Food allergy and intolerance testing kits: are they worth it?

One search for food intolerance or allergy tests and you'll find an overwhelming number of options, promising everything from weight loss to alleviating brain fog.

If you're desperate for answers, these tests might seem tempting, but they can actually end up causing you more problems down the line.

With expert insights from registered dietitian Dr Frankie Phillips and Allergy UK, we’ve looked at the science behind allergy and food intolerance testing at home, to help you make the right choice for you.

How much do food allergy and intolerance testing kits cost?

Food sensitivity, intolerance, or allergy tests will usually set you back between £70-£200.

Some of the cheapest tests we found were around £20, but these were based on testing hair samples which are not accurate.

How accurate are home food allergy and intolerance testing kits?

The only evidence-backed way to test for an allergy at home is through a blood test, so if you pick up a home test kit that says it can give you accurate results based on a hair sample or using a gadget known as a 'Vega machine', for example, you shouldn’t believe it.

Blood tests are pricier, but a blood test isn't necessarily a green flag either - not all blood tests are equally useful.

At-home tests often look for IgG antibodies and advise you to remove any foods from your diet that cause a spike in these levels.

If you got a test on the NHS, the clinical team would instead be looking at IgE antibodies, behind which there is a much more supportive body of evidence.

Dr Frankie Phillips says, 'The bottom line is these home test kits seem like a quick and easy fix, but they’re not recognised as being accurate and they don’t have the scientific evidence research behind them.'

The NHS advises against using home food intolerance testing, because the kits may advise you to cut out foods, or even entire food groups, from your diet which provide you important nutrition.

Dr Phillips explains, 'If you get one of these tests done that aren’t clinically reliable you might end up with a whole list of foods you need to avoid, meaning you end up with a very restricted diet that causes all kind of issues down the line.'  

It can also be expensive, it you end up having to pay a premium for gluten-free options for example when you don't necessarily need to.

Why it's always best to see your GP first

It might be tempting to seek speedy answers if you think you know the cause of your issues, but it's always best to see a GP first about the symptoms you're experiencing.

You might think your symptoms are being caused by a relationship to a specific food, but that might not necessarily be the case.

When you go to see a GP, they’ll be able to think about your symptoms as a whole and could identify something that you hadn’t considered or known about – which a home allergy or intolerance test can’t do.

Of course, it's always possible you might feel you aren't being heard by your GP. But you can go in armed with questions or a symptom diary, and also ask for a second opinion if you aren't feeling happy about the outcome. See our guide to getting the most from your GP appointment.

Food allergy vs intolerance: what's the difference?

Food allergies mean your immune system is overreacting to what you've eaten, while food intolerances relate to how well your body is able to break down and digest certain foods.

Common food intolerance symptoms are gastrointestinal – so you might feel stomach pain, bloating, diarrhoea – while allergy symptoms are wide-ranging like dizzy, developing itchy skin, getting a runny nose or other symptoms after you've eaten certain foods.

With a food allergy, you'll experience allergy symptoms every time you eat that specific food, unlike an intolerance, where you may be able to eat small amounts of that food without any issues.

Can you take a coeliac test at home?

Coeliac disease is when your immune system attacks itself when you eat gluten, and many self-testing kits now offer coeliac disease tests.

Symptoms of coeliac disease include persistent and unexplained gastrointestinal symptoms like diarrhoea or stomach ache, constant fatigue, unintentional weight loss, and severe or persistent weight loss.

If you have symptoms of coeliac disease or close family members with coeliac disease, you should speak to your GP about getting tested.

If you instead test at home, you'll likely need to confirm the results with a GP anyway to get any follow-up treatment and will have wasted money and time in the process.

People at home can lull themselves into a false sense of security by taking the test incorrectly too, Dr Phillips explains, 'The test is only reliable if you’re currently eating gluten. If you’re not eating gluten and take the test, you’ll get a false negative.'

Plus, a GP can assess whether your symptoms might be caused by something else. It's important to get persistent bowel changes checked out properly.

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How can you accurately test for food allergies and intolerances?

A spokesperson for Allergy UK explains, 'We know that the first step in effectively determining if somebody has an allergy is always to take a patient history. This is because it is possible for a test to indicate that someone is not allergic, yet symptoms can persist until the allergen is eliminated. 

'This is why a full patient history needs to be taken alongside any test, because a test alone may not be enough to diagnose an allergy. 

'If a home allergy testing kit is used and does suggest someone has allergies, the individual may still require clinical support to manage their allergies. For this reason, we urge people to continue to seek a clinical test through their GP (rather than self-testing at home).'

What does an NHS allergy test involve?

Getting an allergy test through your GP could take several forms, including a blood test of IgE antibodies.

Dr Phillips explains, 'You might also have a skin prick test which is simple and very quick. The skin will be pricked by the allergen and tested for several things at the same time. You’ll get a prick of a needle and it could be egg, peanut, cow’s milk or a non-food allergen like grass pollen.

'Then within a few minutes, we look at the site of the skin prick and whether a lump comes up that might be itchy and uncomfortable, that would indicate an allergy.

'The other thing is a food challenge, where you’d be avoiding a food and then in a controlled environment you’d have a small amount of that food. Then you’re observed to see what happens when you’re exposed to that food.'

For an intolerance, the process may be more straight-forward.

Dr Phillips explains, 'In most cases it’s possible to work out a tolerance by eliminating the food for a short time (two weeks) then reintroduce very gradually to see where your tolerance lies.'

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What should you do if you think you have a food allergy or intolerance?

The first thing you can do is make a food and symptom diary, where you make a note of everything you eat and any symptoms you experience. 

Allergy UK has a food diary template which can help you and a healthcare professional to identify any patterns.

Dr Phillips says, 'It can be a bit of a detective job to try and unravel what’s going on.

'The first port of call should be your GP, then the next step when you’ve got a clear pattern of symptoms laid out in your food diary, would be to refer you onto an allergy clinic. That can take quite a while and can be frustrating. 

'You can also go private, but it would still need to be a hospital setting.'

The bottom line. It might take some time and persistence, but you're better off working with your GP to figure out if you have allergies than trying to go it alone.