Microplastics May Accumulate in the Brain Faster Than Other Organs, Researchers Warn

Human brains could contain up to 7 grams of microplastics per person, which is approximately the weight of an entire plastic spoon in the brain.

A new study reveals that microplastic levels in the human brain have risen by 50% on average compared to eight years ago, raising concerns over the long-term effects of their rapid accumulation.

In findings published in the journal Nature Medicine on February 3, researchers now warn that the average human brain actually contains up to 7 grams of micro- and nanoplastics, which is a staggering amount.

Microplastics are tiny plastic fragments ranging from 5 millimeters (about the size of a pencil eraser) to 1 nanometer. Nanoplastics, which are even smaller, measure less than 1,000 nanometers. For perspective, a single strand of human hair is approximately 70,000 nanometers wide.

These microscopic plastic particles originate from the breakdown of larger products, such as water bottles, food containers, fast food wrappers, toys and other consumer goods. They are also released into the air through everyday activities, like tire friction on highways, contributing to widespread environmental exposure.

Nanoplastics can impair the cellular process and expose humans to endocrine-disrupting chemicals, like bisphenol, phthalates, heavy metals and per- and polyfluoroalkyl substances (PFAS), all of which have been linked to adverse effects on the reproductive and immune systems, raising concerns about long-term health consequences.

Previous studies have raised concerns about the accumulation of microplastics in the human brain, showing that microplastics are accumulating in the brain’s olfactory bulb, which controls the smelling function.

In the study, researchers from the University of New Mexico examined tissue from the brains, kidneys and livers of deceased people who had autopsies in 2016 and 2024. They also examined brains from people who died between 1997 and 2013.

The autopsies revealed that people now contain an average of 7 grams of microplastics in their brains. This was 50% more than was found in 2016. It was also up to 30 times more than the levels of microplastics found in the kidneys or livers.

People who were diagnosed with dementia before death had three to five times more levels of microplastics in their brains than their peers, or up to 35 grams of nanoplastics. Researchers said the plastics were concentrated in the walls of arteries, the veins of the brain and the immune cells.

“These data are associative and do not establish a causal role for such particles affecting health,” the researchers noted. “For this, refinements to the analytical techniques, more complex study designs and much larger cohorts are needed.”

Widespread Microplastic Health Concerns

Microplastics have been detected on nearly every tested surface of the Earth, from fresh Antarctic snow to remote islands and even the depths of the Mariana Trench. Their pervasive presence means they are also routinely inhaled and ingested, making human exposure nearly unavoidable.

A study published by Arizona State University researchers in 2020, indicated that microplastics are found in every human organ, including the brain. Another study published that same year showed that infants can ingest 1.6 million particles of microplastics every day from baby bottles.

For adults, drinking bottled water can add up to 90,000 microplastic particles to a person’s diet every year.

Research published earlier this year also indicates the particles of microplastics in tap and bottled water are small enough to pass into the bloodstream and then move into the organs, with a separate study finding evidence of microplastics in human testicles.