Myths of food sensitivity tests: what you need to know

Food sensitivity testing has exploded in popularity in recent years, fueled by promises to uncover “hidden food allergies” or hidden causes of fatigue, bloating, brain fog, skin issues and more. People who experience these symptoms are desperate to find answers, but that also leads to vulnerability to being manipulated and targeted by companies waiting to make money off them. This often leaves patients frustrated and more confused after they have spent hundreds or thousands of dollars.

While these tests are widely available online and in wellness clinics, and often marketed as the “tests your traditional doctor just doesn’t know about,” I can assure you that we know about them. But when they are unvalidated and not backed by real science, we are not going to recommend them. There is growing concern among scientists and clinicians that many people are being misled by marketing, anecdote and pseudoscience. If your patients are considering a food sensitivity test, here is what they need to know about the myths surrounding them and what the evidence actually says.

Myth No. 1: Food sensitivity tests accurately identify problem foods

Reality: Most commercial food sensitivity tests measure IgG antibodies in your blood. These antibodies often indicate exposure to a food, not an intolerance or sensitivity. In fact, the presence of IgG is generally considered a sign of a normal immune response, not a pathological one. When we  desensitize patients who truly have life-threatening food allergies, IgG antibodies are one tool we can use to show progress in the treatment and tolerance or desensitization, not intolerance. For example, if you regularly eat eggs or dairy, your body may produce IgG antibodies to those foods, not because they are harming you, but because your immune system has recognized them. Multiple studies, including guidelines from the American Academy of Allergy, Asthma & Immunology, caution that IgG testing is not a reliable indicator of food sensitivity. They do not correlate with clinical symptoms.

Myth No. 2: IgG results can replace an elimination diet

Reality: Elimination and reintroduction diets, while time-consuming, are still the gold standard for identifying food intolerances. Unlike blood tests, they assess patients’ actual symptoms in response to specific foods. IgG testing may suggest cutting out a long list of foods that patients regularly eat, which can lead to unnecessary dietary restrictions, nutritional deficiencies, or increased anxiety around eating without improving their symptoms.

Myth No. 3: Food sensitivities are the same as food allergies or intolerances

Reality: These are often confused, but they are distinct. Food allergies involve IgE antibodies and can cause serious, immediate reactions, such as hives or anaphylaxis. Food intolerances such as lactose intolerance are typically caused by enzyme deficiencies and do not involve the immune system. Food sensitivities are more ambiguous and lack a universally accepted definition or diagnostic test. Some clinicians use the term to describe nonallergic, non-intolerance-related reactions, but the science is still evolving. We need to start learning the differences between these terms and using them correctly.

Myth No. 4: A long list of reactive foods means you’re “sensitive” to everything

Reality: Many people are shocked when test results show reactivity to dozens of foods. But this often reflects frequent consumption, not true sensitivity. Over-restriction based on such tests can cause undue stress and lead to orthorexia-like behavior, or an unhealthy obsession with eating “clean” or “safe” foods. Additionally, if patients feel they are reacting to seemingly everything, let’s stop playing the blame-the-food game and have them meet with a professional who can assess for underlying causes of the over-responsiveness. Instead of relying solely on unvalidated test results, patients need to be evaluated based on their whole clinical context, including medical history, symptoms, testing that assesses their symptoms for other potential root causes, and response to elimination.

Myth No. 5: These tests are FDA-approved for diagnostic use

Reality: Most direct-to-consumer food sensitivity tests are not regulated by the FDA for diagnostic accuracy. That means these tests have not undergone rigorous clinical validation. Marketing often outpaces science, leading to consumer confusion. Many times, companies will market that their lab is certified. Even if a lab is certified and a test is FDA approved, it still does not mean it is clinically relevant. Some labs use proprietary panels with little transparency about their methodology or accuracy, making it difficult for practitioners and patients to interpret results meaningfully.

What to do instead

Patients who suspect they have a food-related health issue should:

The bottom line

Food sensitivity testing is a booming industry, but many tests on the market today are not backed by strong science. While it is tempting to seek quick answers to chronic symptoms, relying on IgG testing alone can lead to misdiagnosis, dietary confusion and even nutritional harm. Further, these tests often lead to the same companies selling these patients their proprietary blend of supplements, which also are not third-party tested in many cases. Between the unnecessary testing and supplements, it can be a costly and quite lengthy “quick fix,” leading to more frustration. As always, the most effective path forward is an evidence-based, individualized approach — one that considers the full picture of the patient’s health, not just a lab report. We are in the business of treating people, not labs.