Food sensitivity tests like Everlywell or DNAfit are all the rage right now, and in theory, they sound great–they’re a lower-cost, more accessible way to test for food sensitivities compared to doing lab work at your doctor’s office. But how do these at-home food sensitivity tests work, and what kind of data do they provide you with? If you suspect you may have a food sensitivity, read this interview between Dr. Carolina Arreola and Melissa Urban to learn more.
Melissa Urban: Over the years, I’ve had people contact me to ask how food sensitivity tests work and whether a food sensitivity test would be faster or more efficient than doing a Whole30. Now that these tests are more available than ever, what do we need to understand about them?
Dr. Carolina Arreola: Food sensitivity tests are certainly popular right now—I am asked about them often in my practice. Before I dive into how these tests work, I think it’s helpful to define a food allergy vs a food sensitivity.
A food allergy is when your immune system identifies a particular food as an invader and then responds to that food by producing allergic (IgE) antibodies. These IgE antibodies bind to mast cells, triggering the release of histamines and an immediate production of symptoms. These symptoms usually include hives, swelling, itching, and difficulty breathing, which can be fatal in extreme cases.
A food sensitivity is when your immune system responds in a similar way but produces different antibodies (IgG) that can cause a much more delayed response. IgG antibodies function differently than IgE antibodies because they do not trigger the histamine release that causes that immediate allergic reaction. Instead, IgG antibodies can mediate inflammatory responses through a variety of different pathways. Due to this response, symptoms of a sensitivity can show up hours to days later, are much more varied, and can include anything from digestive issues and chronic headaches to fatigue, anxiety, or skin issues. Because of the delayed onset, food sensitivities can often go “under the radar” since the link between the food trigger and the symptom it produces isn’t always clear. Generally speaking, food sensitivities are typically more common than food allergies.
Now that we have distinguished the two, let’s talk a little bit more about how these food sensitivity tests work. Food sensitivity tests work by testing your blood for the production of IgG antibodies in response to several different foods (typically ~96 foods), and then rating the responses on a scale. This provides the patient with data on what foods (if any) are causing an immune response in their body.
These at-home tests are convenient because you are able to do everything from the comfort of your home. The lab companies provide you with all the instructions and tools needed to collect a small blood sample as well as a prepaid return mailing envelope to send your results back in. Another perk is that it is quick and easy and typically requires little time or commitment on the patient’s end.
Are Food Sensitivity Tests Worth the Money? What about False Results?
MU: Generally speaking, are they worth the money?
Dr. Arreola: The short answer is no, they’re not always worth the money. Doing a test like this can provide you with valuable information, but they are not perfect and often provide inaccurate results. Additionally, although they do sometimes provide accurate results on which foods can initiate an IgG immune response, they do not address how exactly these reactions can manifest in a patient’s body and what symptoms they are tied to.
MU: What are some of the issues surrounding these kinds of tests? Can they give you false results? Can they tell you which foods are contributing to your energy level fluctuations, digestive distress, joint pain or swelling, skin disruptions, or mental health issues?
Dr.Arreola: A common issue with these tests is that they often give false negatives—meaning they don’t show any reaction when there actually is one. I have had many patients who had clear food sensitivities, most of which they had identified on their own, complete an at-home food sensitivity test and receive results that reported they had no sensitivities. This is common because many people will be sensitive to a food but not sensitive “enough” to trigger an immune response that would be detectable on a blood test.
False positives are also a common issue with these tests. People will receive results that state they produced an immune reaction to nearly every food listed. From my experience, this commonly occurs in cases of intestinal permeability (aka Leaky Gut). Because the barrier of the digestive lining has been compromised, food particles, bacteria, and other toxins are able to gain access to the bloodstream when they normally shouldn’t be able to. When this happens, almost anything you eat can trigger an immune response, but it does not mean that you have a true sensitivity to all those foods. Getting results like this is extremely frustrating for patients because instead of helping them narrow down the cause of their symptoms, they are left feeling even more confused and unsure of how to proceed.
Another issue surrounding tests like this is the misleading concept that you just need to take the test and you’ll magically understand the cause of your symptoms. Food sensitivity tests only show if there is an IgG response to a particular food, but they do not address how exactly these reactions are manifesting in the patient’s body and what symptoms they are tied to. So if someone with chronic joint pain or bloating does a test like this and 4-5 foods come back flagged, they still do not know which food is the culprit of which symptom or if they are related at all.
Because of this, many food sensitivity tests include a two-part elimination & reintroduction diet to supplement the test results. However, I would argue that this elimination and reintroduction phase is the most valuable part of this whole experience and could be done on its own, for free.
Can an elimination program like Whole30 be as effective as a food sensitivity test?
MU: Would a 30-day elimination program like the Whole30 accomplish the same goal–identifying individual food sensitivities–in a more effective (or at least equally effective) way? If so, why?
Dr. Arreola: Absolutely. As I mentioned earlier, many of these food sensitivity testing companies include a 30-day elimination and reintroduction diet as part of their protocol. But this part of the protocol is what is actually providing the patient with valuable information, deeming the blood testing portion unnecessary. The Whole30 program eliminates some of the most common food triggers that have often gone undetected and then provides a structured reintroduction phase to determine the effects on the body. I discussed earlier how if a person does not have a “strong enough” reaction to a food to elicit an immune response, then they increase the risk of receiving inaccurate results such as a false negative. The beauty of doing an elimination diet such as the Whole30, is that there are no false negatives. Your body doesn’t lie to you, and this program reinforces the fact that you are the only one who can determine if a food makes you feel good or bad.
MU: How can someone structure their elimination diet to ensure they capture the most helpful data?
Dr. Arreola: This is such a great question! The key part of any elimination diet is a proper reintroduction phase. After you have eliminated your “suspect foods” for 30 days, you must reintroduce each food group one at a time so you can properly identify symptoms associated with that food. A common mistake people make is they go through the 30 days and as soon as it ends, they are feeling so “deprived” of the foods they had eliminated that they jump back into the deep end and consume anything and everything at one time. Then they are left feeling terrible and back to square one, still unsure of which foods are causing which symptoms.
The proper way to do this is to reintroduce one food group for a day, making sure to eat enough of it in your meals to create a response (if there is one) and then return to the elimination phase for 2-4 days. This may seem odd, but the purpose of doing it this way is to give your body enough time to elicit a response which, as I had mentioned earlier, can be delayed for hours to days after eating said food.
MU: Would you recommend the Whole30 (or a structured elimination diet) over at-home testing kits as a first step in identifying food sensitivities? Why or why not?
Dr. Arreola: I 100% would, and often do, recommend doing the Whole30 or some form of a structured elimination diet over using at-home testing kits. This is because a proper elimination and reintroduction diet provides you with all the information you need without the cost of a food sensitivity test or the risk of being provided with inaccurate results. Not to mention the support that comes along with doing a program such as the Whole30. There are tons of social media channels, meal planning services, websites packed with recipes, YouTube videos, etc… that are dedicated to supporting you on this journey of discovery when doing the Whole30, and I think that is invaluable.
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