Researchers have detected microplastics in the human brain

Plastics are practical and have become an integral part of our lives. However, they also have a threatening downside: In the form of microplastics, they are distributed everywhere, in the environment, in the air and also in the human body — right into the brain.

Researchers at the University of New Mexico in Albuquerque have investigated the concentration of micro- and nanoplastics (MNP) in the human brain. Their results, published in the journal Nature Medicine, are alarming: the team led by Matthew Campen found MNP particles in higher concentrations than in other organs, such as the liver, kidneys, placenta, or testicles.

“I never thought it would be that high,” said Campen. “I definitely don't feel comfortable with that much plastic in my brain, and I don't have to wait another 30 years to find out what happens when the concentrations quadruple.”

91 samples were examined

For the study, the researchers examined tissue from the brains of people who died between 2016 and 2024. Each of the 91 samples came from the frontal lobe, i.e., the area behind the eyes. The researchers were able to detect twelve different polymers, including polyethylene, the most widely used plastic.

It is also worrying that the concentration of plastic in the brains has increased over the study period of just eight years: In 2016, this averaged 3.345 micrograms per gram; in 2024, the average was 4.917 micrograms per gram.

In the brains of people diagnosed with dementia, the researchers found up to ten times as much plastic as in the brains of others. There was a clear correlation, said Campen. However, it cannot be deduced from the result that the larger amount of plastic caused the dementia. It is possible that dementia-related changes in the brain promote the deposition of MNP.

Microplastics can be found everywhere on earth, even in the deep sea. According to Campen, it enters the body through food, especially meat.

How does plastic get into the brain?

However, it is unclear how the particles get into the brain. The researchers found pieces that were 200 nanometers in size. These are small enough to break through the blood-brain barrier that separates the bloodstream and the central nervous system.

It is also unclear what effects the plastic has on the body. The researchers suspect that it is not so much the chemical, but rather the physical properties of the particles that have an effect on the body. It is possible that MNPs impede blood flow in the capillaries or that they disrupt the connections between axons - parts of nerve cells.

“Simply put, we don't know the health effects of microplastics in the brain,” co-author Andrew West told the US scientific journal Science News. However, he advises people to look into the issue and not wait until all the answers are on the table.

Science News also pointed out that the number of samples was small. The results should therefore be viewed with caution.

(wpl)