Our brains may contain up to 0.5% plastics, and this figure will continue to rise in the future - this is a startling discovery from a recent study in Nature Medicine [1].

Once again, the research shows that microplastic pollution has widely infiltrated the human body. Researchers call on people to take action to control plastic waste as soon as possible and conduct a more in - depth assessment of the health risks of plastic particles.

Plastics in the brain

By detecting 91 autopsy samples, researchers from the University of New Mexico analyzed the content of plastic particles in the human brain. They degraded biological tissues by chemical methods, separated the undegradated plastic particles from them, and identified them by pyrolysis - gas chromatography and other methods.

The results showed that there are not only microplastics in the human brain, but also quite a lot, and the content is even far higher than that in the liver and kidneys. In the brain tissue samples collected in 2024, the median plastic content was 4917 μg/g, which is nearly 0.5%. Although the sample size is still small, this discovery is indeed alarming.

According to the research data, in a human brain weighing about 1.3 kilograms, the total amount of plastics may be 6 - 7 grams. If these plastics are gathered together, they are even enough to make a plastic spoon.

A 5 - gram plastic spoon | Photo by the author

In these samples, researchers found a total of 12 different man - made polymers. In the brain, the most common plastic component is polyethylene, which accounts for 75% of all particles. This kind of plastic is often used in packaging materials and containers. The diameter of plastic particles entering brain tissues is typically only a few hundred nanometers, and they are small enough to pass through the human blood - brain barrier.

The plastic content in the human brain seems to be on the rise: during the 8 - year period from 2016 to 2024, the microplastic content in brain tissue samples increased by about 50%, and this increase should be related to the increase in the concentration of microplastics in the environment. Considering that the amount of plastic waste is still growing rapidly, the microplastic content in people's brains is likely to be even more in the future.

This study also found that the brain tissues of patients with dementia contain more plastic particles - however, this alone cannot prove that microplastics can cause brain diseases.

Plastic particles found in human brain tissue samples by researchers. These tiny fragments, measuring less than 200 nanometers in length, can only be clearly seen under an electron microscope | A. J. Nihart et al

The health risks are still unknown

Microplastics are small particles produced during the degradation of plastic products. These pollutants that are difficult to distinguish with the naked eye have spread all over every corner of the world, and even the Mariana Trench and the summit of Mount Everest are not spared.

In the human body, these plastic particles are also widely present. In addition to brain tissues, livers and kidneys, microplastics have also been found in human lungs, blood, placentas and bone marrows.

Microplastics can enter the human body through food, drinking water and the air people breathe. The specific laws of their absorption, accumulation and elimination in the human body are still unclear.

Will microplastics affect human health? Due to insufficient research data, there is still no definite answer to this question at present. However, some early studies have indeed found concerning signs. For example, a study published in The New England Journal of Medicine shows that microplastics deposited in atherosclerotic plaques may be associated with higher risks of cardiovascular diseases and death [2].

How to reduce microplastic exposure?

Although the evidence of harm to health is still insufficient, it is still a wise choice to minimize microplastic exposure as much as possible.

Some simple measures can help us reduce microplastic intake. For example, do not use plastic containers to heat food, drink less bottled water, often use a vacuum cleaner to clean room dust, and avoid washing chemical - fiber clothes too frequently.

However, these measures are far from sufficient to address all issues. Only by reducing plastic waste and properly recycling plastic waste can the microplastic pollution problem be truly improved.

[1]https://www.nature.com/articles/s41591-024-03453-1

[2]https://www.nejm.org/doi/10.1056/NEJMoa2309822

[3]https://www.eurekalert.org/news-releases/1072458

[4]https://www.theguardian.com/environment/2025/feb/03/levels-of-microplastics-in-human-brains-may-be-rapidly-rising-study-suggests

[5]https://www.sciencenews.org/article/plastic-human-brains-microplastics