Researchers find microplastics in human brains, an apparent first

Researchers, in an apparent first, found evidence that microplastics — tiny bits of plastic fiber contained in everything from water bottles to clothes — have made their way into human brains.

A study published this week in JAMA Network Open, an online medical journal, found that eight out of 15 adult cadavers examined in Brazil had microplastics in their brains.

The researchers and other experts said microplastics can enter the brain directly from breathing through the nose. The tiny fibers are emitted from products containing plastic.

"To our knowledge, this is the first study in which the presence of MPs in the human brain was identified and characterized," wrote the researchers, who are from Germany and Brazil, including from the University of Sao Paulo.

The findings came as no surprise to Bernardo Lemos, a professor of toxicology and pharmacology at the University of Arizona who was not involved in the study.

Researchers have already found microplastics in other parts of human bodies including the lungs, Lemos said.

"It’s an interesting paper. I’m glad it is out," said Lemos, who is also an adjunct professor at the Harvard T.H. Chan School of Public Health.

"It puts us all on notice."

Toxicology experts said the study did not address what health impacts microplastics in the brain could cause. 

"It’s a lot of guesswork here, but if I had to hazard a guess, would you want plastic in your brain? No," said Dr. Wells Brambl, a medical toxicology specialist at Northwell Health’s Long Island Jewish Medical Center in New Hyde Park.

The autopsies of 12 males and three females ranging in age from 33 to 100 took place at the Sao Paulo City Death Verification Service of the University of Sao Paulo. All had lived in Sao Paulo for more than five years.

The researchers also examined two stillborn infants. One showed no presence of microplastics. The other had insufficient material for analysis.

"Microplastic pollution is an emerging environmental and health concern," the researchers wrote.

The International Agency for Research on Cancer last year classified microplastics as a carcinogen, said Dr. Robert Schwaner, medical director of the department of emergency medicine and chief of the division of toxicology at Stony Brook University Hospital. 

"I think they are starting to get the attention that they deserve," Schwaner said.

Microplastics are ubiquitous in society, coming in all sorts of products including plastic containers used for food storage, bottle caps, baby bottles, carpets and even clothes — a growing area of use, experts said.

"This is literally everywhere," Brambl said of microplastics. "I think that this study is very thought-provoking in the sense that we need to start thinking about this as a real public health concern for the long term."

He and others cautioned, though, that a link between microplastics in the human brain and health problems has not been proved.

"You don’t need to be up in arms over this study yet," Brambl said.

Stony Brook's Schwaner noted, though, that a study several years ago found cognitive decline, including dementia, in mice given microplastics.

Meanwhile, alternatives to plastics are growing in popularity around the world, with some producers using safer materials such as aluminum, Brambl said.

Other partial solutions might be using HEPA filters to clean air of some microplastics, Schwaner said.

Lemos said it was surprising that nearly half the cadavers examined did not have microplastics in their brains — and wondered why.

"How is it that these other people didn’t have anything?"