The term microplastics was coined 20 years ago, but only in the past 10 years have researchers progressed from studying the particles in the environment and animals to gauging their effects on human health
Campen’s team has already found grim results: as the number of plastics created has increased sharply, so too has the concentration of microplastics found in the brain, liver and kidneys
On average, microplastic levels were about 50% higher in brain samples from 2024 than in 2016 samples. And brain samples contained up to 30 times more microplastics than samples from a person’s liver and kidneys.
Another study published in January2 might offer clues as to how the particles congregate. Researchers fed mice water laced with microplastics and tracked the movements of the particles through the bodies of the mice. The researchers found that the plastics were gobbled up by immune cells, and ended up piling up in and blocking small blood vessels in the brain.
What plastics do to human organs is subject to intense study. When scientists add microplastics to human tissue samples in the laboratory, it can result in cell death, immune reactions and tissue damage. And hundreds of studies have exposed animals — mainly aquatic organisms — to microplastics and found that the particles can clog their guts or hinder their ability to reproduce. On the basis of these findings, researchers suspect that these particles could be linked to cancer3, heart4 and kidney disease5, Alzheimer’s disease6 or fertility issues7 in people.
A landmark study4, published in March 2024, reported that nearly 60% of about 250 people who were undergoing heart surgery had micro- or nanoplastics in a main artery. Those who did were 4.5 times more likely to experience a heart attack, a stroke or death in the three years after the surgery than were those whose arteries were plastic-free.
But, as the authors of the study acknowledge, the presence of plastic might correlate with other factors that would influence health, such as diet or socio-economic status.
