March 19, 2026 • 51 mins
This week, Emily and Perry dive into the here, there, and everywhere of microplastics. We know they're in the air we breathe and the water we drink, but how bad are they for us, really? How do our bodies respond to them, and how long do they even stay inside us? And can they be avoided?
Plus: Leucovorin approved to treat autism, whether ChatGPT is a trustworthy triage nurse, and curious reports of painful sex in college students.
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Episode Transcript
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Speaker 1 (00:01):
Emily, I have a very important and very difficult challenge
for you today.
Speaker 2 (00:06):
I'm ready.
Speaker 1 (00:07):
I am going to give you a word and you
have to tell me. You have to distinguish whether this
is a type of plastic or a spell from the
Harry Potter universe. Okay, are you ready?
Speaker 3 (00:21):
I'm actually I know a lot about Harry Potter, so
I think I'm going to be really good at this.
Speaker 1 (00:25):
Okay, but do you know a lot about plastics. Let's
find out.
Speaker 2 (00:29):
Less that I know about Harry Potter. But I'm optimistic.
Speaker 1 (00:31):
All right, let's try it first. One Avi Foor's plastic incorrect.
That is a Harry Potter spell that transforms objects into birds.
What let's try on evalka spell? Sorry. That is a
type of plastic ethylene vinyl alcohol copolymers that's used in
food and medical packaging. How about loupital That is a
(00:55):
spell that is a plastic thermoplastic. It's used in automotive, electronic,
and medical devices. You're not doing too well, but you're
gonna pull it out here. Langlock spell. That is a spell?
Speaker 4 (01:10):
Yes, nice, it is a jinx that makes you unable
to speak langlock okay, grillamid plastic very good, a high
performance nylon used in sporting goods.
Speaker 1 (01:22):
Two more Vectra plastic awesome liquid crystal polymer for thin
walled electronics and aerospace applications. And lastly Ferula plastic. That
is a spell. It is a bandaging charm if you
are wounded. Point being there's a lot of plastics out there.
Speaker 3 (01:46):
I thought your point was going to be I'm terrible
at this, but thank you for making a point more neutral.
Speaker 1 (01:52):
You know you might need a bandaging charm after that performance.
But yes, I wanted to bring this up because plastics
are everywhere. They are ubiquitous, they are in all the
products we use, and of course, according to recent research,
they are also inside of us.
Speaker 3 (02:11):
And we're going to find out whether that's actually a
problem when we do our deep dive later today.
Speaker 1 (02:15):
Microplastics stick with us.
Speaker 2 (02:20):
I'm Emily Oster, I'm an economist and a data expert.
Speaker 1 (02:23):
And I'm Perry Wilson, I'm a medical doctor.
Speaker 3 (02:25):
It's Thursday, March nineteenth, twenty twenty six. And this is
wellness actually.
Speaker 1 (02:31):
Because you're getting a staggering amount of health and wellness
information nowadays from every source imaginable, and some of it
is awesome and.
Speaker 2 (02:39):
Some of it is well actually both.
Speaker 3 (02:43):
Fortunately we're both people who know how to read studies,
how to parse the data, and can tell you what's
worth thinking.
Speaker 2 (02:50):
About and what you can safely ignore.
Speaker 1 (02:52):
But before we dig in, a note that this podcast
is for educational purposes and should not be construed as
medical advice. We don't know your unique situ, so talk
to your doctor for personal health decisions.
Speaker 3 (03:03):
This week, we'll ask life in plastic is it fantastic?
As we explore what's the deal with microplastics? Perry and
I will give the official smasher pass, and then we'll
get to your question of the week. But first, let's
do the health news roundup after the break.
Speaker 1 (03:32):
Okay, welcome back. This week in health news, Emily, I
want to start with the FDA. You may remember back
to that infamous press conference on autism where President Trump
appeared and said that pregnant women should avoid taking seenomnifin
or tail and all because it causes autism. At that
(03:53):
same conference, FDA Director Marty McCarry said that a therapy
might exist called lucovorren, which, according to him quote could
benefit twenty forty fifty percent of kids with autism. You know,
that's a huge number and a huge statement to make
for a therapy that's already FDA approved for other indications.
(04:15):
It's available, it can be bought today. Well as of
a couple of days ago, the FDA did indeed approve
Luca worn, but for an incredibly rare genetic condition that
limits the delivery of folate to the brain. Fully it's
a form of B vitamin. This condition affects less than
one in a million people in the United States, so
(04:37):
maybe a couple hundred, and they do indeed have an
autism like syndrome. But this is a far cry from
fifty percent of people with autism. So what do you
make of this disconnect between what gets said in the
press and what gets passed by the FDA.
Speaker 3 (04:54):
So I think this is a good example of where
an early stage finding was translated to mean more than
it did, partly for political reasons and partly because the
fact that people would like there to be a better
treatment for autism. So Luke of Wren did show some
has shown some initial promise in some kids with autism,
(05:16):
particularly around speech issues, and so there was sort of
some like early stage, very small scale, not really randomized
evidence that suggested that this could be something to explore,
but I think the bulk of the very good evidence,
as the FDA pointed out, is not consistent with that,
(05:36):
and it isn't really clear what the mechanism would be.
So in terms of treating the particular folate condition in
this very small number of people, it's clear what the
mechanism is, but in general, there's not a lot of
reason to think that this would this would be helpful. So,
you know, I think it's a good example of where
(05:56):
there's kind of an unfortunate interaction between people really wanting
there to be.
Speaker 2 (06:01):
A simple answer to something and a politically expedient set
of claims.
Speaker 3 (06:07):
I mean, they had promised a cure and an answer
to ausism by September, and it was getting to be
the end of September, and this was.
Speaker 2 (06:12):
What was on the table. It's kind of how I
read it.
Speaker 3 (06:15):
I'm curious if people will continue to experiment with this
on their own. I mean, there's not much to keep
parents from asking for this for their children because it
is approved, even if they don't have this condition. My
guess is we will still see a fair.
Speaker 2 (06:29):
Amount of that.
Speaker 1 (06:30):
I think, absolutely, absolutely, yeah, I mean, Luca worn I
mean it is. It's not that dangerous a drug. It
is a sort of modified form of foll late basically,
and as you said, it's already have to approve for
other indications, so you can get it off label. And
I think people people are desperate, and desperate people will
try what is available. Can't really blame them for that.
Speaker 2 (06:50):
Yeah, all right.
Speaker 3 (06:52):
Next up, I want to ask you about chat GPT
and whether it's replaced you yet. In particular, Nature this
week has suggested that Chatgypt is actually not great at
triaging actual medical emergencies, and so I'm curious what you
made of these findings and whether I mean, I think
(07:13):
there's a much more interesting question, broader interesting question about
what is the role of AI in medicine, But let's
keep to the narrower question of Chatgypt as a triage maganism.
Speaker 1 (07:24):
Yeah, yeah, yeah, a medicine is a little bit big.
First of all, let me just say, Emily, that is
such a deep and insightful question. I'm sorry, I was
trying to be chat GPT.
Speaker 2 (07:34):
That's not how chat Gypt would say. I was like, wow,
that's a great question.
Speaker 1 (07:39):
You've cut to the center of this challenging issue. Don't
use chat GPT to tell you whether it go to
the emergency room or not. That's that's what this study says.
And you know, to some extent like yes, probably everyone
kind of knows this deep down in their heart. But
my actual concern is that there are a lot of
sort of edge medical conditions that really are an emergency
(08:02):
but that people might not think are an emergency. And
those are the times where you might go to AI
right like, if you have crushing substernal chest pain, you're
probably not going to chat GPT and being like should
I go to the er, right, like someone's going to
get you to the emergency room. And in this study,
things like that got triaged appropriately by chat GPT. The
stuff that didn't were the cases and these were all
(08:24):
cases made by clinicians, like they were designed to be
things that if a clinician heard, they would send you
to the emergency room. And the cases where it really failed,
which were emergencies, should have gone to the emergency room
and got under triage. In about half of cases or
conditions for example, like diabetic keto acidosis, where the symptoms
(08:45):
are things like you know, fatigue, vomiting, excessive urination, where
you know, a non medical person might convince themselves that okay,
like that's you know, I've got the flu or something
like that, And indeed chat GPT was sayingle let's see
how goes in twenty four to forty eight hours. A
similar case was a case with impending respiratory failure, where
(09:06):
it's like, you've got to get to the emergency room
and chat EPT about fifty percent of the time said
let's give it some time. What's really interesting is that
it could be gas lit a little bit. So if
in the prompt they use the same symptoms, but they
added a sentence that was like my family says I'm overreacting,
or like my family says everything's fine and I look good,
(09:26):
it would actually be less likely to say that you
should go to the emergency room. So it's sort of
it'll be like, okay, Well, as long as people around
you think that things are okay, it's okay, okay.
Speaker 3 (09:35):
So here is the issue with this that I have,
And not to say that I think we should be
using AI for our triage, but when I talk to
pediatricians about the question of whether you should bring your
kid to the doctor, one of the core questions people
ask is how does your kids seem? That is the
most important pediatrician question. If you say my kids had
a fever for two days, a fever is one hundred
(09:56):
and four, the question they ask is does a fever
come down with treatment? And how does your kids seem?
Do they seem very sick? And so if you said you, actually,
they don't really seem that's sick, that's like a really
important piece of information. So I'm sort of wondering here
whether there's something in the construction that's almost like a
little too negative on the AI.
Speaker 1 (10:15):
I see what you're saying, But the fact is that
these cases are designed that like no rational actor would
tell you to wait it out right, no matter what
the people around you are saying. Like, the kids are
a little bit different, for one, because their symptoms can
often seem quite a bit more extreme than adults are
used to. So like a fever of one hundred and
four in an adult is like what is crazy and
(10:36):
something really bad is happening a fever and a one
hundred four in a kid is like Sunday night, right,
Like that's nothing. So, So there is that issue the
thing that like I kept coming back to with this
is that I actually hate the you should probably go
to the doctor right now like default of the world,
Like any time anything gets posted online or like any
(10:58):
question gets asked, there's this very kind of I think
medico legal thing, which is like even when the person's
clearly okay to be like, uh, it's fine, but why.
Speaker 2 (11:06):
Don't you get check check with your doctor, check.
Speaker 1 (11:08):
With the doctor, go get checked out, Like there's that
default because God forbid you miss something. And I was
actually surprised that chat GPT didn't just like jump to
the like, oh yeah, go to the R, Go to
the R, go to the our conclusion. So I think
there is a spot here. It's got to be better
than this. But you know, given how overburdened our healthcare
system is, the truth is there are plenty of people
(11:30):
in the emergency room right now who could be managed
just fine at home or could wait it out twenty
four hours, and that's a tough triage decision to make.
We're not ready to have AI do it yet, but
you know, maybe we'll get there. Maybe maybe.
Speaker 2 (11:43):
Okay.
Speaker 3 (11:43):
Last thing that we want to talk about was a
new study about pain during sexual activity.
Speaker 2 (11:49):
Do you want to you want to tee this one up.
Speaker 1 (11:52):
I This study came across my desk, and I'm like,
I had that experience looking at the data that I
was like, oh my god, am I thing in a
parallel universe? Like this is so bonkers out there that
I don't know what to make of it? And then
I had the second thought that this is me being
a man, being the problem. And so so Emily, I
need you to weigh in on this. Let me give
you the details here. So, this is a survey study
(12:14):
of college students who is just published in the International
Journal of Sexual Health two hundred and sixty three college
students who are reporting on their sexual activities, specifically asking
about pain with various types of sexual activity, so non
penetrative sex, penetrative sex, et cetera. And the key table
from this is kind of crazy. To give you a
(12:37):
sense of the numbers here, looking at the key table
of the individuals who reported being engaging in penile vaginal intercourse,
ninety one percent of women reported pain, forty nine point
one percent of men reported pain, and those numbers are
pretty similar across the board. Fifty one percent of college
(12:59):
men reported pain from non penetrative sexual activity, forty five
percent of women reported pain from non penetrative sexual activity,
and so I saw this. The theme of this paper was, actually,
they're trying to not stigmatize discussion of pain in the space,
particularly for men, because men were much less likely to
report to their partner that they were experiencing pain than
(13:21):
women were. And sure, that's important. Communication is important. But
just like on the surface, these numbers seem really high, Emily,
or am I a man that doesn't you know, isn't
thinking about this the right way?
Speaker 2 (13:33):
So yes, I agree with you. I think these numbers
are very surprising.
Speaker 3 (13:38):
I find the numbers for men actually particularly surprising. Maybe
I am biased by the fact that I mostly talk
to women who have recently had children, but pain during
sex is like quite common postpartum and sort of somewhat
more common for women, I think, quite a lot more
common than for men. The fact that half of men
(13:58):
are reporting pain during sexual intercourse, even for non penetrative
sexual activity, I'm not really sure. I don't I'm not
a man. I don't really know what this is. So
I find that part confusing. I will say that this
is a pretty small sample, and I am wondering about
the recruitment strategy. So you know, if you did this
(14:19):
on a nationally representative sample of college students, I would
be really surprised if you told me I went to
a college and I told people I'm doing a study
about pain during sex and or about you know, discomfort
during sex, and here are some questions. Maybe I'm not
as surprised that you've pulled in a set of people
who have a particular who are coming to you because
(14:41):
they have something to say.
Speaker 2 (14:42):
So for me, this is maybe a little bit more
of a of a kind.
Speaker 3 (14:45):
Of well, what's your sample question, rather than you know,
I have totally misunderstood people's sexual behavior.
Speaker 1 (14:53):
But well, I mean their point is, of course that
men don't talk about it as much, that there's like
a stigma associated with this. I also should point out
this isn't pain every time you have sex. The question
was worded like, you know, do you ever have pain
when you have sex? Which will tend to inflate numbers
a little bit. But this is good to talk about, right, Like,
(15:15):
you know, if you have a sexual partner, this is
not something you should not be suffering in silence. I
promise sex will be better with better.
Speaker 2 (15:22):
Communication, totally could not agree with that more.
Speaker 1 (15:25):
And that's it for the health news of the week.
After the break, we'll ask what's the deal with microplastics?
All right, we are back and today we are trying
to figure out what the deal is with microplastics. I mean,
we hear about this everywhere. Plastics probably not a good thing.
(15:48):
It's certainly not good for the environment. What effect does
it have on us? But Emily, before we like get
into it, got to define our terms. What is a microplastic?
What does that even mean?
Speaker 3 (16:00):
So a microplastic is just a small plastic, as the
name would suggest, I.
Speaker 1 (16:06):
Mean, a Latin scholar, I see exactly.
Speaker 3 (16:09):
These are tiny plastic particles that happen when you decay
larger plastic particles. So think you know a water bottle
or carpeting or any of the enormous number of things
in our world that.
Speaker 2 (16:23):
Are created by plastics. Those things are whether they decay,
they they give off little teeny pieces of plastic.
Speaker 3 (16:33):
And so a microplastic is a plastic particle that's less
than five millimeters in diameter. People will sometimes also talk
about nanoplastics, which are less than one micrometer, and you
want to think about it, like there's a macroplastic, which
is what you know, and then eventually the microplastics come
off and then they turn into nanoplastics, and that is
kind of happens over time.
Speaker 1 (16:54):
Yeah, like little flakes. I've seen people, you know, is
this started as an environmental concern, like before it got
into people. You know, scientists were looking at like the
ocean and lakes and filtering water and pulling out all
these tiny pieces of plastic out of the water. I've
seen those videos which are sort of disturbing.
Speaker 3 (17:11):
And fish eat them. They're all over fish. So there's
like a lot of evidence. I mean, I think it's
an important place to start in this discussion, which is
sometimes when we talk about this health stuff, you sort
of come to the end and be like, man, it's
really not actually a big deal at all. This is
a place where it's definitely true that relative to fifty
years ago, there's way more plastic in the world, and
(17:32):
because it decays over time, this is way more microplastics.
Speaker 2 (17:35):
It's also particularly true that's not good.
Speaker 3 (17:37):
You know, no one's going to go out there and
be like, hey, it's great that the fish are full
of tiny pieces of plastic, Like, that's awesome. I think
the question for us today is really going to be
like how problematic is this and how how should people
think about it in their lives?
Speaker 2 (17:50):
Not like is it awesome? But fish are full of plastic?
Speaker 1 (17:53):
Because no, yes, clearly not. But like everything, right, are
we going to worry about this? Would you rather have
a fish that has a bunch of plastic in it
or a fish that has a bunch of mercury in it?
Speaker 4 (18:03):
Like?
Speaker 1 (18:04):
There are environmental toxins all over the place, and uh,
you know, some of them get sort of more attention
than others.
Speaker 3 (18:11):
Yeah, And we should also say plastic has brought a
lot of important things to people in the world, so
it's not an all bad activity. It is part of
why we are not dead most of the time.
Speaker 1 (18:22):
That's a that's a great point. We probably can't completely
do without plastics exactly.
Speaker 3 (18:26):
Okay, So one question people will have when they when
they start with this, which is why would these plastics
be a problem. So if we accept that they're you know,
they're in fish, maybe they're in people, we'll talk about
didy to.
Speaker 2 (18:36):
What extent, But isn't this just like an inert substance.
Isn't this just kind of not important? Why why am
I worried? Am I basically? Am I just pooping it out?
Why am I not just pooping this out?
Speaker 1 (18:50):
Perry? Yeah, it's a good point because we think of
plastic really it's kind of the fundamental thing that doesn't
react with anything else. Right, It's like why we store
our food and plastic. I mean, it's also light and
it doesn't break like glass and stuff like that, but
you know, we do. We have lab tests that are
in plastic and things like that. It's just supposed to be.
In fact, the reason we have microplastics is because the
(19:11):
plastic doesn't break down into its constitutive molecules very readily.
That being said, the human body is more than willing
to interact in bad ways with things that are chemically inert.
Doesn't just have to be a chemical reaction, and I
think maybe the prototypical example of this is asbestos, which
is an inert fiber. Your body doesn't it doesn't cause
(19:34):
a chemical reaction in your body, but it is quite irritating,
and your white blood cells will see those things and
ingest them, and of course that can lead to cancer. Mesotheliomas,
the cancer associated with asbestos exposure, so we know the
body doesn't like is not a chemistry lab. It's much
more sophisticated than that, and there's you know, quite clear
evidence in the lab that exposing cells and tissues two
(20:00):
microplastics can cause them to do bad things, particularly on
the inflammatory side. So if you take a bunch of
white blood cells in a petri dish and you sprinkle
some microplastics on there, the white blood cells will see
them and start releasing you know, what are called cytokines
and chemokinds, which are these inflammatory molecules that basically say, like,
there's a problem here.
Speaker 2 (20:21):
Listen.
Speaker 3 (20:21):
I got to stop you for this because one of
the wellness influencer terms this is slightly off topic. One
of the things you hear about all the time is inflammation, right, like,
I'm so afraid of being inflamed.
Speaker 2 (20:33):
Why is this a problem? Why am I so concerned
about being inflamed?
Speaker 1 (20:37):
So there's good inflammation and bad inflammation. When you have
an injury or an infection, your immune system targets cells
and antibodies and stuff to that area and does inflammation.
And what inflammation is is an offensive set of chemicals
to destroy the thing that is there. Now, if that
(21:00):
is a bunch of bacteria or something like that, then great,
and your body releases those chemicals to destroy the bacteria.
Does do some damage to your own cells as well,
but that's sort of a risk you're willing to take.
These substances when they're nicely targeted to an injury or
an infection work quite well. When they are flowing throughout
your body. We do know that they can cause significant
(21:23):
problems in the long term. Certain markers of inflammation like
sea reactive protein, if they are higher in your blood,
you have a higher risk of atherosclerotic cardiovascular disease. There
is this sense that there's good inflammation and then inflammation
run amok, and there's stuff that we do to ourselves
that promote inflammation that aren't giving ourselves infections.
Speaker 3 (21:43):
So, just to like dramatically simplify, if there are a
lot of tiny plastic particles around, it is possible that
our body will be like, ah, that's like a thing
I need to go fight, and that will cause there
to be a lot of these inflammatory markers rooting around
in our blood, and that might be bad for our
heart because our body's kind of like overreacting to this
plastic situation.
Speaker 1 (22:04):
And inflammation is supposed to be transient, right, It's supposed
to be like while you heal your wound, while you
cure your infection, and then you're supposed to go back
to baseline. But if you're sitting kind of above baseline
for a long period of time, it really can have
adverse effects. But the problem with the microplastic literature, as
I dug into it, is there's a lot of these
(22:24):
studies in a Petrie dish, and then there's very few
poor quality studies translating this into a human body, And like,
the difference is really really big between those two things.
You can mess with cells a lot in a Petrie dish.
Speaker 3 (22:39):
Yeah, for me, this is also where I landed in
the microplastics debate, And I think it's sort of important
to help people kind of separate two things.
Speaker 2 (22:47):
So one is maybe maybe a three things.
Speaker 3 (22:50):
So one is the question of like how much microplastics
are in people's bodies?
Speaker 2 (22:55):
Could that be bad based on what we know from
the lab?
Speaker 3 (22:59):
And the third is like is it bad given those
two things together? And I feel like in the the
what's been complicated for people in this literature, and I
think we should separate those three things. Is that we
talk a lot about the first thing, how much microplastics
are there. We take a lot about the second thing.
You know, what happens if you feed a mouse exclusively
a diet of microplastics for its whole life, Like, how's
(23:21):
that going? And then and then we sort of assume
things about the third thing. And so let's like talk
about the first two and then talk about the.
Speaker 1 (23:28):
Third, right, Yeah, I mean, just to echo that, I
was like laughing out loud when I was digging into
the literature at how many when you are searching for
like human effects of my microplastics. The ratio of review
articles and perspective pieces versus like hard data articles was obscene.
And there are all these review articles like oh, you know,
(23:50):
it probably causes cancer and you're like, oh it does.
Let me like read what you say, and it's like, well,
if you put it in a Petri diiss, it causes inflammation,
and we know that inflammation might cause cancer, and therefore
maybe humans it causes cancer. It's like, Okay, that's not evidence.
That's you know, connecting dots that you haven't proven are connected.
Yet it's quite frustrated.
Speaker 3 (24:08):
I like in review articles when it's like this might
cause cancer and you're like, and then it's like citation.
Speaker 2 (24:13):
You're like, ooh good, I'd like to read the citation.
Speaker 3 (24:15):
Then you click, and then it's another review article in
which they say that it's like, come.
Speaker 1 (24:19):
On, man, yeah, give us something to work with here.
Speaker 2 (24:22):
This is like, now we're in the weeds of like
stuff I don't like about lecture. But let's talk about
that first question, which is, you know, how like we're
going to put these three things together and get to
the last thing that people care about. But let's unpack
are their microplastics everywhere?
Speaker 1 (24:36):
Plastic is everywhere. We've talked about that, it's an ubiquitous
part of our lives. But microplastics come from a bunch
of different sources, right Emily, So, like, what are the
major ways that microplastics get into us, into humans?
Speaker 3 (24:49):
So basically, to get the microplastics into us, we have
to actually come in. You don't tend to absorb stuff
like that through your skin very much, so it's really
kind of stuff you eat and stuff you.
Speaker 2 (24:59):
Breathe or or inhale.
Speaker 3 (25:00):
So the major sources for people are stuff in your
diet and then like dust, so in your diet, you know,
we can find microplastics everywhere. There's this one study, and
I honestly think this is an over I'm not totally
sure I believe this, but there's one study of tea
bags in Canada which has like these tea bags are
(25:21):
just like basically exclusively made of microplastics, right.
Speaker 1 (25:26):
They forgot to put the tea in. They just filled
the bag with microplass and they.
Speaker 3 (25:30):
Just literally put microplastics. But that's not like all tea. Yeah,
it's just this particular I think, Yeah, I.
Speaker 1 (25:35):
Saw this too. This was a study that had the
amount of microplastics and a cup of tea like one
hundredfold higher than in any other source, which is but if.
Speaker 3 (25:43):
You put aside this particular terrible tea situation, generally most
of people's microplastic disposure is this through indoor dust. So
there's just a lot of plastics in indoor dust, with
a lot of plastics in your house, and they kind
of were indoor spaces and they sort of decay and
you and you.
Speaker 2 (25:59):
Inhale them and then you know of the.
Speaker 3 (26:02):
Diet stuff, plastic bottles, drinking out of plastic bottles is
kind of the biggest thing, and then tapwater, so it's
it's sort of stuff you drink and stuff you breathe
is the biggest set of issues.
Speaker 2 (26:12):
You can generally find.
Speaker 3 (26:14):
Microplastics in a lot of foods, and people store microplastics
and they're fat. So human fat has a lot of microplastics.
But we're not eating human fat, so that's not like
a dietary source.
Speaker 2 (26:24):
Not usually.
Speaker 1 (26:25):
Yeah, I should hope not, But it sounds like you're
I mean, these are hard things to kind of get.
Let's say I'm going to be concerned about microplastics, like,
don't breed dust is going to be a tricky one
for me, right.
Speaker 2 (26:35):
Yeah, I think that that's actually an important point from
the practical practical standpoint Here is, even if we get
to the end of this conversation and we say this
is something you should be worried about, it's actually not
entirely clear how people could really change their behavior to
affect this, And such a large share of your exposure
is just going to be through through breathing. But in general, yeah,
microplastics are around you.
Speaker 3 (26:56):
You're getting them in which leads to the question of
whether they stay, which I will ask you, which is,
to what extent do we actually know that people are
retaining these microplastics in their bodily tissues?
Speaker 2 (27:11):
Why don't they just poop it out? As I've asked
you several times that I don't feel like I've gotten
a straight answer.
Speaker 1 (27:16):
Uh, here, I'll give you a straight answer. They do
poop it out. In fact, when you measure microplastics in people,
one of the highest concentrations of microplastics is in FECs, stool,
is in poop, and that's likely because you are getting
it in the stuff you eat and it is just
passing through you. This is a bit of a problem
(27:38):
of size. So you mentioned earlier that microplastics are anything
that's five millimeters or less, and to give people a sense,
like five millimeters is like like a pencil eraser size.
This is it's like micro kind of but not really.
You know, like if I swallowed a pencil eraser, which
might be made a plastic, like it's passing right through me. Right,
(27:59):
You're gonna that that's going to be okay. You get
down to the nanoplastic scale, where these things are so
tiny that they can, you know, go between cells and
stuff like that, there's going to be a lot higher absorption.
And clearly there is absorption because there have been plenty
of studies looking at human tissues and measuring microplastics in them.
(28:20):
You can, you know, depending on the measurement method, you
get numbers that are a little bit all over the map.
But just to give just to give a sense of
where things kind of stand, there have been quite a
few studies now that show a reasonable accumulation of microplastics
in the placenta. There's been a number of studies looking
(28:42):
at microplastics in the kidney, which kind of makes sense
because the kidney's the major filtering ordering in of the blood,
and so if anything's going to kind of pick up
those little tiny micro or nanoplastics, the kidney would make sense.
You can find microplastics in the lungs. There's a study
showing microplastics in small concentrations, but in breast milk, some
(29:03):
in testicles, some in the intestines. So it's really kind
of everywhere you look, and perhaps most concerningly but also
most controversially, microplastics in the brain.
Speaker 3 (29:16):
Let me ask you before we on the way to
get into microplastics in the brain.
Speaker 2 (29:19):
I want to ask you. So you said there's microplastics
in the kidney. Now you're a kidney doctor, I'm curious
how we know that, Like if you see you must
see people's kidneys, like after they're dead, presumably sometimes.
Speaker 1 (29:33):
I mean there are slides prepared from them.
Speaker 2 (29:35):
Sure, can you like see the microplastics? How do you
know that there's microplastics in people's kidneys?
Speaker 1 (29:41):
There are multiple ways to measure, but yes, you can
see them. So under a microscope you can see little
irregularly shaped things that don't belong there, and essentially those
are microplastics. And in certain tissues you can see even
an inflammatory reaction around or you can find them inside
white blood cells, like the cells have kind of eaten
(30:04):
them or something like that in an attempt to break
them down as a foreign body. But some are even
too small to see under a typical light microscope. And
then there are other methods like mass spectroscopy, where you
literally you burn the tissue and the gas that comes
out with like you burn it with a laser, and
then the gas that comes out you sample and measure
(30:24):
the chemicals in the gas that comes out, and you
can kind of say oh look, there's like polyethylene there,
which it must have come from plastic. And but this
is a problem with the literature is it's like it's
it's really hard to quantify. Most of the data is
in units of like pieces per milligram, Like how many
pieces did we count in this miligram of tissue, which
(30:45):
is such a sort of random thing to me, Like
I want like I want uh grams per million. I
don't know milodgram's permilgram.
Speaker 3 (30:53):
Yeah, so I think it's it's interesting because those numbers
don't have any meaning. But the thing, a thing that
I think has really stuck with a lot of people
in this literature is this paper that said that there's
a spoon worth of plastic in your brain.
Speaker 1 (31:08):
Yeah.
Speaker 3 (31:08):
This is because it's like one thing to be like
there's pieces, I saw them, the mass spishocks, blah blah blah.
But this is like, now in my mind there is
an actual spoon. And in my head, of course, it's
shaped like a spoon. You know, it's like somewhere in here.
Speaker 1 (31:21):
Yeah yeah, yeah, like someone like shoved it right up
your ead.
Speaker 2 (31:24):
Someone shoved it right up it's like right in there.
You know, I could be eating with it.
Speaker 3 (31:28):
But that feels I think to a lot of people
like both very tangible. It is a lot and my
understanding is it's probably not true.
Speaker 1 (31:41):
Let's talk about to get a second.
Speaker 3 (31:42):
Yeah, I think we got to do the brain because
this is like, yeah, we got to do the brain.
Speaker 1 (31:45):
This is the paper. So so this is a paper
that appeared in Nature Medicine obviously got a lot of press.
I think the like plastic spoon's worth of plastic in
your brain. Just yeah, it's very hard for health reporters,
including myself because I wrote about this when it came
out to resist totally.
Speaker 2 (32:03):
The headline rights itself. I mean obviously.
Speaker 1 (32:06):
Headline rights itself. Let me give you just the data
that was in the paper, and then Emily, you tell
me why you're skeptical. Here. So, the way the study
worked was it was an autopsy based study. So University
of Arizona, I think they have like a brain repository
that where people have donated their brains after they died
over a period of time. And the authors sampled brain
(32:30):
tissue from the frontal lobe, the sort of important frontal
part of the brain, and they measured nanoplastics here. So
incredibly small pieces using mass spectroscopy. So that's that shooting
a laser and vaporizing the thing and measuring what comes
out of the vaporizer. And they compared this to the
microplastics and other tissues. And to give you some numbers here,
(32:51):
I'm not even going to say the units but because
they don't make much sense, but I'll give you the numbers. So,
like in the kidney of these patients or in the
kidneys they examined, they was like five hundred units of
microplastics per gram, and in the brain there was about
five thousand units of microplastics. Program So not only is
it in the brain, but they were like, it's in
(33:12):
the brain a lot, like more than everywhere else. They
also showed that that concentration increased over time, So between
twenty sixteen and twenty twenty four, like the amount of
microplastics in the brains that they had had increased. And
they also showed that brains with dementia had higher levels
of microplastics than brains without dementia. And you sort of
(33:34):
put that all together and then you start to get
like the real ick that I'm hurting myself by, you know,
drinking a plastic water bottle.
Speaker 3 (33:42):
Yeah, And I think that the thing that was maybe
on a technical level, more surprising here was people had
thought that the microplastics would not be so prevalent in
the brain because we have a blood brain barrier which
is supposed to protect your brain. Your brain is more
important than your kid is no offense, not to you
as a kidney doctor, but okay, I agree, were like,
(34:05):
your body's like more interested in protecting your brain, And
it was sort of the idea that these probably nanoplastics
were able to kind of get through the blood brain
barrier and populate the brain at these incredibly high levels
was disturbing, I think, is mat of point.
Speaker 1 (34:19):
Yeah, but there's pushback, right, So what's the push.
Speaker 2 (34:21):
There's a lot of pushback.
Speaker 3 (34:23):
So I think that the pushback here is really related
to how hard this is to measure. So again you're
you're like vaporizing this with a laser and seeing what
comes out. But the two criticisms that have come up
when people have talked about this are one, is it
actually microplastics as opposed to something else that you are
(34:44):
misinterpreting the chemical signal of for example, fat maybe more
similar to plastics. Than other things, and because there's a
lot of that kind of tissue in the brain that
could lead you to think that it's microplastics when actually
it's fat.
Speaker 2 (35:01):
And when we think about trends over time, since.
Speaker 3 (35:03):
Fat like obesity has gone up over time, that actually
could relate to some of the trends.
Speaker 2 (35:08):
I think that's one thing people.
Speaker 3 (35:09):
Have raised, and a second is just that it's really
really hard to control this carefully in the laboratory, and
people have raised some questions about this particular study and
whether they did a good job. This is an example
of something where it's so surprising, like it was so
surprising to so many people that you really probably would
want to do it again, and if it were easier
(35:30):
to do, someone would have done it again right away.
Speaker 2 (35:33):
The issue is now it's both hard to do. You
need a lot of brains from dead people who have
agreed to let you vaporize their brains for plastic or whatever,
and it's just so I think it's a bunch of
reasons why this is why it's been hard to replicate,
even though there are a lot of people who think
is probably not right.
Speaker 1 (35:49):
Yeah, I think that's such an important thing. I always
teach my students. I'll say this a million times. No
one study is definitive, right, Like replication is so important
because of these issues, Like you don't get all the
data in a paper, right, you get the sort of
filtered data that the scientists are putting in their paper,
and there's ethics about this and stuff, but you don't
get to see inside their lab. You don't get to
(36:10):
see what's happening. So it really is important to get replication.
To put another spin on this, the total amount of
microplastics that they calculated would be in the full brain
was about a half of a percent of the entire brain,
like the weight of the brain zero point five percent
of that, which to some neurologists is incredibly high, Like
(36:33):
they're like that level that amount of plastic, like, you know,
half of a percent throughout the brain is not something
we would miss. We would you know, we would clearly
see it. And it's so much higher than other tissues
that it just kind of doesn't seem plausible on the
face of it. But yeah, I guess we'll see.
Speaker 2 (36:48):
I guess we'll see.
Speaker 3 (36:49):
All right, So let's just establish whether it's a spoon
or a small spoon, A tea spoon ladle of plastic
in your brain, that there are plastics in our bodies.
And then there's these sort of two other things. So
one is, you know, do we have good evidence that
in laboratory kind of cell settings plastics are bad? And
my read of that is yes, that there's a lot
(37:12):
of evidence that if we take labs, either mice or
cells or organoids, which are like you try to make
like tiny pieces of human organs and you expose them
to a lot of microplastics, all kinds of bad stuff
happens to them.
Speaker 2 (37:27):
Yes, yes, fertility issues in mice.
Speaker 1 (37:30):
Yeah, But like contextually speaking, this is also true of
like everything we do to cells and mice and stuff
in the lab. Like this will come up again and again,
which is you know, if you take a model organism
or you take a cell in the petry dish and
you sort of stress it out with like whatever you're
going to pour on top of it, you know, whether
it's microplastics or whether it's like you know, round up
(37:53):
pesticide or whatever you do, you're going to get a
reaction out of those cells. It's similar to you know,
this particular dye, you know, food dye causing cancer or
something like that. Right, It's it's like that is the baseline. Again,
we always talk about biologic plausibility. Is it plausible that
there's a problem. Sure, we have some evidence, kind of
the floor of evidence, which is like if you soak
(38:16):
a cell in microplastic, it isn't happy about it. But
the you know, wellness world tends to run with that
and like go conclusion, conclusion, conclusion, conclusion, microplastics cause cancer.
Only drink out of like a wooden bowl from now on, right,
And we actually need to tie those together, and we
haven't tied those together very well yet. But maybe Emily,
(38:38):
we can talk about some of the areas that people
have said microplastics effects. So I think we talked about
the brain. We're not too sure what's going on in
the brain yet. But other things that have come out
or that people claim about microplastics are like obesity, for example.
So so do we think that plastic intake is causal
(39:02):
like leads to obesity?
Speaker 2 (39:05):
I don't think so.
Speaker 3 (39:07):
All of the literature that I have so let me
let me say I've read a bunch of this literature,
and it tends to associate levels of microplastic consumption or
you know, eating from takeout containers that have a lot
of microplastics with obesity. And the problem is that that
(39:28):
is an associational study, not a causal study.
Speaker 2 (39:32):
And so the.
Speaker 3 (39:33):
Fact that people who are exposed to more microplastics are
also more likely to be obese could easily, for example,
be explained by microplastic exposure from containers that are more
likely to contain process foods, which we know is associated
with obesity. So there's just looks so difficult to learn
from that kind of evidence. I just think that's I
(39:55):
just think that evidence is all such complete garbage.
Speaker 1 (39:58):
I saw it my favorite graph recently, which looked at
the rate of obesity between nineteen seventy six and twenty
nineteen and the rate of plastic production between nineteen seventy
six and twenty nineteen. It was like, look, they're both
going up. It's like, okay, guys, you know, there's a
lot of things that have gone up since.
Speaker 2 (40:16):
A lot of other a lot of other eventyow.
Speaker 3 (40:19):
But even like, the thing that's amazing about that is
like you could draw an interesting causal story there. You'd
be like, as it's been easy to make plastics, actually
we've that is contributed to like things about our food system.
So it could be that there's a like, in a
weird way, there's a causal link between plastics and what
it has made possible with the food system and obesity.
Speaker 2 (40:41):
But it's not for microplastics.
Speaker 1 (40:43):
Yeah.
Speaker 2 (40:44):
Even if that got for causal, it wouldn't be for
this reason, is what I'm saying.
Speaker 1 (40:47):
It's such a good point.
Speaker 3 (40:48):
The other place I think that that people talk a
lot about this is infertility. Yeah, and so you know,
we see microplastics in sperm, we see microplastics in the placenta,
and people worry about ertility rates. And I will say
in mice evidence again very high exposure to microplastics in
mice does seem to interfere with reproduction.
Speaker 2 (41:09):
What is your read of that literature? In people.
Speaker 1 (41:13):
Again very clear that there are microplastics in the placenta,
and in fact it's one of the tissues that they
see more microplastics than in some other tissues for reasons
that aren't entirely clear to me, Because the placenta is
not like a filtering organ like the liver or the
kidneys are, although maybe it is some kind of interface
(41:35):
that you know, makes microplastics more prone to be there.
The question is does it matter? And it's been very
difficult to show that there's a link between the microplastic
content in the placenta or a microplastic exposures and birth outcomes,
which is the important thing that you know, we care
about here. What do you think, Emily, I mean, this
(41:56):
is this is your your your wheelhouse.
Speaker 2 (41:58):
Yeah, I think you know. So.
Speaker 3 (42:00):
I don't think that there's any compelling evidence of particularly
important effects here. I mean, and I guess this gets
into where I end up on basically all of these things,
you know, cardiovascular disease, dementia, etc. Like Is it possible
that there is at some level of microplastics and effect, Yeah,
I think so. Is it likely that there's an effect
(42:23):
at the levels that we see people being exposed. I
don't think we have any evidence of that, and all
the literature on this is very very poor. And to
the extent you're seeing a correlation, almost certainly like nearly
all that correlation is driven by other differences across people
and not by the microplastics.
Speaker 1 (42:42):
Yeah. Sometimes it's helpful to imagine imagine two people, like
the ultimate microplastic consumer and then the ultimate like non
microplastic person, not because they're deliberately trying to avoid them,
but like, what is sort of the image you have?
And if I think of like, you know, who's not
getting many brighter plastics, well, it's like this this guy
(43:03):
out in a log cabin in the woods who's like,
you know, hunting and fishing and eating whole foods and
you know, doing that kind of stuff and like whittling
his own z at block bags from a cherry tree.
And then you know, I think of the like microplastic consumer,
and you have someone who's you know, yeah, eating a
lot of takeout and all that kind of stuff, and
those are all what we call confounders. Those are all
(43:24):
problems when you're trying to tie microplastics to something because
the type of people who have more microplastics in them
are different than the type of people who have less
microplastics in them, and those differences can matter in terms
of all sorts of health outcomes.
Speaker 3 (43:37):
Yeah, So, I mean, I think I am very skeptical
of claims that exposure to microplastics are an important part
of people's health. So, like, is it possible they are
a little bit of it?
Speaker 2 (43:47):
Maybe? Is it likely that this is a very important
driver of various problems that people have in their health.
Just the answer is I think no.
Speaker 1 (43:56):
I agree, I think this isn't the biggest problem we
face health wise. But I also always like to look
at like, okay, maybe it's not, but are there easy steady?
Like if I care, how easy would it be to
change this? And as we've been talking, you know, you've
told me about dust being a major contributor of microplastics. Like,
all right, I'm not going to change that. But it
feels like if you believe the tea study, right, like, okay,
(44:18):
maybe I'll just make tea using tea leaves and a
stainless steel tea filter. That's pretty easy. Do you think
there's like some easy stuff we should be doing. I
should I have a Stanley water bottle, like low hanging fruit.
Speaker 3 (44:32):
Here, So I think there's the lowest hanging fruit is
avoiding like non reusable water bottles. So like plastic water
bottles are among the higher microplastic giver offers, they are
also not very good for the environment. And so there's
a kind of double whammy positive of just trying to
(44:52):
you know, not be neurotic and never ever use disposable
plastic water bottles, but think a little bit about you know,
limiting those. I think that's that is the simplest thing.
I think for most people that would change their microplastic
exposure some and almost every other change you.
Speaker 2 (45:11):
Would make is totally unrealistic, like don't breathe.
Speaker 1 (45:14):
Yeah, yeah, yeah, we don't recommend that in the medical spheres.
I think for me, yeah, I think I can use
a reusable water bottle. I think when I'm reheating my
takeout food in the microwave, like maybe I'll transfer it
to a bowl that is not plastic before I reheat
it in the plastic thing. I don't know that's easy.
Speaker 2 (45:34):
Sure, yeah, I mean I again, I think that's that
could be easy. I think you have to.
Speaker 3 (45:38):
Ask the question, like what is easy for you? And
maybe that's also a question about reusable water bottles. I
think we could say, like, here are two things you
could do. Use fewer disposable water bottles and don't microwave
your takeout, and then you can think about, you know,
how feasible are those changes for you?
Speaker 1 (45:54):
I like it, all right, let's bottom line this thing, Emily,
microplastics smash your pass or actually should probably say avoiding
microplastics smasher pass.
Speaker 3 (46:06):
I'm a pass on this because I think that in
the space of things people can do with their limited
attention and time for their health, trying to avoid all
sources of microplastics is not a very good use of
that limited time and energy. So, you know, if someone
said I'm going to use fewer single use water bottles, sure,
(46:29):
I think that's a good thing to do for the
environment in general. But from my taste, I think people
could think less about microplastics for their own health.
Speaker 1 (46:38):
I am going to smash this one. I'm going to
smash avoiding microplastics primarily from other earth. I think we
all should be using less plastics, and I you know,
I don't think everything can be avoided, But like, am
I going to maybe not reheat my leftovers in the
plastic container? Maybe use my you know, aluminum water bottle
(46:58):
a little bit more based on what I've seen so far. Yeah,
that's some That's a change I can make. Change I
can live with.
Speaker 2 (47:04):
Okay, it's our first disagreement.
Speaker 1 (47:07):
Is it over?
Speaker 2 (47:09):
I think it's over.
Speaker 1 (47:09):
I feel like we.
Speaker 2 (47:10):
Did a good I feel like we did a good
job on that respectful disagreement. Okay, all right, that's it
for microplastics. Your mailbag question of the week after the break.
Speaker 5 (47:26):
Hi, am LeAnn Perry. This is Rachel from Philadelphia, and
I have a question about my weight, specifically, how I'm
ever supposed to trust.
Speaker 1 (47:34):
What the scale says.
Speaker 5 (47:36):
It's always fluctuating by a few pounds, and I really
can't figure out where those pounds are coming from. I
feel like my eating habits really aren't changing that much.
How often should I be weighing myself? And when is
a good time of day First thing in the morning,
later in the evening. I'm really just trying to get
an accurate idea.
Speaker 1 (47:55):
Thank you, awesome question. I love this question because people
get really obsessed with weight. It's part of their daily habit.
They get on that scale and on a day to
day basis, there's a ton of stuff that makes your
weight fluctuate, and none of it is like the fat
content in your body. The primary driver of day to
day fluctuation and weight is water. So water's very heavy.
(48:19):
A leader of water weighs two point two kilograms, which
is about five pounds almost. That's a big swing. And
you drink water based on how much salt you intake.
So the more salt you eat, the more reflexively the
more water you go for. That's you can experience that,
you know, after driving Chinese food or something. It is
literal water weight. That is what is driving day to
day weight changes. The only utility of that is to
(48:41):
look at large trends over time to get a sense
of what's happening with like fat mass, muscle mass, et cetera. Emily,
do you weigh yourself every day?
Speaker 3 (48:49):
I don't weigh myself every day, but I'm going to
tell you something that's interesting about water and salt, which
is one of the things that I sometimes do before
short distance races is take sodium bycarb, which is just
a really really really high dose of baking soda which
gives you a tremendous amount of sodium, like a billion
(49:10):
times not a billion, but like a lot, like a
lot of sodium. And it's good for performance in various ways.
But it also makes you incredibly thirsty and it makes
you retain like an enormous amount of water. And so
if you weigh yourself in the morning after a race,
after you have taken sodium bycarb, it's like a substantial
amount of we gain that sort of like fades out
(49:31):
over time. I did once experiment by weighing myself every
day for like four or five days after and it
took a few days to kind of come back to normal.
Speaker 1 (49:38):
Yeah, this is classic physiology they teach you in med school.
Speaker 3 (49:41):
So if you are tracking your weight over time, there
are a few different ways you could do. What You
could weigh yourself every day, but look for overall trends
over time. I tend to think that that makes people
who are trying to lose weight very anxious, and so
I don't think it's like a generally recommended thing to do.
But certainly there are some medical circumstances in which it
(50:02):
would make sense. If you are going to weigh yourself
every day, try to do it at the same time.
Speaker 1 (50:07):
Yeah, typically we tell people in the medical field people
who should wag themselves. There typically people with heart failure
where we really are managing that fluid status that's so important,
and we're using it not to see what they're fat
or muscle masses. We're using it to assess water weight.
So if you don't have heart failure, no need to
weigh yourself every day. We do tell people. If you
want consistent results, do it first thing in the morning,
(50:27):
after you pee. That's it for us today. Stick with
us next week when we'll ask what's the deal with
stem cell therapy?
Speaker 3 (50:38):
Wellness Actually is produced in association with iHeartMedia.
Speaker 2 (50:41):
Our senior producer is Tamar Avisheik.
Speaker 3 (50:44):
Our executive producer at iHeart is Jennifer Bassett. Our theme
music is by Eric Deutsch, and our content is for
educational purposes only.
Speaker 1 (50:52):
If you like the show, help other people find us,
leave a rating and review on Apple Podcasts or your
podcatcher of choice and help us spread the word about
the show. You can follow us on Instagram at Wellness
Actually pod and don't forget We want to hear from you.
Head over to Wellness Actually dot fm and leave us
a question for our mailbag or suggest a topic for
(51:12):
a future show.
Speaker 2 (51:14):
We'll let the influencers have the last word.
Speaker 6 (51:16):
Microplastics. Here's a public service announcement. If you go get
a cup of coffee and it's in a paper cup,
the entire paper cup is plastic. When they put the
hot water in there, you're drinking a cup of plastic.
They're already showing that it's disrupting hormones, it's disrupting mitochondria,
is disrupting so much heavy in fertility. They're finding plastics
in people's testicles anyway, So finding a detoxification while your
(51:39):
body is detoxifying in a sauna helps push it all
out
Emily, I have a very important and very difficult challenge
for you today.
Speaker 2 (00:06):
I'm ready.
Speaker 1 (00:07):
I am going to give you a word and you
have to tell me. You have to distinguish whether this
is a type of plastic or a spell from the
Harry Potter universe. Okay, are you ready?
Speaker 3 (00:21):
I'm actually I know a lot about Harry Potter, so
I think I'm going to be really good at this.
Speaker 1 (00:25):
Okay, but do you know a lot about plastics. Let's
find out.
Speaker 2 (00:29):
Less that I know about Harry Potter. But I'm optimistic.
Speaker 1 (00:31):
All right, let's try it first. One Avi Foor's plastic incorrect.
That is a Harry Potter spell that transforms objects into birds.
What let's try on evalka spell? Sorry. That is a
type of plastic ethylene vinyl alcohol copolymers that's used in
food and medical packaging. How about loupital That is a
(00:55):
spell that is a plastic thermoplastic. It's used in automotive, electronic,
and medical devices. You're not doing too well, but you're
gonna pull it out here. Langlock spell. That is a spell?
Speaker 4 (01:10):
Yes, nice, it is a jinx that makes you unable
to speak langlock okay, grillamid plastic very good, a high
performance nylon used in sporting goods.
Speaker 1 (01:22):
Two more Vectra plastic awesome liquid crystal polymer for thin
walled electronics and aerospace applications. And lastly Ferula plastic. That
is a spell. It is a bandaging charm if you
are wounded. Point being there's a lot of plastics out there.
Speaker 3 (01:46):
I thought your point was going to be I'm terrible
at this, but thank you for making a point more neutral.
Speaker 1 (01:52):
You know you might need a bandaging charm after that performance.
But yes, I wanted to bring this up because plastics
are everywhere. They are ubiquitous, they are in all the
products we use, and of course, according to recent research,
they are also inside of us.
Speaker 3 (02:11):
And we're going to find out whether that's actually a
problem when we do our deep dive later today.
Speaker 1 (02:15):
Microplastics stick with us.
Speaker 2 (02:20):
I'm Emily Oster, I'm an economist and a data expert.
Speaker 1 (02:23):
And I'm Perry Wilson, I'm a medical doctor.
Speaker 3 (02:25):
It's Thursday, March nineteenth, twenty twenty six. And this is
wellness actually.
Speaker 1 (02:31):
Because you're getting a staggering amount of health and wellness
information nowadays from every source imaginable, and some of it
is awesome and.
Speaker 2 (02:39):
Some of it is well actually both.
Speaker 3 (02:43):
Fortunately we're both people who know how to read studies,
how to parse the data, and can tell you what's
worth thinking.
Speaker 2 (02:50):
About and what you can safely ignore.
Speaker 1 (02:52):
But before we dig in, a note that this podcast
is for educational purposes and should not be construed as
medical advice. We don't know your unique situ, so talk
to your doctor for personal health decisions.
Speaker 3 (03:03):
This week, we'll ask life in plastic is it fantastic?
As we explore what's the deal with microplastics? Perry and
I will give the official smasher pass, and then we'll
get to your question of the week. But first, let's
do the health news roundup after the break.
Speaker 1 (03:32):
Okay, welcome back. This week in health news, Emily, I
want to start with the FDA. You may remember back
to that infamous press conference on autism where President Trump
appeared and said that pregnant women should avoid taking seenomnifin
or tail and all because it causes autism. At that
(03:53):
same conference, FDA Director Marty McCarry said that a therapy
might exist called lucovorren, which, according to him quote could
benefit twenty forty fifty percent of kids with autism. You know,
that's a huge number and a huge statement to make
for a therapy that's already FDA approved for other indications.
(04:15):
It's available, it can be bought today. Well as of
a couple of days ago, the FDA did indeed approve
Luca worn, but for an incredibly rare genetic condition that
limits the delivery of folate to the brain. Fully it's
a form of B vitamin. This condition affects less than
one in a million people in the United States, so
(04:37):
maybe a couple hundred, and they do indeed have an
autism like syndrome. But this is a far cry from
fifty percent of people with autism. So what do you
make of this disconnect between what gets said in the
press and what gets passed by the FDA.
Speaker 3 (04:54):
So I think this is a good example of where
an early stage finding was translated to mean more than
it did, partly for political reasons and partly because the
fact that people would like there to be a better
treatment for autism. So Luke of Wren did show some
has shown some initial promise in some kids with autism,
(05:16):
particularly around speech issues, and so there was sort of
some like early stage, very small scale, not really randomized
evidence that suggested that this could be something to explore,
but I think the bulk of the very good evidence,
as the FDA pointed out, is not consistent with that,
(05:36):
and it isn't really clear what the mechanism would be.
So in terms of treating the particular folate condition in
this very small number of people, it's clear what the
mechanism is, but in general, there's not a lot of
reason to think that this would this would be helpful. So,
you know, I think it's a good example of where
(05:56):
there's kind of an unfortunate interaction between people really wanting
there to be.
Speaker 2 (06:01):
A simple answer to something and a politically expedient set
of claims.
Speaker 3 (06:07):
I mean, they had promised a cure and an answer
to ausism by September, and it was getting to be
the end of September, and this was.
Speaker 2 (06:12):
What was on the table. It's kind of how I
read it.
Speaker 3 (06:15):
I'm curious if people will continue to experiment with this
on their own. I mean, there's not much to keep
parents from asking for this for their children because it
is approved, even if they don't have this condition. My
guess is we will still see a fair.
Speaker 2 (06:29):
Amount of that.
Speaker 1 (06:30):
I think, absolutely, absolutely, yeah, I mean, Luca worn I
mean it is. It's not that dangerous a drug. It
is a sort of modified form of foll late basically,
and as you said, it's already have to approve for
other indications, so you can get it off label. And
I think people people are desperate, and desperate people will
try what is available. Can't really blame them for that.
Speaker 2 (06:50):
Yeah, all right.
Speaker 3 (06:52):
Next up, I want to ask you about chat GPT
and whether it's replaced you yet. In particular, Nature this
week has suggested that Chatgypt is actually not great at
triaging actual medical emergencies, and so I'm curious what you
made of these findings and whether I mean, I think
(07:13):
there's a much more interesting question, broader interesting question about
what is the role of AI in medicine, But let's
keep to the narrower question of Chatgypt as a triage maganism.
Speaker 1 (07:24):
Yeah, yeah, yeah, a medicine is a little bit big.
First of all, let me just say, Emily, that is
such a deep and insightful question. I'm sorry, I was
trying to be chat GPT.
Speaker 2 (07:34):
That's not how chat Gypt would say. I was like, wow,
that's a great question.
Speaker 1 (07:39):
You've cut to the center of this challenging issue. Don't
use chat GPT to tell you whether it go to
the emergency room or not. That's that's what this study says.
And you know, to some extent like yes, probably everyone
kind of knows this deep down in their heart. But
my actual concern is that there are a lot of
sort of edge medical conditions that really are an emergency
(08:02):
but that people might not think are an emergency. And
those are the times where you might go to AI
right like, if you have crushing substernal chest pain, you're
probably not going to chat GPT and being like should
I go to the er, right, like someone's going to
get you to the emergency room. And in this study,
things like that got triaged appropriately by chat GPT. The
stuff that didn't were the cases and these were all
(08:24):
cases made by clinicians, like they were designed to be
things that if a clinician heard, they would send you
to the emergency room. And the cases where it really failed,
which were emergencies, should have gone to the emergency room
and got under triage. In about half of cases or
conditions for example, like diabetic keto acidosis, where the symptoms
(08:45):
are things like you know, fatigue, vomiting, excessive urination, where
you know, a non medical person might convince themselves that okay,
like that's you know, I've got the flu or something
like that, And indeed chat GPT was sayingle let's see
how goes in twenty four to forty eight hours. A
similar case was a case with impending respiratory failure, where
(09:06):
it's like, you've got to get to the emergency room
and chat EPT about fifty percent of the time said
let's give it some time. What's really interesting is that
it could be gas lit a little bit. So if
in the prompt they use the same symptoms, but they
added a sentence that was like my family says I'm overreacting,
or like my family says everything's fine and I look good,
(09:26):
it would actually be less likely to say that you
should go to the emergency room. So it's sort of
it'll be like, okay, Well, as long as people around
you think that things are okay, it's okay, okay.
Speaker 3 (09:35):
So here is the issue with this that I have,
And not to say that I think we should be
using AI for our triage, but when I talk to
pediatricians about the question of whether you should bring your
kid to the doctor, one of the core questions people
ask is how does your kids seem? That is the
most important pediatrician question. If you say my kids had
a fever for two days, a fever is one hundred
(09:56):
and four, the question they ask is does a fever
come down with treatment? And how does your kids seem?
Do they seem very sick? And so if you said you, actually,
they don't really seem that's sick, that's like a really
important piece of information. So I'm sort of wondering here
whether there's something in the construction that's almost like a
little too negative on the AI.
Speaker 1 (10:15):
I see what you're saying, But the fact is that
these cases are designed that like no rational actor would
tell you to wait it out right, no matter what
the people around you are saying. Like, the kids are
a little bit different, for one, because their symptoms can
often seem quite a bit more extreme than adults are
used to. So like a fever of one hundred and
four in an adult is like what is crazy and
(10:36):
something really bad is happening a fever and a one
hundred four in a kid is like Sunday night, right,
Like that's nothing. So, So there is that issue the
thing that like I kept coming back to with this
is that I actually hate the you should probably go
to the doctor right now like default of the world,
Like any time anything gets posted online or like any
(10:58):
question gets asked, there's this very kind of I think
medico legal thing, which is like even when the person's
clearly okay to be like, uh, it's fine, but why.
Speaker 2 (11:06):
Don't you get check check with your doctor, check.
Speaker 1 (11:08):
With the doctor, go get checked out, Like there's that
default because God forbid you miss something. And I was
actually surprised that chat GPT didn't just like jump to
the like, oh yeah, go to the R, Go to
the R, go to the our conclusion. So I think
there is a spot here. It's got to be better
than this. But you know, given how overburdened our healthcare
system is, the truth is there are plenty of people
(11:30):
in the emergency room right now who could be managed
just fine at home or could wait it out twenty
four hours, and that's a tough triage decision to make.
We're not ready to have AI do it yet, but
you know, maybe we'll get there. Maybe maybe.
Speaker 2 (11:43):
Okay.
Speaker 3 (11:43):
Last thing that we want to talk about was a
new study about pain during sexual activity.
Speaker 2 (11:49):
Do you want to you want to tee this one up.
Speaker 1 (11:52):
I This study came across my desk, and I'm like,
I had that experience looking at the data that I
was like, oh my god, am I thing in a
parallel universe? Like this is so bonkers out there that
I don't know what to make of it? And then
I had the second thought that this is me being
a man, being the problem. And so so Emily, I
need you to weigh in on this. Let me give
you the details here. So, this is a survey study
(12:14):
of college students who is just published in the International
Journal of Sexual Health two hundred and sixty three college
students who are reporting on their sexual activities, specifically asking
about pain with various types of sexual activity, so non
penetrative sex, penetrative sex, et cetera. And the key table
from this is kind of crazy. To give you a
(12:37):
sense of the numbers here, looking at the key table
of the individuals who reported being engaging in penile vaginal intercourse,
ninety one percent of women reported pain, forty nine point
one percent of men reported pain, and those numbers are
pretty similar across the board. Fifty one percent of college
(12:59):
men reported pain from non penetrative sexual activity, forty five
percent of women reported pain from non penetrative sexual activity,
and so I saw this. The theme of this paper was, actually,
they're trying to not stigmatize discussion of pain in the space,
particularly for men, because men were much less likely to
report to their partner that they were experiencing pain than
(13:21):
women were. And sure, that's important. Communication is important. But
just like on the surface, these numbers seem really high, Emily,
or am I a man that doesn't you know, isn't
thinking about this the right way?
Speaker 2 (13:33):
So yes, I agree with you. I think these numbers
are very surprising.
Speaker 3 (13:38):
I find the numbers for men actually particularly surprising. Maybe
I am biased by the fact that I mostly talk
to women who have recently had children, but pain during
sex is like quite common postpartum and sort of somewhat
more common for women, I think, quite a lot more
common than for men. The fact that half of men
(13:58):
are reporting pain during sexual intercourse, even for non penetrative
sexual activity, I'm not really sure. I don't I'm not
a man. I don't really know what this is. So
I find that part confusing. I will say that this
is a pretty small sample, and I am wondering about
the recruitment strategy. So you know, if you did this
(14:19):
on a nationally representative sample of college students, I would
be really surprised if you told me I went to
a college and I told people I'm doing a study
about pain during sex and or about you know, discomfort
during sex, and here are some questions. Maybe I'm not
as surprised that you've pulled in a set of people
who have a particular who are coming to you because
(14:41):
they have something to say.
Speaker 2 (14:42):
So for me, this is maybe a little bit more
of a of a kind.
Speaker 3 (14:45):
Of well, what's your sample question, rather than you know,
I have totally misunderstood people's sexual behavior.
Speaker 1 (14:53):
But well, I mean their point is, of course that
men don't talk about it as much, that there's like
a stigma associated with this. I also should point out
this isn't pain every time you have sex. The question
was worded like, you know, do you ever have pain
when you have sex? Which will tend to inflate numbers
a little bit. But this is good to talk about, right, Like,
(15:15):
you know, if you have a sexual partner, this is
not something you should not be suffering in silence. I
promise sex will be better with better.
Speaker 2 (15:22):
Communication, totally could not agree with that more.
Speaker 1 (15:25):
And that's it for the health news of the week.
After the break, we'll ask what's the deal with microplastics?
All right, we are back and today we are trying
to figure out what the deal is with microplastics. I mean,
we hear about this everywhere. Plastics probably not a good thing.
(15:48):
It's certainly not good for the environment. What effect does
it have on us? But Emily, before we like get
into it, got to define our terms. What is a microplastic?
What does that even mean?
Speaker 3 (16:00):
So a microplastic is just a small plastic, as the
name would suggest, I.
Speaker 1 (16:06):
Mean, a Latin scholar, I see exactly.
Speaker 3 (16:09):
These are tiny plastic particles that happen when you decay
larger plastic particles. So think you know a water bottle
or carpeting or any of the enormous number of things
in our world that.
Speaker 2 (16:23):
Are created by plastics. Those things are whether they decay,
they they give off little teeny pieces of plastic.
Speaker 3 (16:33):
And so a microplastic is a plastic particle that's less
than five millimeters in diameter. People will sometimes also talk
about nanoplastics, which are less than one micrometer, and you
want to think about it, like there's a macroplastic, which
is what you know, and then eventually the microplastics come
off and then they turn into nanoplastics, and that is
kind of happens over time.
Speaker 1 (16:54):
Yeah, like little flakes. I've seen people, you know, is
this started as an environmental concern, like before it got
into people. You know, scientists were looking at like the
ocean and lakes and filtering water and pulling out all
these tiny pieces of plastic out of the water. I've
seen those videos which are sort of disturbing.
Speaker 3 (17:11):
And fish eat them. They're all over fish. So there's
like a lot of evidence. I mean, I think it's
an important place to start in this discussion, which is
sometimes when we talk about this health stuff, you sort
of come to the end and be like, man, it's
really not actually a big deal at all. This is
a place where it's definitely true that relative to fifty
years ago, there's way more plastic in the world, and
(17:32):
because it decays over time, this is way more microplastics.
Speaker 2 (17:35):
It's also particularly true that's not good.
Speaker 3 (17:37):
You know, no one's going to go out there and
be like, hey, it's great that the fish are full
of tiny pieces of plastic, Like, that's awesome. I think
the question for us today is really going to be
like how problematic is this and how how should people
think about it in their lives?
Speaker 2 (17:50):
Not like is it awesome? But fish are full of plastic?
Speaker 1 (17:53):
Because no, yes, clearly not. But like everything, right, are
we going to worry about this? Would you rather have
a fish that has a bunch of plastic in it
or a fish that has a bunch of mercury in it?
Speaker 4 (18:03):
Like?
Speaker 1 (18:04):
There are environmental toxins all over the place, and uh,
you know, some of them get sort of more attention
than others.
Speaker 3 (18:11):
Yeah, And we should also say plastic has brought a
lot of important things to people in the world, so
it's not an all bad activity. It is part of
why we are not dead most of the time.
Speaker 1 (18:22):
That's a that's a great point. We probably can't completely
do without plastics exactly.
Speaker 3 (18:26):
Okay, So one question people will have when they when
they start with this, which is why would these plastics
be a problem. So if we accept that they're you know,
they're in fish, maybe they're in people, we'll talk about
didy to.
Speaker 2 (18:36):
What extent, But isn't this just like an inert substance.
Isn't this just kind of not important? Why why am
I worried? Am I basically? Am I just pooping it out?
Why am I not just pooping this out?
Speaker 1 (18:50):
Perry? Yeah, it's a good point because we think of
plastic really it's kind of the fundamental thing that doesn't
react with anything else. Right, It's like why we store
our food and plastic. I mean, it's also light and
it doesn't break like glass and stuff like that, but
you know, we do. We have lab tests that are
in plastic and things like that. It's just supposed to be.
In fact, the reason we have microplastics is because the
(19:11):
plastic doesn't break down into its constitutive molecules very readily.
That being said, the human body is more than willing
to interact in bad ways with things that are chemically inert.
Doesn't just have to be a chemical reaction, and I
think maybe the prototypical example of this is asbestos, which
is an inert fiber. Your body doesn't it doesn't cause
(19:34):
a chemical reaction in your body, but it is quite irritating,
and your white blood cells will see those things and
ingest them, and of course that can lead to cancer. Mesotheliomas,
the cancer associated with asbestos exposure, so we know the
body doesn't like is not a chemistry lab. It's much
more sophisticated than that, and there's you know, quite clear
evidence in the lab that exposing cells and tissues two
(20:00):
microplastics can cause them to do bad things, particularly on
the inflammatory side. So if you take a bunch of
white blood cells in a petri dish and you sprinkle
some microplastics on there, the white blood cells will see
them and start releasing you know, what are called cytokines
and chemokinds, which are these inflammatory molecules that basically say, like,
there's a problem here.
Speaker 2 (20:21):
Listen.
Speaker 3 (20:21):
I got to stop you for this because one of
the wellness influencer terms this is slightly off topic. One
of the things you hear about all the time is inflammation, right, like,
I'm so afraid of being inflamed.
Speaker 2 (20:33):
Why is this a problem? Why am I so concerned
about being inflamed?
Speaker 1 (20:37):
So there's good inflammation and bad inflammation. When you have
an injury or an infection, your immune system targets cells
and antibodies and stuff to that area and does inflammation.
And what inflammation is is an offensive set of chemicals
to destroy the thing that is there. Now, if that
(21:00):
is a bunch of bacteria or something like that, then great,
and your body releases those chemicals to destroy the bacteria.
Does do some damage to your own cells as well,
but that's sort of a risk you're willing to take.
These substances when they're nicely targeted to an injury or
an infection work quite well. When they are flowing throughout
your body. We do know that they can cause significant
(21:23):
problems in the long term. Certain markers of inflammation like
sea reactive protein, if they are higher in your blood,
you have a higher risk of atherosclerotic cardiovascular disease. There
is this sense that there's good inflammation and then inflammation
run amok, and there's stuff that we do to ourselves
that promote inflammation that aren't giving ourselves infections.
Speaker 3 (21:43):
So, just to like dramatically simplify, if there are a
lot of tiny plastic particles around, it is possible that
our body will be like, ah, that's like a thing
I need to go fight, and that will cause there
to be a lot of these inflammatory markers rooting around
in our blood, and that might be bad for our
heart because our body's kind of like overreacting to this
plastic situation.
Speaker 1 (22:04):
And inflammation is supposed to be transient, right, It's supposed
to be like while you heal your wound, while you
cure your infection, and then you're supposed to go back
to baseline. But if you're sitting kind of above baseline
for a long period of time, it really can have
adverse effects. But the problem with the microplastic literature, as
I dug into it, is there's a lot of these
(22:24):
studies in a Petrie dish, and then there's very few
poor quality studies translating this into a human body, And like,
the difference is really really big between those two things.
You can mess with cells a lot in a Petrie dish.
Speaker 3 (22:39):
Yeah, for me, this is also where I landed in
the microplastics debate, And I think it's sort of important
to help people kind of separate two things.
Speaker 2 (22:47):
So one is maybe maybe a three things.
Speaker 3 (22:50):
So one is the question of like how much microplastics
are in people's bodies?
Speaker 2 (22:55):
Could that be bad based on what we know from
the lab?
Speaker 3 (22:59):
And the third is like is it bad given those
two things together? And I feel like in the the
what's been complicated for people in this literature, and I
think we should separate those three things. Is that we
talk a lot about the first thing, how much microplastics
are there. We take a lot about the second thing.
You know, what happens if you feed a mouse exclusively
a diet of microplastics for its whole life, Like, how's
(23:21):
that going? And then and then we sort of assume
things about the third thing. And so let's like talk
about the first two and then talk about the.
Speaker 1 (23:28):
Third, right, Yeah, I mean, just to echo that, I
was like laughing out loud when I was digging into
the literature at how many when you are searching for
like human effects of my microplastics. The ratio of review
articles and perspective pieces versus like hard data articles was obscene.
And there are all these review articles like oh, you know,
(23:50):
it probably causes cancer and you're like, oh it does.
Let me like read what you say, and it's like, well,
if you put it in a Petri diiss, it causes inflammation,
and we know that inflammation might cause cancer, and therefore
maybe humans it causes cancer. It's like, Okay, that's not evidence.
That's you know, connecting dots that you haven't proven are connected.
Yet it's quite frustrated.
Speaker 3 (24:08):
I like in review articles when it's like this might
cause cancer and you're like, and then it's like citation.
Speaker 2 (24:13):
You're like, ooh good, I'd like to read the citation.
Speaker 3 (24:15):
Then you click, and then it's another review article in
which they say that it's like, come.
Speaker 1 (24:19):
On, man, yeah, give us something to work with here.
Speaker 2 (24:22):
This is like, now we're in the weeds of like
stuff I don't like about lecture. But let's talk about
that first question, which is, you know, how like we're
going to put these three things together and get to
the last thing that people care about. But let's unpack
are their microplastics everywhere?
Speaker 1 (24:36):
Plastic is everywhere. We've talked about that, it's an ubiquitous
part of our lives. But microplastics come from a bunch
of different sources, right Emily, So, like, what are the
major ways that microplastics get into us, into humans?
Speaker 3 (24:49):
So basically, to get the microplastics into us, we have
to actually come in. You don't tend to absorb stuff
like that through your skin very much, so it's really
kind of stuff you eat and stuff you.
Speaker 2 (24:59):
Breathe or or inhale.
Speaker 3 (25:00):
So the major sources for people are stuff in your
diet and then like dust, so in your diet, you know,
we can find microplastics everywhere. There's this one study, and
I honestly think this is an over I'm not totally
sure I believe this, but there's one study of tea
bags in Canada which has like these tea bags are
(25:21):
just like basically exclusively made of microplastics, right.
Speaker 1 (25:26):
They forgot to put the tea in. They just filled
the bag with microplass and they.
Speaker 3 (25:30):
Just literally put microplastics. But that's not like all tea. Yeah,
it's just this particular I think, Yeah, I.
Speaker 1 (25:35):
Saw this too. This was a study that had the
amount of microplastics and a cup of tea like one
hundredfold higher than in any other source, which is but if.
Speaker 3 (25:43):
You put aside this particular terrible tea situation, generally most
of people's microplastic disposure is this through indoor dust. So
there's just a lot of plastics in indoor dust, with
a lot of plastics in your house, and they kind
of were indoor spaces and they sort of decay and
you and you.
Speaker 2 (25:59):
Inhale them and then you know of the.
Speaker 3 (26:02):
Diet stuff, plastic bottles, drinking out of plastic bottles is
kind of the biggest thing, and then tapwater, so it's
it's sort of stuff you drink and stuff you breathe
is the biggest set of issues.
Speaker 2 (26:12):
You can generally find.
Speaker 3 (26:14):
Microplastics in a lot of foods, and people store microplastics
and they're fat. So human fat has a lot of microplastics.
But we're not eating human fat, so that's not like
a dietary source.
Speaker 2 (26:24):
Not usually.
Speaker 1 (26:25):
Yeah, I should hope not, But it sounds like you're
I mean, these are hard things to kind of get.
Let's say I'm going to be concerned about microplastics, like,
don't breed dust is going to be a tricky one
for me, right.
Speaker 2 (26:35):
Yeah, I think that that's actually an important point from
the practical practical standpoint Here is, even if we get
to the end of this conversation and we say this
is something you should be worried about, it's actually not
entirely clear how people could really change their behavior to
affect this, And such a large share of your exposure
is just going to be through through breathing. But in general, yeah,
microplastics are around you.
Speaker 3 (26:56):
You're getting them in which leads to the question of
whether they stay, which I will ask you, which is,
to what extent do we actually know that people are
retaining these microplastics in their bodily tissues?
Speaker 2 (27:11):
Why don't they just poop it out? As I've asked
you several times that I don't feel like I've gotten
a straight answer.
Speaker 1 (27:16):
Uh, here, I'll give you a straight answer. They do
poop it out. In fact, when you measure microplastics in people,
one of the highest concentrations of microplastics is in FECs, stool,
is in poop, and that's likely because you are getting
it in the stuff you eat and it is just
passing through you. This is a bit of a problem
(27:38):
of size. So you mentioned earlier that microplastics are anything
that's five millimeters or less, and to give people a sense,
like five millimeters is like like a pencil eraser size.
This is it's like micro kind of but not really.
You know, like if I swallowed a pencil eraser, which
might be made a plastic, like it's passing right through me. Right,
(27:59):
You're gonna that that's going to be okay. You get
down to the nanoplastic scale, where these things are so
tiny that they can, you know, go between cells and
stuff like that, there's going to be a lot higher absorption.
And clearly there is absorption because there have been plenty
of studies looking at human tissues and measuring microplastics in them.
(28:20):
You can, you know, depending on the measurement method, you
get numbers that are a little bit all over the map.
But just to give just to give a sense of
where things kind of stand, there have been quite a
few studies now that show a reasonable accumulation of microplastics
in the placenta. There's been a number of studies looking
(28:42):
at microplastics in the kidney, which kind of makes sense
because the kidney's the major filtering ordering in of the blood,
and so if anything's going to kind of pick up
those little tiny micro or nanoplastics, the kidney would make sense.
You can find microplastics in the lungs. There's a study
showing microplastics in small concentrations, but in breast milk, some
(29:03):
in testicles, some in the intestines. So it's really kind
of everywhere you look, and perhaps most concerningly but also
most controversially, microplastics in the brain.
Speaker 3 (29:16):
Let me ask you before we on the way to
get into microplastics in the brain.
Speaker 2 (29:19):
I want to ask you. So you said there's microplastics
in the kidney. Now you're a kidney doctor, I'm curious
how we know that, Like if you see you must
see people's kidneys, like after they're dead, presumably sometimes.
Speaker 1 (29:33):
I mean there are slides prepared from them.
Speaker 2 (29:35):
Sure, can you like see the microplastics? How do you
know that there's microplastics in people's kidneys?
Speaker 1 (29:41):
There are multiple ways to measure, but yes, you can
see them. So under a microscope you can see little
irregularly shaped things that don't belong there, and essentially those
are microplastics. And in certain tissues you can see even
an inflammatory reaction around or you can find them inside
white blood cells, like the cells have kind of eaten
(30:04):
them or something like that in an attempt to break
them down as a foreign body. But some are even
too small to see under a typical light microscope. And
then there are other methods like mass spectroscopy, where you
literally you burn the tissue and the gas that comes
out with like you burn it with a laser, and
then the gas that comes out you sample and measure
(30:24):
the chemicals in the gas that comes out, and you
can kind of say oh look, there's like polyethylene there,
which it must have come from plastic. And but this
is a problem with the literature is it's like it's
it's really hard to quantify. Most of the data is
in units of like pieces per milligram, Like how many
pieces did we count in this miligram of tissue, which
(30:45):
is such a sort of random thing to me, Like
I want like I want uh grams per million. I
don't know milodgram's permilgram.
Speaker 3 (30:53):
Yeah, so I think it's it's interesting because those numbers
don't have any meaning. But the thing, a thing that
I think has really stuck with a lot of people
in this literature is this paper that said that there's
a spoon worth of plastic in your brain.
Speaker 1 (31:08):
Yeah.
Speaker 3 (31:08):
This is because it's like one thing to be like
there's pieces, I saw them, the mass spishocks, blah blah blah.
But this is like, now in my mind there is
an actual spoon. And in my head, of course, it's
shaped like a spoon. You know, it's like somewhere in here.
Speaker 1 (31:21):
Yeah yeah, yeah, like someone like shoved it right up
your ead.
Speaker 2 (31:24):
Someone shoved it right up it's like right in there.
You know, I could be eating with it.
Speaker 3 (31:28):
But that feels I think to a lot of people
like both very tangible. It is a lot and my
understanding is it's probably not true.
Speaker 1 (31:41):
Let's talk about to get a second.
Speaker 3 (31:42):
Yeah, I think we got to do the brain because
this is like, yeah, we got to do the brain.
Speaker 1 (31:45):
This is the paper. So so this is a paper
that appeared in Nature Medicine obviously got a lot of press.
I think the like plastic spoon's worth of plastic in
your brain. Just yeah, it's very hard for health reporters,
including myself because I wrote about this when it came
out to resist totally.
Speaker 2 (32:03):
The headline rights itself. I mean obviously.
Speaker 1 (32:06):
Headline rights itself. Let me give you just the data
that was in the paper, and then Emily, you tell
me why you're skeptical. Here. So, the way the study
worked was it was an autopsy based study. So University
of Arizona, I think they have like a brain repository
that where people have donated their brains after they died
over a period of time. And the authors sampled brain
(32:30):
tissue from the frontal lobe, the sort of important frontal
part of the brain, and they measured nanoplastics here. So
incredibly small pieces using mass spectroscopy. So that's that shooting
a laser and vaporizing the thing and measuring what comes
out of the vaporizer. And they compared this to the
microplastics and other tissues. And to give you some numbers here,
(32:51):
I'm not even going to say the units but because
they don't make much sense, but I'll give you the numbers. So,
like in the kidney of these patients or in the
kidneys they examined, they was like five hundred units of
microplastics per gram, and in the brain there was about
five thousand units of microplastics. Program So not only is
it in the brain, but they were like, it's in
(33:12):
the brain a lot, like more than everywhere else. They
also showed that that concentration increased over time, So between
twenty sixteen and twenty twenty four, like the amount of
microplastics in the brains that they had had increased. And
they also showed that brains with dementia had higher levels
of microplastics than brains without dementia. And you sort of
(33:34):
put that all together and then you start to get
like the real ick that I'm hurting myself by, you know,
drinking a plastic water bottle.
Speaker 3 (33:42):
Yeah, And I think that the thing that was maybe
on a technical level, more surprising here was people had
thought that the microplastics would not be so prevalent in
the brain because we have a blood brain barrier which
is supposed to protect your brain. Your brain is more
important than your kid is no offense, not to you
as a kidney doctor, but okay, I agree, were like,
(34:05):
your body's like more interested in protecting your brain, And
it was sort of the idea that these probably nanoplastics
were able to kind of get through the blood brain
barrier and populate the brain at these incredibly high levels
was disturbing, I think, is mat of point.
Speaker 1 (34:19):
Yeah, but there's pushback, right, So what's the push.
Speaker 2 (34:21):
There's a lot of pushback.
Speaker 3 (34:23):
So I think that the pushback here is really related
to how hard this is to measure. So again you're
you're like vaporizing this with a laser and seeing what
comes out. But the two criticisms that have come up
when people have talked about this are one, is it
actually microplastics as opposed to something else that you are
(34:44):
misinterpreting the chemical signal of for example, fat maybe more
similar to plastics. Than other things, and because there's a
lot of that kind of tissue in the brain that
could lead you to think that it's microplastics when actually
it's fat.
Speaker 2 (35:01):
And when we think about trends over time, since.
Speaker 3 (35:03):
Fat like obesity has gone up over time, that actually
could relate to some of the trends.
Speaker 2 (35:08):
I think that's one thing people.
Speaker 3 (35:09):
Have raised, and a second is just that it's really
really hard to control this carefully in the laboratory, and
people have raised some questions about this particular study and
whether they did a good job. This is an example
of something where it's so surprising, like it was so
surprising to so many people that you really probably would
want to do it again, and if it were easier
(35:30):
to do, someone would have done it again right away.
Speaker 2 (35:33):
The issue is now it's both hard to do. You
need a lot of brains from dead people who have
agreed to let you vaporize their brains for plastic or whatever,
and it's just so I think it's a bunch of
reasons why this is why it's been hard to replicate,
even though there are a lot of people who think
is probably not right.
Speaker 1 (35:49):
Yeah, I think that's such an important thing. I always
teach my students. I'll say this a million times. No
one study is definitive, right, Like replication is so important
because of these issues, Like you don't get all the
data in a paper, right, you get the sort of
filtered data that the scientists are putting in their paper,
and there's ethics about this and stuff, but you don't
get to see inside their lab. You don't get to
(36:10):
see what's happening. So it really is important to get replication.
To put another spin on this, the total amount of
microplastics that they calculated would be in the full brain
was about a half of a percent of the entire brain,
like the weight of the brain zero point five percent
of that, which to some neurologists is incredibly high, Like
(36:33):
they're like that level that amount of plastic, like, you know,
half of a percent throughout the brain is not something
we would miss. We would you know, we would clearly
see it. And it's so much higher than other tissues
that it just kind of doesn't seem plausible on the
face of it. But yeah, I guess we'll see.
Speaker 2 (36:48):
I guess we'll see.
Speaker 3 (36:49):
All right, So let's just establish whether it's a spoon
or a small spoon, A tea spoon ladle of plastic
in your brain, that there are plastics in our bodies.
And then there's these sort of two other things. So
one is, you know, do we have good evidence that
in laboratory kind of cell settings plastics are bad? And
my read of that is yes, that there's a lot
(37:12):
of evidence that if we take labs, either mice or
cells or organoids, which are like you try to make
like tiny pieces of human organs and you expose them
to a lot of microplastics, all kinds of bad stuff
happens to them.
Speaker 2 (37:27):
Yes, yes, fertility issues in mice.
Speaker 1 (37:30):
Yeah, But like contextually speaking, this is also true of
like everything we do to cells and mice and stuff
in the lab. Like this will come up again and again,
which is you know, if you take a model organism
or you take a cell in the petry dish and
you sort of stress it out with like whatever you're
going to pour on top of it, you know, whether
it's microplastics or whether it's like you know, round up
(37:53):
pesticide or whatever you do, you're going to get a
reaction out of those cells. It's similar to you know,
this particular dye, you know, food dye causing cancer or
something like that. Right, It's it's like that is the baseline. Again,
we always talk about biologic plausibility. Is it plausible that
there's a problem. Sure, we have some evidence, kind of
the floor of evidence, which is like if you soak
(38:16):
a cell in microplastic, it isn't happy about it. But
the you know, wellness world tends to run with that
and like go conclusion, conclusion, conclusion, conclusion, microplastics cause cancer.
Only drink out of like a wooden bowl from now on, right,
And we actually need to tie those together, and we
haven't tied those together very well yet. But maybe Emily,
(38:38):
we can talk about some of the areas that people
have said microplastics effects. So I think we talked about
the brain. We're not too sure what's going on in
the brain yet. But other things that have come out
or that people claim about microplastics are like obesity, for example.
So so do we think that plastic intake is causal
(39:02):
like leads to obesity?
Speaker 2 (39:05):
I don't think so.
Speaker 3 (39:07):
All of the literature that I have so let me
let me say I've read a bunch of this literature,
and it tends to associate levels of microplastic consumption or
you know, eating from takeout containers that have a lot
of microplastics with obesity. And the problem is that that
(39:28):
is an associational study, not a causal study.
Speaker 2 (39:32):
And so the.
Speaker 3 (39:33):
Fact that people who are exposed to more microplastics are
also more likely to be obese could easily, for example,
be explained by microplastic exposure from containers that are more
likely to contain process foods, which we know is associated
with obesity. So there's just looks so difficult to learn
from that kind of evidence. I just think that's I
(39:55):
just think that evidence is all such complete garbage.
Speaker 1 (39:58):
I saw it my favorite graph recently, which looked at
the rate of obesity between nineteen seventy six and twenty
nineteen and the rate of plastic production between nineteen seventy
six and twenty nineteen. It was like, look, they're both
going up. It's like, okay, guys, you know, there's a
lot of things that have gone up since.
Speaker 2 (40:16):
A lot of other a lot of other eventyow.
Speaker 3 (40:19):
But even like, the thing that's amazing about that is
like you could draw an interesting causal story there. You'd
be like, as it's been easy to make plastics, actually
we've that is contributed to like things about our food system.
So it could be that there's a like, in a
weird way, there's a causal link between plastics and what
it has made possible with the food system and obesity.
Speaker 2 (40:41):
But it's not for microplastics.
Speaker 1 (40:43):
Yeah.
Speaker 2 (40:44):
Even if that got for causal, it wouldn't be for
this reason, is what I'm saying.
Speaker 1 (40:47):
It's such a good point.
Speaker 3 (40:48):
The other place I think that that people talk a
lot about this is infertility. Yeah, and so you know,
we see microplastics in sperm, we see microplastics in the placenta,
and people worry about ertility rates. And I will say
in mice evidence again very high exposure to microplastics in
mice does seem to interfere with reproduction.
Speaker 2 (41:09):
What is your read of that literature? In people.
Speaker 1 (41:13):
Again very clear that there are microplastics in the placenta,
and in fact it's one of the tissues that they
see more microplastics than in some other tissues for reasons
that aren't entirely clear to me, Because the placenta is
not like a filtering organ like the liver or the
kidneys are, although maybe it is some kind of interface
(41:35):
that you know, makes microplastics more prone to be there.
The question is does it matter? And it's been very
difficult to show that there's a link between the microplastic
content in the placenta or a microplastic exposures and birth outcomes,
which is the important thing that you know, we care
about here. What do you think, Emily, I mean, this
(41:56):
is this is your your your wheelhouse.
Speaker 2 (41:58):
Yeah, I think you know. So.
Speaker 3 (42:00):
I don't think that there's any compelling evidence of particularly
important effects here. I mean, and I guess this gets
into where I end up on basically all of these things,
you know, cardiovascular disease, dementia, etc. Like Is it possible
that there is at some level of microplastics and effect, Yeah,
I think so. Is it likely that there's an effect
(42:23):
at the levels that we see people being exposed. I
don't think we have any evidence of that, and all
the literature on this is very very poor. And to
the extent you're seeing a correlation, almost certainly like nearly
all that correlation is driven by other differences across people
and not by the microplastics.
Speaker 1 (42:42):
Yeah. Sometimes it's helpful to imagine imagine two people, like
the ultimate microplastic consumer and then the ultimate like non
microplastic person, not because they're deliberately trying to avoid them,
but like, what is sort of the image you have?
And if I think of like, you know, who's not
getting many brighter plastics, well, it's like this this guy
(43:03):
out in a log cabin in the woods who's like,
you know, hunting and fishing and eating whole foods and
you know, doing that kind of stuff and like whittling
his own z at block bags from a cherry tree.
And then you know, I think of the like microplastic consumer,
and you have someone who's you know, yeah, eating a
lot of takeout and all that kind of stuff, and
those are all what we call confounders. Those are all
(43:24):
problems when you're trying to tie microplastics to something because
the type of people who have more microplastics in them
are different than the type of people who have less
microplastics in them, and those differences can matter in terms
of all sorts of health outcomes.
Speaker 3 (43:37):
Yeah, So, I mean, I think I am very skeptical
of claims that exposure to microplastics are an important part
of people's health. So, like, is it possible they are
a little bit of it?
Speaker 2 (43:47):
Maybe? Is it likely that this is a very important
driver of various problems that people have in their health.
Just the answer is I think no.
Speaker 1 (43:56):
I agree, I think this isn't the biggest problem we
face health wise. But I also always like to look
at like, okay, maybe it's not, but are there easy steady?
Like if I care, how easy would it be to
change this? And as we've been talking, you know, you've
told me about dust being a major contributor of microplastics. Like,
all right, I'm not going to change that. But it
feels like if you believe the tea study, right, like, okay,
(44:18):
maybe I'll just make tea using tea leaves and a
stainless steel tea filter. That's pretty easy. Do you think
there's like some easy stuff we should be doing. I
should I have a Stanley water bottle, like low hanging fruit.
Speaker 3 (44:32):
Here, So I think there's the lowest hanging fruit is
avoiding like non reusable water bottles. So like plastic water
bottles are among the higher microplastic giver offers, they are
also not very good for the environment. And so there's
a kind of double whammy positive of just trying to
(44:52):
you know, not be neurotic and never ever use disposable
plastic water bottles, but think a little bit about you know,
limiting those. I think that's that is the simplest thing.
I think for most people that would change their microplastic
exposure some and almost every other change you.
Speaker 2 (45:11):
Would make is totally unrealistic, like don't breathe.
Speaker 1 (45:14):
Yeah, yeah, yeah, we don't recommend that in the medical spheres.
I think for me, yeah, I think I can use
a reusable water bottle. I think when I'm reheating my
takeout food in the microwave, like maybe I'll transfer it
to a bowl that is not plastic before I reheat
it in the plastic thing. I don't know that's easy.
Speaker 2 (45:34):
Sure, yeah, I mean I again, I think that's that
could be easy. I think you have to.
Speaker 3 (45:38):
Ask the question, like what is easy for you? And
maybe that's also a question about reusable water bottles. I
think we could say, like, here are two things you
could do. Use fewer disposable water bottles and don't microwave
your takeout, and then you can think about, you know,
how feasible are those changes for you?
Speaker 1 (45:54):
I like it, all right, let's bottom line this thing, Emily,
microplastics smash your pass or actually should probably say avoiding
microplastics smasher pass.
Speaker 3 (46:06):
I'm a pass on this because I think that in
the space of things people can do with their limited
attention and time for their health, trying to avoid all
sources of microplastics is not a very good use of
that limited time and energy. So, you know, if someone
said I'm going to use fewer single use water bottles, sure,
(46:29):
I think that's a good thing to do for the
environment in general. But from my taste, I think people
could think less about microplastics for their own health.
Speaker 1 (46:38):
I am going to smash this one. I'm going to
smash avoiding microplastics primarily from other earth. I think we
all should be using less plastics, and I you know,
I don't think everything can be avoided, But like, am
I going to maybe not reheat my leftovers in the
plastic container? Maybe use my you know, aluminum water bottle
(46:58):
a little bit more based on what I've seen so far. Yeah,
that's some That's a change I can make. Change I
can live with.
Speaker 2 (47:04):
Okay, it's our first disagreement.
Speaker 1 (47:07):
Is it over?
Speaker 2 (47:09):
I think it's over.
Speaker 1 (47:09):
I feel like we.
Speaker 2 (47:10):
Did a good I feel like we did a good
job on that respectful disagreement. Okay, all right, that's it
for microplastics. Your mailbag question of the week after the break.
Speaker 5 (47:26):
Hi, am LeAnn Perry. This is Rachel from Philadelphia, and
I have a question about my weight, specifically, how I'm
ever supposed to trust.
Speaker 1 (47:34):
What the scale says.
Speaker 5 (47:36):
It's always fluctuating by a few pounds, and I really
can't figure out where those pounds are coming from. I
feel like my eating habits really aren't changing that much.
How often should I be weighing myself? And when is
a good time of day First thing in the morning,
later in the evening. I'm really just trying to get
an accurate idea.
Speaker 1 (47:55):
Thank you, awesome question. I love this question because people
get really obsessed with weight. It's part of their daily habit.
They get on that scale and on a day to
day basis, there's a ton of stuff that makes your
weight fluctuate, and none of it is like the fat
content in your body. The primary driver of day to
day fluctuation and weight is water. So water's very heavy.
(48:19):
A leader of water weighs two point two kilograms, which
is about five pounds almost. That's a big swing. And
you drink water based on how much salt you intake.
So the more salt you eat, the more reflexively the
more water you go for. That's you can experience that,
you know, after driving Chinese food or something. It is
literal water weight. That is what is driving day to
day weight changes. The only utility of that is to
(48:41):
look at large trends over time to get a sense
of what's happening with like fat mass, muscle mass, et cetera. Emily,
do you weigh yourself every day?
Speaker 3 (48:49):
I don't weigh myself every day, but I'm going to
tell you something that's interesting about water and salt, which
is one of the things that I sometimes do before
short distance races is take sodium bycarb, which is just
a really really really high dose of baking soda which
gives you a tremendous amount of sodium, like a billion
(49:10):
times not a billion, but like a lot, like a
lot of sodium. And it's good for performance in various ways.
But it also makes you incredibly thirsty and it makes
you retain like an enormous amount of water. And so
if you weigh yourself in the morning after a race,
after you have taken sodium bycarb, it's like a substantial
amount of we gain that sort of like fades out
(49:31):
over time. I did once experiment by weighing myself every
day for like four or five days after and it
took a few days to kind of come back to normal.
Speaker 1 (49:38):
Yeah, this is classic physiology they teach you in med school.
Speaker 3 (49:41):
So if you are tracking your weight over time, there
are a few different ways you could do. What You
could weigh yourself every day, but look for overall trends
over time. I tend to think that that makes people
who are trying to lose weight very anxious, and so
I don't think it's like a generally recommended thing to do.
But certainly there are some medical circumstances in which it
(50:02):
would make sense. If you are going to weigh yourself
every day, try to do it at the same time.
Speaker 1 (50:07):
Yeah, typically we tell people in the medical field people
who should wag themselves. There typically people with heart failure
where we really are managing that fluid status that's so important,
and we're using it not to see what they're fat
or muscle masses. We're using it to assess water weight.
So if you don't have heart failure, no need to
weigh yourself every day. We do tell people. If you
want consistent results, do it first thing in the morning,
(50:27):
after you pee. That's it for us today. Stick with
us next week when we'll ask what's the deal with
stem cell therapy?
Speaker 3 (50:38):
Wellness Actually is produced in association with iHeartMedia.
Speaker 2 (50:41):
Our senior producer is Tamar Avisheik.
Speaker 3 (50:44):
Our executive producer at iHeart is Jennifer Bassett. Our theme
music is by Eric Deutsch, and our content is for
educational purposes only.
Speaker 1 (50:52):
If you like the show, help other people find us,
leave a rating and review on Apple Podcasts or your
podcatcher of choice and help us spread the word about
the show. You can follow us on Instagram at Wellness
Actually pod and don't forget We want to hear from you.
Head over to Wellness Actually dot fm and leave us
a question for our mailbag or suggest a topic for
(51:12):
a future show.
Speaker 2 (51:14):
We'll let the influencers have the last word.
Speaker 6 (51:16):
Microplastics. Here's a public service announcement. If you go get
a cup of coffee and it's in a paper cup,
the entire paper cup is plastic. When they put the
hot water in there, you're drinking a cup of plastic.
They're already showing that it's disrupting hormones, it's disrupting mitochondria,
is disrupting so much heavy in fertility. They're finding plastics
in people's testicles anyway, So finding a detoxification while your
(51:39):
body is detoxifying in a sauna helps push it all
out
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