This post will help you understand more about food sensitivity tests, what they are looking for, how they differ from a celiac disease and food allergy test, and how they should be used to diagnose and treat disease. This post contains affiliate links and is not a substitute for medical advice. Please read my disclosures.
Diagnosing food sensitivity is challenging as it’s a relatively new phenomenon. When someone is sensitive or intolerant to a particular food, he or she may experience classical gastrointestinal ailments such as bloating, gas, and abdominal pain and non-classical symptoms like rashes, migraines, and fatigue.
The growing interest in food sensitivities has created a new marketplace for food sensitivity tests – and with the creation of this industry comes a lot of questions and confusion.
A lot of holistic health professionals use food sensitivity testing so they can better understand how food may impact their clients both in negative and positive ways.
On the other hand, some medical professionals are skeptical of food sensitivities (and testing) and often demean holistic approaches to healing. Many medical professionals have resorted to calling food sensitivity testing “junk science,” name-calling that carries little merit in my book.
While I am pro food sensitivity testing (after all, the more knowledge you have about yourself, the better), I do want to present a balanced look at food sensitivity testing, its accuracy, and how the results of a food sensitivity test should be used to help you overcome your personal health challenge(s).
How Food Sensitivity Testing Differs from Allergy and Celiac Disease Testing
Testing for food sensitivity vs. allergy vs. celiac disease is very different, as each disorder challenges the body in different ways. Here are the differences between each disorder and how to test for each.
You can determine if you have food sensitivity through a simple blood test. The test will determine how the immunoglobulin G (IgG) antibodies bind to each food and to what degree.
IgG accounts for 75 percent of the antibodies circulating in your blood. Antibodies are an important part of your body’s response to toxins because they recognize and bind to particular antigens, such as bacteria or viruses, and then help to destroy those toxins.
It’s important to note that an IgG test is a test for food sensitivity only – not a food allergy. Unfortunately, the terms “food sensitivity” and “food allergy” are used interchangeably, adding to marketplace confusion. (IgE tests for allergies, not IgG.)
Experts believe that IgG reactions can take hours or days to develop, making it difficult to determine exactly which food is responsible for symptom flare-ups. This means you can’t always blame the last thing you ate to understand how food sensitivity affects you fully.
On one side of the coin, you have researchers say that an IgG subclass, known as IgG4 (which stands for immunoglobulin G4), is simply a marker of exposure to a particular food and possibly signifies a person’s tolerance – not intolerance – to that food.
On the other side, a researcher found that IgG testing showed “promise,” netted “clinically meaningful results,” and could serve as a “useful guide for elimination diets.” Another article published by an otolaryngologist found the majority of his patients experienced “substantial health improvements after an elimination of foods positive by IgG food allergy tests.”
Here is what this all means:
One, it means that more research is needed to understand the accuracy of food sensitivity tests. Hopefully, the science will catch up, but don’t be fooled. Just because the research isn’t there (yet) doesn’t mean food sensitivities are not real. There are many diseases that we don’t know about (yet), and it doesn’t make them any less real, does it?
Two, it means that food sensitivity tests should not be the only diagnostic tool used to determine your food intolerances. For example, you should use an elimination diet to complement/confirm your food sensitivity test findings.
Additionally, testing for gluten sensitivity, for example, can be complicated and may require additional and very specific testing not found in conventional food sensitivity tests. (Read more about testing for gluten sensitivity in this article.)
Remember, celiac disease is a completely different test. It is not food sensitivity; rather, celiac disease is an autoimmune disease that impacts the body differently. Please read my article, How to Get Tested for Celiac Disease if you suspect you have celiac disease.
Three, what we are seeing is that food sensitivity testing, at this point, is controversial. That is okay. Many medical and diagnostic procedures are controversial but still widely recommended and used in the medical community.
One procedure that comes to mind is mammograms. Before you attack me, please know that I am mammogram neutral. I only say this to illustrate the point that there are differing viewpoints when it comes to understanding how to diagnose and test for diseases in our bodies.
Limitations to Food Sensitivity Tests
While I encourage everyone who believes they have a food sensitivity to purchase a food sensitivity test, I recommend you proceed cautiously and optimistically. As discussed, the verdict remains on whether such tests are 100 percent accurate. Tests can come back with a wide array of possible trigger foods, causing you much anxiety as you try to figure out what to eat.
That said, knowledge is power.
I believe these food sensitivity tests should be used as a starting point on your journey to figure out what ails you. You are your best detective.
I believe we will all be better off if we stop relying on our doctors, who have little-to-no nutrition education, to fix us. You can heal your body, put your chronic symptoms to rest, and possibly reverse disease in your body. (Read How I Healed My Body from Celiac Disease.)
How Should Food Sensitivity Tests Be Used?
In my opinion, food sensitivity tests should not be used as a diagnostic tool but rather as a starting point for an elimination diet. You can eliminate the foods that you are most sensitive to first for 4-6 weeks, then over time, add each food item back into your diet to see how you feel.
For example, if you eliminate eggs, corn, and dairy for 4-6 weeks, you can first add eggs back into your diet and see how you feel over the next few days. If you feel fine, then a few days later, you can add corn back in and so forth. Go slow, and don’t rush through the process.
Note, before removing gluten from your diet, please take a moment to get tested for celiac disease first. You must be consuming gluten for a celiac disease test to be accurate. There are many reasons why you want to get tested for celiac disease before implementing a gluten-free diet. (Read: Stop! Don’t Go Gluten-Free Until You Read This.)
If you find out in this process that gluten makes you feel awful, it is very difficult to consume it again (called the Gluten Challenge) just to get tested for celiac disease (something you’ll have to do if you want to know for sure if you have celiac disease). Rule out celiac disease first and foremost, please!
Food Allergy Tests
As mentioned, IgG tests also do not test for food allergies. This is an important distinction, as an allergy and food sensitivity differ.
When I was tested for celiac disease (via a blood test), I was also tested for food allergies to cow’s milk, wheat, corn, peanuts, soybeans, pork, beef, fish/shellfish, egg (whole), and chocolate/cocoa. I am thankfully not “allergic” to cocoa. Whew!
In a fascinating twist of fate, however, my IgE food allergy tests came back positive for wheat (class I), corn (class II), and peanuts (class III). This meant not only did I have high levels of t-Transglutaminase (tTg) IgA (which indicated celiac disease), but also I had elevated IgE levels when it came to wheat! I had tested positive for both an autoimmune response and a histamine (allergic) reaction to wheat. (In case you’re wondering, I confirmed my celiac disease diagnosis with a biopsy, which you can read about here).
In my research for this post, I learned that many patients with celiac disease also have a food allergy to wheat, gluten, gliadin, rye, or barley. (Source: Clinical Usefulness of IGG Food Allergy Testing)
How to Get a Food Sensitivity Test
With the rise in popularity of food sensitivity awareness, so comes the flood of at-home testing products.
I believe that many doctors are hesitant to order food sensitivity tests for their patients because enough research on testing methods has not been done – and many doctors are not trained to help their patients interpret and act on the results. Because of the disconnect between patient desires for a food sensitivity test, and a doctor’s hesitation in ordering one, many patients resort to self-help.
I researched a few of the big food sensitivity names on the market and finally settled on Everlywell as the one I wanted to try for myself. Some of the tests did not feel right to me (like the hair test one – huh?), and I felt Everlywell had an excellent reputation to boot. Everlywell even secured a partnership with Lori Greiner on Shark Tank!
For under $200, Everlywell will send you an at-home blood test that you can do in the comfort of your own home with a finger prick. It’s super easy if you ask me – although I was a little squeamish at first. You can watch me do the test (and blood draw) in the following video.
I returned my test to the Everlywell lab, and within a few days, I could view my results on my computer. I wrote about my food sensitivity results in this post.
After the Results
I write more about what to do with the results of your food sensitivity test in this article, but for the most part, you should take the information with a grain of salt. Don’t let yourself become overwhelmed with the idea of eliminating every possible food noted as high or moderate reactivity on your test.
Instead, use the results of your food sensitivity test as a means to do some simple experiments on yourself over time. Go easy; this is a marathon, not a sprint.
I recommend you eliminate the top foods (the ones with the highest IgG ranking) for 4-6 weeks. Then, slowly over time, reintroduce each food one by one and see how you feel.
You will likely know, at this time, which foods bother you and which do not. Continue to eliminate and reintroduce foods until you get to the bottom of what is ailing you most. I recommend you work with a trained holistic health coach or other health care professional during this process.
Again, you are your best scientist and detective. No one can figure this out but you – these food sensitivity tests give you a starting point.
Additionally, if your food sensitivity test comes back with a slew of foods to avoid, it might signal something more is going on, like a leaky gut. This is extremely common and should be taken very seriously.
Take the time to limit highly inflammatory foods (gluten, sugar, dairy) and eat as many fresh anti-inflammatory foods as possible (vegetables and fruits). Also, consider taking a high-quality probiotic to help improve your gut health.
You may notice that as your gut heals, so too will your tolerance for certain foods. The food sensitivity test may have simply been signaling that your gut is leaky, and it was detecting all the foods you’re eating, not the foods you’re sensitive to, after all.
Once you’ve restored your gut health, you can retake the food sensitivity test and see which foods are still bothering you vs. everything and anything leaking out of your gut and getting picked up on your blood test. Make sense?
For guidance on how to heal your gut, take my 7-Day Heal Your Gut Challenge (it’s free!).
Prognosis of Food Sensitivities
It’s important to know if food is sabotaging your health and do something about it if you want to feel better and deter chronic disease.
In fact, ignoring food sensitivities often lead to chronic inflammation. Chronic inflammation can lead to the development of chronic conditions including but not limited to autoimmune disease, behavioral problems, psychological disorders, diabetes, hyperthyroidism, infertility, neurological conditions, obesity, osteoporosis, and even cancer.
Continued consumption of foods you are sensitive to may also contribute to weight gain or difficulty losing weight. (Source: Dr. Rita Marie Lascalzo). Jennifer Fugo of The Gluten School often talks about how she quickly shed 20 lbs of “inflammation weight” once she realized she had gluten sensitivity and eliminated gluten from her diet.
What Should You Do?
For me, I decided to get a food sensitivity test. I err on the side of knowledge is power vs. ignorance is bliss. Plus, my results will give me a starting point for my own elimination diet.
I believe that we all need to take charge of our health and not decide on whether or not we do a test based on the opinion of others (even doctors) who may not have researched food sensitivities in earnest.
Research is continually changing, and I may be proven wrong one day, but for now, my gut tells me this kind of information is powerful in aiding in my healing journey. Remember, just because the research isn’t there doesn’t mean something you feel isn’t real.
PS: Don’t forget to read about the results of my Food Sensitivity Test!