NEW YORK, Aug 26: Human brain samples collected during autopsies in early 2024 showed a significant increase in tiny plastic shards compared to samples from 2016, according to a preprint study posted online in May. The study, which has not yet been peer-reviewed, found that brain tissue from individuals aged 45 to 50 contained 4,800 micrograms of plastic per gram, equivalent to 0.5% by weight. This represents a 50% increase from the levels found in 2016.
Lead author Matthew Campen, a professor of pharmaceutical sciences at the University of New Mexico, noted that while the increase indicates higher exposure to plastics, it does not necessarily mean there is corresponding brain damage. Phoebe Stapleton, an associate professor at Rutgers University, emphasized that more research is needed to determine if these particles accumulate in the brain and contribute to neurological diseases.
The study also found that brain samples contained 7 to 30 times more plastic than samples from the kidney and liver. Pediatrician and biology professor Dr. Philip Landrigan, who was not involved in the study, highlighted that microplastics have been found in various human organs, including the heart, lungs, and placenta.
Landrigan cautioned against panic, stating that while avoiding all plastics is impossible, individuals can take steps to minimize exposure. The American Chemistry Council responded by noting that current scientific evidence does not demonstrate that microplastics in foods pose a risk to human health, though research continues to address data gaps.
Researchers analyzed tissues from 92 people who underwent forensic autopsies in both 2016 and 2024. The brain samples were taken from the frontal cortex, which is associated with reasoning and is most affected by diseases like Alzheimer’s. Campen suggested that the brain may absorb the smallest plastic particles, while larger ones accumulate in the liver and kidneys.
Microplastics are tiny fragments, less than 0.2 inches in size, while nanoplastics are even smaller, measured in billionths of a meter. Experts consider nanoplastics particularly concerning for human health due to their ability to infiltrate individual cells and tissues.
Diet is considered the main route of exposure to micro- and nanoplastics, though inhalation also plays a role. Polyethylene, commonly used in plastic bags and bottles, was the predominant type of plastic found in the tissue samples. This plastic is also linked to the release of 1,4-dioxane, a solvent considered possibly carcinogenic to humans.
The potential health risks of microplastics include the disruption of cellular processes and the deposition of harmful chemicals such as endocrine disruptors. These disruptors can lead to reproductive issues, including infertility and declining sperm counts.
Experts recommend several steps to reduce plastic exposure, such as avoiding heating food in plastic containers, using cloth or paper bags instead of plastic, and opting for glass or metal containers for food and drinks. Landrigan also encouraged community efforts to ban plastic bags and reduce reliance on single-use plastics.
