Researchers Detect ‘Alarming’ Levels of Microplastics in Human Brain Samples

It’s well-known that microplastics are pervasive, with scientists finding microplastics in testicular tissue, lungs and even blood. But now, researchers have discovered microplastic pieces in samples of the human brain at higher levels than expected.

In a new pre-printed study published early by the National Library of Medicine, scientists analyzed plastic content in the livers, kidneys and brains of autopsied human bodies. While the team found microplastics in all of the organs, the scientists were concerned that the average amount of microplastics in the 91 brain samples was between 7 and 30 times higher than the amount of microplastics in the liver and kidney samples.

“It’s pretty alarming,” Matthew Campen, lead author of the study and professor of pharmaceutical sciences at the University of New Mexico, told The Guardian. “There’s much more plastic in our brains than I ever would have imagined or been comfortable with.”

In the study, the authors revealed that 24 of the brain samples that had been collected earlier this year were comprised of about 0.5% plastic. The amount of plastic found in the 2024 brain samples was also around 50% higher than the plastic amount in brain samples from 2016.

Of the detected microplastics, scientists found that polyethylene was the most prevalent. As reported by Britannica, polyethylene is the most widely used plastic polymer globally and is commonly used in packaging and plastic bags.

The study further revealed that microplastics are selectively accumulating in the brain, causing an increase in the concentration of plastic in the brain in the long-term. This could present links between microplastics and certain diseases, but more research is needed to determine the risks.

“The parallels between the present data showing an increasing trend in MNP concentrations in the brain with exponentially rising environmental presence of microplastics and increasing global rates of age-corrected Alzheimer’s disease and related dementia, given the potential role of anionic nanoplastics in protein aggregation, add urgency to understanding the impacts of MNP on human health,” the study concluded.

The study builds on previous research, also led by researchers at the University of New Mexico, which revealed that microplastics that are ingested could move from the gut to other organs, including the brain. As Reuters reported, humans ingest an average of 5 grams of microplastics per week, or around 20 kilograms in the average 79-year lifespan, further raising concerns over accumulation risks.

“I don’t know how much more plastic our brain can stuff in without it causing some problems,” Campen told The Guardian.