27 May 2025
Scientific studies suggest that every one of us probably has microplastics in our bodies. We breathe them in, swallow them in food and drink — unknowingly. Some are even absorbed through our skin.
And while larger bits might pass through us, the smallest nanoplastics don’t always. They’re tiny enough to cross cell membranes, slipping into the bloodstream and organs.
The placenta is a temporary organ. It only grows for about eight months, tasked with nourishing the developing baby. But that short window is all microplastics need.
In December 2020, Italian researcher Dr Antonio Ragusa was the first to detect microplastics in the human placenta. He tested six placentas from women with healthy pregnancies. In four of them and in the membrane surrounding the foetus, he found plastic particles. This was the first hard evidence of microplastics inside human organs. Scientists expressed concern that they could interfere with foetal immune system development and called for further research.
That was less than five years ago. Since then, microplastics have been found in nearly every major organ; the liver, kidney, heart and even the brain. (We’ll explore the sources of that contamination; food, water, packaging in the next episode in our series.)
In 2024, researchers at the University of New Mexico confirmed Ragusa’s findings. They analysed 62 placenta samples and found microplastics in every single one. The concentrations ranged from 6.5 to 790 micrograms per gram of tissue. Those amounts are minute, but meaningful.
Earlier this year, researchers at the same university revealed a striking figure: the average adult brain may contain up to 7 grams of plastic, which is about the weight of a plastic teaspoon. And people with dementia had even higher levels.
Plastic isn’t inert. It breaks down, reacts, and leaches. Of the roughly 16,000 chemicals used in plastic production, more than 4,000 are known to be toxic to humans or the environment.
Worse still, plastics can absorb other harmful substances like heavy metals and persistent pollutants, and carry them into the body like a Trojan horse. Once inside, they can trigger inflammation, disrupt hormones, and damage cells.
Phthalates, bisphenols, heavy metals, and flame retardants are among the plastic-related chemicals known to pose health risks. We know this because these chemicals leach into food and water that we processed through our digestive system. But with fragments of plastic now inside our organs, their full impact remains unknown.
We don’t yet know if nanoplastics, once inside an organ, stay there for life, or if the body can remove them. That uncertainty is part of what makes them so worrying.
There are, as scientists cautiously say, “correlations.” One is the decline in sperm counts since the 1950s, where plastic exposure is considered a possible contributing factor.
Another emerged this month (May 2025), from the University of New Mexico: researchers found microplastics and nanoplastics embedded in the carotid artery plaque of stroke patients. The results were stark. Symptomatic patients had 50 times more plastic in their arterial plaque than those without symptoms. While the study didn’t prove that plastics caused the strokes, it raised urgent questions about their potential role.
Scientists don’t yet know the full implications, but they’re increasingly concerned about what they’re finding.
In our next episode, we’ll look at tap water versus bottled water, and what steps you can take to reduce your plastic exposure.
One simple change? Switch to a reusable glass or stainless steel bottle instead of take away coffee cups. It cuts down on plastic waste and helps you avoid microplastics that can leach from the plastic lining of the cups, especially when exposed to heat.