food sensitivity testing

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Before you buy food sensitivity testing, you need to hear this because so many people are harmed by these tests. For one thing, food sensitivity testing is touted as a miracle, cure-all answer for skin rashes. So when you take the test, cut out the foods, and your rash is still flaring up — it can leave you feeling really lost and even hopeless that things will ever change.

AND for many, food sensitivity tests trigger food fear that drives unnecessary diet restrictions that do more harm than good negatively impacting not just your physical health, but also your mental well-being.

That’s not a great place to be.

And then there’s the fact that these tests are expensive. So, if you fork out the money for one of these food sensitivity tests, and you don’t see the results you were hoping for, now you’re out of hope and you’re out a serious bit of money too which could have been better spent on other tests which are more helpful.

Especially since food sensitivity testing CAN’T identify root cause problems triggering skin rashes or flare-ups.

That’s why today, we’re diving into food sensitivity, what results mean for your rash, and asking the big question, “Does food sensitivity testing work?”

And because it’s so common to have low stomach acid when you struggle with skin rashes – especially if you suspect that your rash is triggered by the foods you eat — be sure to try my completely free DIY Low Stomach Acid Test before you do anything else. This simple at-home test can help put you on the right track!

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In This Episode:

  • What’s a Food Allergy Vs Food Sensitivity Vs Intolerance?
  • What exactly is food sensitivity testing, anyway?
  • Are food sensitivity tests accurate? My answer might surprise you!
  • Hair Vs Blood Food Sensitivity Test — Which Is better?
  • Can you become sensitive to a food you eat daily? (like eggs?)
  • Leaky gut + your skin rash: What’s the connection?
  • How to reintroduce a food after an elimination diet
  • What I recommend instead of food sensitivity testing


“The problem is that food sensitivity tests are not accurate. There’s little evidence to support the idea that IgG testing can uncover food sensitivities. In fact, both the American Academy of Allergy, Asthma, and Immunology and the Canadian Society of Allergy and Clinical Immunology warn against using food sensitivity tests as diagnostic tools.”

“Food sensitivity testing results are highly changeable depending on your current diet. So it’s not uncommon to see all of your favorite foods that you eat daily show up as moderate or even high food sensitivities leading you to think that they are now bad for you.”


different foods people may or may not be sensitive to

321: Food Sensitivity Testing {FULL TRANSCRIPT}

Welcome back to episode 321 of the Healthy Skin Show! In today’s episode, I’m going to talk about the problems with food sensitivity testing, elimination diets, and how they may not be helpful in stopping your skin rash.

I did a deep dive on food fear and elimination diets in episode #305 that you don’t want to miss. You can check it out HERE.


Food Sensitivity Rash: Is It A Real Thing?

There’s so much confusion when it comes to rashes and food triggers.

And it makes sense. There’s an overabundance of information online — from “wellness gurus” to Facebook groups full of skin rash warriors looking for answers and making claims based on what has (and has not) worked for them. It makes it hard to distinguish fact from fiction.

I totally appreciate the idea that “food is medicine” and that diet does play a role in your health. So I can certainly understand why the idea of cutting out certain offending foods to potentially heal your skin rash is so alluring.

Why? Because the idea of having a rash triggered by food sensitivities means that you can control your rashes simply by manipulating what you eat. Therefore, if you can change what you eat daily, you then have the power to control your skin and health.

I have to be honest – this line of thought is HIGHLY problematic (and I’m going to lay out why).

To be clear, I’m not saying I’m against changing your diet, or using food as a tool to improve your skin or health. Food absolutely plays a role in your health and the health of your skin. Nutrients are tools that your body requires as much of what is derived from food (and even supplements) is not something your body makes. The lack of these tools creates stress in your body which now can’t operate optimally.

So when you nourish your body with protein, fiber, healthy starches, vitamins, minerals, antioxidants, and fatty acids… in time, your skin can respond because your cells have the tools they need to thrive.

At the same time, it is equally possible that certain foods could be problematic for your particular case. An example of that would be having an IgE allergy or an intolerance to that food (more on this in a moment).

As a clinical nutritionist, I find that generally people overly rely on food being THE problem. And often do so to their detriment because they think that it’s the only thing left to change or control.

BUT food isn’t always the answer to your skin rash puzzle. For one thing, you may be attributing your flare to a food when really, it’s something else happening at the same time that you can’t quite piece together.

I’ve shared many times that food is just ONE of sixteen root causes that trigger skin issues.

What many people claim is a food sensitivity is actually the result of your gut’s inability to process the food correctly. (I call this gut dysfunction.)

It can also be a sign that your liver’s detox capacity is struggling because of a LACK of specific nutrients it requires to process certain things (ie. salicylates).

Also, it can be a sign of a gut microbiome imbalance as foods interact with this complex ecosystem.

AND to make matters even more confusing – any combo of these issues I just shared could be going on simultaneously. So it’s often not just ONE problem.


woman with food allergies

Food Allergy Vs Food Sensitivity

Before we go any further, this is a good time to clarify — food sensitivities are not food allergies.

I realize that people often use the terms “food sensitivities” and “food allergies” interchangeably, but it’s highly inaccurate (even if your practitioner described it to you, mixing up the terms).

Don’t be confused by the similarity in terms here. A food allergy is most commonly referring to an IgE-mediated immune response that for some can be potentially life-threatening (like when someone has a peanut allergy and they need to carry an epi-pen).

A food sensitivity refers to an IgG immune reaction to a food that may cause less severe symptoms. However, this will never result in the need for an epi-pen or death due to anaphylaxis.


man with lactose intolerance

Food Sensitivity Vs Intolerance

Also — food sensitivities are not the same thing as food intolerances.

Food intolerances are a reaction to a particular component of food due to a lack of an enzyme in your body that is required to process that food.

The most common example is lactose intolerance – where you can’t eat dairy containing lactose in high quantities because your body has low or no lactase enzyme production.

I would categorize this more as a “gut dysfunction” issue since enzyme production is part of your body’s digestion process.

And therefore, a food intolerance is also not the same thing as a food allergy either.

So you can see that these are three very distinct issues that are the result of very different problems in your body.


Woman thinking about food sensitivity testing

What Is Food Sensitivity Testing?

So, with all of this buzz online about food sensitivity testing, tons of people started sharing their experiences about cutting out foods saying things like, “I cut out nightshades and cured my rash!”

Because you aren’t satisfied with the results based on your doctor’s recommendations or want to do things more naturally – the concept of food sensitivities and cutting out various foods (or entire food groups) that worked like magic for someone else caught fire.

Many nutritionists and other practitioners started labeling certain foods as “bad” and they claimed that foods could elicit an IgG response to the partially undigested food proteins that slip in between gut cells and enter your body — thereby triggering an IgG immune response that could, in theory, trigger inflammation that causes various conditions and health complaints.

And this is where the food sensitivity testing industry was born – with LOADS of money behind it marketing directly to you and your frustrating symptoms.

These companies claim that their tests can measure your body’s IgG response to certain foods and tell you which ones to avoid — and then all of your problems will be solved once you eliminate said foods from your life.


food sensitivity testing in lab

Are Food Sensitivity Tests Accurate?

The problem is, food sensitivity tests are not accurate. In fact, there’s little evidence to support the idea that IgG testing can uncover food sensitivities. Both the American Academy of Allergy, Asthma, and Immunology and the Canadian Society of Allergy and Clinical Immunology warn against using these food sensitivity tests as diagnostic tools. (1,2)

What’s more, food sensitivity testing results are highly changeable depending on what you are currently eating. (3) So it’s not uncommon to see all of your favorite foods that you eat daily show up as moderate or even high food sensitivities leading you to think that they are now bad for you.

Also, these food sensitivity tests can produce some really weird results, telling you you’re sensitive to things you’ve never eaten before. I’ve seen this so many times in my clinical practice that I’ve lost count.

AND what’s even more misleading are those daily foods you commonly consume that got flagged on the test. If you follow through and remove them, you shouldn’t be surprised that a repeat test in a few months will likely show that you are no longer reactive to them.

BUT you’ll also discover that you’re now “sensitive” to the foods in the new diet plan you’ve been following. This then increases your list of foods to restrict and puts you on that slippery slope to disordered eating.

How frustrating, right?

This shift in results happens because the IgG markers for these daily foods present in your blood are just a normal response to eating that particular food.

And if a bunch of foods do show up as moderate and/or high sensitivity foods, the results should potentially be viewed more as a sign of leaky gut (more formally known as gut permeability) than anything else. The foods themselves do NOT cause leaky gut (more on this in a moment).

So these tests — and the restrictive diets they encourage needlessly contribute to food confusion, food fear, nutrient deficiencies, and can potentially lead to developing IgE anaphylactic allergies to foods that are removed from your diet.

Plus, there’s also the chance of masking an eating disorder under the guise of “healthy” or “clean” eating, which is especially significant if you have a past history of an eating disorder or disordered eating.


woman with long hair

Hair Vs Blood Food Sensitivity Test — Which Is Better?

One type of food sensitivity test that is THE WORST and most pointless is the type that uses a hair sample.

This is such an utter waste of money because, despite all the marketing promises that you can tell food sensitivities from hair, it’s simply untrue.

Tests that require a piece of hair are by far one of the biggest scams out there.

I get a lot of questions from listeners wondering if I recommend the hair food sensitivity test and could build a protocol from it – the answer is NO.

The same goes for the blood test for sensitivity from food.

I very much understand wanting to get to the root causes, but neither of these tests will tell you root causes. So if you’re going to spend the money on something, I’d rather see you use it on testing that can actually help you rather than waste it.

I realize that many wellness experts promote these types of food sensitivity tests and offer coupon codes – and that’s a red flag that the test you’re buying is not a clinical lab and won’t actually be useful if you’re serious about a root cause approach.


eggs and salad

Can Eating A Food Daily Make You Sensitive To It?

When I did a food sensitivity test back in 2008, my nutritionist at the time told me that I had become very sensitive to eggs because I ate them every day.

This pervasive myth still is alive and well despite the fact that this is NOT TRUE.

You do not become “sensitive” to foods or “intolerant” of them because you eat them often (even daily).

Nor can you make yourself sensitive to something by eating it so frequently. The underlying issues that cause some level of sensitivity include gut permeability (aka. Leaky gut) which is typically triggered by some combination of gut dysfunction and gut microbiome imbalances.

While removing the foods might reduce symptoms (if you even have any), it will not make your gut less leaky. And it won’t fix the issue.

So no – you can’t “heal leaky gut” simply by eliminating foods since it doesn’t address the underlying reason your gut became leaky in the first place.


woman with leaky gut

Leaky Gut Skin Rash Connection

There’s a lot of confusion too when it comes to leaky gut. And there definitely is a leaky gut skin rash connection!

But I’d like to clarify — when it comes to skin rashes leaky gut isn’t a root cause – you have to dig deeper than that. As I already shared, it is true that a “leaky gut” can increase your reactivity to certain foods.

Leaky gut triggers include:

  • gut microbiome dysbiosis (an unfriendly group of gut bugs)
  • gut dysfunction (ie. low stomach acid, low digestive enzyme output, slow motility/constipation)
  • chronic frequent NSAID use
  • gluten exposure (with tolerance to gluten being lost)
  • unmanaged stress or trauma, and high-intensity exercise/workouts

There’s also some interesting information that’s come out on the connection with glyphosate exposure in the food supply also potentially being a player.

This is why blaming food and solely focusing on ONLY eliminating foods isn’t the best nor most effective approach (unless you’ve got a confirmed IgE allergy). It’s crucial to identify and address these actual root cause issues.

Because again – you can’t heal a leaky gut simply by avoiding certain foods.


reintroducing foods after elimination diet

How To Reintroduce Food After Elimination Diet

Now, it’s important to mention…even if you do find that you have a food sensitivity, the plan cannot be to just stop eating those foods for the rest of your life.

Overstriction of your diet for longer than 3 to 6 months can cause a significant drop in nutrient intake as well as diet diversity (which also causes a drop in gut microbiome diversity).

It can also make you afraid to reintroduce those foods!

And, if you’ve strictly removed one or more of the top 9 allergens for about a year or more, it’s best to work with an allergist using an Oral Food Challenge for reintroduction. Unfortunately, we are seeing more individuals developing allergic reactions to these foods who have strictly eliminated them for around a year or more.

In fact, we’ve had 2 clients in the past year who this has happened to. They were not previously allergic or sensitive to the foods as they removed the foods based on advice from a Facebook group. Upon reintroduction, they developed a severe allergic reaction now requiring an epi-pen.

Also — if your diet is becoming more limited because you feel like you’re becoming increasingly sensitive to everything, you need to seek help from a qualified nutrition professional. This is something we offer in my practice to help guide clients back to a much more diverse diet while addressing skin issues with a root cause approach.


Scientist doing food sensitivity test in lab

Why There Is No Best Food Sensitivity Test

Again, I do not recommend food sensitivity testing. We don’t EVER ask clients to get this type of testing. I’d rather you spend money on a good stool test rather than on any type of food sensitivity testing (including the MRT).

Bottom line: food sensitivity test companies take advantage of your vulnerability as well as influencers who promote them. The promise of waking up without a rash you’ve been living with for so long is powerful. When you’re struggling like this, you’ll happily bypass any doubts about effectiveness or price because you want so badly for it to be true.

As a clinical nutritionist who has helped thousands of clients worldwide with chronic skin issues – food sensitivity testing at home isn’t a worthy investment. Especially when you consider that the science is SUPER shaky for these tests, and that following the results will not heal “leaky gut” since food sensitivities aren’t a root cause problem.

One final point – if a practitioner recommends food sensitivity testing, ask what the benefit would be, how long they plan on having you eliminate them, AND if they plan to guide you through the process of reintroducing foods.

It’s my belief that if a practitioner recommends any sort of food elimination (especially based on these tests), they are responsible for helping you reintroduce the foods with a definitive plan – not just tell you to “add these back into your diet.”

Reintroducing foods is an actual process. It’s not a skill most people know how to do (unless they have that sort of training), especially once you develop a fear of the food.


digestive enzyme supplements

What I Recommend Instead Of Food Sensitivity Testing

At the end of the day, I don’t find food sensitivity tests helpful and they only add to food confusion/food fear and potentially disordered eating. Plus, the cost of food sensitivity tests is ultimately a waste of money which could be better spent on other tests that are clinically relevant.

Instead of a food sensitivity test, here’s where I recommend starting when it comes to uncovering the root cause of your rash:

  1. Test your stomach acid especially if you suspect that your rash is triggered by the foods you eat (like animal proteins) — try my completely free DIY Low Stomach Acid Test before you do anything else. This simple test can help put you on the right track.
  2. Add in an appropriate digestive aid before each meal. Digest Aid or Digest Aid Plus (with betaine HCl) is often helpful in making sure that foods are properly broken down.
  3. Consider getting a clinical stool testing for a much more comprehensive and helpful skin rash diagnostic tool. Since there are so many stool test options out there, check THIS out so you get the right one.

I hope this clears up any misinformation about food sensitivity testing and gives you some better options instead!

Now I’d love to hear from you in the comments below – what are your questions or experiences with food sensitivity testing?



food sensitivity testing

Jennifer Fugo, MS, CNS

Jennifer Fugo, MS, CNS is an integrative Clinical Nutritionist and the founder of Skinterrupt. She works with women who are fed up with chronic gut and skin rash issues discover the root causes and create a plan to get them back to a fuller, richer life.

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