What to do about that spoon’s worth of plastic inside your brain

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When Dr. Nicholas Fabiano broke down a recently published study that found human brains contain a plastic spoon’s worth of microplastics — higher concentrations than found in other organs — many of his followers on X responded with a logical question: How do I get it out?

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So, Fabiano set out to explore “feasible pathways” by which people can reduce their intake of microplastics — microscopically tiny particles that can be absorbed via food, water and air — and potentially remove them, once ingested.

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There wasn’t a whole lot of evidence around the latter, though one small study suggests sweating might facilitate the removal of certain plastic-derived compounds like bisphenol A (BPA).

However, Fabiano and his co-authors did find, in a commentary published this week, some practical strategies for reducing intake, like switching from bottled to tap water and choosing whole chicken breasts over chicken nuggets.

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“The increased levels of microplastics and nanoplastics (MNPs) found in human brain tissue are alarming, particularly in patients with dementia,” Fabiano’s group wrote in Brain Medicine.

A paper published in Nature Medicine in February not only confirmed the presence of MNPs in human kidney, liver and brain tissue taken at autopsy, brain tissues harboured seven to 30 times greater concentrations than the other organs, higher amounts than previously reported.

Brain tissue sampled from people who had been diagnosed with dementia had three to five times as much shard-like fragments of plastic.

The rate of brain contamination also appears to be increasing: Brain (and liver) samples from 2024 had higher concentrations of microplastics and nanoplastics than brain and liver tissue dating back to 2016. (The New Mexico Officer of the Medical Investigator donated the tissue samples from several dozen postmortems.)

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The findings align with the “exponential increase we’re seeing in environmental plastic levels,” said Fabiano, a third-year psychiatry resident and researcher at the University of Ottawa.

Some ten to 40 million tonnes of emissions of microplastics to the environment are estimated per year, “with this figure expected to double by 2040,” he and his co-authors wrote. “Microplastics are pervasive in the food we eat, the water we drink and the air we breathe.”

“What we’re starting to see now is that these microplastics aren’t just staying in the environment,” Fabiano said. “More and more studies are showing that they are starting to accumulate in human bodies.”

Still, their impact on various organ systems isn’t clear, he noted. In addition to the liver, kidney and brain, microplastics have been identified in the lungs, intestine, placenta and testes.

Current evidence, based largely on studies in animals and cell cultures, suggests microplastics can lead to poor outcomes via “oxidative stress, inflammation, immune dysfunction,” abnormal organ development and other pathways, they wrote.

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One team recently reported that people who had microplastics lodged in the plaque lining their carotid arteries had a higher risk of heart attack, stroke or death from any cause.

Others have found that people with inflammatory bowel disease have stool containing higher concentrations of microplastics than healthy people.

There is no evidence microplastics, which can be formed from the breakdown of larger plastics, cause dementia, just an association between the two.

The microplastics detected in brain tissues in the Nature Medicine study were shaped like sharp plastic shards or flakes, 200 nanometres or less in size, and most often polyethylene, the most common plastic that’s mostly used for packaging.

“We’re seeing these plastics in people’s brains, and we don’t know 100 per cent what this is doing to someone’s cognition or mental health,” said Fabiano who, in an accompanying interview with Brain Medicine, is described as a “research rising star.”

It’s not clear how microplastics are reaching the brain, or why they aren’t being completely removed. The smaller the particle, the easier it is to cross the blood-brain barrier, Fabiano said. The brain “has a high lipid (fat) content and receives high blood flow. Thus, it may be easier for microplastics, which have an affinity for lipids, to enter and stay in the brain,” he said.

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Dementia itself is associated with dysfunctions in the blood-brain barrier, potentially allowing more microplastics to seep in.

Whatever the mechanisms, “I think it’s a very valid question for patients to have: ‘How do we remove these plastics from our brains, our bodies,’” Fabiano said.

Before getting into possible “elimination pathways,” he and his co-authors highlighted strategies for reducing exposure, such as switching from bottled to filtered tap water, which could reduce microplastic intake from 90,000 to 40,000 particles per year.

How food is stored and heated might also matter. The researchers recommend avoiding plastic and opting for glass or stainless-steel containers for storage, and glass when heating food. “Heating food in plastic containers, especially in the microwave, can release staggering amounts of microplastics and nanoplastics — up to 4.22 million and 2.11 billion particles per square centimetre in just three minutes,” they wrote.

Other sources of exposure include plastic tea bags — one McGill University study found that when steeped in hot water, the number of particles released is “thousands of times higher” than those reported in other foods — seafood, beer, and highly processed foods. Chicken nuggets contain 30 times more microplastics per gram than chicken breasts, Fabiano and colleagues wrote, “highlighting the impact of industrial processing, which often uses plastics at some point.”

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Still, “we don’t have studies to say, if you swap out or avoid this, what impact does it have on your body,” Fabiano said.

According to the U.S. Food and Drug Administration, “current scientific evidence does not demonstrate that levels of microplastics or nanoplastics detected in foods pose a risk to human health.”

A HEPA (high-efficiency particulate air) filter can remove a significant amount of airborne microplastics. Whether that translates to meaningful changes in absorption isn’t clear, Fabiano said.

There’s also wasn’t a whole lot of literature around the effective removal of plastic particles, once absorbed.

One study that measured BPA in the blood, sweat and urine of 20 people — ten healthy, ten with various health problems — found 16 had BPA in their sweat. Sweat was the only identified source of BPA. “By extension, this may suggest that sweating or induced sweating through exercise or sauna may help reduce the amount of microplastics,” Fabiano said. What’s missing are studies directly showing it.

One hopeful finding from the Nature Medicine paper was that there was no correlation between the concentration of microplastics and the person’s age, suggesting the body has ways to clear the plastic particles over time. “It’s just not building up indefinitely,” Fabiano said.

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Nanoplastics can cause behavioral disorders in fish. One study found they swim less and aren’t as efficient hunters. When fish are moved from environments heavily polluted in microplastics to less polluted ones, it takes about 70 days to clear 75 per cent of the accumulated brain microplastics.

Of course, humans aren’t fish, but that suggests that “decreased input and increased output, if maintained, can get rid of these plastics,” Fabiano said.

Future research should establish exposure limits and assess any long-term health impacts of microplastic intake, he and his co-authors wrote.

“We need more research to wrap our heads around microplastics — rather than wrapping our brains in them — since this could one of the biggest environmental storms most people never saw coming,” said Dr. David Puder, of Loma Linda University School of Medicine.

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