A groundbreaking study in Nature Medicine has shown a startling incidence of microplastics in the human brain, even though it is the most guarded organ in the body. Scientists examined 52 brain samples from autopsies and found that plastic pollution in the brain was seven to 30 times greater than in the kidney and liver samples.

A spoonful of plastic in the brain

According to lead author Matthew Campen, the amount of plastic found in an average brain sample is roughly equivalent to a plastic spoon.“We’re working hard to get to a very precise estimate,” Campen said in a press conference, emphasizing that measurement methods are still being refined.

What does this mean for brain health?

The tested samples were drawn from the prefrontal cortex, the part of the brain that deals with behavior and decision-making. Polyethylene was the most prevalent form of plastic found, commonly used in household items such as plastic bags, food packaging, and water bottles. Although the health effects are unknown, scientists reported that those with reported cases of dementia had greater concentrations of nanoplastics within the brain tissue.

Still, experts advise not to make any direct conclusions "We can't conclude, based on this study, that micro-nanoplastics are inducing dementia," Jaime Ross, assistant professor of neuroscience at the University of Rhode Island, said. She noted that people with dementia usually have compromised blood-brain barriers, which might be the reason for increased levels of plastics in their samples.

Microplastics are everywhere—But what are they doing to us?

Microplastics have also been discovered in different regions of the human body, such as the heart, liver, testicles, and even breast milk. Certain studies indicate that microplastics can cause conditions such as heart disease, stroke, and reduced sperm count. Studies are also being conducted to find out if exposure to plastics increases cancer risk.

Ross, a co-author of a 2023 paper on microplastic exposure in mice, indicated that the possible health hazards should not be ruled out. “It wouldn’t surprise me if micro-nanoplastics are affecting us. We just don’t know to what extent, yet,” she said.

How do microplastics enter the brain?

One of the greatest enigmas is how these small plastic particles are able to penetrate the brain's protective blood-brain barrier. Unlike all other organs, the brain possesses a natural filter that is meant to keep out harmful substances. Campen hypothesized that the brain's high lipid (fat) content could be involved.

“If you’ve ever cleaned a Tupperware bowl that had bacon grease or butter in it, it takes a lot of soap and hot water. It’s really hard to get the plastics and fats apart. We think that’s part of this process,” he explained.

A silver lining: No long-term buildup?

Interestingly, the study found no major difference in microplastic levels between older and younger brains, suggesting that the body may be capable of eliminating these particles over time. “So we’re not just accumulating these over time, over our lifetimes,” Campen said. However, more research is needed to confirm this finding.

Rising plastic pollution and its impact

What is evident from the research is that microplastic exposure is on the rise. Brain and liver tissue from those who perished in 2024 had higher levels of microplastics than samples from 2016, possibly because plastic pollution in the environment was on the increase.

“This is significant because it suggests that if we were to reduce environmental contamination with microplastics, the levels of human exposure would also decrease,” said Tamara Galloway, a professor of ecotoxicology at the University of Exeter.

How to reduce your microplastic exposure

Microplastics are almost impossible to escape—they're in the air we breathe, the water we drink, and the food we eat. Still, there are ways to cut exposure:

Wash your hands before you eat to decrease the amount of plastic particles ingested.

Don't microwave food in plastic containers.

Use glass or stainless steel bottles rather than plastic ones.

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