Plastic seems to end up in every nook and cranny known to humans, from the depths of the ocean to the stomachs of woodland creatures.

As one surgeon discovered, there's a dangerous new addition to the list: our arteries. 

What's happening?

Ross Clark, a vascular surgeon and scientist at the University of New Mexico, led a study examining plaque buildups in the veins of people who had strokes. 

He found that samples from those individuals had over 50 times the amount of broken-down plastic particles in their carotid arteries than those of a non-stroke patient. Even people who had not suffered a stroke but had plaque were living with 16 times more plastic in their arteries, according to Down to Earth.

Clark's findings suggest that microplastics and smaller nanoplastics can find their way into our bloodstreams and plaque blockages. Since the carotid artery supplies blood to the brain, anything that gets in the way can have life-changing and potentially fatal health impacts, such as strokes and heart attacks.

The full findings were presented at the American Heart Association's Vascular Discovery 2025 Scientific Sessions in April. 

Why is plastic in our bodies important?

The presence of microscopic bits of plastic flowing through our veins is alarming, to say the least. 

Karen L. Furie, chair of neurology at Brown University's medical school, was also surprised.

"Up until this point, we have known that plaque components include elements of fat, calcium, fibrous tissue, inflammatory elements in the blood," she explained, per Down to Earth. "But we did not know that micronanoparticles of plastic might be associated with atheromas [plaques]." 

Beyond the normal dangers of plaque buildups, Clark and his team suspect the plastic particles may mess with the immune responses of certain anti-inflammatory genes.

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The findings also showcase the extent of the world's plastic problem, which wreaks havoc on all kinds of ecosystems. Products cover the Earth that will degrade into particles less than one-hundredth the size of a human hair, Down to Earth explained. 

What's being done about plastic pollution?

There are tons of ways to pitch in to reduce plastic pollution, from upgrading your personal belongings to supporting businesses that do the right thing when it comes to plastic. 

As for keeping our arteries safe, the researchers have their work cut out for them. Further studies will be needed to understand what's going on behind the scenes, from how plastic gets in our bodies to whether it is a cause of artery disease or just a related symptom. 

Clark and his team are already refining their process for sifting out other particles and identifying plastics. 

"Now that we are aware of the presence of these materials in atherosclerotic plaques, the next steps will be to investigate what exactly they are doing there (if anything)," he told Down to Earth.

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