Note: This advice is given by the CAP Executive about non-broadcast advertising. It does not constitute legal advice. It does not bind CAP, CAP advisory panels or the Advertising Standards Authority.

What is Food Allergy/Intolerance Testing?
What is IgE Testing?
What is igG Testing?
What is Electrodermal Testing?
What claims are likely to be problematic?
What about serious medical conditions?

What is Food Allergy/Intolerance Testing?

Both the ASA and CAP have seen marketing communications for various devices and screening methods that claim to identify food intolerances, allergies or sensitivities. These products have included blood and hair tests, a pen-like probe applied to acupressure points and a device that claimed to measure and replicate the body’s electro-magnetic oscillations. Marketers often claim that by identifying certain foods and eliminating them from the diet, consumers can avoid medical conditions associated with food intolerance.

Some marketers have claimed that the benefits of removing certain foods include freedom from memory lapses, migraine, eczema, nausea, dermatitis, joint pains, chronic fatigue and irritable bowel syndrome (IBS).

What is IgE Testing?

The IgE test is a well-established food intolerance test and is backed by a large body of scientific literature. CAP understands that it is the most robust laboratory test for identifying the allergens responsible causing symptoms of immediate-type hypersensitivity (also known as Type I hypersensitivity). However, CAP also understands that some results will be false negatives (the test indicates the individual can tolerate substances that he or she is genuinely allergic to) and some will be false positives (the test suggests individuals should avoid substances that he or she can tolerate). Because of these potential discrepancies, marketers should not claim that they can “clinically validate” test results or that IgE Testing can function as a sole diagnostic tool (Yorktest Laboratories, 24 October 2007).

What is IgG Testing?

CAP understands that this testing is intended to establish the allergens responsible for causing symptoms of delayed hypersensitivity (also known as Type III hypersensitivity). Although IgG testing could conceivably work, the ASA and CAP have yet to see consistent evidence that the technique is accurate or useful.

In 2021 the ASA investigated claims that testing from a finger prick blood sample could identify those food intolerances which were identified through the presence of IgG antibodies, which could have an impact on a range of medical conditions and symptoms including migraines, depression and some digestive disorders.  The ads indicated that following the results of tests, the company could suggest changes to customers’ diet. The ads included testimonials which included statements about an improvement in overall health and also with specific symptoms (including migraine and depression) following the suggested diet changes.

The ASA considered that the overall impression of the ads was that the IgG antibody testing and elimination programme could identify food intolerances and could ‘treat’ or alleviate symptoms and experiences, including those customers with migraine and depression. It assessed the submitted evidence and found that whilst a few clinical trials potentially supported the theory that an IgG elimination diet could potentially identify specific food intolerances in people with particular digestive health conditions, the evidence overall was not sufficiently robust to demonstrate that the elimination diet based on the IgG testing alone could be used to diagnose specific food intolerances or alleviate symptoms of conditions such as migraines or depression (Yorktest Laboratories Ltd, 23 June 2021).

What is Electrodermal Testing?

CAP understands that practitioners of Electrodermal Testing (most commonly known as the Vega test), claim to measure changes in skin resistance and skin conductivity when potential allergens are placed in a metal plate in the measuring device to which the patient is connected. The substances being tested are sealed in glass vials and are in direct contact with neither the machine nor the patient. CAP understands that several published double-blind studies have concluded that the test was not capable of diagnosing respiratory allergy and sensitisation to common aero-allergens.


What claims are likely to be problematic?

Because neither CAP nor the ASA have, to date, seen convincing evidence that, when used in isolation, food allergy or intolerance testing kits can effectively identify food allergies, sensitivities or intolerances or the claimed effects of such allergies, any claims that testing services or testing kits can indicate potential food intolerances (and similar claims) would need to be supported by a robust body of evidence (Rule 12.1).

In 2011, the ASA investigated advertising claims that electrodermal testing (Vega Testing) could be used to diagnose symptoms and could also be used to detect food sensitivities, vitamin or mineral deficiencies and digestive enzyme requirements.  Whilst some evidence was submitted to substantiate the claims, the ASA ruled that this evidence was not sufficiently robust to substantiate claims that this method of testing could be used to identify intolerance to substances, nor identify potential causes of presented symptoms (The Ladbroke Clinic, 2 March 2011).

In 2013, the ASA ruled against unsubstantiated claims on a marketer’s own website that their hair analysis techniques could be used for test for a large range of food intolerances and could specifically help people with conditions including IBS, Eczema and lethargy (Oatmeal Health, 9 October 2013).


What about conditions for which medical supervision sould be sought?

Claims by marketers that food intolerance testing and testing kits can be used to diagnose conditions for which medical supervision should be sought are likely to be considered to discourage essential treatment, unless that diagnosis is carried out under the supervision of a suitably qualified health professional (Rule 12.2).

Also see Medical Devices.


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