Study finds microplastics in our brains are accumulating, with unknown outcomes on our health

Dr. Matthew Campen, a professor at the University of New Mexico College of Pharmacy, has been searching the brains of dead people to find something virtually all of us have polluting inside our skulls: Tiny particles of plastic known as micro and nanoplastics. But despite the ubiquity of microplastics in the human body, they’re not always easy to find.

Microplastics have been found everywhere in the human body, including blood, breast milk, testicles, heart tissue, lung tissue and various other organs. So it’s not entirely a surprise that these “shard-like fragments” have made their way into our brains as well. But the authors of a recent study in the journal Nature Medicine are the first to actually visualize these particles, as well as help document their cumulative effect on human health. A big issue is that the amount of plastics in our brains seems to be growing.

To demonstrate this, Campen’s colleague Dr. Eliane El Hayek figured out how their research team could visualize these cerebral  nanoplastics. Through analysis of more than 20 years of brain, kidney and liver tissue, they found that these tiny plastic particles systematically accumulate. Their discovery has significant implications for human health, since most of these plastics contain unregulated chemicals which have been linked to dangerous health outcomes.

Indeed, the authors of the study found that an “even greater accumulation of [micro and nanoplastics] was observed” among the dead brains of dementia patients, particularly within the cerebrovascular walls and immune cells. This presents a potential health issue for everyone, since “plastic concentrations in these decedent tissues were not influenced by age, sex, race/ethnicity or cause of death” — although patients who died in 2024 tended to have higher concentrations compared to those who died in 2016. If there is a frustrating aspect to this news, it is that experts are only just beginning to grapple with the full scope of this pollution. Yet plastic pollution has been linked to (though not causally proven related to) plummeting sperm counts, childhood cancer, organ lesions and heart disease, among other ailments.

Still, more research is needed to fully understand how detrimental all this is to our health. This study only looked at 52 brains, and the researchers couldn’t rule out independent variables that could be contributing to disease. Salon spoke with Campen about his recent study about the challenges of visualizing nanoplastics, why eating meat might be a primary source of microplastic contamination and why it matters that we seem to be increasing the level of plastics on our brains.

This interview has been lightly edited for clarity and length.

What does your research tell us that wasn’t known before?

I think the big thing is the increase in body tissues over time. That's the most crucial thing. There have been a lot of studies showing microplastics in different organ systems of the body, but they've been relatively cross-sectional [studies with data from many individuals over a single point in time]. This is the first one where we've taken a look across over 20 years of samples. We have very tight data comparing 2016 and 2024, and in the kidneys, in the liver and in the brain. These concentrations are increasing in that timeframe by a measurable amount.

What challenges did you overcome in this research?

What has come out of this is that we are working in a world with no textbook. It's been sort of purifying for the lab — for the boss, that's me, to say "We're going to entertain all hypotheses and we're going to test things and we're going to accept the fact that I'm going to be wrong a lot!" That's really been great. It's opened up the world for the postdocs and graduate students to ask challenging questions, to take my ideas and go to the lab and show that I'm wrong and throw it in my face and say, "Dr. Campen, you're wrong!" I think it's been a good learning environment.

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One of the most poignant moments of this was when we were having trouble visualizing the plastics using a light microscope.

We were having trouble seeing them in the brain, and we said, "Well, they're probably just nanoscale." They're too small to be seen with light. You need to just assume they're there, though. And Dr. Elian El Hayek, one of our co-authors, said, “If you're going to say ‘nano,’ you better see ‘nano.’ And it really challenged us to try different approaches. We used transmission electron microscopy [and] we were eventually able to visualize these things. I think that's probably going to be the most impactful part of all of this: It is seeing these things, these little tiny nanoscale particles that are polymers. For the first time we've pulled them out and visualized them from the human brain.

What can ordinary people do to protect themselves from microplastics and nanoplastics? For that matter, what kind of symptoms of nanoplastic contamination should they look out for?

I don't think we have a lot to offer there. There is a lot of advice online about avoiding microplastics that is really not based on what we are seeing, which are these nano-sized things. I hope that there are opportunities to avoid plastics. Right now, our best advice is to limit meat in your diet. We think that there's a bit of a bio-magnification that happens with livestock. We don't suggest completely eliminating or having dramatic changes to your diet, but certainly being conscientious about not overeating meat, because we do think diet in general is the source.

As for symptoms right now, we don't have strong evidence that plastics are really driving any pathology or any disease. It's important to keep in mind that we're still at the beginning of this science. People have known about microplastics since Richard Thompson described them in 2004 in the oceans. We've learned a lot about their spread around the planet in the last 20 years, but it's only in the last three or four years that people have started showing them in the human body, and just showing them is a long way away from proving that they do anything. We're still just at the tip of this iceberg.

Let’s talk about this from a policymaking standpoint. President Donald Trump and his various appointees to science-related positions are openly vocal against  regulation. What are your thoughts on how deregulatory policies make it easier or harder for humanity to get a hold of this problem?

I think there's a huge opportunity for the President of the United States, as well as for leaders of other countries, to establish truly revolutionary, highly beneficial, durable policies that are protective of human health related to plastics, but also friendly to industry and commerce. In 1970, a Republican president of notoriety, Richard Nixon, signed into law the Clean Air Act. Over the past 54 years, we've had incredible improvements in air quality in the United States, and that has been a model for countries all over the world.

At the same time, our gross domestic product has continued to increase. We drive more miles than we ever have. We have a tremendous functioning economy in this country, and it has to do with a sensible policy in the Clean Air Act. I've spoken with [Herbert Fisk Johnson III], who's the CEO of S. C. Johnson & Son. They make Ziploc bags and other household products. They're highly dependent on plastics. He agrees 100% that policies to help regulate industry and allow industry to make good decisions for the environment are really needed right now. So I feel that Donald Trump and his team, [new EPA head] Lee Zelden and other folks, have an amazing opportunity to do something existentially and generationally impactful, for not just our country, but for the entire planet. So I'm trying to be optimistic.