Food intolerance: Testing methods under the microscope

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It’s estimated that around 45% of the UK population has a food intolerance. With almost half of us experiencing an issue relating to our diet, it’s not surprising that we want to get to the bottom of it.

But what are the options when it comes to testing? What scientific methods do the tests on the market use, and are all home and alternative tests reliable?

What is a food intolerance?

When considering food intolerance testing, it’s always a good idea to look at what we mean by the term ‘food intolerance’, as this can have an impact on the type of testing that might be right for us.

Allergy vs. intolerance

Firstly, it’s important to note that an intolerance is not the same as an allergy. Although the terms are often used interchangeably, the two are very different. Food allergies are generally present from birth and reactions, which are usually instantaneous, can be serious and life-threatening.

Food intolerances, on the other hand, are far less severe. Reactions can take up to 72 hours to present and, although often uncomfortable, are not life threatening.

What happens in the body?

Food intolerances occur when the body mistakenly identifies a food or drink ingredient as a threat and releases antibodies to fight it, causing an inflammatory response.

This response can result in a range of physical symptoms, including IBS and bloating, itchy skin, acne and eczema, tiredness, headaches and migraines or joint pain.

Different tests on the market

VEGA testing

VEGA testing is a method of food intolerance diagnosis favoured by alternative therapy practitioners. Using a VEGA machine, a type of electroacupuncture device, the electromagnetic conductivity of the body is measured. The patient holds one electrode while another is placed over an acupressure point. A range of allergens are then placed into a metallic container. If a dip shows in the conductivity reading, an allergy or intolerance is supposedly present for that allergen.  

Independent experts have conducted double-blind trials, comparing VEGA testing with conventional testing for allergy sufferers, which showed that VEGA testing has no diagnostic accuracy or reproducibility – a key indicator of reliability.

Hair analysis

Home testing kits involving hair samples have become a popular option, with tests frequently offered on discount voucher websites.

These tests look for food sensitivities by analysing the levels of heavy metals such as lead and mercury, and for deficiencies of selenium, zinc and magnesium.

While hair testing is very effective at indicating previous consumption of substances like drugs, there is no scientific evidence to support the hypothesis that the presence of heavy metals demonstrates food sensitivities or allergies. 


Popular with Chiropractic practitioners, Kinesiology looks at energy fields within the body to determine allergy and intolerance. The test works by examining a patient’s muscle strength when the allergen is placed in front of them.

The deltoid muscle in the shoulder is usually tested for weakness.  As the patient holds out their arm, the practitioner applies a counter pressure. If the patient is unable to resist that pressure, the patient is considered to have a positive reaction to that allergen.

Currently, there is no convincing evidence to show that Kinesiology is effective in the diagnosis of allergies or intolerances.

IgG antibody blood tests

Home-to-laboratory IgG tests involve the collection of a small finger-prick sample of blood which is then sent to a laboratory for analysis using the ELISA method, a globally established and universally accepted technique for laboratory diagnosis.

Intolerances are indicated by the presence of IgG antibodies in the blood, increasing in response to specific food proteins. This mimics the behaviour of the antibodies in the body when presented with ingredients it mistakenly perceives to be a threat, resulting in an inflammatory response.

There have been many studies within the scientific community supporting the use of ELISA testing for the determination of food intolerances.

Trial and error

If you are experiencing symptoms mentioned in this article, and they have persisted for a while, it’s important that you speak with your GP to rule out any serious underlying conditions. If you suspect the cause may be something you’re eating, it might be time to take a closer look at your diet.

Getting to the bottom of a food intolerance can be frustrating. Elimination diets, where you remove one food at a time for a few weeks to see how you feel, can be a long process. And, as many of us react to between two and six ingredients, it can take a long time to understand the bigger picture.

Additionally, the foods that you react to can often be surprising. It’s common to blame a few ‘usual suspects’ when it comes to food intolerance but in reality, anything, from tuna to tomatoes, could be the cause.

Get answers faster with Smartblood

When it comes to food intolerance testing, it’s important to do your research and choose a reputable laboratory testing company.

At Smartblood, we offer a comprehensive test to help you take control of your diet quickly and discover your own trigger foods.

Our home-to-laboratory service, using ELISA plate testing, gives you fast, accurate results that pinpoint exactly which foods you are reacting to. Tests are completed in our accredited laboratory by trained experts, with clear, easy to understand results sent to you via email within three days.

The test is supported by a 30-minute telephone consultation with our BANT registered Nutritional Therapist to help you understand your results and make safe, sustainable changes to your diet.

Could you have a food intolerance?

If you think that food intolerance may be responsible for your symptoms then we believe that our easy-to-complete tests could help you. Find all your food intolerances at once with a full Smartblood test.

Around 10% of our customers exhibit no IgG reactions to the 134 foods whatsoever – we provide non-reactive customers with a 100% REFUND so they can continue their investigations through other testing.

Find out today with Smartblood.

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