Human Brains Contain A Spoon's Worth Of Nanoplastics, New Study Suggests

The human brain may contain an entire spoon's worth of nanoplastics, according to new findings published in the journal Nature Medicine. The researchers detected "unbelievable" levels of microplastics and nanoplastics in human brain samples collected at autopsy in early 2024. They said that based on their analysis, the amount of microplastics found in the cadaver brain samples appears to be increasing over time. Overall, the study authors revealed that the brain samples contained seven to 30 times more tiny shards of plastic than their kidneys and liver. 

"The concentrations we saw in the brain tissue of normal individuals, who had an average age of around 45 or 50 years old, were 4,800 micrograms per gram, or 0.48% by weight," said co-lead study author Matthew Campen, Regents' Professor and professor of pharmaceutical sciences at the University of New Mexico in Albuquerque, as per CNN. That's the equivalent of an entire standard plastic spoon, he said. 

"Compared to autopsy brain samples from 2016, that's about 50% higher. That would mean that our brains today are 99.5% brain and the rest is plastic," Mr Campen added. 

The study authors also found that microplastic concentrations were higher in the brains of deceased patients who had been diagnosed with dementia compared to the brains of deceased individuals without dementia. 

"It's a little bit alarming, but remember that dementia is a disease where the blood-brain barrier and clearance mechanisms are impaired," Mr Campen explained. Additionally, there are inflammatory cells and atrophy of brain tissue with dementia which may create "a sort of sink for plastics to go," he said. 

However, he added, "We want to be very cautious in interpreting these results as the microplastics are very likely elevated because of the disease (dementia), and we do not currently suggest that microplastics could cause the disease." 

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Phoebe Stapleton, an associate professor of pharmacology and toxicology at Rutgers University, was not involved in the study, but she clarified that finding plastic deposits in the brain does not prove they cause damage. 

"It is unclear if, in life, these particles are fluid, entering and leaving the brain, or if they collect in neurological tissues and promote disease," she said, per CNN. "Further research is needed to understand how the particles may be interacting with the cells and if this has a toxicological consequence," she added. 

Microplastics and nanoplastics are miniscule plastic fragments that result from the breakdown of everyday objects like packaging, containers, clothing, tyres and more. These small particles have spread all over the planet. According to previous studies, they've also made their way into the human body, showing up in blood, poop, lungs and placentas.