Claim Check: "Food Sensitivity Tests Find Your Trigger Foods"

Urgent first

Swelling of the lips, tongue or throat, trouble breathing, a tight throat, fainting or a child who is limp can be signs of a serious allergic reaction. Call 911 in the US. The NHS lists the same signs as needing emergency help. [1] This page is information only.

The claim

Some clinics and home kits claim that a blood or finger-prick "food sensitivity" test can show which foods trigger your symptoms, often by measuring IgG antibodies to dozens or hundreds of foods. The claim is that cutting out the listed foods will relieve fatigue, bloating, headaches or skin problems.

Three different things get mixed up

An allergy involves the immune system and can be life-threatening. A food intolerance is difficulty digesting a food, and the NHS says it is not caused by the immune system overreacting. [1] MedlinePlus says allergies can become life-threatening while intolerances and sensitivities rarely do. [2] The third, an IgG result, is a lab number that is not the same as either one.

What allergy societies say about IgG tests

The Canadian Society of Allergy and Clinical Immunology (CSACI) states there is no body of research supporting use of food-specific IgG tests to diagnose adverse reactions to food or predict future ones. [3] It says positive IgG results are to be expected in normal, healthy adults and children, because IgG is a marker of exposure and tolerance. [3] The European Academy of Allergy and Clinical Immunology task force reached a matching conclusion: food-specific IgG4 does not indicate food allergy or intolerance. [4]

Two risks are named. A person with a true IgE-mediated food allergy "may very well not have elevated levels of specific IgG to their particular allergen," and could be wrongly advised to eat it again. [3] And such tests may lead to exclusion diets that carry risks of poor growth and malnutrition in children. [3]

What the NHS suggests instead

The NHS says tests you can buy that claim to diagnose food intolerances are not recommended, with limited evidence that they are accurate, and that they may suggest avoiding multiple foods, which can be harmful. [1] Clinical routes it lists include a special diet that avoids a suspected food and then reintroduces it, a symptom and food diary, and for some people a lactose breath test. [1] It advises not cutting foods out of a child's diet without a GP's or dietitian's advice. [1] For suspected allergy, see an allergist: MedlinePlus notes even IgE-based allergy tests can give false positives, so results need a clinician's interpretation. [2]

Neutral note on who offers these tests

CSACI says IgG testing was historically offered by alternative or complementary providers but is also sold through other channels, and that it does not support licensed physicians or pharmacists offering it. [3] Titles do not settle the question; the evidence for the test does. Read food sensitivity panels, lab tests ordered in integrative practice and elimination diets in integrative practice.