Microplastics could be contributing to clogged arteries, potentially increasing the risk of heart attack or stroke, according to new research presented at the American Heart Association (AHA). Researchers found that fatty plaques in the neck arteries can contain over 50 times more microplastics than arteries without any plaque. These levels were even higher in individuals who had already experienced a stroke, a mini-stroke, or temporary vision loss caused by blocked blood vessels."These types of plastics are commonly found in the environment, especially in ocean garbage patches," said lead researcher Dr. Ross Clark, a vascular surgeon-scientist at the University of New Mexico in Albuquerque, said at the AHA meeting. "Over many years, these plastics break down, mix into the soil and water, and can build up in the food chain.""Many people think that micro and nanoplastics mainly come from using plastic utensils, cutting boards, packaging, water bottles and other plastic items,” Clark continued. “However, the main source is the food and water we eat and drink."Nanoplastics—particles smaller than 1,000 nanometers—are invisible to the human eye. By comparison, a human hair measures between 50,000 and 80,000 nanometers wide. The new findings build on a 2024 Italian study that detected nanoplastics in arterial plaques removed during surgery. That study found that individuals with nanoplastic-laden plaques were more likely to die or suffer a heart attack or stroke.AHA Study Found 16 Times Higher Nanoparticles In Blocked ArteriesIn the current study, researchers analysed tissue samples from the carotid arteries of 48 individuals. About one-third of the samples came from people aged 60 to 90 who had undergone surgery to remove plaques after suffering from stroke-related conditions. Another third were from patients who had plaques removed as a preventive measure, while the remaining samples were from tissue donors without any carotid artery blockage.The results showed that nanoplastic levels were 16 times higher in plaques from people with clogged arteries who had not yet experienced symptoms, and 51 times higher in those who had already had a stroke or mini-stroke. While the presence of nanoplastics was not associated with sudden inflammation, researchers did find links to changes in the genetic activity of cells involved in plaque stability and inflammation control."These findings indicate that the biological effects of micronanoplastics on fatty deposits are more complex and nuanced than simply causing sudden inflammation,” said Clark. "It's very important to study what these materials do to our bodies. However, we should be cautious about the early results of this study. We won’t fully understand the biological effects for many years to come," Clark added. Dr. Karen Furie, chair of neurology at Brown University's Warren Alpert Medical School and a spokeswoman for the American Heart Association, called the results "very interesting and troubling." "To date, we have not considered exposure to plastic micronanoparticles a modifiable risk factor for stroke," she said. "This association presents a novel potential target for stroke prevention." As with all findings presented at medical conferences, these results should be considered preliminary until they are published in a peer-reviewed journal.