). IgG4 only consists of 1-4% of the food-specific IgG antibodies present.


In most cases, people are sensitive to foods they eat every day, often several times a day. However, identifying which foods you are intolerant to by keeping a food diary can be hard as symptoms of food intolerance are delayed, often coming on hours, or even days, after eating the food. This means that the symptoms from one meal run into the symptoms from another meal.

Add the fact that reactions to several different foods may be going on, and you can see that it is virtually impossible to determine the specific food culprits just from using a diary.


An IgG food intolerance test can pinpoint what foods and drinks your body could be reacting to which can be a useful starting point for an elimination diet. Usually there is more than one food and drink ingredient that the body is reacting to and, therefore, an IgG test could override the guesswork on what works for and against your body.

We will always encourage you to see your GP first to rule out any underlying conditions. Food intolerance is often the last possible cause people investigate for their symptoms. Did you know medically unexplained symptoms account for up to a fifth of GP consultations in the UK[1]? These symptoms include, tiredness, anxiety, skin issues and digestive problems.

Learn more about our food intolerance tests
salmon food intolerance
salmon food intolerance

What is an IgG test?

IgG is a fancy word for testing the reaction to proteins in foods. This simple blood test is used as a measurement strategy of food-specific IgG antibodies for identifying foods to which a person may be sensitive. This type of testing is now considered mainstream as many choose to use this approach as a starting point for an elimination diet.

The yorktest food-specific IgG antibody programmes test for food-specific IgG antibody reactions to 200+ different whole food extracts. The test is not diagnostic of any condition but is used as an aid to management of dietary intake, a “starting point” for an elimination diet.

How long do the effects of food intolerance last?

The onset of symptoms is usually much slower compared to a food allergy and may be delayed by many hours after eating the offending food. Because of this, it makes it challenging to pinpoint what foods and drinks are triggering your symptoms. The signs of food intolerance are often prolonged, especially if offending foods are eaten on a regular basis. You can find out more on the symptoms here.

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

When it comes to the difference between food allergy and food intolerance, many people assume they are the same thing, especially when they’re used interchangeably in conversation. However, they are both very different.

An allergy could be life-threatening, and symptoms often develop soon after consumption. A food intolerance, on the other hand, is not life-threatening and symptoms could develop as far as 72 hours after eating the problematic food. In scientific terms, the body produces IgE antibodies during an allergic reaction and IgG antibodies can be involved when it comes to a food intolerance. This means that the biological processes behind a food allergy and a food intolerance are notably dissimilar.

Find out more on the difference between a food intolerance and an allergy.


Worrying that you’re a fussy eater, having to cancel dinner plans or simply avoiding social events that might risk bringing on uncomfortable symptoms is a fear for many food intolerant sufferers. However, this doesn’t have to be the case. More and more restaurants, cafes and even entire supermarkets are opening with food intolerant sufferers in mind. The majority of restaurants, especially the chains, will cater to food intolerant sufferers – they want your custom after all!

Furthermore, free-from foods are becoming a phenomenon, although processed free-from foods are not usually that healthy and its better use fresh produce or check the labels carefully.


There is evidence that you can use digestive enzymes and probiotics for treatment of food intolerance when used correctly, such as lactase enzyme for treating lactose intolerance.

However, most food intolerances are not caused by major enzyme deficiencies and balancing the gut flora with probiotics on its own will not get to the route cause. The most effective way to reduce symptoms of food intolerance is to identify the culprit foods, and then to eliminate those foods from your diet.

Thinking of a food intolerance test? Here’s what to look for:

Pipette in the lab

Good question! It’s fair to say that the market for food intolerance tests is heavily saturated due to an increased demand of interest in health and wellbeing. That’s why it’s important for you, the customer, to make sure you make well-informed choices when it comes to purchasing a food intolerance test.

How are you meant to tell the difference between the plethora of diagnostic tests that are available to you? How can you tell those based on good science and those that have no basis? It’s a difficult task. Luckily, there are simple things you can look out for to check the reputation of a diagnostic test:

There should be consumer data to show that the test works – This can come in the form of customer survey results, real-life testimonials or statistics
On the topic of statistics, look out for reproducibility stats. This means that two separate results of the same person’s sample should correlate with each other. At yorktest, we have a >98% rate. Sounds technical, but make sure the test has got a CE mark. This symbol is applied to products which complies with EU safety, health and environmental requirements
What post-test support is on offer? You want to get the most of your money so see if you get nutritional consultations included in the programme, guidebooks, food diaries and access to a support team to help you along the way. We’re proud to say that here at yorktest we have all of the above.

How our blood tests compare to other methods:

At your fingertips, you have a range of tests online to choose from. There is hair testing which analyse a sample of your hair against energy fields all the way through to VEGA tests which measure the electromagnetic conductivity in the body. These food intolerance tests often appear to be cost-effective and found on discounted websites, but unfortunately these methods have no scientific basis and are not proven to work.

Results from these types of tests can lead to many foods being eliminated from the diet unnecessarily and research studies show that these tests provide information that is no better than chance.

You also have the option to choose the IgG method which, according to one study, “shows promise with clinically meaningful results. It has proven useful as a guide for elimination diets, with clinical impact for a variety of diseases[2]”. This is what we expertly specialise in at yorktest – a leading provider in IgG food intolerance testing.

We are different compared to the many food intolerance companies out there. Not only do we hold substantial evidence to support IgG food intolerance testing, but we’re in a unique position with 35 years of experience, a wealth of customer feedback and proven robust methodologies that work.

Find out more

How much does it cost to get a food intolerance test?

Let’s compare food intolerance tests to buying a car. You’ve seen a car that has taken your interest, but it doesn’t feature a built-in Satnav, it has high mileage and the garage isn’t reputable. It’s relatively inexpensive and there’s uncertainty how long you will see the benefits of having a car, or whether it’ll fail you straight after you’ve bought it. When that happens, you have no safety net in terms of guarantee and support to fall back on.

There’s another car that you’ve seen which you’re also interested in. It has a built-in Satnav, so you have extra guidance in terms of where you’d like to drive to. The price is more expensive than the first car, but it has a reliable track history and has a money-back guarantee and aftercare support in place should you need it

You wouldn’t take a gamble on buying a car, so why would you take a gamble on a food intolerance test which has no basis in science, offers no aftercare and has no substantial studies behind it?

Here at yorktest, we care about our customers. We don’t provide you with a food intolerance kit and leave you wondering what to do next. This is why we provide a start-to-end service, packed with post-care support in the form of nutritional therapist consultations and ongoing support from our Customer Care team in between.

intolerance lab

Who are YorkTest?

We have over 35 years of excellence in laboratory testing, specifically IgG testing. Did you know we’ve also been voted the best food intolerance company 2018? Over the course of our service, we have expertly developed programmes which analyse your reactions to up to 200 food and drink ingredients.

Find out more

Our customer promise

Our customers are at the heart of what we do, which means we support you every step of the way. After all, changing and optimising your diet can be challenging.

Many people come to us with problematic symptoms to see if there is something in their diet that might be aggravating or triggering their symptoms. If you’ve consulted with your GP and you’re still suffering, you can take a look at our testimonials page. You’ll see first-hand who we’ve helped, and you might even read a story that resonates with you.

We are here to answer all your questions

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