Microplastics are accumulating in the human brain at rates far higher than in other organs, and researchers say the levels have surged by 50% in just eight years. Scientists from the University of New Mexico (UNM) who made the discovery believe this should set off alarm bells.
Toxicologist Matthew Campen, one of the lead researchers, summed it up bluntly: “This really changes the landscape. It makes it so much more personal. I have yet to encounter a single human being who says, ‘There’s a bunch of plastic in my brain and I’m totally cool with that.’”
Scientists Find Plastic Particles Deep in Human Brain Tissue
The research team analyzed brain samples collected through autopsies conducted by the New Mexico Office of the Medical Investigator (OMI). Tissue samples dating back to 2016 were compared to those taken in 2024, revealing a stark increase in plastic contamination.
By dissolving the samples into a slurry and using a centrifuge to separate out non-biological material, researchers were able to isolate microplastics and nanoplastics embedded in brain tissue. A mass spectrometer was then used to identify the chemical structure of the plastic.
Key findings:
- Twelve different types of plastic were detected.
- Polyethylene—found in plastic bottles and food packaging—was the most common.
- Microplastics were particularly concentrated in fat cells surrounding neurons, possibly interfering with signal transmission.
One major concern is that nanoplastics are small enough to cross the blood-brain barrier, a protective membrane that usually keeps harmful substances out. Scientists still don’t fully understand how these particles are moving through the brain—or what damage they may be causing.
Potential Links to Dementia and Brain Disorders
One of the more disturbing aspects of the study was the discovery that individuals with dementia had up to 10 times more plastic in their brain tissue compared to those without the disease.
But there’s a major caveat. Researchers only examined 12 brain samples from dementia patients, making it impossible to determine whether plastic buildup causes dementia—or if neurodegenerative disease simply accelerates plastic accumulation.
That said, Campen pointed out several possible ways microplastics might interfere with brain function:
- Blocked capillaries could restrict blood flow, depriving neurons of oxygen.
- Interference with axon connections might disrupt communication between brain cells.
- Triggering protein aggregation could contribute to neurodegenerative diseases like Alzheimer’s.
Again, these are hypotheses, not proven mechanisms. But the sheer presence of plastic particles in human brains is alarming enough on its own.
How Are Microplastics Getting Into the Brain?
Researchers suspect that most of the plastic we consume comes from food—especially meat. The way plastics cycle through the food chain could be amplifying the problem.
Campen explained: “The way we irrigate fields with plastic-contaminated waste, we postulate that the plastic builds up there. We feed those crops to our livestock. We take the manure and put it back on the field—so there may be a sort of feed-forward biomagnification.”
Supporting this theory, the researchers analyzed store-bought meat and found high concentrations of microplastics.
Plastics are nearly impossible to avoid. They are in:
- Water: Bottled and tap water both contain microplastics.
- Food: Fish, shellfish, and even vegetables absorb plastic particles.
- Air: We inhale airborne plastic particles daily.
And even if plastic production stopped today, existing plastics would continue breaking down into smaller particles for decades—if not centuries.
Some Experts Caution Against Overreaction
Not all scientists are convinced that microplastics pose an immediate health crisis.
Environmental toxicologist Theodore Henry of Heriot-Watt University acknowledged that the study’s detection methods were impressive. But he also emphasized that merely finding plastic in brain tissue does not automatically mean it causes harm.
Similarly, chemist Oliver Jones from the Royal Melbourne Institute of Technology pointed out limitations in the study’s methodology.
- Only 52 brain samples were tested, which is a small dataset.
- Data was collected from just two years (2016 and 2024), making long-term trends difficult to establish.
- Results may vary in different regions, so findings from New Mexico might not represent global trends.
Jones put it simply: “You simply can’t make a trend from data from just two years.”
The Bigger Picture: Plastic Pollution Isn’t Going Away
Even if the health risks of microplastics remain uncertain, one thing is clear: Plastic contamination is increasing.
Between 2016 and 2024, the concentration of microplastics in human brain tissue rose by 50%. If that trend continues, future generations could face even higher levels of plastic exposure.
Scientists agree that more research is needed to understand the long-term effects of plastic accumulation in the body. But as Campen put it, “This really changes the landscape.”
At what point do these particles start affecting cognitive function, behavior, or even mental health? Right now, no one knows. But for many, the idea of plastic building up in their brain is disturbing enough.