This post was adapted from episode 56: “Debunking Food Sensitivity Tests (with Andrea Love, PhD)” of the Nourished & Free podcast.
Listen to the full episode for more information about food sensitivity tests
Is food sensitivity testing a scam or are food sensitivity tests accurate? Learn more about the truth behind food sensitivities and how they differ from food intolerance and allergies.
If you’ve spent any time exploring the world of nutrition and wellness, then you know there is a lot of pseudoscience being used to market everything from supplements to diets. But one of the biggest examples of pseudoscience is the growing field of food sensitivity testing.
As a dietitian, I often hear from clients that they took these tests and discovered that they were sensitive to dozens of foods. They’re left feeling like they need to cut these foods out of their diets and are often having a very hard time with it – both physically and mentally.
But it’s important to look at these tests with an objective, science-based lens before immediately cutting foods out of your diet. So, are food sensitivity tests accurate or are they a scam? Or, even worse, could they potentially be dangerous?
To help me dive into this exploration further, I recently had my friend, Dr. Andrea Love, on the Nourished & Free podcast. Dr. Love is a microbiologist, immunologist, and science communicator who deeply understands how food allergies, intolerances and sensitivities are tested and managed.
Keep reading to learn more about whether food sensitivity testing is worth it.
What Are Food Sensitivities?
The phrase food sensitivity is often used to describe a variety of symptoms that occur when eating certain foods. These symptoms typically include gas, abdominal pain, bloating, diarrhea, nausea, headaches, joint pain and fatigue. Unlike food allergies, which involve the immune system and can cause severe reactions, food sensitivities are generally considered less severe.
The terms food sensitivity and food intolerance are sometimes used interchangeably, but they refer to two different things. Food allergies and food intolerances are true medical conditions that can be diagnosed by credentialed doctors with various tests, detailed medical history, and clinically-prescribed dietary challenges. Food sensitivities, on the other hand, are typically only diagnosed by non-validated and inaccurate direct-to-consumer tests and are not a legitimate health condition.
Understanding Food Sensitivity Tests
Food sensitivity tests purport to measure your body’s reaction to specific foods, to identify which ones might cause adverse symptoms such as digestive issues, headaches, or fatigue.
Food sensitivity tests are considered direct-to-consumer tests, which means you can buy them over the counter at pharmacies and online. Food sensitivity tests are also lab-developed, a designation that sounds like it’s based in science but is really just marketing jargon, said Love.
“A lab-developed test means nothing besides the fact that it was created in a lab,” she said.
These tests typically analyze blood samples (or sometimes urine, hair, or saliva) to try and detect a specific type of antibody, IgG. While these companies tell people these IgG antibodies can indicate reactions to particular foods or food ingredients, this is actually not the case. Unfortunately, these tests are based on flawed science, which is why they are not accepted by credible scientific and medical authorities.
In fact, all major clinical allergy and immunology organizations in the U.S. and beyond advise against using food sensitivity tests, including the American Academy of Allergy, Asthma and Immunology and the European Academy of Allergy and Clinical Immunology.
Are Food Sensitivity Tests FDA Approved?
Food sensitivity tests are not approved by the U.S. Food and Drug Administration for any sort of diagnostic or clinical use. Food sensitivity testing companies are actually not allowed to recommend prescriptive changes – like elimination diets – based on your results.
Of course, anyone who has spent time looking into food sensitivities knows that removing foods you’re “sensitive to” from your diet is common practice after receiving test results.
“These companies really have a lot of leeway to kind of sell things with no evidence, because they fall outside of the scrutiny of FDA,” said Love.
Before we dig deeper into the accuracy of food sensitivity testing and whether testing is worth it, let’s get clear on what a food sensitivity really is and how it compares to allergies and intolerances.
Are Food Sensitivities Real? Allergy vs Intolerance vs Sensitivity
While the phrases “food allergy,” “food intolerance” and “food sensitivity” might be confused by some, they are all very different, said Love.
True food allergies impact only about 2 to 3% of the population. Meanwhile, studies have shown that up to 25% of adults think they are sensitive or intolerant to foods. This number has grown in recent years alongside the marketing of food sensitivity tests.
Understanding Food Allergies
A food allergy is an immune response that occurs after ingesting certain molecules in a food. Allergies generally result in a fast response, with symptoms appearing within minutes to hours after consumption.
Because allergies are an immune response, they tend to occur in predictable ways. The first time your body encounters a molecule or chemical in a food, it will recognize it as not belonging in your system. While you may not experience a severe reaction with this first introduction, your body is busy producing antibodies so it can attack right away the next time it encounters the same molecule.
True food allergies are rare, affecting about 2 to 3% of the total population. The most common allergic reactions include respiratory distress, hives, eczema, swelling, itching, nausea, vomiting and diarrhea.
Food allergies are diagnosed by a clinical allergist by reviewing your medical history, conducting a food challenge test and potentially a skin scratch test or blood test.
Understanding Food Intolerance
Food intolerances differ from allergies in that “they are a digestive issue – not an immune response”, said Love. Intolerances typically result from a deficiency or lack of enzymes required to process certain chemicals.
When you digest food, there are many enzymes at work breaking down the food and delivering nutrients to various parts of your body. When you are intolerant to a certain food, it means that you have an issue in that digestive process, usually due to an enzyme deficiency. As a result, you might experience GI symptoms like bloating, abdominal cramps and more.
Unlike a food allergy, food intolerances do not elicit an immediate response. Symptoms of food intolerance typically take anywhere from a few hours to a full day to set in, because it’s based on the speed at which a food is digested within your body.
The severity of food intolerances also varies based on how your individual tolerance of the food you’re intolerant of. If you’re lactose intolerant, for example, you may be able to eat a small bite of cheese. Eating a big bowl of ice cream, on the other hand, might not feel good.
If you suspect you may have a food intolerance, you’ll need to work with a gastroenterologist. Typically, these professionals will review your medical history and potentially try a specific elimination diet guided by a registered dietitian.
Understanding Food Sensitivity
So, how are food sensitivities different from food intolerances and allergies? In reality, Love said, they’re not a true medical diagnosis at all.
When you use a finger-prick food sensitivity test, they are looking for an antibody called IgG. IgG is an antibody produced as a result of ingesting food molecules. But it doesn’t indicate a sensitivity to the food, said Love.
Instead, it’s quite the opposite. The body produces IgG antibodies when it has been exposed to a food and decided not to react to it. The next time you eat the same food, the IgG antibodies act as a memory for your body, reminding your body that it actually does tolerate this food and it does not need to react negatively. This is called oral tolerance, and it is an important way our body knows that it does NOT need to react to things you routinely eat.
Therefore, food sensitivities really don’t exist. At best, it’s another way to refer to an intolerance (which would not be diagnosed using an IgG-based “food sensitivity” test).
Debunking Food Sensitivity Test Results
So, if food sensitivities are not a diagnosable medical issue, then how can we interpret food sensitivity test results? It’s important to understand what IgG in your blood actually means.
“The problematic nature of these tests is that they’re telling you that we’re going to measure these levels of IgG, and that is then going to tell you what you’re sensitive to,” said Love. “And higher levels (of IgG) are supposed to mean you’re more sensitive to it, when in reality it means the opposite.”
In fact, higher levels of IgG on a food sensitivity test more often mean that you eat a certain food regularly or you’ve eaten it very recently. IgG production and levels are indicative of an exposure of the food in question – and have nothing to do with whether you’re sensitive to it.
This is why it’s common to see people who have taken these at-home food sensitivity tests lamenting that they are sensitive to all of their favorite foods! These tests are better at measuring which foods you consume often than they are at measuring foods your body may not tolerate well.
If you take a food sensitivity test in the summer, for example, you might see really high IgG levels against shellfish proteins because you’ve been regularly enjoying lobster at the beach. But this doesn’t mean you shouldn’t eat them. If you took the same test again in the winter, months after your last round of lobster tail, your IgG levels would likely come back much lower.
“There’s no science to support (food sensitivity tests),” said Love.
Are Food Sensitivity Tests Dangerous?
Any time you rely on inaccurate information to make choices about your health, there is risk involved. Food sensitivity tests are no exception. While the test itself may not be dangerous, the recommendations that come along with your results can be.
One of the biggest health issues with these tests is that by incorrectly diagnosing a sensitivity to certain foods, tests encourage users to remove these (often healthy) foods from their diets altogether.
This can result in a number of mental and physical health issues, said Love, including increased health anxiety and a less varied diet.
Food Sensitivity Tests and Elimination Diets
One of the biggest dangers of food sensitivity testing is the connection between these tests and elimination diets. In fact, eliminating the foods identified through these tests is often worse for your health than eating them.
If you’re suddenly eliminating broccoli, nuts, wheat and onions from your diet, for example, you might be at risk for malnutrition and adverse GI symptoms as a consequence of removing those foods. Not eating these foods might also lead your body to produce fewer enzymes to break them down, leading to actual food intolerances over time.
The only time an elimination diet should be considered is when you’re working with a medical professional on a food intolerance or allergy. In this case, foods should be eliminated for a short period of time and then added back in to see how your body reacts.
Food Sensitivity Tests and Binge Eating
Another issue with food sensitivity testing is the connection between elimination diets and binge eating. I work with many women who struggle with binge eating and I’ve heard their stories first hand.
When you believe you’re sensitive to several foods and remove them from your diet, it makes it really hard to have variety in your meals and snacks. Eventually, it’s too hard to follow and you may experience binges on the foods you were trying to cut out.
Binge eating can cause a variety of mental health and physical health issues and pave the way for additional disordered eating and even eating disorders in the future.
Final Verdict: Are Food Sensitivity Tests Worth It?
If you haven’t figured it out already, I’m not a fan of food sensitivity testing. The way they work is quite literally the opposite of how they claim to work. In fact, eliminating foods identified by sensitivity tests can actually cause more harm than good. They’re a waste of money and complete garbage.
My podcast guest Dr. Andrea Love agrees.
“Because they’re not based on science, it leads people to omit and eliminate foods that are perfectly safe for them, that are often very nutritious and are a really great component of a healthy and diverse diet,” said Love. “It’s very predatory. It’s really exploitative. And this is particularly true for people who do have challenges with their relationship with food.”
If you’re struggling with digestive issues or common symptoms of allergic reactions, don’t reach for the online sensitivity test. Instead, work with a medical professional to determine if you have a food allergy or intolerance.
Food sensitivity tests are just not worth it.
Listen to the full podcast episode with Dr. Andrea Love HERE.