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Food Sensitivity Testing: How It Works – And How It Can Improve Your Well-Being

Food Sensitivity
Everlywell Food Sensitivity Test box surrounded by a variety of foods, such as eggs, coconut, and oranges

Last updated January 2, 2024.


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As any devoted foodie can attest to, food can be fun, comforting, and (of course) lip-smackingly delicious. Unless, that is, you’re sensitive to a particular food – which can make that food anything but fun and comforting for you. Eat something you’re sensitive to, and you might experience very unpleasant symptoms like fatigue, migraines, bloating, depression, and dry or itchy skin. But it’s often difficult to pinpoint exactly which foods you’re sensitive to – thanks to the large number of ingredients you probably consume each day.

One effective (and easy) way to identify your food sensitivities is through the Everlywell food sensitivity blood test.

This test checks your level of sensitivity to 96 different foods – including gluten and dairy products, as well as various meats, fruits, and veggies. It measures your sensitivity levels by examining your body’s IgG immune response to each type of food included in the panel.

What Is the IgG Immune Response–and What Does It Have to Do With Food Sensitivity?

Your blood plasma is loaded with antibodies – also called immunoglobulins – that help protect your body from dangerous bacteria, viruses, and other threats. These antibodies can “spot” harmful, foreign objects (called “antigens”) that invade your body, triggering a protective response from your immune system’s cells.

There are five main types of antibodies, one of which is immunoglobulin G – also known as IgG. We’ll come back to IgG shortly.

In some people, certain foods evoke a swift response from the immune system – an allergic reaction. If you have allergies of some kind, then you’ve experienced this rapid-response from the immune system – perhaps in the form of sneezing or a stuffy nose (or, worse, difficulty breathing). Allergies are mediated by IgE immune responses.

However, food sensitivities are not allergic reactions! (And the at-home Everlywell Food Sensitivity Test is not an at-home food allergy test.)

Instead, food sensitivities can be caused by a delayed immune response. If you’re sensitive to a particular food, it may be because some of your antibodies – IgG antibodies, to be exact – mistakenly label that food as “dangerous” when it enters your bloodstream. IgG antibodies do this by attaching themselves to certain molecules of that food. So, basically, IgG antibodies can act as markers on that food – which tells your immune system that the food you ate is a threat to your body.

Let’s say, for example, that you’re sensitive to coffee. When you take that satisfying sip of coffee, the coffee enters your body – and is detected by coffee-specific IgG antibodies, which mark coffee particles as a menace to the body.

Next, some of your immune system’s cells see these IgG “marks” on the coffee in your body. Immune cells then attempt to neutralize the supposed coffee threat by shooting out a mix of chemicals (known as inflammatory cytokines) that circulate throughout the body. It’s these chemicals that can wind up hurting you, causing food sensitivity symptoms. These symptoms include abdominal pain, muscle or joint pain, mood changes, and headaches (for a fuller list of some of the symptoms of food sensitivity, go here).

Sensitivity to coffee – and many other foods – can be detected with the Everlywell Food Sensitivity Test. A food sensitivity test requires a few drops of your blood as a sample. A lab then measures the amount of IgG antibodies found in the blood for each type of food under consideration. In this way, your specific food IgG reactivity levels can be detected.

(What foods are tested with the Everlywell Food Sensitivity Test? Go here to see the full list.)

Why Test for Food Sensitivity?

Think a food sensitivity could be hampering your well-being? Then you might be considering an elimination diet – or have already tried one. By helping you find the foods you’re sensitive to, elimination diets can minimize or completely obliterate food sensitivity symptoms.

However, if you’re removing foods from your diet at random, then it can take quite a long time before you find the specific foods you’re sensitive to! And that’s why a food sensitivity test can be so powerful: it gives you a specific list of foods that you’re potentially sensitive to based upon the IgG reactivity results. You can then use this list to guide your food elimination plan – saving you time and effort. (Included with the results of the Everlywell Food Sensitivity Test is information that helps you craft an elimination diet.)


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