New research finds plastic in human brains

In some ways, it’s not a surprise that there are plastic particles all around us. Plastic is everywhere in our lives, from the packaging of our food, to the fabric of the clothes we wear, to the case of the phone we carry every day. But when plastic breaks down into tiny particles, it can infiltrate our environment – and our bodies – more deeply than you might think.

Scientists discovered microplastic in human brain tissue

Researchers who collected brain samples from autopsies and examined them for plastic particles were surprised and alarmed by what they found.

Their pre-print study, which is still undergoing peer review, found plastic in the human brains at a concentration of 4,800 micrograms per gram. That’s a small amount, but it still adds up. In total, the results of this study indicate that our brains may be only 99.5% brain, and 0.5% plastic by weight. 

Perhaps even more alarming is the fact that these results indicate that microplastic pollution of the brain is on the rise. In this most recent study, the scientists found 50% more plastic in the brain than they did in a previous study eight years ago.

How does plastic get into the brain?

Scientists are not yet totally sure how microplastics are entering our brains, but they have some theories.

The most worrisome type of plastic pollution when it comes to infiltrating the human body is “nanoplastic,” or particles so tiny they can’t be seen. They are so small that they can enter individual cells.

One scientist from this study theorizes that tiny plastics are hitching a ride into our brains by attaching themselves to the fats we eat.

This idea has been tested before, in mice. Scientists who gave mice water laced with polystyrene, a type of plastic, found plastic particles in the rodents’ brains just two hours later. Their results suggest that the plastic is getting absorbed into cholesterol molecules. These little packages of fat with hidden plastic are capable of crossing the blood-brain barrier and entering the brain itself.

What are the health impacts of microplastics in the brain?

This most recent study only indicates that our brains are exposed to microplastics. It does not yet definitively reveal anything about brain damage from these tiny plastic particles. 

Even though little is certain, the evidence we do have is alarming.

Twelve of the brain samples from the recent study were from patients who died with dementia, including Alzheimer’s disease. Those brains had ten times more plastic by weight than the healthy samples.

Scientists are interested in figuring out how microplastics might interact and impact the brain. Other studies have suggested the presence of microplastics could increase the risk of various conditions such as oxidative stress, which can lead to cell damage and inflammation. Animal studies have linked exposure to certain types of microplastics to impairments in learning and memory.

Microplastics may be harming other parts of the human body, too

The brain is just the most recent – and perhaps most alarming – entry into the list of human bodily systems infiltrated by plastic. Microplastics have been found in many different parts of the human body, including the heart, blood vessels, digestive system, and more.

Studies on humans and other animals show that all this plastic can have dangerous health impacts on all these different bodily systems. Learn more in our overview of how microplastics are harming human health with some tips about how to reduce your exposure here:

Take action to reduce plastic pollution and microplastic contamination

It’s not possible to totally avoid plastic in our society. But it’s vital that we cut back on unnecessary plastic in our lives and in our environment.

Existing laws aren’t stopping companies from discharging plastic pellets directly into waterways. Stopping this source of plastic in our environment is a great first step to reduce overall plastic pollution and protect our health.

Tell your U.S. senators to keep plastic out of our water by supporting the Plastic Pellet Free Waters Act.