Recent headlines have sounded the alarm about microplastics in seafood, teabags and bottled water. That’s the tip of the iceberg. These tiny plastic particles—less than 5 millimeters wide—have been observed in virtually every habitat on the globe, from Mount Everest to the deep sea.

Studies are increasingly showing that they’ve found their way into our bodies, too. And evidence is emerging that microplastics are linked to a higher risk of heart disease.

We spoke with Martha Gulati, MD, director of preventive cardiology and the Anita Dann Friedman Chair in Women’s Cardiovascular Medicine and Research at Cedars-Sinai, about what we know about microplastics and heart health, and how patients can protect themselves.

Martha Gulati: Plastic is literally everywhere, because we use it so much. Microplastics can be in the air we breathe, in the food we eat and in the things that we drink. When I touch my computer, the keys are made of plastic, and even if I wash my hands, I’m not sure how much residual plastic is left. It’s in synthetic clothing, toys and more.

Microplastics and nanoplastics—which are the size of a human hair divided by 1000—have been found everywhere in our bodies. Researchers have observed them in the blood, lungs, liver, plaque in the arteries, urine and feces. They’re even in the placenta of somebody carrying a baby. In animal studies, there’s evidence that when a pregnant mouse inhales microplastics, they’re in the fetus within 24 hours.

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MG: Recent research has linked the presence of nanoplastics and microplastics to an increased risk of heart attacks, strokes and early death. A study published last year in The New England Journal of Medicine looked at 304 patients who’d had surgery in which they removed plaque from the carotid arteries. They examined the plaque and saw that people with more micro- and nanoplastics had a higher risk of heart attack, stroke and death from any cause after 34 months.

Another recent study looked at the levels of microplastics in the carotid arteries of people who had died. Some had had cardiovascular symptoms due to plaque buildup, some had plaque but no symptoms and others had neither. They saw that microplastic levels were 16 times higher in people with plaque but no symptoms and 51 times higher in people who’d had a stroke or related health problems, compared to people of similar ages with no plaque.

Separately, we’ve seen some relationship between micro- and nanoplastics and abnormal heart rates and heart function.

These are associations—we can’t say that the microplastics caused the disease. We just don’t know yet. But the association is disturbing, and we’re wondering what is happening.

MG: The truth is, we don’t know. We don’t know if people with higher levels of microplastics in arterial plaque had different environmental exposure, whether some people are more prone to keeping microplastics in their body, or whether microplastics are initiating the plaque because they are present.

Some people have hypothesized that microplastics can damage heart health by increasing chronic inflammation, which is strongly associated with cardiovascular disease. It may potentially be that, but not every study has shown that people who developed disease had more inflammation.

Another possible explanation is that micro- and nanoplastics, which are jagged in shape, could be the perfect place for plaque to deposit. Another proposed mechanism is that exposure to micro- and nanoplastics can trigger the body to produce free radicals, which are unstable molecules that are damaging. Scientists have also suggested that exposure to these particles can cause apoptosis, where cells literally die.

Others have found that high exposure to micro- and nanoplastics may be associated with problems with the vascular system, known as endothelial dysfunction. And there may be a relationship between these particles and the way the blood clots. We’re at the earliest stages of figuring this out, and we need better studies in both animals and humans.

MG: As a society, we should push for changes in how our food and water is packaged to avoid using plastic. We should ask companies to label whether there are microplastics in clothing and makeup. If consumers demand that products are safer, it will change how people sell things to us and help us stay better informed.

On an individual level, the biggest thing we can do is avoid single-use plastics. At home, I don’t buy plastic bags anymore; I use compostable bags made of natural fibers and paper storage bags for cheese. I recommend getting rid of plastic food storage containers and using glass. Carry your own cotton bags to the grocery store, or ask for a paper bag if you need one. Drink out of metal or glass bottles if you need to buy water. Washing your clothes less frequently can reduce microplastic shedding. Avoid pods for your washing machine and dishwasher, since they release microplastics into our water systems. I also recommend getting rid of nonstick pots and pans, since the coating is plastic.

After the fires in Los Angeles, I bought HEPA filters for my home in hopes that they can reduce exposure to microplastics, in addition to other pollutants. Unfortunately, making things safer right now is a little more expensive, because it’s not the standard.

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MG: The hardest part is that we just don’t know enough yet. We don’t have a way to test somebody’s microplastic levels or interpret the results. But I still advise patients that they’re being exposed to something that isn’t natural and has become such a big part of our lives. As scary as headlines about plastics can be, and even though they’re widespread, it’s always worth trying to reduce your exposure.

In the meantime, there are things you can do to protect your heart: exercise regularly, eat a heart-healthy diet, keep your blood pressure and cholesterol controlled, don’t smoke or get help to quit, and see your doctor on an annual basis. Focus on what you can control.