The Peter Attia Drive - #332 - AMA #67： Microplastics, PFAS, and phthalates： understanding health risks and a framework for minimizing exposure and mitigating risk

00:00:00.000 Hey everyone, welcome to a sneak peek, ask me anything or AMA episode of the drive podcast.

00:00:15.820 I'm your host, Peter Atiyah. At the end of this short episode, I'll explain how you can access

00:00:20.280 the AMA episodes in full, along with a ton of other membership benefits we've created,

00:00:24.900 or you can learn more now by going to peteratiyahmd.com forward slash subscribe.

00:00:30.600 So without further delay, here's today's sneak peek of the ask me anything episode.

00:00:38.900 Welcome to ask me anything AMA episode 67. For today's AMA, we're going to focus on something

00:00:45.960 that's gotten a lot of attention lately in the news, online, social media. And as a result,

00:00:50.420 we've received an endless stream of questions, not only from our audience, but also from our

00:00:54.880 patients. And that topic is microplastics and all other accompanying chemicals, such as BPAs,

00:01:01.460 PFASs, and phthalates. Given the interest, we decided to dedicate an AMA to this topic.

00:01:07.760 In this conversation, we dive deeply into what we know and what we don't know about these chemicals,

00:01:13.540 why they seem to appear all of a sudden everywhere, how we're exposed to them, how much exposure we

00:01:20.080 have, and how dangerous they may or may not be to our health. Ultimately, and perhaps most importantly,

00:01:25.980 I think, we propose a framework for how someone can think about avoiding and mitigating exposure

00:01:32.120 to these chemicals. If you are a subscriber and you want to watch the full video of this podcast,

00:01:38.280 you can find it on the show notes page. If you're not a subscriber, you can watch a sneak peek of the

00:01:43.200 video on our YouTube page. So without further delay, I hope you enjoy AMA 67.

00:01:54.420 Peter, thanks for coming back for another AMA. How are you doing?

00:01:58.200 Good. Thank you for having me.

00:01:59.640 Before we get started today, quick question. Do you have a beverage in front of you?

00:02:03.580 I do.

00:02:04.540 What type of glass is that in? Is it a plastic? Is it glass?

00:02:08.280 It is plastic.

00:02:10.440 Huh. Okay. Interesting then. That will be interesting for this AMA, which is going to 0.98

00:02:16.140 cover one topic, which is something that seems to be growing in interest. We've been getting a ton

00:02:21.560 of questions on, a ton of conversation online. That's microplastics and other chemicals such as

00:02:27.580 BPAs, PFAS, and phthalates. So what we did, gathered all these questions that have come through,

00:02:34.520 pull them together, and are ultimately going to try and help people understand,

00:02:39.840 should they be worried? What should they be worried about? What's dangerous? Based on all

00:02:45.040 that, what can they do about it? Before we get started, anything you want to add?

00:02:51.100 I think there's actually a lot I need to say before we dive into this for context. So I'll

00:02:56.640 preface maybe by saying the following. Obviously, people who are regular listeners of the AMA can

00:03:01.660 appreciate that these are not off-the-cuff remarks that we make here, and we put a lot of work into

00:03:07.680 doing this. When I sit up here and do these AMAs, I'm doing them based on the work that me and a team

00:03:12.940 of analysts have done for usually about a month in preparation for them. I think it would be safe to

00:03:18.840 say that in the six years we've been doing this, or is it seven or eight now? I've lost track.

00:03:26.260 To date, at least, this will go down as the AMA that has required the most work, that has probably

00:03:36.040 generated the most swear words, and probably resulted in the secretion of the most adrenergic

00:03:44.620 compounds from the adrenal glands. In other words, this has been a royal pain in the ass to prepare for. 0.99

00:03:52.200 And as recently as last night at 10 o'clock, I was emailing you saying, what the F? Why are we doing 0.99

00:04:01.200 this? It's a never-ending morass of information, most of which is incomplete. There's so much I could

00:04:10.240 say on this. And then the most wonderful thing happened, which always happens. Anyone has experienced

00:04:15.160 this if they think back to being in college. Even the night before the exam, you're like, I don't know

00:04:19.240 what the hell is going on. And the best advice is usually just go to bed, get a good night's sleep,

00:04:24.640 get up nice and early, fresh cup of coffee. And I think that sort of happened this morning.

00:04:31.440 Me and a couple of the other analysts went to bed, got up this morning, and all of a sudden,

00:04:36.680 I just had more clarity about, in my words, how to land the plane. And I took to writing a couple of

00:04:43.520 pages out. And I think I've got kind of a sensible way to make sense of something that is incredibly

00:04:50.800 noisy. So what I'm going to say at the outset is, if you are listening to this thinking that there is

00:04:57.360 a punchline and a one-word answer, I'm going to spare you the disappointment. This is a very nuanced

00:05:04.180 topic. If I could answer this in a word, I promise you I would, and I would never try to go through

00:05:13.840 the 75 pages of notes that our team has assembled to help me think about this topic. I swear to you,

00:05:21.200 there are a hundred things I'd rather be doing right now than going through this. However, it is

00:05:27.060 important in an area where there is so much uncertainty, so much asymmetry and such complete

00:05:34.580 and incomplete information that we have to understand the boundary conditions so that we

00:05:40.240 can each make a reasonably informed decision. So with that as my preamble, let's do our best to guide

00:05:48.120 people on a journey that we've been on and acknowledge our shortcomings, acknowledge where we wish we knew

00:05:53.500 more, where maybe others do know more, but leave people with a framework such that at the end of

00:05:59.600 this AMA, which will hopefully be sometime today and not tomorrow, everyone can sort of make a risk

00:06:06.440 based decision for themselves, for their families. Definitely. And it kind of reminds me of what Bob

00:06:12.800 Kaplan always used to say, right? Which is further from the shore, the deeper the water. So as we've kind

00:06:17.920 of like gone deeper and deeper on this, it seems more complicated, more complicated.

00:06:22.760 The last question I'll ask before we get started, that coffee you drank this morning,

00:06:26.940 was that in a glass mug or like a Starbucks paper mug with the plastic lid on top?

00:06:34.320 It was actually in a metal Yeti camping coffee cup. That's sort of my favorite way to drink coffee.

00:06:41.860 All right. So you redeemed yourself a little bit there, which is good. Starting off,

00:06:45.960 I think it'd be helpful as we kind of typically do definitions. What are microplastics? What's BPA?

00:06:52.560 What are these chemicals we're talking about? Let's just define them now. So as we say them going

00:06:57.540 forward, people understand what we're talking about. Part of this is you just have to suck 1.00

00:07:01.960 it up through the semantics. And part of the challenge is that some of the definitions are

00:07:06.480 not very helpful. So starting with microplastics, they're typically defined as any particles of

00:07:13.200 plastic that are smaller than five millimeters. Now, again, I realize that not everybody is facile with

00:07:19.400 the metric system, but anybody who is will realize five millimeters is huge. You can see five

00:07:24.480 millimeters. That's half a centimeter. So we're not really talking about that. I think most current

00:07:30.440 studies would really classify microplastics as those smaller than one millimeter, one-tenth of

00:07:36.100 a centimeter, about one-twenty-fifth of an inch. And then, of course, we talk about what are called

00:07:41.420 nanoplastics, which are particles that are smaller than one micrometer or micrometer. So one-one-thousandth

00:07:50.060 of a meter. So we abbreviate these as MNPs or micro-nanoparticles. And we should just acknowledge

00:08:00.440 that these things are completely ubiquitous. They're found anywhere that we have looked for them,

00:08:07.300 which is to say we find them in water. We find them in food. We find them in fruit, on fruit,

00:08:12.320 in vegetables, on vegetables, in meat, in the air. And therefore, micro-nanoplasticles or MNPs

00:08:18.720 are completely ubiquitous. Okay, you asked about BPA. Now, there are lots of these bisphenol chemicals,

00:08:27.520 but bisphenol A or BPA is the one that most people are familiar with. Ironically, the presence of BPA,

00:08:34.380 at least being used actively, has been reduced quite a bit over the past 15 years. But just

00:08:40.200 understand that there's a whole family of these bisphenols, and typically we substitute one for

00:08:44.760 the other. But what are they? They're chemicals that are used to make polycarbonate plastic.

00:08:50.140 Polycarbonate plastic is the hard plastics we have in our world. So if you think about all the places

00:08:55.000 where you use plastic and it's hard, I think of the Nalgene-type water bottles, epoxies, resins,

00:09:02.400 things like that, that's where you're going to have historically found a lot of BPA. Of course,

00:09:06.860 today, this is less the case, but the truth of the matter is they're now replaced by other

00:09:13.360 bisphenols, so BPS and BPF. And the truth of the matter is not clear that we know if those are any

00:09:20.400 better than BPA. So when I say BPA, I think it's just easiest to sort of think of the broad category of

00:09:26.660 these families. Another thing that we're going to talk a bit about, and I've talked quite a bit about

00:09:30.720 this in the past, is actually particulate matters of the 2.5 or smaller variant. These are abbreviated

00:09:36.200 PM 2.5. And again, it refers to particulate matters in the air that are smaller than 2.5

00:09:44.600 micrometers. So why is that important? Well, there's something relevant about a particle that's that small,

00:09:52.580 which is that if inhaled, it has the potential at least to become systemic. And the reason for that

00:10:00.060 has to do with the anatomy of the lung and the size of both the alveolar air sacs and the epithelial

00:10:08.300 linings of them, which again, it's not necessarily that intuitive that you could breathe something,

00:10:14.220 but that it is small enough that it could actually get across a cell barrier at the innermost part of

00:10:19.160 the lungs and enter the systemic circulation just as though it had been injected into you.

00:10:24.740 A PM 2.5 refers to any particulate matter that is inhaled in the air that is of that size or

00:10:31.880 smaller. Now, are there some microplastics or micro nanoplastics that fit that description? Yes,

00:10:38.720 but most are not. So most PM 2.5s are not microplastics. I forget the exact number. I know

00:10:46.540 it's somewhere. We did look it up. It's on the order of a few percent. I would say that the greatest

00:10:51.320 contribution to PM 2.5s probably come from air pollution. So anything that has to do with when

00:10:57.140 there's a fire, burning wood, obviously burning fossil fuels, but coal being hands down the leader

00:11:03.020 of this. I mean, natural gas combustion produces much less of this. And then we'll talk about

00:11:07.520 phthalates, which are another class of chemicals that are kind of like, I think of them as sort of

00:11:13.180 the opposite of the BPAs. So these are the things that are used in plastics to make plastic more

00:11:18.920 flexible, to have more bend in it. They're also found in products that we use like shampoos,

00:11:25.900 lotions, laundry detergents. It makes fragrances last longer. Now, there's been a constant regulatory

00:11:32.820 shuffling around all of these things, and I'm not going to get into it because I could just put

00:11:38.660 everybody to sleep right now. We're going to leave a ton of this in the show notes section where we're

00:11:43.120 going to kind of go through the regulatory machinations on this and which of these products

00:11:49.100 were banned and when and what got substituted in. But the bottom line is that the use of phthalates

00:11:55.300 are still currently allowed in food content application, but many companies have undergone

00:12:00.420 voluntary reductions in this. There doesn't appear to be any restriction in the use of phthalates for

00:12:06.680 personal care products. And I think this is probably where people are going to see their greatest

00:12:11.380 exposure to them. So I guess I'll stop there, Nick, but that's the whirlwind tour of what all

00:12:18.860 these different compounds are. Do we have any idea why it seems like we're now hearing about

00:12:26.100 microplastics being everywhere? It doesn't seem like that was always the case. So do we know why

00:12:31.780 there's been this huge uptick in this? Yeah, I think there's two things going on. So the first is that

00:12:38.520 obviously plastics are relatively new, didn't really exist much prior to the 1950s. And if you think

00:12:47.280 about it, I mean, they were pretty remarkable. So incredibly lightweight, remarkable strength to

00:12:53.200 weight ratio, resistant to rotting and corrosion and shattering. I mean, there are lots of reasons we

00:12:59.340 use plastic. So when you combine the fact that they've been increasing in their proliferation

00:13:05.380 population over the past 70 years, that would certainly explain why we might be seeing more

00:13:12.300 of them. But there's also a little bit of what is the expression, the drunk under the streetlight

00:13:16.500 problem. People are also looking at this more and more and more. In fact, if you don't mind,

00:13:21.620 if you could pull up, there's a figure we've got that shows the number of scientific publications

00:13:27.080 focusing on microplastics in the last 20 years. So if you go back, it's showing basically 2000 to

00:13:34.260 2020. It's a linear scale, but it's still pretty remarkable. It still looks like you're basically

00:13:39.660 watching Bitcoin from 2010 to 2020. That's effectively what's been going on. So I don't doubt that there are

00:13:48.100 more and more microplastics accumulating in the environment. That's likely, but we can't lose sight of

00:13:53.040 the fact that we're also looking for it nonstop. So one of the questions that I didn't come up with

00:13:59.340 a satisfactory answer to was, if you just look at the last five years, are we seeing a true increase?

00:14:06.820 I wouldn't doubt that there's more 2020 versus 1980. That strikes me as, hey, over that 40-year

00:14:13.060 period, I could really see it going up. But 2020 to 2025, is that a real increase or is that an

00:14:20.100 artifact of observation? You touched on a teeny bit when you were kind of going over the definitions,

00:14:25.980 but I think it'd be helpful to just dive into it a little deeper, which is how are humans being

00:14:30.400 exposed to microplastics currently? We should always be thinking about this through the lens of

00:14:35.760 relevant versus not so relevant exposure. But again, we're going to always try to focus on a relevant

00:14:40.520 exposure, which is an exposure that has the potential to accumulate. So the most common route of human

00:14:47.400 exposure is from inhaling plastic dust and fibers and from consuming food and beverages that contain

00:14:53.940 these micro nanoplastics. And again, that's why I prefer to talk about NMPs rather than just micro

00:15:00.420 plastics. Why? Because my concern about consuming a five millimeter piece of plastic is nil because it

00:15:10.040 can't be absorbed. It's going to come right out my body the next day. This is not the thing that we need

00:15:15.060 to be afraid of. So what are the foods and beverages we need to be concerned with? The highest places we

00:15:20.920 tend to see these are in seafood, salts, water, both tap water and bottled water, but also in fruits,

00:15:28.560 vegetables, meats, even beverages like milk, beer, and wine, which obviously contain water as well.

00:15:35.100 Nanoplastics in soil can accumulate within plants, and obviously the exposure gets magnified as you go up

00:15:41.080 the food chain. This again explains why we would see it in seafood, given that we understand the role

00:15:46.860 of plastics in the oceans. And that's why obviously you can see seafood and land animals accumulating

00:15:52.840 these as well. The epithelial barrier is the first line of defense. And remember, there's an epithelial

00:15:58.840 layer on the outside of your body that we can see, but there's also an epithelial layer on the inside

00:16:02.680 of your body. Everything between your mouth and your anus is also an epithelial layer. And that's why

00:16:07.840 generally micro nanoparticles don't enter the body through the skin or through the gut unless they

00:16:16.120 are small enough. We've already talked about it. The pulmonary epithelium requires them to be smaller

00:16:21.620 than 2.5 microns. And in the lining of the gut, it could probably be as big as 150 microns to be

00:16:30.580 absorbed. Do we know how much plastic humans actually consume? And is it even

00:16:37.100 knowable? You often hear numbers thrown around a lot. Curious what we know on that.

00:16:42.980 It's difficult to know, but I think we can probably put some brackets around it. So

00:16:46.740 first, there's a huge amount of variability based on a lot of factors. So where you live,

00:16:53.280 what type of food you eat, and what your source of drinking water is would probably be the three

00:16:59.840 biggest determinants of your exposure to MNPs. That's worth noting again, and I think it's worth 0.99

00:17:07.040 stating. Your geography, your source of food, your source of water plays the biggest role.

00:17:12.860 If you aggregate the data from all of the studies, it would suggest that humans are consuming,

00:17:19.820 and this is a broad range, so that's just unfortunately the nature of this stuff,

00:17:23.660 somewhere between 10 and 300 micrograms a week. This is 10 to 300 thousandths of a gram per week.

00:17:34.200 Now, a study that was published in 2021 estimated that on average, we consume about four micrograms

00:17:42.940 per week from fish and other sea things like crustaceans, mollusks, tap water, bottled water,

00:17:50.080 beer, et cetera, et cetera. The study simulated the expected exposure to amounts that agreed with

00:17:56.500 measured quantities in microplastics and stool. So I think this is probably an underestimate,

00:18:02.240 given that it didn't look at some of the other areas that have already been found to contain some

00:18:07.960 MNPs, such as fruits, meat, vegetables, potentially plastic off cutting boards, utensils,

00:18:13.760 plastics that may come from things we'll talk about, like reheating food and things like that.

00:18:18.700 So the point is that the mass of these things is pretty small, and that might not be the right

00:18:24.780 way to think about it, and we can talk about some of the misinterpretations of that stuff.

00:18:29.600 There was a recent study published in 2023. It was in Korea, and it estimated that the population

00:18:36.660 was consuming somewhere between 140 and 310 micrograms per week. That's a nice narrower band. It also

00:18:44.300 ports with largely the upper limit of the US-based study as well. I think that's probably the ballpark

00:18:51.340 of where people are consuming. How do those numbers compare to the credit card worth of plastic that

00:18:58.340 was all over the news? I think you couldn't go anywhere without seeing that we're eating or consuming

00:19:04.360 a credit card worth of plastic a week. So the numbers that we're seeing in those studies compared

00:19:09.680 to what that would be, how do those compare? Not even in the same zip code. So that soundbite

00:19:15.160 that humans consume a credit card worth of plastic refers to a report that estimated weekly consumption

00:19:21.360 was five grams of MMPs. That has been largely debunked, despite what you've said, which is the

00:19:28.720 prevalence in popular media. But, and I don't remember who famously stated that a lie will travel

00:19:34.240 around the world or halfway around the world before the truth has a chance to pull its boots on.

00:19:38.920 I don't even need to go into that. We'll link in the show notes to both the original analysis,

00:19:44.520 which came out of the university of Newcastle commissioned by the WWF was released, I think

00:19:50.680 in 2019. And then obviously the rebuttals to that, but yeah, the long and short of it is I don't think

00:19:57.360 any serious person believes that we're consuming five grams of plastic a week. Based on what we consume,

00:20:03.400 what do we know about how they're eliminated from our body?

00:20:07.000 The main way that these things are eliminated is largely through coughing and sneezing them out.

00:20:13.540 So anything that's coming into our lungs, we can get it out by a cough or a sneeze,

00:20:17.720 as well as urine and stool. So the largest particles, those that are greater than 10 microns,

00:20:25.260 will generally be removed with relatively high efficiency, regardless of how they enter the body.

00:20:32.540 It's really the smaller particles that are eventually going to make their way to the

00:20:37.540 immune system. If you were going to do a mass balance on this stuff, the majority to the tune

00:20:43.340 of 99% of ingested microplastics are going to be eliminated through stool. And this is a relatively

00:20:50.580 short transit time. We're talking about 24 to 72 hours. Plastics have a very difficult time crossing

00:20:56.400 the GI epithelium. So when you look at animal studies, we would see that it's about 0.3%,

00:21:04.400 maybe with a ceiling of about 1.7% of microplastics have the capacity to be absorbed across the GI

00:21:11.480 epithelium. And of course, it's heavily, heavily size dependent. So it's the particles that are going

00:21:16.960 to be less than 10 microns, which remember that's four times larger than what is required to get into

00:21:24.820 the lungs. So again, just think in the lung, we're anchoring to 2.5 microns or less. In the gut,

00:21:30.660 even though in theory, the gut could absorb something close to maybe a hundred, I think

00:21:36.160 that's more theoretical. And in practical terms, we tend to see it as 10 micron or four times that size.

00:21:41.300 So the bottom line is this, if you're encountering a microplastic that's less than 2.5 microns,

00:21:47.220 you could absorb it both in your gut or via your lungs. Now, when we go through this type of

00:21:53.340 analysis in urine, we again see that we also excrete microplastics through the urine, but this is less

00:22:00.000 than what we do through the gut. For the things that are not eliminated, where do they end up and

00:22:06.940 why are there growing concerns about that? So this is really the crux of what's going on.

00:22:12.420 Thank you for listening to today's sneak peek AMA episode of The Drive. If you're interested

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00:25:17.720 Thank you.

The Peter Attia Drive - January 20, 2025

#332 - AMA #67： Microplastics, PFAS, and phthalates： understanding health risks and a framework for minimizing exposure and mitigating risk

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