Humans could have up to a spoonful of microplastics in their brains - and the serving is just growing
Troubling ling new research shows that the shocking amount of plastic is more likely to be found in the brain than anywhere else in the body, a paper published this week found.
That is according to scientists at the University of New Mexico, Oklahoma State University, Duke University and Universidad del Valle in Colombia in a paper published in Nature Medicine, a monthly peer-reviewed medical journal.
Microplastics are small plastic pieces less than five millimeters long that derive from everyday plastic items. The pieces are making their way past the blood-brain barrier but it’s unclear how they’re making their way into the brain, researchers wrote.
The team analyzed the brains of 52 decedents and found the individuals had higher concentrations of microplastics in the brain compared to the liver and kidneys.
The average amount, 4,800 micrograms per gram of microplastics in brain tissue, was found to be the same as the amount found in a standard plastic spoon, according to the study.
Matthew Campen, PhD, at the University of New Mexico College of Pharmacy, said the trend was reflective of increased environmental exposure to microplastics during a virtual news conference this week.
“I would never have imagined it was this high,” Campen, the paper’s lead toxicologist, said in a written statement. “I certainly don’t feel comfortable with this much plastic in my brain.”
Still, he said the group’s analysis suggests some microplastics aren’t remaining in the body indefinitely. Lower concentrations in the liver and kidneys indicate those organs are doing their jobs and working to clear plastic from our systems. But, plastics in the liver can be widespread.
Images of the plastics in those organs support that theory.
However, the number of microplastics in the brain and liver increased within the past 20 years, samples from the decedents showed. Some of them had higher concentrations of plastic in the brain by as much as 50 percent.
Twelve of the decedents had been diagnosed with dementia and researchers found they exhibited even greater microplastic levels than people who had not been diagnosed with the disease, particularly in the cerebrovascular walls and immune cells.
There is no evidence to prove the level of plastics in the brain increases the likelihood of developing dementia, researchers emphasized.
To come to the findings, the team analyzed 28 bodies autopsied in 2016 and 24 autopsied in 2024. Brain tissue samples were donated by the New Mexico Office of the Medical Investigator.
Scientists still don’t fully understand how dangerous microplastics are to humans. Other studies examining the issue have determined the presence of microplastics in people with carotid artery disease, a condition where fatty deposits built up in the arteries which carry blood to the brain.
“These results highlight a critical need to better understand the routes of exposure, uptake and clearance pathways and potential health consequences of plastics in human tissues, particularly in the brain,” the researchers wrote.
Microplastics typically accumulate in fat cells in the brain’s insulating myelin sheath. Experts theorize this could account for the large concentrations in the brain.
Prior studies have shown microplastics have been found in the lungs, placentas and testes.
Researchers suspect the plastics end up in the bloodstream through food, particularly by ingesting meat. Commercial meat production tends to have plastics in the food chain, Campen noted.
“We irrigate fields with plastic-contaminated water, we postulate that the plastics build up there,” said Campen.
“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.” His team found high concentrations of plastic in meat bought at grocery stores.
The researcher wants people to take note of the findings, especially as plastic production ceases to abate.
“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,’” he said.
The research is somewhat revolutionary as only a few studies about the concentration of plastics in the body have been published. In September, researchers found that plastic fragments were making their way into our bodies through nasal cavities.
That study examined the samples of 15 human cadavers. Only eight of them were determined to have microplastics.
It’s not known why all of the samples didn’t contain plastics but researchers suggest that the inflammation of the lining within the nasal cavity made it easier for the plastic to enter the bodies of some individuals and not others.
