Everyone knows cigarettes are full of chemicals: nicotine, tar, carbon monoxide, and a long list of others you probably do not want anywhere near your lungs.
Now researchers are wondering whether smokers are also inhaling plastic.
A new study published in the European Heart Journal found that people with a history of smoking were almost six times as likely to have microplastics in their blood. Smoking was the only factor that still predicted the presence of microplastics after researchers adjusted for heart disease, inflammation, air pollution, and other variables.
The study looked at 61 patients undergoing heart procedures at two hospitals in Italy. Nineteen were suffering serious heart attacks, 20 had chronic coronary disease, and 22 had normal coronary arteries. Researchers found microplastics in 84.2% of the heart attack patients.
Microplastics are also in the air we breathe.
By comparison, they found plastic particles in 40% of the patients with chronic coronary disease and 31.8% of those with normal arteries.
But the smoking numbers were even harder to ignore. Every heart attack patient with a history of smoking had plastic in their blood. None of the nonsmokers with normal arteries did.
Patients who both smoked and had high long-term exposure to fine-particle air pollution all tested positive for microplastics. Among nonsmokers with lower pollution exposure, just 12.5% tested positive.
Not just the filters
That does not prove cigarettes are directly injecting plastic into your bloodstream. This was a small study, and the researchers cannot say exactly where the particles came from.
Still, the connection is strong enough to raise an uncomfortable question: Are smokers literally smoking plastic?
Cigarette filters are usually made from cellulose acetate, which is a type of plastic. Public health researchers have increasingly described discarded filters as a major source of microplastic pollution.
The World Health Organization has warned that cigarette filters contain microplastics and eventually break down into smaller particles after they are discarded.
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But the plastic found in the patients’ blood was mostly polyethylene, the material commonly used in grocery bags, bottles, food packaging, and countless other everyday products. So the cigarette filter itself may not be the main source.
Another possibility is that smoking makes it easier for plastic particles already floating in the air to get into the body. Microplastics are not just in water and food. They are also in the air we breathe. Smoking repeatedly pulls particles deep into the lungs while damaging the body’s normal defenses. It harms the cilia and mucus-clearing systems that are supposed to catch and remove unwanted material.
In other words, cigarettes may not be creating all of the plastic. They may simply be opening the door.
A disturbing clue
Once the particles get through the lungs, they can enter the bloodstream.
Researchers found microplastics in blood taken directly from the coronary circulation, the blood vessels that feed the heart. Heart attack patients had the highest concentrations and the widest variety of plastic particles. They also had higher levels of inflammation.
That matters because one of the big questions surrounding microplastics is whether they are simply passing through the body or actively causing damage. Scientists suspect they may contribute to inflammation, oxidative stress, and damage to blood vessels. But human research is still in the early stages.
A 2024 study published in the New England Journal of Medicine found microplastics and nanoplastics embedded in plaque removed from patients’ carotid arteries. Patients with plastic in their plaque were more likely to suffer a heart attack, stroke, or death over the next three years.
That study did not prove that plastic caused those outcomes. Neither does this one. There are plenty of reasons to be cautious.
The new study involved only 61 people. Just 19 were having heart attacks. The researchers did not fully measure diet, drinking water, packaging exposure, occupation, or every other possible source of microplastics.
They also tracked whether someone had a history of smoking, not exactly how much he smoked or how recently.
So this is not proof that every drag from a cigarette fires plastic particles straight into your arteries, but it is a disturbing clue. Smokers in this study were far more likely to have plastic in their blood. Every smoker suffering a heart attack tested positive.
Cigarettes already come with enough reasons to quit. You can apparently add “possibly smoking plastic” to the list.
Health, Microplastics, Cigarettes, Smoking
