Microplastics in Artery Plaque Were Linked to Heart Attacks and Strokes

Plastic particles have now been found in human blood, lungs, placentas and breast milk. Most of those discoveries answered a narrow question, whether the particles are present at all. A 2024 study in the New England Journal of Medicine¹ went further and asked whether people with more plastic in their arteries did worse over time.

Inside the study

Raffaele Marfella and colleagues at the University of Campania in Italy enrolled 304 patients who were scheduled for carotid endarterectomy. That is surgery to remove fatty plaque from the carotid arteries in the neck, which supply blood to the brain. All of the patients had significant narrowing but had not yet had a stroke from it.

After surgery, the team analyzed the removed plaque using several methods, including a technique that heats a sample and identifies the chemicals released, along with electron microscopes that can show individual particles. Of the patients enrolled, 257 completed follow-up, which averaged about 34 months.

They detected polyethylene, the plastic used in food packaging and bags, in the plaque of 150 patients, or 58.4 percent². In 31 of them, polyvinyl chloride, known as PVC, was also present. Under the microscope, the researchers saw jagged foreign particles inside immune cells within the plaque and scattered in the surrounding debris.

What happened next

During follow-up, 20 percent of patients with plastic in their plaque had a heart attack, a stroke or died from any cause. Among patients without detectable plastic, the figure was 7.5 percent. After adjusting for other cardiovascular risk factors, the hazard ratio was 4.53³, meaning the risk was roughly four and a half times higher.

The plaque containing plastic also showed higher levels of inflammatory markers. That fits a plausible story in which particles lodged in artery walls draw in immune cells and keep plaque inflamed and unstable.

How plastic might get there

Microplastics are fragments smaller than five millimeters, and nanoplastics are far smaller still, small enough in some cases to cross the lining of the gut or lungs. The likely routes into the body are food, drinking water and air. Packaging, synthetic textiles, tire wear and the breakdown of larger plastic waste all shed particles into the environment.

The authors noted that many of the particles they saw were well under the size thought to allow passage from the gut into the bloodstream. In an editorial published alongside the study⁴, Philip Landrigan of Boston College called the finding a breakthrough that raises urgent questions, including whether plastic is truly a cardiovascular risk factor, which other organs may be affected and how exposure can be reduced. He argued that solving the problem will ultimately require a broad shift away from fossil fuels, the raw material for most plastics.

Why caution is warranted

The size of the effect is striking, and that is part of why scientists are careful with it. A fourfold difference in a single observational study is a strong signal to investigate, not an established risk factor.

Several limits matter. The patients were already sick enough to need surgery, so the results may not apply to the general population. Particles were measured once, at the end of a disease process that took decades. And people with more plastic in their tissues may also have more exposure to traffic pollution, processed food or occupational hazards, any of which could raise cardiovascular risk on their own. The study could not rule those out.

Measurement is another challenge. Plastic is everywhere in hospitals and laboratories, and detecting tiny particles without introducing contamination is difficult. The authors took steps to guard against this, but independent replication with standardized methods is still needed.

What a reasonable person can do

There is no clinical test for plastic in your arteries, and no treatment to remove it. Reducing exposure is sensible, as long as it does not crowd out what is known to work.

Practical steps with little downside include not heating food in plastic containers, choosing glass or steel for hot drinks and leftovers, filtering tap water if you are concerned about your local supply, and cutting back on heavily packaged processed food. These habits have other benefits too.

The bigger gains still come from the familiar list. Controlling blood pressure and cholesterol, not smoking, staying active and managing blood sugar each have decades of trial evidence behind them. If this study prompts a conversation with your doctor about those numbers, it will have done some good, whatever future research shows about plastic.