Especially in the brain

People have more plastic particles in their bodies

Microplastic particles on a finger

(Bild: gradt)

More and more tiny plastic particles are accumulating in the body's tissues. The load in the brain is particularly high, as a study by the University of New Mexico (USA) has now shown. Microplastics have previously been detected in the lungs, intestines and placenta.

However, conventional microscopy methods usually only detect particles larger than five micrometers. "Smaller nanoplastics are therefore unintentionally excluded," the scientists write. A micrometre is a thousandth of a millimetre, a nanometre a millionth of a millimetre. The team led by Matthew Campen used special infrared and electron microscopy to determine the quantities of plastic in the body more precisely.

The result: the average concentration of microplastics and nanoplastics in the kidneys was similar in 2016 and 2024. However, liver and brain samples from 2024 showed significantly higher values. In the liver, the average concentration rose from 141.9 to 465.3 micrograms per gram of tissue, and in the brain from 3,420 to 4,763 micrograms per gram. Tissue samples from 24 deceased persons from 2024 and 28 deceased persons from 2016 were analyzed.

Polyethylene most frequently contained
The researchers also used a chemical analysis to determine the composition of the plastic. They most frequently found polyethylene, which is used for films and surfaces. It made up 40 to 65 percent of the plastic in the liver and kidneys, and as much as 75 percent in the brain. Analyses of preserved brain tissue from 1997 to 2013 also showed that the amount of tiny plastic has increased significantly in recent years.

The plastic load was particularly high in brain samples from people who were proven to have dementia. They contained between 12,000 and 48,000 micrograms of plastic per gram of tissue. Some differences could also be due to geography. The health effects are not yet fully understood.

Mice were less well oriented
Just recently, a group led by Haipeng Huang from the Chinese Research Academy of Environmental Sciences in Beijing presented research findings according to which microplastics can potentially block blood vessels in the brains of mice. The affected mice moved less, were less able to orient themselves and had less stamina, according to the study. However, the results cannot be easily transferred from mice to humans due to differences in brain structure, according to the journal "Science Advances".