Are microplastics really a problem?

25:20This is Professor Emily Oster. She's an economist. A lot of her research is on health and development. She's made a career helping people decide what the evidence is actually showing us when it comes to questions about our own health and often the health of our children. Nobody's like, great idea, consume a lot of tiny pieces of plastic to become like a bionic plastic human, right? Nobody thinks that. And so it's sort of our upper bound on the possible thing is maybe it doesn't matter. That's like the best case scenario is just a gross, weird thing that doesn't matter. And then the worst case scenario is it is in some way damaging.

25:58Emily and Tracy are going to be our guides through the science here. There have been a number of studies around microplastics. We at Search Engine have now spent a good amount of time in them. Frankly, the science does not yet seem entirely settled. A fair amount is uncertain. And so these two experts are going to help us walk through all this. They've both spent time thinking about microplastics and have ended up with slightly different conclusions, which we'll get to. But for now, what we know is that microplastics are inside of us, and we know that that is not optimal. But what is actually happening to our bodies once they become hosts to microplastic collections?

26:36Professor Tracy Woodruff leads and collaborates on a research team that studies exposures to chemicals in plastics and how they influence our health, particularly when it comes to pregnancy. She talked to me about how this research even works, given you can't ethically just expose one group of people to lots of microplastics on purpose in order to study them? When we're talking about looking at chemical exposures, for example, typical ways that we do this in environmental health is we use animal studies, so rats and mice, where you can control their exposures and you could have a control. Basically, what we see in animals reflects what we would see in humans.

27:15And in the animal studies, were the animals being exposed to the chemicals in microplastics or microplastics themselves? Like, is it like you're giving a mouse water and you're putting tiny little particles of a plastic spoon in it? So they basically purchase small microbeads. And plastics is made of different types of materials. Some of them are polystyrene, some of them are polyvinyl chloride. So they purchase these beads and they're microbeads and then they put it in the water or they put it in the food and the animals eat it.

27:50So these animals are dosed with water and food that has lots and lots of plastic microbeads inside. What happens to their bodies? Nothing you'd want to happen to your body. Mice pumped full of microplastics, for instance. Males have their fertility rates dropped. The females miscarry more often. Their offspring, if they have them, can have metabolic disorders. And this is not just one study or one kind of animal. Feed a honeybee microplastics, it'll lose some of its memory. In fish, microplastics can cause tissue damage. In birds, a new disease called plasticosis, where the birds suffer fibrotic scarring to their digestive tracts.

28:31Again, these are mostly animals in labs, not humans in the world. But it's concerning. Tracy Woodruff explained her hypothesis for how microplastics could be affecting human bodies once they get inside of us. inflammation. They can cause your cells to react to the microplastic and attack it as a foreign body, or they can increase immunosuppression because it's not just microplastics we're exposed to. We're also exposed to perfluorinated chemicals, which we know can increase health effects. We're exposed to these phthalate chemicals. We're exposed to BPA. We're exposed to flame return chemicals.

29:09So we think some of the chemicals could come off of the microplastics and then those can perturb different type of biological systems. What Professor Tracy Woodruff is saying here is a little complicated. She's saying that we're both trying to study how microplastic particles alone could hurt us, these tiny little fragments in our bodies wandering around, damaging our tissue, but also how the toxic chemicals inside of those fragments can hurt us once they leach out. And this is the part of the story that I most experience as the feeling of a dark forest filled with question marks. What we know is that there are chemicals in plastics that are endocrine disruptors, meaning they confuse our body's hormonal systems, which in some cases could affect people's reproductive health.

29:57We know that. And then there's been a lot of strange things happening to our bodies over the past few decades that we cannot definitively explain. Men, on average, have lower testosterone levels than they did a few decades ago. There are more adult women struggling to conceive. There are more girls entering puberty earlier. We don't know how connected these things are to environmental toxins, but a lot of scientists are looking at this, including Professor Woodruff. And scientists have noticed that sometimes, not always, but sometimes, when we compare one group of people having these health issues with a group that isn't, we'll find that the group that's struggling has more microplastics in their bodies.

30:40From Professor Tracy Woodruff's perspective, we've made a big change to our environment. We're seeing changes to our health. We know that microplastics make animals really sick. And so there's a real possibility that we're all poisoning ourselves in a way that, 100 years from now, will seem like a real calamity. That is the scary version of the story. But I should say that that version of the story is a hypothesis. It includes some educated guesses. And it is possible for a reasonable person to look at the same studies and come to a somewhat different conclusion. Professor Emily Oster, a reasonable person, an economist who is very skilled at studying health data and assessing risk, she says, wait a minute.

31:24Let's look at all this from another perspective. She starts with the same animal studies. And at first, she sees the same things. So if you expose mice, which is our most standard animal model, to like very high doses of microplastics, it causes a bunch of different negative consequences in different body systems, digestion, respiratory system, the fertility system, the endocrine system. But when it comes to extrapolating this to humans, Emily Oster has a good question. Do we believe that human beings are being exposed to microplastics at doses that would actually affect our health? That is the question.

32:02And that is where the evidence, I think, is not especially compelling. So the doses that humans are exposed to, even though there's a bunch of it in your brain, they are way, way lower than the doses that we're exposing animals to in these studies. And there is a fair amount of disagreement about whether those doses are in fact bad enough to have any measurable negative impacts on people. We don't have a lot of direct evidence or really any direct evidence that would say having a lot of microplastics makes you less healthy. So I think there's actually a legitimate disagreement about, you know, whether at the levels people are exposed to, this is actually a health problem that would be kind of important, like you would want to be concerned about it for yourself.

32:50When you say that level of disagreement, you mean like it's not that there's strong, clear evidence that this is definitely okay. hey, it's just there hasn't been strong, clear evidence that it's having an effect? Yes, that's what I mean. And I would also add to that that if the effects were very large, I think we would see them. So we're sort of in a space where I would say the disagreement is at this level of exposure, would there be any measurable negative effect or not? I think if the effects were enormously big at these low levels, those we would have already seen.

33:29Emily Oster's point, and this is where she and Tracy Woodruff really do depart from each other, Emily Oster believes that if microplastics, at their current levels, directly caused serious health problems in humans, that would be obvious in the data. We wouldn't be wondering about it. We'd know it. And that's not what she sees. Tracy Woodruff, she's much more concerned with where we are right now with microplastics, generally with toxic chemicals in our environment. And she has questions about illnesses whose rates have increased. For instance, she suspects a possible link between rising colon cancer rates and microplastic exposure.

34:08Emily Oster says the scientists she's spoken to see alternate explanations for that rise. For instance, it could be our rising rates of obesity. But it's interesting how much we don't know. It could be obesity. It could be microplastics. It could even be the two together. Microplastics could disrupt our digestive systems, which could contribute, along with diet and lifestyle, to obesity, all of which might spike colon cancer rates. One day we will probably know with more certainty. Today, we're still trying to reach a consensus about how dangerous microplastics are to human beings in the present moment.

34:47Oddly, our conversation about the future is actually a lot more harmonized. Since we know that microplastics can reach toxic levels in our bodies, and that more plastic means more microplastics, we also know that we want to try to find ways to avoid increasing our global plastic consumption. Professor Tracy Woodruff told me, though, that is unfortunately not how things seem to be shaking out. Right now, the projection is for plastic production to triple by 2060. So think about it now. We know something about plastic and its impacts on our health. if we wait another 30 years to address this problem, we'll just have even more plastic and it'll just be even harder to address.

35:29Wait, we're planning to triple our plastic production in the next 35 years? That's what the estimates are, yes. And where is that coming from? Why are we making so much more plastic? Everybody gets three water bottles?

35:45How many do you have? A lot, and they're all plastic, frankly. I like an algae, even if it might be, you know, nuking my testosterone. So, okay, here's the thing. This is the relationship between climate change, fossil fuels, and plastic. So the fossil fuel industry has had a couple factors influence the production of fossil fuels. And now, of course, things are a little bit in flux now with the new administration. But there had been a lot of regulatory policy, government focus on transitioning to electricity away from fossil fuel gas coming from the ground, away from coal in order to address climate change.

36:28Well, once you do that, right, more electric cars, more electrification of houses, well, you're a fossil fuel company and you've got all this fracking product coming out of the ground. You're not going to be like, oh, I guess I'm going to hang it up and go home. and we're like, well, what are we going to do with all this product we have? Well, we're going to turn it into plastic. That's our new product line is plastic. It's a funny paradox. The thing most of us agree is good, less reliance on fossil fuels, could create a strong incentive for something most of us would agree is bad. Way more plastic in our environment, creating much higher levels of microplastics in our lungs, our hearts, the tissues throughout our bodies.

37:09We live in a very complicated world.

37:22After a short break, we return to the question that brought us here. I ask what now feels like a relatively small question. How do these two experts think that Louisa, our listener, should think about her sister's anxiety around her baby's exposure to microplastics? It's after these ads.

37:49Thank you.

38:18Thank you.

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40:45Welcome back to the show. If it's okay with you, I'd like to take a moment to just talk about worry. As a human being, I worry more than most people I know. It's the first thing close friends notice about me when I get comfortable enough to show them the realer version of myself. I have a very 4K imagination for stories about how things in my life might suddenly go wrong. I experience my own worry often more vividly than I experience actual reality. Obviously, there's a lot of downsides to that. But an upside is that I connect very easily with other worriers. And I can actually be pretty calming for them, since the nightmares playing in their heads are different from whatever's screening in my personal hell matinee.

41:28Which is probably why Louise's email jumped out at me. A person writing to describe how overwhelmed she was with worry. So overwhelmed, it made her mad. Her worry about her sister's worries, about her sister's twins. I identified with everyone. The new parents, most of all. Parenting is such an amplifier for worry. Newborn twins, I can't even imagine. Before I spoke to Emily Oster, who you heard from in the last part of the story, I spent a lot of time reading her work. I read it because of my own worries and my project of trying to learn to live less fitfully within them. Emily is famous on some parts of the internet for this book series and website she's built called Parent Data.

42:10It's a project with a neutral-sounding name, but a very ambitious mission. Emily is very good at sifting through evidence. And she'd noticed that there was a lot of media, blog posts, articles, podcasts, designed to spike parental worry. But very few public thinkers carefully just looking at the evidence, deciding which of the possible dangers to our children might be somewhat overrated or underrated. Just what did the data actually say versus what were people worried about because the conventional wisdom told them to worry about it? At some point, I realized that there were things I wanted to tell parents, parents who were interested in data that were not in the books.

42:51And I thought, well, I'll start a newsletter about pregnancy and parenting, and I'll answer questions for parents like, can my kid have juice? How big a thing is the juice debate? People are very interested in the question of whether their kids can have juice. It used to be that people had juice. When I was a kid, people had juice. My brother exclusively drank juice. He drank so much juice. I'm surprised he's not orange. But now you're not supposed to give your kid juice. Juice is verboten. And how is the evidence on the juice question? You know, the drinks your kid needs are water and milk. Your kid doesn't need juice.

43:26Juice has a lot of sugar, and so people probably used to drink too much juice, but I think the current generation may be a bit too afraid of juice. They've become too juice conservative. Too juice conservative. Exactly. Too juice conservative. This is where Emily Oster lives, at least online, telling you not that juice is great or that juice is evil, but instead using her expertise to help you decide how much you should turn the dial on your own juice worries, how you'd like to live your life. Emily's skill is that she helps set these kinds of dials for the parents who read her across all sorts of topics.

44:03She looks at the data, she looks at the science, and she tries to answer some version of this question over and over again. Given what we actually know right now about Topic X, how do we make the best possible choice about how to live in the world? Her view is that for parents in particular, there's an infinite amount of things they could worry about and they need to prioritize. And given that, and given the evidence, she isn't yet convinced that microplastics should be at the top of most parents' list of concerns. I don't know. I mean, I have sort of a couple of different reactions. I think one is if there are any effects, they are relatively small at the levels we are exposed to.

44:44And so there are a lot of other things I would be worried about first.

44:51I don't think we do a good enough job helping people understand, like, what are the things we really know that you shouldn't do? And what are the things that are kind of like a nice to have? You know, so if someone came to me and they said, look, I'm smoking a pack of cigarettes a day and I'm drinking my water out of water bottles. I'm thinking of quitting the water bottle thing because of microplastics. I would tell them, hey, you should quit smoking first. And like later you can worry about the water bottles, but like the smoking is really bad. And so I think the microplastics are likely not to be for most people very important or even the most important thing they could do to kind of improve their overall health given where most people are.

45:28The second thing I would say is that in the kind of space of the stuff we consume, for most people, probably the one strong modifiable microplastic exposure is disposable plastic water bottles. So if someone said, I really worry about this, I want to do something about it, I would say, look, stop drinking out of disposable plastic water bottles. That's probably like the most significant thing that you can do that is a reasonable change that wouldn't like totally upend your entire life. And with your kids, do you think about their plastic consumption? Like, do you make the small marginal education modifications or no?

46:06We don't drink a lot of bottled water, but not for this reason. And I think that's actually a good point, which is that I think there is a question of, like, could we limit the amount of plastic we are introducing to the environment? Having nothing to do with microplastics, you know, plastic is not good for the environment. It's not good for animals. The environment is not good for the ocean. We produce plastic. we do need, but we produce a lot of plastic we don't need. And I think it would be great if we could try to limit the amount of plastic that we consume that we don't need, even if we didn't care about microplastics at all.

46:37So in my own household, I guess we try not to consume a lot of water out of plastic disposable water bottles. But other than that, I don't do a lot of the other things that people ask me about. Like, for example, I will run our plastic glasses through the dishwasher, even though many people are horrified at that idea.

47:01there's this question of like what is the value of worrying which like my dad when i started thinking about this i'd written this long thing in parent data about this partly motivated because my dad was like well is this something i should worry about and i was sort of thinking about that question and like i don't like that question because the answer is almost never you should worry about it like we do worry a lot but that's an incredibly useless way to spend our time Really, the question you want to say is, is there something I should do about this? And the answer is like, here's a thing you can do.

47:30But then you shouldn't spend your time worrying about it because worrying is not a productive way to use your day. It's not productive, but it's like so hard not to do. Totally. No, I mean, of course, that's like the inherent thing of being a parent. You spend your whole day worrying about your kids and there's like nothing you can do about any of it. You know, how did their math test go? I hope the beach day was fun. It's just like constantly, but it isn't productive. If you can avoid it, it's better. I also took this question, how much should I worry about the microplastics in my own home, particularly with kids in the house, back to Professor Tracy Woodruff.

48:03And it was interesting. When I relayed some of the things that our listener, Louisa, had told me her sister was doing, dressing her kids in organic cotton, only using certain pots and pans, Professor Woodruff said she thought those choices sounded reasonable. Actually, a lot like choices she makes. She's a professor who studies the toxins in our environment, and she does not put plastic in her microwave or dishwasher. She tries to wear natural fabrics like cotton and linen. She uses a vacuum with a HEPA filter. The question we often want answered from experts is just like, okay, but what do you do at your home?

48:39And the vexing thing here is that Tracy Woodruff and Emily Oster are making different choices and both seem reasonable. Tracy does not sound to me neurotic. Emily does not sound to me reckless. us. They're just doing what all of us have to do when we face uncertainty. Make a decision that lets us live our lives today and that we imagine we could live with tomorrow. Which left me with one last question for Professor Tracy Woodruff. In a world where microplastics are, you know, floating off the tires of the cars on the street outside my house and, you know, like rising off my friend's fleece and into my pores or whatever.

49:21I'm curious, like how much does it really, does being highly scrupulous at an individual level move the needle versus like really this gets solved socially? Okay. So both things are true. You can actually lower your exposures to certain types of toxic chemicals by individual practices. That's been shown. For example, it's well established that if you eat an organic diet, you will have lower exposures to pesticides. Now, can you get rid of all of them? No, it's like air pollution. You filtered the air in your house and that works for that. But you're not going to get rid of all the air pollution because it's also being produced by sources that you don't control.

50:05Cars, factories. But you do control it because the government can control them. I want people to be concerned at the level that they are telling the government what they care about is that they address these toxic chemicals and plastics, but not so concerned that it makes them paralyzed in their individual life.

50:32Professor Tracy Woodruff. You can find her at the University of California, San Francisco, where she researches and teaches. is. You can find Professor Emily Oster at Brown University or at her home on the internet, Parent Data. And me, you'll be able to find me this week staring at my plastic water bottle, trying to decide whether or not I trust it.

51:29Search Engine is a presentation of Odyssey. It was created by me, PJ Vogt, and Truthy Pinnimanini. Garrett Graham is our senior producer. This episode was produced by Kim Kupol and fact-checked by Claire Hyman. Theme, original composition and mixing by Armin Bazarian. Special thanks this week to Professor Richard Thompson and Oscar Noxon. Our executive producer is Leah Reese-Dennis. And thanks to the rest of the team at Odyssey. Rob Mirandi, Craig Cox, Eric Donnelly, Colin Gaynor, Maura Curran, Josephina Francis, Kurt Courtney, and Hilary Schaaf. Our agent is Oren Rosenbaum at UTA. If you'd like to support our show, get ad-free episodes, zero reruns, and for the bonus audio that we're putting out next week, please consider signing up for Incognito Mode.

52:11You can learn more at searchengine.show. Follow and listen to Search Engine for free on the Odyssey app or wherever you get your podcasts. Thanks for listening. We'll see you next week.

52:37Thank you.