Microplastics and Nanoplastics in the Human Body: What New Research Reveals About Health Risks

May 09, 2025by Oskar Thorvaldsson

Microplastics and Nanoplastics in the Human Body: What New Research Reveals About Health Risks

The infiltration of microplastics and nanoplastics (MNPs) into our environment is no longer a distant, theoretical concern. These minuscule polymer-based particles, ranging from 500 micrometers down to just 1 nanometer, have risen exponentially in concentration over the last fifty years. Scientists are now racing to understand not just where these particles end up in the human body, but what harm they may be causing.

How Do Microplastics and Nanoplastics Enter Our Bodies?

MNPs are virtually everywhere—in the air we breathe, the water we drink, and the food we eat. Our bodies can absorb them primarily through ingestion (eating or drinking contaminated substances), inhalation (breathing them in), and even skin exposure. Once inside, MNPs can interact with tissues and organs throughout the body.

Recent studies have identified MNPs in multiple human tissues, including the lungs, placenta, liver, kidney, blood, breast milk, and urine. These findings have largely been made possible thanks to improved detection technologies, particularly pyrolysis gas chromatography–mass spectrometry (Py-GC/MS). Unlike traditional microscopy, which might miss the smallest plastic particles, Py-GC/MS can quantitatively detect even nanoplastics, offering a more complete picture of internal exposure.

A recent study took postmortem samples of human liver, kidney, and brain tissue, all from carefully selected standard regions. Remarkably, the brain's frontal cortex was found to have higher concentrations of MNPs than either the liver or kidney. This is an especially alarming discovery, as previous reports have associated high MNP presence in carotid artery plaques with inflammation and a greater risk of adverse cardiovascular events.

Such findings point to the unsettling reality that MNPs are not only entering our bodies, but accumulating in multiple organs—including, perhaps most concerningly, the brain.

The Link Between Microplastics and Cardiovascular Risk

The risk that microplastics pose to human health is becoming clearer through targeted clinical research. A pivotal study by Marfella et al. followed patients undergoing carotid endarterectomy, a procedure used to treat carotid artery disease. Researchers detected MNPs, particularly polyethylene and polyvinyl chloride, in more than half of the excised atheromatous plaques.

Patients were divided into groups depending on whether their artery plaques contained MNPs. Disturbingly, those with detectable MNPs were significantly more likely to experience myocardial infarction, stroke, or death over a follow-up period of nearly three years. High-resolution images revealed jagged-edged particles inside plaque macrophages and debris, suggesting direct involvement in vascular inflammation.

These findings support previous laboratory and animal studies showing that MNPs can drive oxidative stress, inflammation, and damage to blood vessels. While observational data cannot prove direct causation, the strong correlation raised by this clinical study is difficult to ignore.

Challenges in Studying Microplastics’ Health Effects

While toxicologists agree that "the dose makes the poison," real-world doses and their health impacts are not straightforward to determine. Laboratory studies have documented MNP toxicity in cells and animal models, but usually at much higher concentrations than what is measured in human tissues. The critical unknown remains how much chronic, low-level exposure increases disease risk over time.

Additionally, detection techniques still have limitations. Early research often missed nanoplastics, while new methods like Py-GC/MS improve detections but require careful validation. Even so, growing consensus suggests that MNPs are widespread across major bodily organs and may accumulate to levels that influence health.

What Does This Mean for Public Health?

Emerging evidence now links the presence of MNPs in blood vessels and organs to serious health consequences, particularly cardiovascular disease. The association between MNP-laced arterial plaques and increased heart attack and stroke risk puts these tiny particles squarely in the spotlight for future public health interventions.

Key Takeaways

Microplastics and nanoplastics enter the body through ingestion, inhalation, and skin exposure.
Advanced techniques now detect MNPs in major organs (brain, liver, kidney) and cardiovascular plaques.
Higher concentrations of MNPs in arterial plaques are linked to increased risk of heart attack, stroke, and mortality.
Current research underscores the need for stronger efforts to limit plastic pollution and assess chronic exposure effects.

Final Thoughts

The body of research connecting environmental plastics to human disease is growing. With mounting data on organ accumulation and disease risk, the call to tackle plastic pollution has never been more urgent—for the health of our planet and ourselves.