Transcription:
The Truth About At-Home Food Sensitivity Tests: A Critical Discussion With Melissa Watts, MD


Melanie Cole, MS: Welcome to Better Edge, a Northwestern Medicine podcast for physicians. I'm Melanie Cole. And joining me today is Dr. Melissa Watts. She's an Assistant Professor of Allergy and Immunology at Northwestern Medicine, and she's here to highlight at-home food sensitivity tests and are they really effective?

Host: Dr. Watts, it's a pleasure to have you join us today. Can you please start by sorting the difference between a food allergy and a food sensitivity, so it gives us a place to start?

Melissa M. Watts, MD: Absolutely. How we define a food allergy versus a food sensitivity, as some people may call it, or a food intolerance as I prefer to call it, really will help to provide a lot of clarity for the audience. So, a true food allergy actually involves the immune system in which the immune system inappropriately responds to a specific food protein.

In this scenario, the body actually makes an antibody called immunoglobulin E or IgE for short against a specific food protein. And then if or when the patient eats that food protein such as a peanut or peanut butter, for a child that may be peanut allergic, for example, they will develop adverse symptoms and these symptoms will occur in a sudden onset, usually only a few minutes to up to two hours after ingestion. And the classic symptoms will be an itchy temporary rash, also called hives, swelling of the lips, the tongue, the face, respiratory symptoms such as shortness of breath, wheezing, or chest tightness, or gastrointestinal symptoms such as abdominal pain, vomiting or diarrhea. And in the worst case scenarios, some people can even develop syncope or passing out or become lightheaded if their blood pressure drops too low. And these symptoms can be potentially life-threatening or what we call anaphylaxis. And because it is an immune response, these symptoms are going to occur every time that food protein is ingested.

Guest: Now, in contrary, a food intolerance or food sensitivity, as some people call it, and it's sometimes mislabeled by non-allergists as a food allergy, is quite different, a food intolerance typically involves the digestive system, and it typically occurs when your body is unable to properly process or digest certain foods. And there's some key differences here, which mainly is that patients that have this can usually tolerate small amounts of the food without any significant problems. But sometimes when eating larger amounts, they may develop unpleasant, typically isolated GI symptoms such as abdominal pain, bloating, sometimes even diarrhea, or even constipation. And while a true food allergy or allergic reaction is immediate because it involves the immune system, a food intolerance symptoms are often delayed. And they can occur several hours or even days after eating the food.

Host: That was a very comprehensive explanation, Dr. Watts. Thank you for that. So, how can the knowledge of food intolerance and allergies be applied in the treatment of ear, nose, and throat conditions?

Guest: This is a great question. And in reality, the knowledge of these two conditions and exactly how they are defined are appropriate for all medical specialties across the board. So, all clinicians really should be aware of them. And this is because patients who have true food allergies or food intolerances often initially will present first to a non-allergist, and some of the symptoms that may occur in the setting of a true food allergy can involve the mouth and throat, such as lip swelling, tongue swelling, or throat swelling, which we call angioedema. And these patients may be seen by an ear, nose, and throat physician or provider before they see an allergist. And so, I think it is important for all other physicians to recognize both of these clinical presentations as well as their key differences because people who have symptoms concerning for a true food allergy should always be referred to see an allergist for further management.

Host: Well then, can you share a clinical example where understanding a patient's food intolerances or allergies played a key role in the treatment process?

Guest: Absolutely. When someone presents to my clinic for symptoms concerning for a true food allergy, as I explained earlier, those patients warrant a very specific workup. So when someone comes into my clinic and they say, "Every time I eat shrimp, I get this feeling of like I'm going to pass out" or they develop vomiting or swelling or hives, that patient would then get skin testing to that specific food that is causing those symptoms. And we would sometimes also do blood testing as well if indicated and then the treatment and the management going forward, if the skin testing confirms the diagnosis, would actually be strict avoidance of that food. And we would also provide that patient with EpiPens, which are epinephrine autoinjectors, which are used for the treatment of anaphylaxis, and we would provide that patient with what we call an emergency action plan that details when and how to use that EpiPen. And this is actually a completely different management and workup than if someone comes into my clinic with symptoms more concerning for a food intolerance or food sensitivity.

So, those patients often will not have a trigger pinpointed. And as I discussed earlier, a lot of times those patients will have specifically isolated gastrointestinal symptoms, although sometimes we also see people report other symptoms that are not consistent with the food allergy as well after eating certain foods like perhaps headaches or feeling kind of fatigued or acne. But the workup for patients that have isolated GI symptoms, we typically will tell them to keep a food diary. And so, a food diary is when a patient keeps track of what they ate and when. And then, the patient can start to see a pattern in their diet as it relates to their adverse gastrointestinal symptoms.

The most common example of this is actually something that most people have heard of, which is called lactose intolerance where a patient notices these adverse GI symptoms like diarrhea or bloating after they eat a large amount of dairy. And once they keep a food diary and they see that pattern, they can actually either try avoiding large amounts of dairy or they can try taking a Lactaid pill beforehand and then, that tends to help delineate what could be potentially causing those symptoms.

And for patients that have widespread GI symptoms to multiple foods, sometimes we recommend that they see a gastroenterologist specialist for further workup and management. So, the treatment for these two entities is quite different.

Host: Well, it certainly is. So, as we're talking about at-home food sensitivity tests for patients that want to know and for the general public that kind of does it outside the healthcare system, discuss the potential drawbacks and limitations of using these.

Guest: So, the biggest limitation and drawback of these tests is that they're actually not based on any real scientific evidence. To be clear as possible, they are inaccurate. So in medicine, we provide recommendations based on good evidence, which comes from robust scientific studies. And so, I mentioned earlier about how when someone has a true food allergy, it's actually due to an inappropriate immune response to a food protein in which these patients make an antibody, which we call an allergic antibody called immunoglobulin E or IgE for short to that implicated food such as peanut or to a shellfish such as shrimp, for instance.

Most of these food sensitivity tests that are advertised on the market claim to provide helpful information. But in reality, most of them are actually checking for the presence of an antibody called immunoglobulin G or IgG antibody for short to these various foods. And this antibody is actually not an allergic antibody at all. This antibody is actually your memory antibody. So in reality, any food that you have ever eaten can come back with a positive IgG antibody level, which is not surprising because again, this is your memory antibody, and these tests are not based on any robust scientific studies. Instead, these tests have never been scientifically proven to be able to detect what they claim to be able to do. In fact, the leading organization of allergists called the American Academy of Allergy, Asthma and Immunology of which I am a part of, actually recommends against using these tests to diagnose any food intolerances, sensitivities or food allergy. And the real reality here is that at this time, there is no testing available for these reported sensitivities and intolerances.

Host: Well then, how do you see the use of these, Dr. Watts, impact an individual's health and diet? Because using them without that scientific background could really make somebody choose or not choose certain foods.

Guest: You are correct. And this is a really great question, because I think especially in this day and age, there's this assumption that more testing is always better, right? And that the more information a patient can get, the better their health will be. But what I want to really highlight and stress here is that these food sensitivity and intolerance tests really can be harmful to patients due to their inaccuracy. And overall, these tests can and do negatively impact a patient's diet. And I would say the same thing as well for indiscriminate food IgE or immunoglobulin E testing as well, or food panels as some would call them. We discourage running food panels even when the patient does not have a history concerning for true food allergy. We discourage running any food panels when a patient does not have a clinical history concerning for a true food allergy. And that's because there is a high rate of false positives in these tests. And in order to diagnose a food allergy, we really take a focused history and do guided testing based solely on the patient's clinical presentation.

The reason I know that these tests can be harmful is because I've seen many patients come into my clinic after they have either taken these nebulous food sensitivity or intolerance tests or indiscriminate IgE food panels, and these tests always inevitably come back saying something that the patient is positive to, right? That this patient is sensitized to some various foods, usually multiple foods, including foods that many of these patients have actually been eating fine and tolerating in their diet and some foods that the patients have actually been enjoying. And this adds a lot of confusion for these patients. And then, these patients come and make an appointment with an allergist and they're afraid to eat foods, they're afraid that they're eating foods that are leading to their symptoms, because it's hard to remove a lot of these foods from their diet. And then, these patients end up being on very restrictive diets, which can lead to increased anxiety, can lead to malnutrition. And so in reality, these tests can actually be quite harmful.

And additionally, I've also seen these tests lead to a delay in the accurate diagnosis for some of these patients because a lot of these patients may have adverse GI symptoms to various foods. And then, you know, they do these tests. And then, they come in and they're so frustrated and confused. And after taking a really good history, some of these patients actually fit the clinical presentation for other clinical conditions such as irritable bowel syndrome or IBS or lactose intolerance. And we end up giving them the proper recommendations or end up referring them to see a gastroenterologist where they can actually get the proper recommendations for their symptoms.

Host: Such an interesting issue we're discussing here today, Dr. Watts. The general public may see these at-home tests like food sensitivity tests as an avenue to more accessible healthcare. And knowing what we know about these less reliable options, what steps can be taken to ensure that those with limited access to healthcare aren't relying on these inaccurate at-home tests for food intolerance or allergies? And please, while you're answering that, tell us what you see as better avenues to more accessible allergy and asthma testing and treatment, some better options for providers to discuss with their patients, both in office and at home.

Guest: This is a really great question and I think this is really especially an excellent question because, ultimately, we still have a lot of work to do in medicine as a whole to make access to care more equitable for everyone. And I really do think that the lack of access to good healthcare really helps to fuel the ability for so much misinformation out there, especially like misinformation about these food insensitivity or intolerance tests, for instance.

And so, I think one of the key strategies here in helping to limit people falsely relying on these inaccurate testing is to get out the word to the general public and, quite frankly, all physicians and other healthcare providers, that these tests are not recommended, right? That the specialists, allergists who take care of and diagnose people with food allergies, our organization, actually strongly advises against using these tests. And as I alluded to earlier, many of these patients initially present to a non-allergist, so sometimes they present first to an emergency room or a primary care physician's office or another type of physician. And so, I think just getting the word out that these tests are not advised and that they're not helpful, I think that's one of the big steps that we can make.

And while we continue to work on improving health equity and equal access to all physicians and specialists, including allergist immunologists, I think one of the best ways to get this important information out is using alternative avenues to spread accurate information. And one of the best ways to do this, I think, are doing things like what we're doing right now, right? This podcast.

Also, I think one of the things that we saw with the recent COVID-19 pandemic is that social media is a really powerful platform. And while I think it definitely has been used to spread a lot of misinformation, I think that clinicians can use these same forums and platforms to combat misinformation by just putting out actual, accurate, evidence-based information for other clinicians as well as our patients too. So, I think just putting out the information that these tests are inaccurate, that we don't advise them, that we don't recommend them on places like Twitter and Instagram and Facebook and blogs and articles and news forums, I think all of these can be helpful.

In thinking about other avenues to try to improve access to people with limited access, I think one of the silver linings that came out of the recent COVID-19 pandemic was the increased utilization and benefit of telemedicine. So, I think that that has really helped, especially patients that may live in communities that an allergist may be too far to drive or not as accessible. I think using telemedicine, in those situations to even just have a conversation sometimes to quell a patient's concerns about whether they meet the clinical criteria possibly for a food intolerance or food sensitivity versus a food allergy can be super helpful.

So, I think ultimately we have a lot of work to do, but I think there are some tools, that us, as clinicians, can use to try to spread the information out more to the general public as well about these inaccurate tests.

Melanie Cole, MS: I agree with you completely. That is just so interesting. Thank you for joining us today, Dr. Watts, and really telling us about these tests that not a lot of people may have heard about, but such an important aspect for providers to discuss with their patients. So, thank you so much again. And to refer your patient or for more information, please visit our website at breakthroughsforphysicians.nm.org.

That wraps up this episode of Better Edge, a Northwestern Medicine Podcast for physicians. I'm Melanie Cole. Thanks so much for joining us today.