Microplastics and Heart Attacks: What the 2026 Studies Found, and What Scientists Now Dispute

What the new July 2026 study actually found

In mid-July 2026, researchers led by Professor Emanuele Barbato at Sapienza University of Rome published a study in the European Heart Journal (Paolisso et al.) that did something simple and pointed: they measured micro- and nanoplastics in the blood of people at three different stages of heart health and compared the loads. The paper appeared online on July 14; the European Society of Cardiology publicised it on July 15, and the wire coverage followed within 48 hours.

The 61 participants fell into three groups: people admitted with a STEMI (an ST-elevation myocardial infarction, the most serious kind of heart attack), people with chronic coronary syndrome (stable, long-standing heart disease), and people with no coronary artery disease at all. Crucially, the team sampled not just peripheral blood but coronary blood, drawn from the heart's own circulation during angiography, which is what made the study novel. The heart-attack group had both the highest concentration and the widest variety of plastic polymers. Particles were detected in 84% of the STEMI group. The healthy-artery group had the least.

The particles also travelled with two other things: raised inflammatory markers and higher PM2.5 (fine particulate air pollution) exposure. That combination is what the authors lean on for a mechanism, and it is also, as the next section explains, the reason several cardiologists think the plastics may be a passenger rather than a driver.

One detail matters more than the headline: the people who both smoked and lived with higher air-pollution exposure almost all had plastics in their blood, while only about 12.5% of non-smokers with lower pollution exposure did. Smokers were roughly six times more likely to test positive. Read carefully, that is not a supporting detail. In the adjusted analysis, smoking was the only independent predictor of blood plastics that survived, which means the cleanest reading of this study may be a study about smoking.

Why this landed so hard: the 2024 NEJM study it echoes

The reason this new paper got wall-to-wall coverage is that it lines up with the most alarming microplastics finding to date. In March 2024, Marfella et al. published a study in the New England Journal of Medicine that examined the fatty plaque surgically removed from the carotid arteries of 257 patients. They found micro- and nanoplastics embedded in the plaque of 58% of them.

Then they followed those patients for about 34 months. The people with plastics in their artery plaque had a 4.5 times higher rate of the combined outcome of heart attack, stroke, or death from any cause (hazard ratio 4.53) than the people whose plaque was plastic-free. That is a very large effect for an environmental exposure, and it is the study that turned microplastics from an ecological worry into a cardiovascular one.

The July 2026 study doesn't replace the NEJM one, it complements it from a different angle. NEJM looked at plastic in the plaque; the new study looks at plastic circulating in blood and shows it tracks with how sick the heart is. Two independent teams, two different tissues, same direction. That consistency is what makes researchers take it seriously, even while they caution against over-reading it.

The three studies at a glance

What happened after the headlines: six scientists pushed back

This is the part that never made the news cycle, because it arrived after it. When the study was published, the UK and New Zealand Science Media Centres ran the standard practice of asking uninvolved specialists to comment on the record. Six did. None of them called the work fraudulent or bad, several called it valuable. But between them they raised four objections serious enough that the honest summary of this study is not the one you read in July.

1. After adjustment, only smoking survived

Dr Vahitha Abdul Salam of Queen Mary University of London noted that the study “remains relatively small (61 patients) and cross-sectional, so it cannot determine causation” — and, more pointedly, that smoking emerged as the only independent predictor after adjustment. Every other candidate, including the plastics themselves, failed to hold up once the statistics accounted for the others. A study where the plastic signal collapses into the smoking signal is a much weaker result than “microplastics linked to heart attacks.”

2. The IV line problem

Prof Alun Hughes of the UCL Institute of Cardiovascular Science raised the objection that is hardest to dismiss. Someone having a STEMI is rushed into a cath lab and given intravenous infusions through plastic tubing, and IV infusions are a known route for plastic particles to enter the bloodstream directly. The blood was sampled during that treatment. So the group with the most plastic in their blood is also the group that just received the most plastic-delivered medicine. That is not a subtle confound, and the study design cannot rule it out.

3. Was it even plastic? The lipid false positive

The deepest objection is about measurement itself. Prof Kevin Thomas of the Queensland Alliance for Environmental Health Sciences put it bluntly: “It is just as plausible that endogenous lipids in the blood are being misidentified as plastics.”

This is not a hunch. His Queensland colleague, environmental chemist Cassandra Rauert, published the underlying finding: “Lipids and fats will give you a false positive for polyethylene. Lipids are made up of the same building blocks as polyethylene, so when we analyze them, they look identical.” Polyethylene is the most commonly produced plastic on earth and therefore the one these studies most often report finding. Rauert identified 18 previous blood microplastics studies that did not account for the problem: “To our knowledge, these previous studies didn't know about this issue and haven't considered it.”

In other words, an unknown fraction of the human-blood microplastics literature may be measuring body fat. That does not mean the plastics aren't there. It means the field does not yet have a method reliable enough to tell you how much.

4. This is now a field-wide reckoning

The scrutiny is not confined to one paper. Seven studies in this area have been formally challenged in scientific journals, and the Nature Medicine brain-accumulation study — the source of the widely repeated “a spoon's worth of plastic in your brain” claim, and a study we cite in the table above — drew a formal Matters Arising rebuttal from an international group led by Fazel Monikh in November 2025 disputing its methodology. There is still no internationally standardised method for sampling, extracting, identifying, and quantifying these particles, which is why two labs can analyse similar samples and disagree wildly.

Rauert, notably, is not a blanket sceptic. She is confident about a different measurement: “Analysis of stool samples has shown a wide variety of plastic particles in them.” We are definitely eating plastic and definitely excreting it. What remains genuinely unresolved is how much stays, where it goes, and what it does when it gets there.

Does this prove microplastics cause heart attacks? No, and here's why

Set the measurement dispute aside for a moment and assume the particles are real and correctly identified. Even then, everything above is correlation. Sick hearts have more blood plastic, and plaque with plastic in it is more dangerous, but no study has shown that removing plastic lowers risk, because that experiment is essentially impossible to run on people. Dr Ria Devereux of the University of East London stated the bottom line plainly: the study “does not show that micro and nanoplastics cause heart attacks.” Three structural caveats sit underneath that:

• Small samples. 61 people is enough to detect a difference but not to rule out chance or untangle causes. Neither patients nor analysts were blinded, and Prof Hughes flagged patient selection as a further source of bias.
• Confounding. Plastic exposure rides along with smoking, air pollution, ultra-processed diet, and lower income, all independent heart-disease drivers. In this study the adjusted analysis left smoking standing alone. Some of the “plastic effect” may be those other things wearing a plastic costume.
• Reverse direction is possible. Beyond the IV-line issue, a damaged, inflamed cardiovascular system might trap or retain particles differently than a healthy one, so the heart attack could partly drive the reading rather than the other way around.

None of that makes the finding meaningless. A plausible biological mechanism plus repeated human associations across independent teams is exactly how a risk factor first shows up before the causal proof arrives, it is the stage tobacco and air pollution were once at. But that pattern only counts if the underlying measurements are sound, and that is precisely what is now in dispute. The honest position in August 2026 is narrower than the one we took in July: microplastics are a plausible but unconfirmed cardiovascular risk factor, resting on a measurement method the field has not yet standardised. Reduce exposure because it is cheap, low-regret, and supported by clearer evidence elsewhere — not because this study settled anything.

The plausible mechanism

Why would plastic particles hurt arteries? The leading hypothesis is chronic inflammation. Nanoplastics are small enough to cross from the gut and lungs into the bloodstream, and lab and animal work shows they can lodge in the vessel wall, be engulfed by immune cells, and trigger a low-grade inflammatory response, the same process that destabilizes atherosclerotic plaque and precipitates heart attacks. The particles may also ferry adsorbed chemicals (bisphenols, phthalates) that have their own cardiovascular signals. This is mechanistically coherent, which is why cardiologists aren't dismissing the human data outright.

What actually reduces your exposure (in order of payoff)

If you take one action from this study, make it a real one. Exposure reduction is where the evidence is strongest and the cost is lowest, and the ranking is not what the supplement ads suggest.

• Filter your drinking water. A certified reverse-osmosis or microplastic-rated pitcher removes the bulk of waterborne particles. See our water filters compared guide.
• Stop heating food in plastic. Heat is the single biggest multiplier of microplastic release. Never microwave in plastic, and don't pour boiling liquid into it, glass or stainless instead.
• Cut bottled water. PNAS (2024) found roughly 240,000 plastic particles per liter in bottled water, an order of magnitude more than most tap. It is one of the largest single ingestion sources.
• Ditch plastic food storage for glass or steel, especially for hot, fatty, or acidic foods.
• Address the confounders that ride with plastic: don't smoke, and reduce indoor air pollution, the study suggests these amplify blood-plastic levels dramatically.

What's not on the list: “microplastic detox” supplements, cleanses, or postbiotics. There is no human evidence any of them clear plastics from tissue, see our honest microplastics detox breakdown before spending money on one.

Who should care most

The signal is strongest for people who already carry cardiovascular risk: smokers, people in high air-pollution areas, and anyone with existing heart disease, high blood pressure, or a strong family history. For that group, exposure reduction is a cheap add-on to the things that matter far more, not smoking, controlling blood pressure and cholesterol, exercise, and diet. Microplastics are a rational thing to reduce; they are not a reason to ignore the established basics, which still dwarf any plastic effect measured so far.

For the deeper science on how these particles get into artery walls, see our explainer on microplastics in arterial plaque, and on where they end up in the body, microplastics in human blood and how long microplastics stay in your body.