Food intolerance tests - are they scientifically backed?

directdietitians
4 days ago
3 min read

As professionals in the Dietetics field, we hate to see people fall for common commercial misleading advertisements when they start to feel desperate. More and more people are paying for these tests for a 'quick fix' but are they accurate and scientifically backed? The short answer is no. Find out why below!

What Do Commercial Food Intolerance Tests Claim to Do?

Most commercial intolerance tests claim to identify "sensitivity" or "intolerance" to a variety of foods through one of the following:

1. IgG Antibody Testing

This is the most common form of commercial food intolerance testing. The test typically involves taking a blood sample (or sometimes a finger prick test at home) to measure levels of Immunoglobulin G (IgG) antibodies for dozens or even hundreds of foods.

Claim: High IgG levels indicate a food sensitivity or intolerance.
Reality: The presence of IgG antibodies simply shows that you have been exposed to a food. In fact, developing IgG is a normal and healthy immune response and may even be linked to tolerance, not intolerance.

📌 The British Dietetic Association states: “There is no convincing evidence to support the use of IgG testing to diagnose food intolerance. High levels of IgG antibodies to a food are more likely to indicate that the person eats that food regularly, not that they are intolerant to it.” (BDA Food Allergy & Intolerance Testing)

2. Hair Analysis or Electrodermal Testing

Some providers use hair samples or skin conductivity devices to “diagnose” intolerances.

Claim: These tests measure nutritional imbalances.
Reality: These are pseudoscientific methods with no biological basis and no clinical evidence supporting their reliability.

The BDA and the NHS both state that these tests are not recommended and can be misleading.

Scientific Evidence Against Commercial Testing

Multiple professional organisations including the BDA, British Society for Allergy & Clinical Immunology (BSACI), and American Academy of Allergy, Asthma and Immunology (AAAAI) have reviewed the science and concluded that:

IgG testing is not a valid method of diagnosing food intolerance.
Hair testing, kinesiology, and other alternative tests have no evidence base and should be avoided.
No test outside of a structured elimination and reintroduction diet — under dietitian supervision — is accurate or clinically valid for food intolerance.

What Are the Risks?

Choosing commercial tests over evidence-based approaches can have consequences:

Unnecessary Dietary Restrictions: Many people cut out large food groups (e.g. dairy, gluten, fruits), risking nutritional deficiencies.
Increased Anxiety: Constant worry over “trigger” foods can lead to disordered eating behaviours.
Delayed Diagnosis: Digestive symptoms may be signs of coeliac disease, IBS, IBD, or other medical conditions that require proper testing and management.
Waste of Money: These tests are often expensive and not recognised by any reputable clinical body. We have had many patients who are frustrated that they fell into this trap - don't let this happen to you!

What Should You Do If You Suspect a Food Intolerance?

If you’re experiencing symptoms you think are linked to food:

See a GP to rule out serious conditions (e.g. coeliac disease, allergies, IBD).
Work with a Registered Dietitian to try a structured food and symptom diary, followed by an elimination and reintroduction diet — the gold standard for identifying food intolerances. This can be done via a referral to a Dietitian in the NHS by your GP, or you can contact us directly if you would like a private one to one consultation to discuss your food intolerances.
Avoid Self-Diagnosing or Restricting: You risk nutritional harm and missing underlying conditions.

Conclusion

While commercial food intolerance tests are widely marketed and readily available, the science simply doesn’t support their claims. If this blog post can stop one person from spending their money unnecessarily, then we have at least done our job!

The gold standard diagnosis and treatment for food intolerances is elimination and reintroduction, guided by a Registered Dietitian. So, if you are wanting to finally take control of your symptoms with scientifically backed evidence, get in contact with us today and we will be happy to help you every step of the way!