Episode 96: Understanding Food Reactions: Why Foods Affect People Differently

One of the central goals of the Autoimmune Protocol is figuring out which foods work for you and which ones don’t. But when a symptom appears after eating a food, what actually counts as a food reaction—and does every reaction mean the same thing?

In this episode of the Autoimmune Wellness Podcast, Mickey Trescott explores the science of food reactions and why they can look so different from person to person. She breaks down the major categories of reactions, including food allergies, celiac disease and non-celiac gluten sensitivity, digestive intolerances, and reactions to specific compounds in foods.

Mickey also explains why a reaction and its underlying mechanism aren’t necessarily the same thing, and why that distinction matters when personalizing your diet. She explores how dose, timing, preparation, digestive function, and other factors can influence food tolerance, plus why a reproducible reaction can still provide useful information even when science can’t yet explain exactly why it happens.

In this episode, you'll learn:

• The many ways a food reaction can show up, including changes in autoimmune symptoms
• The difference between a food reaction and its underlying biological mechanism
• How food allergies, celiac disease, food sensitivities, and digestive intolerances differ
• Why dose, timing, preparation, and digestive function can influence food tolerance
• How compounds like histamine and sulfites can trigger symptoms in some people
• Why meaningful food reactions can occur even when we don’t fully understand the mechanism
• Why food reactions can be difficult to identify when symptoms fluctuate
• How AIP elimination and reintroduction help identify the foods that work for you

Resources:

• The Autoimmune Protocol: theautoimmuneprotocol.com
• The New Autoimmune Protocol by Mickey Trescott

Episode Timeline:

00:00 – Understanding what constitutes a food reaction

03:24 – What can a food reaction actually look like?

07:29 – Food allergy: When the immune system reacts to food

15:22 – Gluten reactions: Celiac disease and non-celiac gluten sensitivity

21:54 – Food intolerances: When digestion and absorption are the problem

27:35 – Reactions to compounds in food: When it isn’t the food itself

35:37 – Why food reactions can be so hard to figure out

40:06 – Bringing it back to AIP: Finding the foods that work for you

42:06 – Wrap-up and closing

One of the central goals of the Autoimmune Protocol is figuring out which

foods work for you and which ones don't.

That's really what the elimination and reintroduction process

is designed to help us do.

We create this period of consistency, pay attention to how our symptoms

respond, and then systematically bring foods back in so that we can build

the broadest, most nutrient-dense diet that supports our individual health.

But there's a question underneath that whole process that we

don't talk about nearly enough.

What exactly constitutes a food reaction?

Sometimes it's obvious.

You eat a food, and within minutes, you develop hives or swelling.

Sometimes it's digestive.

Maybe you drink some milk, and a few hours later, you're bloated.

You have some cramps.

You might be running to the bathroom.

But in the autoimmune community, we also hear about reactions

that are much harder to explain.

Somebody who eats tomatoes and notices that they have

more joint pain the next day.

Somebody who reintroduces eggs, and their skin breaks out or has a flare.

Somebody eats a food that they thought they tolerated and then wakes up with

fatigue and brain fog, maybe a return of the symptoms that they associate

with their autoimmune disease.

Are all of these food reactions?

Potentially, but they aren't necessarily the same kind of reaction, and we don't

always know what's happening biologically.

That's what makes this topic so important for anybody who's using AIP.

If we're going to use an elimination and reintroduction protocol to personalize

our diets, we need to understand what we're actually looking for and

what we can and can't conclude when a symptom appears after we eat a food.

Welcome back to the Autoimmune Wellness Podcast.

I'm your host, Mickey Trescott, and as always, this podcast is for

educational purposes only and is not a substitute for individualized medical

advice, diagnosis, or treatment.

Today, we're going to dig into the science of food reactions.

Now, the term food reaction covers a lot of territory.

There are food allergies.

There are autoimmune reactions like celiac disease.

There are digestive intolerances and problems with absorption.

There are also reactions to specific compounds in foods, and then there are

symptoms that people associate with particular foods where we don't have a

well-established biologic explanation, and I'm going to get into that.

So today, I want to give you a framework for making sense of all of this.

We'll talk about the different symptoms food reactions can cause,

the medical conditions that can be responsible for them, which of

these conditions can actually be diagnosed and tested for, and where

the science becomes much less certain.

And one idea that I want you to keep in mind throughout this episode is

that a reaction is what we observe, and a mechanism is why it happened.

Sometimes we get the opportunity to know both.

Sometimes we only know the first.

And when we're using AIP to make decisions about which foods belong

in our long-term diet, understanding that difference is really important.

So before we get into the different mechanisms behind food reactions, I

want to spend some time talking about what a reaction can actually look

like because that spectrum is actually much wider than people realize.

When we hear the phrase food reaction, we might immediately think of something

dramatic and obvious, like hives or swelling after eating a food.

We might think of digestive symptoms like bloating, abdominal pain, diarrhea.

Those absolutely can be considered food reactions, but they are

not the only possibilities.

Depending on what's happening in the body, a food reaction can involve

the digestive system, the skin, the respiratory system, the nervous

system, or symptoms that are much more systemic or across the whole body.

Those digestive symptoms can include things like bloating, gas, abdominal pain

or cramping, nausea, reflux, diarrhea, constipation, or changes in bowel habits.

Skin symptoms can include hives, itching, flushing, rashes, eczema, or swelling.

Respiratory symptoms can include congestion, sneezing, coughing,

wheezing, or difficulty breathing.

Other people might experience headaches or migraines, dizziness, fatigue, brain

fog, changes in energy, disruptions to their sleep, mood changes, joint pain

or stiffness, or muscle and body aches.

And I wanted to be really comprehensive about this because there really is

a wide spectrum of what people can experience as food sensitivity reactions.

And there's another category that is really important for those of us

with autoimmune disease, and that is simply a flare or worsening of

our primary autoimmune symptoms.

It's something that sometimes can be missed when you're doing

reintroductions because you might be looking just for something new instead

of a change in a familiar symptom.

So somebody with rheumatoid arthritis might notice an

increase in their joint symptoms.

Somebody with inflammatory bowel disease might notice a return of GI symptoms

like bowel frequency or bleeding.

Somebody with a skin-related autoimmune condition might notice

their skin beginning to flare.

So for another person, it might actually just feel like a cluster

of symptoms that they associate with their disease starting to return.

I'm thinking of people with Hashimoto's, that has very nebulous symptoms, right?

So I just want to validate how broad that experience of

suspected food reactions can be.

You don't need to develop hives or have this immediate digestive

response for an observation to be worth paying attention to.

And one of the reasons we track symptoms during AIP reintroductions is that

this might show up somewhere very different from your digestive tract.

It might look different from person to person.

Our reintroduction guidance intentionally asks people to watch for this wide range

of changes, including the digestive ones, the skin ones, aches and pains,

and even things that you might not associate, like your energy levels,

your sleep, your mood, headaches, and the return of autoimmune symptoms.

At the same time, recognizing a possible food reaction isn't the same as knowing

exactly what caused it or knowing why it happened, and that's really important when

we're talking about symptoms like fatigue or brain fog, headaches, joint pain.

These symptoms can fluctuate for many reasons, even when

nothing in your diet has changed.

So we're not dismissing symptoms because it doesn't fit our preconceived idea of

what a food reaction should look like.

We're not assuming that every symptom that follows a meal must have been

caused by something that we ate.

But recognizing the symptom is the first step.

The next question is, what might actually be causing it?

Because two people can experience symptoms after eating the exact same

food and have completely different things happening in their bodies.

Now let's start looking at some of the different mechanisms that can cause

food reactions, beginning with the one that most people are familiar with,

and that's going to be food allergy.

A true food allergy involves the immune system reacting to something

in a food that would normally be harmless, and the type most of us think

of is an IgE-mediated food allergy.

IgE is a type of antibody involved in allergic reactions, and when somebody with

an IgE-mediated allergy eats the food that they are allergic to, the immune system

can respond very, very quickly, often within minutes, although timing can vary.

Symptoms usually include things like hives, itching, flushing, maybe

swelling of the lips, tongue or throat, vomiting, diarrhea, coughing,

wheezing, difficulty breathing, or even a drop in blood pressure.

And in severe cases, a food allergy can cause anaphylaxis,

which is a medical emergency.

Some of the most common food allergens include milk, eggs, peanuts, tree nuts,

fish, shellfish, wheat, soy, and sesame.

And if you have a food allergy, you likely already know about it because

of the extreme reaction that it gives.

But even within food allergy, reactions don't always look the way that we

expect them to, and there are a couple interesting examples I want to talk

about because they challenge some of the assumptions we make about how an

allergic food reaction should behave.

The first is alpha-gal syndrome, which is an allergy to a sugar

molecule called alpha-gal that's found in most mammalian meat.

What's really unusual about alpha-gal is that it can develop after a tick

bite, and in the United States it's most strongly associated with the lone star

tick, although other ticks have been implicated in other parts of the world.

Somebody can have previously eaten beef, pork, or lamb without any

problem, and then develop this allergy after being bitten by a tick.

And alpha-gal breaks another rule we tend to associate with food allergy.

The reaction is usually delayed.

Instead of eating something and then developing those symptoms within

minutes, somebody might eat a hamburger at dinner and then develop hives

and those GI symptoms, swelling, difficulty breathing, or maybe even

anaphylaxis several hours later.

That delay can make the connection incredibly difficult to recognize,

and a lot of people don't think about what they ate hours earlier,

especially if it's a food that they have eaten their entire life.

Another type of food allergy I really want people to know about is pollen-food

allergy syndrome, which you might also hear called oral allergy syndrome.

And if you have seasonal or pollen allergies, I want you to pay

particular attention to this one because it is surprisingly common.

Pollen-food allergy syndrome happens because of something

called cross-reactivity.

Your immune system has made IgE antibodies against a protein in a

particular pollen, but those proteins in certain fruits, vegetables, and nuts

are structurally similar enough that those antibodies recognize them too.

This is especially common in people that have a birch pollen allergy.

Estimates vary quite a bit between studies and population, but pollen

food allergy syndrome can affect a substantial proportion of people that

have pollen allergies, and some studies suggest around half or more of people

with birch pollen allergy experience it.

So here's a classic example that I have seen in my practice time and time again.

Somebody with a birch pollen allergy bites into a raw apple and almost

immediately their lips, their mouth, or their throat start to itch or tingle.

Maybe there's even a little bit of swelling.

The reaction might be mild and disappear fairly quickly, so

they might not even recognize it.

But here's a really interesting clue.

If they take the apple and they cook it, there is no reaction.

So they can have applesauce, they can eat baked apples, but it's just the

fresh raw apple that causes the reaction.

The same thing can happen with carrots, and I actually have a family

member for whom this happens to.

Somebody might tell you raw carrots make my mouth itch, but I eat cooked ones

all the time and I'm completely fine.

That is just so weird, right?

That's because many of the proteins involved in pollen food

allergy syndrome are heat labile.

Cooking changes the structure of the protein enough that the immune system may

no longer recognize it in that same way.

There's also a seasonal component to these reactions too.

Some people find that their food reactions are worse during the time

of year when their pollen allergy is activated and triggered by all of the

pollen that is in the environment.

So if you have significant allergies and you notice that your mouth

suddenly gets itchy when you eat certain foods, particularly if you

then tolerate those foods when they're cooked, that is a really useful clue.

Different pollen allergies also have a different pattern of cross-reactivity.

So birch pollen is associated with foods like apple, carrot, peach,

cherry, pear, celery, and some nuts.

Ragweed can cross-react with foods like melon and banana.

And there are other pollen food relationships as well.

Most pollen-food allergy syndrome reactions remain localized to the

lips, the mouth, and the throat.

They're usually pretty mild, but more significant reactions can occur, so

we don't want to automatically assume that every reaction is harmless.

If somebody ever gets throat swelling, difficulty breathing, or reactions

that are beyond the mouth, and other concerning symptoms, you definitely

want to get evaluated by an allergist.

And I think this is especially useful in the context of AIP because a lot

of these foods we're eating, right?

If you have a birch pollen allergy, you've been eating carrots, and then

you start getting an itchy mouth, you might start to get confused about

foods, especially fruits and vegetables that we're told to eat, and wondering

why we're having a reaction to them.

The issue is actually not the carrots or the plum or the peach, it's actually

your allergies that are causing that issue, and you might need to modify to

cook or try things in a certain time of year that it might be better for you.

This is a great example of how understanding a mechanism behind a food

reaction can sometimes help us expand our diet rather than just restrict it further.

There are also non-IgE-mediated and mixed immune-mediated food reactions, which can

look quite different and might be delayed.

So conditions like food protein-induced enterocolitis syndrome, or FPIES

and eosinophilic esophagitis, or EoE, are examples of recognized

medical conditions in which foods can play a role, but the mechanism and

diagnostic process are different from that classic immediate food allergy.

Now, I don't want to get too deep into each of these individual conditions

because the larger point is this: even within medically recognized

food allergy and immune-mediated food reactions, symptoms can look different,

timing can be very different, and appropriate testing can be different.

And this is why I want to draw a clear line between what we're doing

with AIP in reintroducing foods and investigating a suspected food allergy.

If a food has caused hives, significant swelling, difficulty breathing,

fainting, or any of these, like, very allergic reactions, it's not a food

you should challenge yourself with at home just to see what happens again.

That is absolutely a situation to discuss with your healthcare

provider or your allergist.

And from here we're going to move into another food-triggered immune

condition that is really important for the autoimmune community, but

it actually isn't an allergy at all.

It's celiac disease, and the broader question of how people react to gluten.

Gluten deserves some special attention in this conversation

because reactions to gluten are really relevant in the autoimmune community.

There is more than one way that somebody can react to gluten-containing

foods, and the condition we tend to understand best is celiac disease.

Celiac disease is sometimes casually described as a gluten allergy or

gluten intolerance, but neither of those descriptions are accurate.

Celiac disease is an autoimmune disease, and in somebody with celiac, eating

gluten, which is a group of proteins found in wheat, barley, and rye,

triggers an immune response that damages the lining of the small intestine.

And the symptoms of celiac disease can be really varied.

Some people have classic GI symptoms like diarrhea, abdominal pain,

bloating, nausea, or weight loss.

But celiac can also cause symptoms outside of that digestive tract,

including iron deficiency anemia, fatigue, headaches, bone or joint pain,

mouth ulcers, neurological symptoms, and certain skin manifestations.

And some people, myself included, have very few noticeable

digestive symptoms at all.

This is a great example of why we need to think broadly about food reactions.

A food-triggered reaction doesn't necessarily show up in the digestive

tract, even when the small intestine is central to the disease process.

Celiac disease is something that has an established process for testing.

The diagnostic process generally begins with specific blood tests looking for

antibodies associated with the disease, and in many cases, an intestinal biopsy

is used to confirm the diagnosis.

But there's this very frustrating catch.

With our current standard testing, you generally need to be eating

gluten for the testing to be accurate.

This is really relevant for anybody considering AIP.

Because gluten-containing grains are eliminated on both Core and Modified,

if you suspect gluten is contributing to your symptoms and you haven't been

evaluated for celiac, it's important to talk to your healthcare provider

about testing before you go gluten-free.

Now, there is some really interesting research happening here as well.

Researchers are developing new approaches to diagnosing celiac in people who

are already on a gluten-free diet without requiring the traditional

weeks-long gluten challenge.

That could be a enormous improvement because for somebody who has been

gluten-free and feels dramatically worse when they eat it, going back on

gluten for weeks just to get an accurate diagnosis can be a really big barrier.

These newer tests aren't yet a replacement for the current standard

diagnostic process, but I'm really hopeful that we will see a validated

option become clinically available.

It would solve a real problem for people who eliminated gluten

before realizing they should have been tested for celiac disease.

And knowing whether you actually have celiac disease actually does matter.

For someone with celiac, gluten isn't simply a food that just doesn't

work during reintroductions, right?

Strict lifelong avoidance is the treatment for the underlying autoimmune disease.

But celiac disease is not the end of the gluten story.

There's also a condition known as non-celiac gluten sensitivity,

or NCGS, sometimes referred to as non-celiac wheat sensitivity.

This describes people who experience symptoms after consuming gluten-containing

foods but don't have celiac disease or that IgE wheat allergy.

And I want to emphasize this because people in this category

have sometimes felt very dismissed.

Non-celiac gluten sensitivity is a real clinical phenomenon.

The fact that we don't have a single laboratory test that can diagnose it does

not mean that your symptoms are not real.

And in my own clinical experience, this has been a major player

in the autoimmune community.

I have seen so many people who don't meet that diagnostic criteria for

celiac but experience meaningful and reproducible changes in how

they feel when gluten-containing foods are removed and reintroduced.

And again, we're not just talking about digestive symptoms.

People with non-celiac gluten sensitivity might report bloating, abdominal pain,

diarrhea or constipation, but also fatigue, headache, brain fog, joint or

muscle pain, skin symptoms, and other symptoms outside of the digestive tract.

And for somebody with autoimmune disease, what they notice might simply be a

worsening or flare of the symptoms they already associate with their condition.

Where things get more complicated is when we ask why is this happening.

Unlike celiac, we don't currently have a specific biomarker or a

standalone diagnostic test for this non-celiac gluten sensitivity.

It's generally identified after celiac disease and wheat allergy

have been excluded, and there's a consistent relationship between

eating gluten and your symptoms.

And we're still learning what component of those foods is actually responsible.

For some people, it might be the gluten itself, but wheat contains other compounds

that can produce symptoms in some people.

One important example is fructans, which are fermentable

carbohydrates in the FODMAP family.

Other components of wheat have also been investigated.

So if somebody consistently feels worse when they eat gluten-containing foods,

that improves when they are removed, and then experiences the same symptoms when

they're systematically reintroduced, that is extremely useful information about

that person's tolerance, even if their celiac testing is negative, and we can't

tell them exactly why they're reacting.

Again, this is so important in the autoimmune community.

We do not want to make the mistake of saying that everybody with autoimmune

disease needs to avoid gluten forever.

But we also don't want to make the opposite mistake of assuming that if

somebody tests negative for celiac, gluten or wheat couldn't possibly

be contributing to their symptoms.

So there is a lot of territory between those two positions.

Now let's move into another major category of food reactions,

and that is food intolerances.

Unlike food allergies, food intolerances generally do not

involve an allergic immune response.

Instead, symptoms can happen because we have difficulty digesting or absorbing

a particular component of a food.

Because maybe the amount of that food that we're eating or because

our digestive system simply isn't equipped to handle that food well

at the particular time in our life.

The classic example is lactose intolerance.

Now, lactose is a sugar naturally found in milk, and we need an enzyme

called lactase to break it down.

If we don't produce enough lactase, lactose can pass into the colon

undigested, where it's fermented by bacteria, which causes uncomfortable

bloating, gas, abdominal pain, cramping, and sometimes diarrhea.

There are other carbohydrates that can cause similar problems.

Some people have a difficulty absorbing fructose, for example,

and a larger group of fermentable carbohydrates, commonly referred to

as FODMAPs, can cause significant digestive symptoms, particularly

in people with irritable bowel syndrome or small intestine bacterial

overgrowth, otherwise known as SIBO.

Another food that can cause an intolerance due to digestion are beans and legumes.

They contain fermentable carbohydrates called galacto-oligo-saccharides or GOS.

Again, gut microbes ferment some of those carbohydrates and fibers,

producing gas in the process.

And for somebody who isn't accustomed to eating much GOS who suddenly eats

this large serving of beans, or who has a particularly sensitive digestive

system, that can mean, again, a lot of bloating, gas, cramping, or

changes in their bowel movements.

Those reactions are real.

But now that you guys know the difference between an immune and a digestive

reaction, you now know that it doesn't necessarily mean that you're always

having an immune reaction to the beans, or that the beans are an inflammatory

food that you need to avoid forever.

It just means that your system could not tolerate the type, quantity,

or preparation that you ate.

Another example here is just fiber in general.

We generally want a diverse intake of fiber because they play important

roles in digestive and microbiome health, but increasing fiber too

quickly can absolutely cause symptoms.

And some people with certain gastrointestinal conditions might

find particular types or amounts of fiber difficult to tolerate,

especially during a flare.

I'm thinking of the members of our community who have

inflammatory bowel disease like Crohn's or ulcerative colitis.

Now, the same principle applies to fat.

Certain quantities or types of fats can cause nausea, abdominal

discomfort, urgency, or diarrhea.

And fat digestion may be especially challenging for somebody who has

had their gallbladder removed or who has a condition that affects

their bile production or flow.

The gallbladder normally stores and concentrates bile and

releases it in response to a meal to help with fat digestion.

And without a gallbladder, bile is still produced by the liver, but its

delivery into the intestine is different.

Some people do perfectly well after their gallbladder removal, while others find

that larger amounts of fat, especially all at once, trigger digestive symptoms.

There can also be problems with digestive enzymes.

The pancreas produces enzymes we need to digest fat, protein, and carbohydrate,

and certain pancreatic or gastrointestinal conditions can result in insufficient

enzyme production or activity, leading to poor digestion and symptoms after meals.

So if somebody says, "Every time I eat a specific food, I get diarrhea,"

it is tempting to conclude that they are sensitive to that specific food.

But the more useful question might be, is something interfering with

their ability to digest that meal?

This is an important distinction for those of us using AIP because

elimination can sometimes make it really easy to attribute every symptom

specifically to the particular food.

If you reintroduce beans and you experience significant bloating, that

is very useful information, right?

You didn't imagine it.

But that experience alone doesn't tell us whether you have a intolerance to

beans, whether the serving was too large, whether your digestive system needed time

to adapt to the specific fiber, whether those fermentable carbohydrates were

contributing, or whether an underlying digestive issue needs attention.

And that's why dose and context matter.

You might tolerate half a cup of a food, but not two cups.

You might tolerate a gradual increase in fiber, but not a sudden one.

You might tolerate small amounts of fat spread out through the day,

but not one very high-fat meal.

And tolerance can change as digestive function and underlying

health conditions change.

So again, the message isn't that the symptoms that you're having

aren't reactions to the food.

They could absolutely be reactions to eating a particular food.

The distinction is that the food itself might not be the fundamental problem.

Sometimes what we're observing is the interaction between the food

and your current body's capacity to digest, absorb, and process it.

So we've talked about food allergy, gluten-related conditions, and problems

with digestion and absorption, but there's another category of food reactions

that can be particularly confusing.

Sometimes a person might be reacting to a compound within the food

rather than the food as a whole.

These reactions can produce real symptoms, but they aren't necessarily allergies, and

they don't all involve the immune system.

My first example is caffeine.

Caffeine is a stimulant, and people vary tremendously in how

they metabolize and respond to it.

One person can drink several cups of coffee and feel absolutely fine, while

another might experience a racing heart, shakiness, anxiety, digestive urgency, or

insomnia from a relatively small amount.

Alcohol is another example.

Alcohol itself has physiological effects, of course, but alcoholic beverages

also contain or interact with other compounds that can cause symptoms.

So wine, for example, can contain histamine, sulfites,

and other fermentation products.

So when you tell me, "I react to wine," there can be several

different explanations for what you might be experiencing.

So let's talk about sulfites.

They're naturally present in some foods and beverages and

are also used as preservatives.

Some sensitive people can experience reactions, and sulfites are particularly

known for provoking respiratory symptoms in people with asthma.

And then we have histamine, which I want to spend just a little more

time on because this is an area where understanding the mechanism

can actually give us clues about what else might be going on.

Histamine is a normal signaling molecule that our bodies make.

We talked about it earlier in the context of food allergy, where mast cells release

histamine as part of an allergic reaction.

But histamine is also present naturally in food, so anything that is aged, fermented,

cured, or stored tends to accumulate higher levels of histamine, things like

aged cheeses, cured meats, fermented vegetables, wine, beer, and certain fish.

Normally, dietary histamine is broken down in the intestine, particularly by

an enzyme called diamine oxidase, or DAO.

The theory behind histamine intolerance is that some people have a reduced

capacity to break down dietary histamine.

If the amount of histamine coming in exceeds their body's ability to

metabolize it, they can develop symptoms across multiple body systems: bloating,

abdominal pain, diarrhea, constipation, headaches, flushing, itching, hives, nasal

congestion, dizziness, or a racing heart.

And here's the part I think is especially interesting.

Histamine intolerance might sometimes be a clue rather than the end of the story.

So why isn't a person breaking down histamine effectively?

There can be a genetic component.

Variations in genes related to DAO have been associated with differences in the

production or activity of the enzyme.

But reduced DAO activity can also be acquired because DAO is

produced in the intestinal mucosa.

So conditions that affect the health of the small intestine might

interfere with the body's ability to degrade histamine effectively.

I'm thinking people with celiac and Crohn's disease, right?

Certain medications can interfere with DAO as well, and there's also emerging

research looking at whether changes in the gut microbiome, including greater

abundance of histamine-producing bacteria, could contribute.

This is where something like SIBO, or small intestine bacterial

overgrowth, becomes relevant.

If somebody suddenly develops what looks like histamine intolerance along

with significant digestive symptoms, I don't necessarily want them to

conclude, "I can never eat fermented foods again." I want to know whether

there is an underlying GI issue that needs to be identified and treated.

In our AIP troubleshooting guidance, this is exactly why persistent

digestive symptoms can warrant evaluation for conditions such

as SIBO or histamine intolerance, rather than simply layering more and

more dietary restrictions onto AIP.

And I think it's a much more useful way to think about histamine intolerance.

Sometimes reducing high-histamine foods can be an effective tool

for managing your symptoms.

But particularly when the problem is acquired, the long-term goal should

be also to ask why histamine tolerance is impaired in the first place.

Another thing that makes histamine intolerance tricky is that we don't

currently have a single validated laboratory test that definitively tells

us if somebody is having histamine intolerance, and those symptoms

overlap with a lot of other conditions.

So this is another area where working with a knowledgeable healthcare provider,

maybe an AIP Certified Coach, to rule out other explanations can be really valuable.

And then there are other compounds in foods that have been proposed as

explanations for different reactions, things like oxalates, salicylates,

lectins, alkaloids, and others.

And this is where we need to be careful not to jump from a plausible

biochemical theory to a claim that hasn't been demonstrated in people.

Nightshades are a perfect example, and obviously a very relevant one for AIP.

Tomatoes, peppers, eggplant, white potatoes are all excluded in both Core

and Modified AIP elimination phases, and over the years, one of the reactions

I've heard reported most often in our community is an increase in joint pain

or stiffness after reintroducing them.

And we actually do have some research showing that this isn't

just something that people in the AIP community talk about.

Patients with inflammatory bowel disease and rheumatoid arthritis have reported

nightshades among foods that they experience as worsening their symptoms.

Now, what we don't have is good evidence telling us what compound in

the nightshades is responsible for those reported reactions, or even whether

there is a single compound responsible.

You'll hear a lot of possible explanations about glycoalkaloids, lectins, capsicum,

or other constituents of nightshades, and there are some interesting hypotheses

and mechanistic research around some of these compounds, but that's not the same

as demonstrating that the particular compound is what causes the individual

with rheumatoid arthritis to experience more joint pain after eating tomatoes.

And to me, that's not a reason to dismiss this observation.

If somebody reintroduces tomatoes and their joint pain increases, removes

them, they return back to baseline, and then experiences the same thing

when they challenge it again, that is such useful information, right?

And at the same time, we shouldn't take the individual experience, or even the

fact that this pattern has been reported by so many autoimmune patients, and

turn it into this universal statement that nightshades are inflammatory

for people with autoimmune disease.

We just don't have the evidence to support that claim.

And that brings us back to one of the central ideas of this episode.

A reaction is what we observe.

A mechanism is why it happened.

Sometimes we know both.

Sometimes, as with histamine, understanding the possible mechanism

might even point us towards an underlying problem that deserves attention.

And sometimes, as with nightshades and joint pain, we have this

meaningful observation, but we don't yet have a good explanation for it.

And all of this is also why food reactions can be so difficult

to sort out in the real world.

Dose, timing, preparation, what else we ate, and what was happening in our bodies

that day can all change the picture, and that's where I want to go next.

By now, we've covered a pretty wide range of food reactions.

Some have mechanisms that we can understand well and diagnose medically.

Others are much harder to explain.

But even when you know what kinds of symptoms you're looking

for, there's another challenge.

How do you know that the food actually caused them?

Our autoimmune symptoms don't exist in a vacuum.

They can be influenced by sleep, stress, infections, hormonal changes,

medications, how much exercise you got that day, and all kinds of other factors.

So if you eat eggs on a Tuesday and wake up with rash on Wednesday,

the timing is interesting.

It doesn't always prove that eggs caused the rash.

This is where we need to start looking for patterns, and timing

is one piece of that pattern.

Some food reactions happen very, very quickly.

With that IgE-mediated allergy, for example, symptoms appear within minutes

or a few hours, which makes that connection really easy to identify.

But many of the reactions that people report during AIP

reintroductions are delayed.

Maybe your digestion changes later that evening.

Maybe you don't notice the joint pain, fatigue, or change in your

primary autoimmune symptoms until the following day or even the day after.

The longer the time between eating the food and experiencing the

symptom, the harder it becomes to confidently connect the two.

Now, dose can also change the picture.

As we talked about with digestive intolerances, tolerating a small amount

of a food doesn't necessarily mean you're going to tolerate a large amount,

and sometimes frequency matters, too.

You might tolerate something occasionally, but notice symptoms

when you begin eating it every day.

I have this experience personally with eggs.

Food tolerance isn't necessarily an on/off switch.

Preparation can also matter.

So raw versus cooked, peeled versus unpeeled, fermented versus

unfermented, soaked or sprouted.

How a food is prepared can change its composition and digestibility.

That means the eventual answer might not be, "I tolerate this," or, "I don't

tolerate that." It might be, "I tolerate this food in this amount, prepared this

way, in this frequency." Like somebody who doesn't tolerate raw cabbage,

but sauerkraut works for them, right?

And then there's everything else happening at the same time.

We don't eat foods in a laboratory.

We eat meals, we travel, we go to restaurants, we have stressful weeks.

And if you eat five gray area foods you haven't had in months, maybe you have a

little bit to drink, you stay up late, and you wake up feeling terrible the

next morning, good luck figuring out which variable was responsible, right?

And this brings me to what I think is the biggest challenge in identifying

food reactions in autoimmune disease.

You need this reasonably stable baseline in order to recognize a change.

If your symptoms are changing dramatically from one day to the next, it's going

to be really difficult to tell whether a particular food made a difference.

This doesn't mean your symptoms need to disappear.

It doesn't mean you need to achieve remission before you can learn

anything about how diet can help you.

What we're looking for is enough consistency that

change becomes noticeable.

There's also one more factor we don't talk about enough.

Our expectations can influence how we perceive symptoms.

So if you've been told for years that nightshades are inflammatory for people

with autoimmune disease, you're probably going to pay very close attention to

every ache and pain after eating a tomato.

And if you get that reaction, it might be related to the food.

If you remove that food, return to your baseline, eat it again under

reasonably controlled circumstances, and the same distinctive symptoms return,

that becomes much more interesting.

And if you keep getting a repeat of that pattern, now you've

gathered useful information about your individual tolerance.

Now, you might not know whether that's because of a particular compound

in the tomato, an immune pathway we haven't identified yet, or something

happening in your digestive tract.

And for making a practical day-to-day dietary decision, you don't

necessarily need to know, right?

And this is exactly why the Autoimmune Protocol is structured the way it is.

So let's bring all of this back to AIP and talk about how elimination

and reintroduction can help us answer the question we started with.

Which foods actually work for you?

So what does all of this mean for somebody using the Autoimmune Protocol?

We've spent this episode looking at just how varied food reactions can be.

Some are medically diagnosable conditions with mechanisms we understand fairly well.

Others are reproducible reactions where the mechanism is much less clear.

And we've seen how things like dose, preparation, timing, digestive function,

and even what's happening with our health at the particular moment can influence

whether or not we tolerate a food.

This is exactly where the structure of AIP can be useful.

The elimination phase gives us this period of dietary consistency.

We are temporarily removing a defined group of foods while emphasizing

nutrient density and the lifestyle factors that support health with the

goal of establishing a clear baseline.

But elimination is not the destination, right?

Reintroduction is the central part of the process.

This is where we begin to systematically bring foods back

in and ask the big question, which foods actually work for me?

And importantly, we're not trying to prove that the foods that we eliminated

are bad or universally inflammatory.

In fact, successfully reintroducing a food is a great outcome.

Every food we can comfortably bring back has the potential to add nutritional

variety and dietary diversity, but also affordability, convenience, cultural

connection, flexibility, and enjoyment.

A more expansive diet is generally easier to sustain over the long term.

And this is one of the reasons I made reintroduction such a strong

focus in the new Autoimmune Protocol.

The elimination phase was never intended to become a permanent diet.

The goal is to use what we learn during elimination and reintroduction to build

the least restrictive nutrient-dense diet that supports our individual health.

And that raises a pretty obvious question.

Wouldn't it be easier if we could just take a test and find out

what foods we're sensitive to?

There are plenty of tests that claim to do exactly that.

So in the next episode, we are going to dig into food sensitivity

testing, including IgG panels, MRT, ALCAT, and other approaches.

We'll look at what these tests are actually measuring, what the

research says about their accuracy and usefulness, and more importantly,

whether they can really tell us which foods are causing our symptoms.

Take care.

I'll see you in the next episode.