Your Brain Could Be Holding A Spoon’s Worth Of Microplastics

As plastic production continues to rise, tiny particles of the ubiquitous polymer are collecting pretty much everywhere on Earth. Scientists have found microplastics in the deepest oceans, the clouds in the sky and even inside our own bodies.

Research from the University of New Mexico now shows these tiny shards are collecting in our brains much far more than other organs. Samples from kidneys and livers tested by toxicologist Matthew Campen and team contained between seven and thirty times less than our thinking organs.

The levels of microplastics in the brain also seem to be accelerating fast, according to the study published in Nature Medicine. The team found 50% more microplastics in human brain samples from 2024 than in those from 2016 — just eight years before.

In total, they found 12 different polymers in tissue sampled from the frontal cortex of normal adult brains — the part of the brain sitting just behind the eyes. Based on the results, an average brain could be holding 4,800 micrograms of microplastics per gram, or about 0.48% by weight — the equivalent of an entire plastic spoon, Campen told CNN.

Hunting Microplastics In The Body

Scientists at the university’s Health Sciences Center devised their own method for measuring microplastics in biological tissue, which they’ve previously used to find the material in human placentas and testes. If you have a sensitive stomach, it might be best to scroll past this section.

The researchers first dissolve each tissue sample and ran this slurry-like substance through a centrifuge to create little concentrated pellets. They heat these to 600 degrees Centigrade and probe the gases they release.

The scientists looked at samples with lots of plastic under the microscope and found deposits of microplastics less than 200 nanometers. That’s really tiny and small enough to pass the blood-brain barrier. But that doesn’t mean that’s how these particles are getting into the brain and why they’re collecting in this organ in such quantities. The team doesn’t really know how that happens.

But they do suspect microplastics largely get into our bodies through our food, particularly through meat, which they also found harbored high levels of the degraded polymers.

“The way we irrigate fields with plastic-contaminated water, we postulate that the plastics build up there,” Campen said in a statement. “We feed those crops to our livestock. We take the manure and put it back on the field, so there may be a sort of feed-forward biomagnification” of the microplastics.

Potential Harm From Microplastics

The researchers don’t yet know if and how these microplastics might be harmful. But they’re still very concerned by the fact all this plastic is sitting in the brains they tested.

They found that brains with dementia contained more microplastics than others, for example. But they don’t know if that plastic influenced the disease, or if it reflects dementia-related changes to blood flow in the brain.

Plastic itself is considered inert and is used in a host of medical applications like artificial joints. Because of this, the scientists wondered if the physical presence of microplastics could be a danger, rather than the chemicals they contain.

“We start thinking that maybe these plastics obstruct blood flow in capillaries,” Campen said. “There’s the potential that these nanomaterials interfere with the connections between axons in the brain. They could also be a seed for aggregation of proteins involved in dementia. We just don’t know.”

More research will be needed to pinpoint if and how microplastics harm people. But for now, Campen hopes the research alerts consumers to the fact they may have significant amounts of plastic in their brains. “I have yet to encounter a single human being who says, ‘There’s a bunch of plastic in my brain and I’m totally cool with that,’” he said.