Plastic is everywhere, including in our brains. According to a preprint in the National Library of Medicine, samples from human brains collected in 2024 contain 50% more plastic than samples collected in 2016. On average, the researchers found that today 0.48% of the human brain is made up of micro and nano plastic particles.
For the study, the researchers collected liver, kidney, and brain samples during autopsies in 2016 and 2024. They found plastic particles in all samples, but the amount of plastic in the brain was 7 to 30 times greater than the amount of plastic in other organs.
“Somehow these nanoplastics hijack their way through the body and get to the brain, crossing the blood-brain barrier,” lead author Matthew Campen told CNN. “Plastics love fats, or lipids, so one theory is that plastics are hijacking their way with the fats we eat which are then delivered to the organs that really like lipids—the brain is top among those.”
What types of plastic were found?
The most common plastic found was polyethylene, which made up 74% of the plastic found in the brain, and between 44% and 57% of the plastic found in liver and kidneys. Polyethylene is the most widely used plastic in the world, commonly used in packing materials. It can be found in items such as cling wrap, plastic bags, and bottles.
Although it’s unclear what implications this has for people’s health, the researchers noted that microplastics have been linked to increasing rates of Alzheimer’s and dementia.
“The parallels between the present data showing an increasing trend in [plastic] concentrations in the brain with exponentially rising environmental presence of microplastics and increasing global rates of [Alzheimer’s disease and dementia] add urgency to understanding the impacts of [plastics] on human health,” the study’s authors wrote.