Pollen counts are rising and more of us are experiencing hay fever symptoms than ever before. From airborne allergens to the food on our plates or the chemicals and plants that touch our skin, around 40% of the global population has some form of allergic disease. By 2030, today’s guest reveals, 50% of us will be affected.
Professor Theresa MacPhail is a medical anthropologist and writer, who made it her life’s work to understand more about allergy after her father died following a bee sting. Her book Allergic: How Our Immune System Reacts To A Changing World, is a detailed, enlightening look at the history of allergies and their growth in line with the industrial revolution.
Why are allergies on the rise? Why is it that 200 years ago allergies barely existed, yet today they are in our pets and farm animals? We talk about what actually happens to cause the release of histamine - which is responsible for many of our allergic symptoms. Theresa also covers the main historical theories as to the cause of allergies from the ‘hygiene hypothesis’ to the ‘farmhouse effect’ and the ‘old friends theory’.
What we do know is that allergies occur in the interaction between humans and our environment. Our environment has changed so much over the past 200 years and our immune systems simply cannot keep up. Theresa explains the body’s three main barriers to infection and allergy – our skin, respiratory system and gut. When these barriers are damaged, they become more porous and can let unwanted molecules into our bodies – causing infection, inflammation, or allergy. And what’s damaging them is things like air pollution, diesel fumes, chemicals, antibiotics, to name just a few.
We cover the practical steps we can take to mitigate allergies but there are much wider societal issues that need addressing as well. Theresa explains that we are part of a bigger ecosystem - our bodies are continually making decisions on what they can tolerate and what they can’t. We can try our best to build up our own barriers to tolerate more of the modern environment but the uncomfortable truth is that we collectively have a lot more to do to protect each other and the natural world.
This is a deep dive into a very important topic. My hope is that anyone suffering from allergies will feel seen, and anyone lucky enough not to, will gain more empathy and understanding. I hope you enjoy listening.
*Please note that this conversation refers to studies on mice.
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30 to 40% of the global population have some form of allergic disease.

But all the experts I spoke to said it's easily going to be 50% in the next decade.

So as countries move into the middle class and upper class, they tend to get more disease.

So it really is the richer you get, the more problems you have.

Ron Gonchategee and this is my podcast, Feel Better, Live More.

This summer is already proving a tricky 1 for people who suffer with hay fever.

Pollen counts are rising and more of us are experiencing symptoms than ever before.

From airborne allergens to the food on our plates, or the chemicals and plants that touch our skin, around 40% of the global population has some form of allergic disease and this week's podcast guest reveals that by 2030 that number will be 50%.

Teresa Macphail is a medical anthropologist and writer who made it her life's work to understand more about allergy after her father died following a bee sting.

Her book, Allergic, How Our Immune System Reacts to a Changing World, is a detailed, enlightening look at the history of allergies and their growth in line with the industrial revolution.

Why is it that 200 years ago allergies barely existed, yet today we're even seeing them in our pets and farm animals?

Well these are some of the questions we try to address in this week's conversation.

Now Teresa starts off talking about our immune systems and explains what actually happens to cause the release of a chemical called histamine, which is responsible for many of our allergic symptoms.

She also covers the main historical theories as to the cause of allergies, from the hygiene hypothesis to the farmhouse effect and the old friends theory.

Each 1 offers us a potential part of the explanation, but none of them in isolation are able to explain at all.

What we do know is that allergies occur in the interaction between humans and our environment.

And our environment has changed so much over the past 200 years that our immune systems simply cannot keep up.

Teresa explains that the body has 3 main barriers to infection and allergy.

Our skin, our respiratory system and our gut.

When these barriers are damaged, they become more porous and can allow unwanted molecules into our bodies, causing infection, inflammation, or allergy.

And what's damaging these barriers is modern life.

Things like air pollution, diesel fumes, chemicals, antibiotics, to name just a few.

So what can we actually do to mitigate this?

Well, of course, we try our best in this conversation to cover the practical steps we can all take.

But it's not just an individualized approach that we need.

There are much wider societal issues that need addressing as well.

You see, talking with Teresa, what shone through most was the fact that we are all part of a much bigger ecosystem.

We're basically in constant conversation with the world around us.

Our bodies are continually making decisions on what they can tolerate and what they can't.

Yes, on an individual level, we can all try our best to build up our own barriers so that we can tolerate more of the modern environment.

But the uncomfortable truth is that we all collectively have a lot more to do to protect each other and the natural world.

I think this was a wonderful, thorough, deep dive conversation into a very important topic.

My hope is that anyone suffering from allergies will feel seen and Anyone lucky enough to not will gain more empathy and understanding.

So it's 30 to 40% now, but all the experts I spoke to said it's easily gonna be 50% in the next decade.

So we're just gonna continue seeing a rise.

And partially that's because it tends to track with socioeconomic status.

So as countries move into the middle-class and upper-class, they tend to get more allergic to disease.

So as some countries are stabilizing, so the United States, the UK, there's constant rates, but in places like India and China, they're just playing catch up.

So their numbers are growing exponentially.

50% of the world's population in the next decade are gonna have some form of allergic

And for me, Like when I think about allergies, when I think about this beautiful book that you've written, you've done a really deep dive into the history, what we know, what we don't know, but it strikes me as though the topic of allergies, the rising rates of allergies, really says something quite profound about us as humans and us as humans and our ability to live in harmony or disharmony with our environment.

I mean, 1 of the fascinating things is the immune system is so old.

So evolutionarily speaking, it's 1 of the first biological systems to develop.

So mass cells, which are 1 of the main components of the immune system, they're about 500 million years old.

So organisms, mammals developed an immune system to cope with their environment.

So we've co-evolved with the things in our environment for literally millions of years.

And within the past 200 years, we've changed things to the extent that that old system, so the system that we have to cope with our environment hasn't kept up with the changes that we've made to our environment.

So I like to say that it's almost as if we're running Windows 95 in a 2023 world where we have to run all of these apps and there's no possibility for an upgrade because your immune system, it's fairly fast evolutionarily speaking, but it's not as fast as the changes that we're making.

Mass cells being 500 million years old, that is quite something.

I mean, I guess we should explain at this point what a mast cell is.

You've also mentioned the immune system in relation to the topic of allergies.

So I wonder if we could maybe at this point just go back to basics and go, what's the relationship between the immune system and allergies?

And then maybe unpick the immune system a little bit and explain innate, adaptive, what a mast cell is.

Because I think that'd be really useful right at the top.

So there are basically your immune system is 2 systems working side by side and they overlap in their function but your innate system is Older so that is mass cells and basophils.

So white blood cells who are the first line of defense basically.

And like I said, the 500 mils, 500 million years, we think for mast cells.

So it developed first and it's called innate because it's online from the time of your birth.

And it's basically a system that responds pretty much similarly to everything.

So it's there if something is entering us that is harmful or otherwise shouldn't be there, it clicks on and either sends out things like macrophages or something to like eat whatever is in us that shouldn't be there to rip it apart, to get rid of it, to consume it, to eject it.

The adaptive immune system is newer, so to speak.

And that is the system that remembers things.

So that is, it's called adaptive because it adapts to whatever situation that it's dealing with.

So those are the antibodies that will remember, say the SARS coronavirus.

So it remembers a part of that, takes a snapshot of it, and then creates cells specifically matched to that thing.

And so when they come across it again, they remember it, so to speak, and can put into play a response much more quickly.

So the more times that you see something, the more reactive those cells get.

So the innate immune system or the innate part of the immune system, something we're born with, it's very, very old.

I think that's what we often say when we're talking to patients is, you know, it, yeah, it has a few tools, has a few ways of dealing with things.

And as you say, it uses things like macrophages and mast cells, which of course are really important for allergies.

I think natural killer cells also are part of the innate immune system.

And these things I think people, you know, I think it's useful for people to understand that you're born with it.

So I guess as a kid or as a, I don't know, let's say you're 4 weeks old and you're exposed to a bug, it's likely that your innate immune system is gonna be the 1 that kicks in.

Whereas this adaptive 1 is, I guess what gets tuned up through life as well through our exposures, doesn't it?

And in terms of the adaptive immune system and allergies, What's the relationship?

Because mast cells are behind a lot of the symptoms and allergies.

But that's from your innate immune system.

Yet, often in the book, you're talking about the adaptive immune system in relation to allergies.

So can you help tie that together for us?

Sure, I mean, I should say that the innate system is good for most things.

So the innate system will still kick in in your adulthood when you're exposed to something like a virus.

And so the adaptive system kicks in if whatever you've come into contact with has escaped the innate system.

So if it usually like sitting here right now, our innate systems are just keeping us healthy and fine.

So it's a situation where something's been able to evade the innate system and then the adaptive system kicks in, so to speak.

So it's kind of like the secondary mechanism that kicks in.

And that is the 1 that is driving some of the allergic reactions via the antibodies.

So there are 5 different antibodies that your body makes and they all have different jobs, so to speak.

And the 1 that we're most interested in with allergies is called IgE.

And that is the 1 that's behind most allergic reactions, though not all, it's tricky, because there are some allergies that are not mediated by IgE.

So the definition of what an allergy is can get really tricky really fast, especially if you're tying it to that IgE.

Like my father died of a bee sting, but technically speaking, allergy to bee venom is not IgE mediated, it's the innate system.

So it gets really tricky really fast when you dive into it.

Yeah, that's something you made, I think, really clear towards the start of the book that a lot of these different esteemed allergy experts have kind of different ways of looking at allergies, different definitions.

And I think that's a theme that that comes through the book very nicely is that this is a complex issue.

There's a combination of different factors.

Which I think's useful to keep in mind because we are living in a culture now where we want quick fixes and quick answers and what's gonna get rid of my allergies?

We're definitely going to get to treatments later on in this conversation, but I think it's really important to understand what these allergies are.

Now, we've mentioned how prevalent they are.

You know, in the next 10 years, it's going to be half of us are going to have some form of allergy.

Some people, it's unpleasant at certain times of year, yet other people, like your father, end up dying from allergies.

So I wonder if you could, if you're open to it, explain what happened to your dad and also then relate that to this continuum and maybe to the innate and adaptive system if you feel it's appropriate.

So I guess what I'll start with is the basic mechanism.

So I mentioned these IgE antibodies and a lot of us have heard the metaphor that our immune cells, our antibodies, or our T cells specifically are the policemen of the body.

So T cells are just a class of white blood cells that circulate throughout the body, looking for things that shouldn't be there or suspicious activity, I guess you can say.

And so in that way, they are kind of like policemen patrolling a neighborhood, but what they do is they'll come across something like a virus or an oak pollen.

And if they decide it shouldn't be there, what will happen is they'll take a snapshot or almost like a protein signature fingerprint of that thing.

But then they take it to another class of cells called B cells, another type of white blood cell.

I like to think of them as the store managers or the nightclub managers on the street.

And so it's basically, hey, this neighborhood is under threat.

Here's a picture of the perp, please be on the lookout.

And then the B cells are producing the antibodies.

And so I like to think of IGE as a bouncer, that they're there at the door to these neighborhoods, these different stores, nightclubs, and their job is to decide who gets to come in and who has to stay out.

And, but if you think of it this way, every bouncer or every security guard has only 1 picture.

And so at any entrance, you're going to have maybe, depending on what you've been in contact with, that your body has remembered that it needs to take care of, you'll have 50, 100 bouncers, and they're all looking for their 1 thing.

But the problem is, like say the description is, oh, this person is 5, 7, dark hair, light eyes.

A lot of things are gonna look like that, which is why often we'll get cross reactivity.

So you might be allergic to 1 tree nut, but you're actually going to probably be allergic to more than 1 because they're all in the same family.

And then they turn on the mechanism of let's get this out of here.

And I guess the nightclub turns into a very unpleasant experience because then they're signaling to other cells, hey, we've got a problem.

And it starts that system in play, which is driven by histamine.

So what happened with my father is partly driven by just his innate cells.

So mast cells are basically the drivers, the conductors, if you will, of this whole orchestra of things that happen.

It's just a chemical compound that your cells use to signal other cells when they are damaged or stressed.

And they are signaling to cells in their neighborhood that there's a potential threat, that something is happening.

And so the cells that receive the histamine signal will send out histamine as well.

So it's a bit like those nuclear reactions, the ping pong.

We've all seen the video of someone throwing a ping pong into the mousetrap ping pong room.

And before you know it, the whole room is just exploding.

So the histamine is the ping pong ball and it just sets off everything around it.

And so what histamine ends up doing in the body is it produces all of our symptoms fairly, yeah, most of our symptoms.

So histamine will drive your mucus production, which is why we get congested and runny nose and eyes.

In my dad's case, he was stung in the neck.

So it's swelled his neck tissue, which was not great for breathing, but it also histamine can constrict your muscles around your lungs, which is what happens during an asthma attack.

So when the muscles tighten, it gets harder to take a full breath of air.

But then histamine is also dilating your blood vessels.

And there's a good reason for that, because it makes it more permeable, so all of those first responders of the immune system can get somewhere quickly.

But the other effect of that is it crashes your blood pressure.

So as your blood vessels dilate, it just makes it harder to get blood to your heart.

So it can send people into a cardiac event, which is what happens a lot of the time during anaphylaxis, if you don't stop that histamine reaction.

And your dad, I believe, died within 30 minutes of that sting.

So if you don't control a severe reaction and you're going into an anaphylactic reaction you have about 30 minutes before someone dies.

Okay, now let's just pause there because I want this to be an empowering conversation.

So you know, if we're saying that almost half of us are going to be allergic to something, you have outlined, and thank you for sharing the case of your dad's, a very severe episode of allergy, right?

But most people, I think, are not going to experience it at the same level.

So, you know, because a lot of people will recognize some of those symptoms, okay, swelling, itchiness, maybe a bit of tightness.

And there's other things with your dad's story that I think are really really interesting and insightful when we think about the history of allergy and the history of treatment in that, if I remember rightly from the book, his girlfriend at the time drove him to a pharmacist or a drug store and an EpiPen was there, I believe, but it wasn't administered, is that right?

They had adrenaline on hand because of course, you know, they're a pharmacy, but the laws at the time, pharmacists weren't allowed to dole out the medicine on their own.

Without a prescription, he couldn't do anything.

His hands were tied, so he couldn't give the adrenaline.

And that's possibly because, I mean, of course, like say it looks similar to a heart attack at the end stages when you're going into the cardiac event.

And if you give someone who's having a heart attack adrenaline, that's the exact wrong thing to do and you're gonna make it worse.

And so he was just, he thought he knew what was happening.

I mean, It was obvious that he had been stung, but just legally he was afraid to give my dad the treatment, but also at the time, so this was 1996.

And it's important to note that date because in the United States, the explosion of food allergies really only started in the 1990s.

So now I think a lot more people are prepared and there have been laws put in place that people have to have access to adrenaline.

And so you would be able to find 1 more quickly, but then there weren't any mandates.

So if you were an ambulance company, you didn't necessarily have to have an EpiPen available in your cab.

So in 1996, ambulances in America would not necessarily have an EpiPen.

that is, I guess that really speaks to this whole issue, which is how quickly allergies have exploded.

30ish years ago, under 30 years ago, and ambulance maybe would not carry an EpiPen.

Right, yeah, it would have, I mean, perhaps some people were definitely carrying it.

So there were people with severe allergies that would have had a prescription for something like an EpiPen, but it wouldn't have been to the extent.

So prescriptions for EpiPen have just quadrupled over the span of 30 years.

So I think the last statistic I saw was about 5 million Americans have a prescription for an EpiPen.

It's interesting because that is not who fills them.

So about 85% of people who are given a prescription fill it.

And some people just never even fill the prescription.

Do you ever reflect and think, had that pharmacist given your dad an EpiPen, what might've happened?

Or if that ambulance company had had the access to the adrenaline, but they didn't so all they could do was stabilize him.

So they were trying to keep his heart stabilized, they were giving him chest compression Once he started into the cardiac event, they were trying to stabilize his vitals.

But after that, when you've reached that point, it's very hard to stabilize your system, especially outside of the hospital.

So the survival rates, if you can get to a hospital within 30 minutes are quite good.

But it's that key time where you need to halt the reaction in time.

EpiPens do that wonderfully, which is why we have mandated that they be in schools in the US.

So every grade school and middle school and high school has to have a pen on hand.

And we have mandated, although the United States is interesting.

So some states have mandated that all ambulances have to have them, but there are still states where they leave it up to the discretion of whoever is running the service.

Yeah, I mean, there's some wider cultural and ethical issues, I think, around allergies as a whole, which you, which you, which you do talk about in the book and we'll hopefully talk about later on today.

But you know, that's, it's, it's really, really interesting.

I mean, how I know you start the book with that story about your dad's, it's clearly a big driver for you to go and explore this topic.

Was there frustration and anger for a while that an EpiPen was not given?

It was not administered when it was actually there?

No, it's strange because I was so young, I was only 24 at the time.

And it was just such a shock that to be honest, I didn't really think about those things until later, until I started researching the book, I never really questioned why there wasn't something on hand.

It was just such a shocking thing to get that phone call that he had passed away.

And otherwise, I mean, he had a few underlying health issues, which is obviously part of this story.

So he had a little bit of heart issue anyway.

So obviously if you have underlying issues and then you go into anaphylaxis, it's much harder.

I mean, it's so, I basically just thought about that and I was terrified of bees for the longest time.

Still am not, I mean, I love that they're pollinators and I support bees, but at the same time I do not like to be in the vicinity of a bee.

So let's just make it super practical then for someone who's hearing this or watching and thinking okay well I've had a bee sting before and had a bit of a reaction but you know I was okay And then they're hearing the story about your father dying within 30 minutes of a bee sting.

Have you got anything to say that's gonna help them feel better?

Because what I don't want is people on the back of this to be panicked about everything in life, go, wow, allergies on the rise, I could die at any moment, right?

And so I think we need to be just mindful of that.

Most people are not gonna have that reaction to a bee sting.

So the population will have that reaction.

So if you're stung by a bee or a wasp, your chances of dying are so slim.

I think in the last 5 years, it was 60 people total.

It's a little bit bigger in globally simply because a lot of people don't have access to things like EpiPens everywhere.

They have to be stored at a constant temperature.

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#374 Why Allergies Are On The Rise with Professor Theresa MacPhail