Our brains are filled with chunks of microplastics, now what?

A summary of the state of the science, testing complexities, and a call to action

When I read about microplastics, I’m admittedly haunted by a memory from a few years back. It was a warm Sunday afternoon in LA and I watched my toddler jumping on a trampoline in our backyard. Unlike the trampolines of my childhood, the springs were safely covered, the sides contained by safety nets, and I took solace knowing my daughter was protected and having fun while I nursed my newborn. As the sun shifted I glanced up and noticed something that looked like dust falling gently on her head. The wind was swirling and I walked over to take a closer look. 

The poles used to hold up the nets were covered in a flexible material that had started to degrade from the sun, wind, and rain. The “safety” covers for these poles were shedding a fine spray of plastic dust which was raining down on my two year old, who was breathing hard from all her jumping. A pit of fear formed in my stomach. I don’t know if her exposure was for just that day, but based on the status of the plastic covers, it’s likely she had been inhaling the stuff for weeks. I know I’m not the only one who has these pangs of regret and worry when learning about the emerging science of microplastics.   

I usually try to calm people down when the press run sensational headlines, contextualizing exposures while still calling us to drive larger systemic change. A piece in last week’s New York Times, however, isn’t one of these instances. 

The article sounds the alarm on microplastics—and even smaller fragments called nanoplastics—which are tiny particles that break down from plastics into our air, food and water. And then into us.

The crux: Aptly-named microplastics are so incredibly miniscule that they are able to evade our tissue’s barrier systems, ending up in organs including: our brains, testicles, placentas, semen, blood, breast milk and a even in baby’s first stool. 

It makes a sick kind of sense when you consider that microplastics are everywhere in our environment— synthetic clothing, furniture, home building materials like carpets, food containers and packaging, water containers, dental products like toothbrushes, even the lab tools used to measure microplastics, ironically. 

Scientists who’ve been tracking microplastic concentrations over time have discovered that the brains of people in 2024 contain 50% more microplastics than brains studied in 2016.

We are all likely walking around with a spoon’s worth of plastic, or 7 grams, in our heads. It’s gross, alarming, and honestly feels like an invasion of privacy. 

Aside from the mere presence of plastic, early evidence is alarming and should call us to curb plastic use ASAP. Microplastics are linked to a range of conditions and diseases, including Parkinson’s, memory loss, fertility issues, MS, even heart disease and cancer. 

People with dementia had more plastic in their brains, possibly because their brains are more porous and less able to clear materials like plastic. While we can’t currently state that microplastics cause dementia, the early evidence is clearly disturbing and calls for more research. 

This is easier said than done.

Microplastics are currently very difficult to identify and study due to a number of things: 

• The testing methodology is new, especially when looking to identify and measure nanoplastics

• Testing thoroughly is expensive and takes time

• Health impacts are hard to understand when they are structural (i.e. what does plastic lodged in our brain or lungs do—if anything—to organ functions and long term health?)

• Microplastics are also an amalgam of many resins and compounds, some of which leach hazardous chemicals linked to cancer and reproductive harm—teasing out the effects of those impacts from microplastics and cumulative impacts is tricky to say the least

I’ve been here before, on the cliff’s edge, that moment when we suspect that something might be harmful, but don’t yet know for sure.

Twenty years ago, I was a lobbyist working on legislation to rid BPA and phthalates from baby bottles and toys in Minnesota. We were following what was, at the time, cutting-edge science that showed that the reproductive systems of mice were negatively impacted from very low levels of BPA and phthalates.

Scientists on the front lines were urging lawmakers and consumer health advocates to take a precautionary approach rather than a wait-and-see one. I and my fellow advocates—pediatricians, pissed-off moms who’d joined the fight, scientists doing the research—succeeded in passing the country’s first ban on BPA and phthalates. As the science evolved, it became undeniably clear: These chemicals are toxic to humans and we were right to ban them outright. 

That’s where we are now with microplastics. We have enough data to tell us these particles are likely dangerous. Scientists are learning more by the day, but until we know enough to say for sure, the question before us is: Do we want to wait until the building is on fire before we do something about it? (In the environmental health field, this is called the precautionary approach. Better safe than sorry, as mom says.) 

One scientist Shanna Swan—whose research in the 1990s and 2000s was instrumental in making the case for state and federal bans on certain phthalates in children’s toys—recently helped launch a novel microplastics testing initiative for researchers. Plasticlist.org is an open-source list of hundreds of food and consumer items tested for plasticizers (If you’re a chemistry buff or just curious about the types of products microplastics have been found in, you can go to https://www.plasticlist.org/ and view the massive spreadsheet, after you click the “I agree not to freak out” button that pops up to warn people not to draw firm conclusions.) 

I have known Swan for years, and an entire chapter of my upcoming book Cleaning House centers on her seismic research contributions to environmental health, particularly our understanding of how a fetus’s prenatal exposure to toxic chemicals such as phthalates can have lifelong consequences. If Swan is raising her hand with concerns, turn on funding research please. 

Another one of my guiding principles as a science educator, besides separating fear-mongering from fear-worthy concerns, is to offer actionable ways we can safeguard ourselves based on the evidence. 

You can take these steps to avoid exposing yourself and loved ones to microplastics:

• Choose tea bags made of paper, not plastic mesh, which releases some of the highest amounts of microplastic studied. 

• Ditch plastic cutting boards—some research finds that knife blades can dislodge plastic bits while chopping.

• Avoid plastic packaging where possible, choosing glass and metal instead. That also means cutting back on plastic bottled water.

• Use an NSF/American National Standards Institute-certified water filter. 

• Vacuum frequently, and use one with a HEPA filter—dust harbors microplastics, which break away from pretty much anything plastic (including synthetic rugs and drapes, plastic furniture, and utensils) and settle in dust.

• Choose organic when you can—a new study that reviewed over 90 pieces of research found that microplastics can reduce the efficacy of pesticides, requiring more to be applied.

• If something is shedding plastic, dispose of it asap. 

Next week I’ll be interviewing a top environmental health researcher and pediatrician, Dr. Leonardo Trasande from New York University on my Substack hosted podcast. Please forward this article to a friend that might find this information useful and you’ll get the notification when the podcast goes live. 

You can now pre-order my book (please do!), Cleaning House: The Fight to Rid our Homes of Toxic Chemicals.