Study finds human brain contains shocking amount of plastic

CNN
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Human brain samples taken during an autopsy in early 2024 showed: Small plastic pieces than samples collected eight years ago, according to a preprint. Post online In May. A preprint is research that has not yet been peer-reviewed and published in a journal.

“The concentrations we found in brain tissue from normal people, with an average age of about 45 to 50 years old, were 4,800 micrograms per gram, or 0.5 percent of the weight,” said Matthew Campen, a professor of pharmacology at the University of New Mexico in Albuquerque and lead author of the study.

“That's about 50 percent higher than the 2016 autopsy brain samples,” Campen said. “That means our brains today are 99.5 percent brain, and the rest is plastic.”

But this increase only indicates exposure and doesn't provide information about brain damage, said Phoebe Stapleton, an associate professor of pharmacology and toxicology at Rutgers University in Piscataway, New Jersey, who was not involved in the preprint.

“It is unclear whether these particles enter or leave the brain in fluids during life or whether they collect in neural tissue and promote disease,” she said in an email. “Further research is needed to understand how the particles interact with cells and whether this results in toxicological effects.”

The brain samples contained 7 to 30 percent more tiny plastic fragments than kidney and liver samples from the cadavers, according to a preprint.

“Studies have found these plastics in the human heart, large blood vessels, lungs, liver, testes, digestive tract and placenta,” said Dr. Philip Landrigan, a pediatrician and professor of biology who is director of Boston University's Global Public Health and Public Good Program and the Global Observatory for Earth and Planetary Health.

“The science in this area is still evolving, and it's important not to scare people, because no one will be able to live without plastic in 2024,” said Landrigan, who was not involved in the preprint.

“I tell people: 'Listen, there are plastics that you can't avoid. You can't have a plastic-free phone or computer.' But try to minimize your exposure to plastics that you can avoid, like plastic bags and plastic bottles.”

CNN reached out to the American Chemistry Council, a trade group, but did not receive a response before publication.

For the study, researchers looked at brain, kidney, and liver tissue from 92 people who underwent forensic autopsies to confirm the cause of death in 2016 and 2024. Brain tissue samples were taken from the frontal cortex, the area of ​​the brain associated with thinking and reasoning, which is the area most affected. Frontotemporal dementia (FTD) and Late stage Of Alzheimer's disease.

“Our observations suggest that the brain inhales very small nanostructures, such as those 100 to 200 nanometers long, whereas some of the larger particles, between 1 and 5 micrometers, make it into the liver and kidneys,” Campen said.

Microplastics Nanoplastics are pieces the size of a pencil eraser, ranging from less than 0.2 inches (5 millimeters) down to 1 nanometer. According to the U.S. Environmental Protection Agency, the width of a single human hair is about 80,000 nanometers. Anything smaller than that is a nanoplastic, and must be measured in billionths of a meter.

Nanoplastics Experts say it is this plastic that poses the greatest concern for human health because tiny fragments can live inside individual cells.

“Somehow, these nanoplastics make their way through the body, through the blood-brain barrier and into the brain,” Campen says. “Plastics love fats, lipids, so one theory is that they get transported through the fats that we eat and into organs that really love lipids, and the brain is number one of them.”

The human brain Fat 60% By weight, the brain stores far more fatty acids than any other organ. Essential fatty acids, such as omega-3, are necessary for the strength and function of brain cells. The human body cannot produce essential fatty acids on its own, so they must be obtained from food or supplements.

The main route of exposure to micro- and nanoplastics is through diet, said Landrigan, lead author of the paper. March 2023 Report from Minderoo – Monegasque Commission on Plastics and Human Health, An international coalition of scientists, health professionals and policy analysts tasked with tracking plastics from their production through to the final product.

In the report, the consortium concluded that plastics pose harm to human health at every stage of their life cycle.

“Some microplastics can become airborne,” Landrigan said. “For example, when you're driving down the highway and your tires rub against the road surface, they release a certain amount of microplastic particles into the air.”

“If you live near a coast, some of the microplastic particles in the ocean get lifted into the air by wave action,” he says, “so ingestion is probably the primary route, but inhalation is also an important route.”

Among the plastics found in the tissue samples, polyethylene dominated — a non-biodegradable material used in plastic bags, film and bottles — and was found to be more prevalent in the brain than in the liver or kidneys, according to the preprint.

Polyethylene is also the predominant polymer type found in human and dog testicles. Survey in August 2024 By Kampen and his team.

The production of various forms of polyethylene, such as polyethylene terephthalate (PET) plastic, is the largest source of environmental releases of the solvent 1,4-dioxane, according to a new study published in the journal Environmental Protection Agency. Industry Data The data was collected by the environmental group Defend our Health.

of U.S. National Toxicology Program The International Agency for Research on Cancer has Possibly carcinogenic In 2023, the EPA Draft Report It says the solvent poses “unreasonable health risks” to plastic workers and local residents whose drinking water is contaminated by emissions from PET plastic plants.

“The big question is: 'Well, what are these particles doing to us?' And honestly, there's a lot we still don't know,” Landrigan says. “What we really know for sure is that these microplastic particles are like Trojan horses, carrying thousands of chemicals that are in plastic, some of which are very bad.”

Nanoplastics penetrate individual cells and tissues in major organs, disrupting cellular processes and Endocrine disrupting chemicals Like Bisphenol, Phthalates, Flame retardants, heavy metal and Per- and polyfluorinated substances (PFAS).

Endocrine disruptors interfere with the human reproductive system, causing reproductive and genital malformations, female infertility, and reduced sperm counts. Endocrine Society.

“We have pretty good indications that microplastics and nanoplastics pose harm, but we're nowhere near knowing the full extent of that harm,” Landrigan said. “We now have enough information to take protective measures.”

Experts say there are a number of steps individuals can take to reduce their exposure to plastic and their plastic footprint.

“While it's difficult to avoid foods wrapped in plastic film, always remove foods from plastic packaging before cooking or microwaving them,” Landrigan said. “Heating the plastic accelerates the migration of microplastics from the packaging into food.”

She suggested buying ziplock cloth bags and asking the dry cleaner to return your clothes in them instead of the flimsy plastic sheets. Natural Resources Defense Councilan environmental organization. Bring a takeaway travel mug to your local coffee shop and bring cutlery to the office to reduce your use of plastic cups and dishes.

“When you go shopping, don't use plastic bags. Use cloth bags, paper bags or recycled bags. Avoid plastic water bottles if you can,” Landrigan said.

a March 2024 Survey They found that a one-liter bottle of water — the equivalent of two standard-sized bottles of water that consumers typically purchase — contained an average of 240,000 plastic particles from seven types of plastic, of which about 90% were nanoplastics.

“Use metal or glass cups instead of plastic ones. Store food in glass containers instead of plastic ones,” Landrigan says. “Work to ban plastic bags in your community, as many communities across the U.S. have already done. There are lots of things you can do.”