In December 2024, Ellen Bearer, a neuropathologist at the University of New Mexico, was examining brain tissue when she noticed what she later called “strange brown lumpy things.” They were not the usual blood vessels, clots, or debris. It turned out to be plastic.
A study later published in Nature Medicine measured microplastics and nanoplastics in human brain tissue collected after death. Concentrations were higher in the brain than in the liver or kidney, and samples from people with documented dementia contained more.
For years, we have imagined plastic pollution as something outside ourselves: bags in drains, bottles in rivers, nets in the ocean, pieces inside fish and seabirds. But plastic is no longer just an environmental problem. It exists within us.
In 2024, a study in the New England Journal of Medicine examined people who had surgery to remove plaque from their carotid arteries, the vessels that supply blood to the brain. When the researchers analyzed the extracted plaques, they found microplastics and nanoplastics in many of them. Over about three years of follow-up, patients whose plaques contained these molecules had a greater risk of heart attack, stroke, or death than those whose plaques did not contain them.
Plastic reaches us through two main routes: we eat it and we breathe it. Plastic is found in food and water, but it is also in the air. Plastic particles can be inhaled from synthetic clothing, furniture, household dust, building materials, smoke, and tires. Every time the tires meet the road, small splinters fall off. Every time synthetic textiles are rubbed, washed, dried or aged, they release fibres. We live in a plastic atmosphere.
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When we eat food, the body digests it. Carbohydrates, fats, and proteins are broken down into smaller molecules that can be absorbed, used, stored, or excreted. Plastic doesn’t work the same way. It physically breaks down into smaller and smaller pieces. The smallest particles can cross biological barriers, enter cells, settle in tissues, and carry with them additives or other contaminants. There is a lot we still don’t know. Scientists are still working to determine the important sizes and doses, and how long the different molecules remain in the body.
A recent study by researchers at the University of Western Australia, also published in Nature Medicine, asked a different question: Can we reduce the amount of plastic-related chemicals entering the body? The study measured chemicals associated with plastic, especially phthalates and bisphenols, which can leach from food packaging, processing equipment, kitchen utensils, and personal care products.
We can’t escape plastic completely. Across 211 healthy adults, every study participant had detectable levels of several chemicals associated with plastic. Possible sources were highly processed foods, plastic-packaged foods, canned goods and beverages, plastic appliances, and personal care products.
But we may be able to reduce some of the plastic-related chemicals entering our bodies. For 60 participants over seven days, researchers attempted to remove plastic from the food chain. The team worked with more than a hundred farmers and food producers to reduce contact with plastic “from field to plate.” Some participants ate low-plastic foods, used stainless steel and wooden kitchen utensils, and switched to low-plastic personal care products.
You succeeded. After a week, many chemical markers in the urine decreased sharply. In the strongest intervention, phthalates were reduced by more than 40%, and bisphenols by about half compared to the control group. BPA also decreased in the groups that received low-plastic foods.
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The study shows that daily exposure to plastic can be measured and modified and is closely intertwined with food production, storage and consumption.
But this isn’t the story of a seven-day plastic detox. The trial did not show that a week of living plastic-free improves health. It has not been shown that molecules already present in tissues can be eliminated. In fact, we know little about how much exposure is safe.
Plastic is everywhere because it is cheap and convenient. Families cannot solve a global problem on their own. But there are still sensible steps people can take, such as not heating food in plastic, avoiding scratched and old plastic containers, using glass or steel for hot foods and drinks, and avoiding single-use plastic bottles and packaging where practical.
Anirban Mahapatra is a scientist and author. His latest book is When Medications Don’t Work. The opinions expressed are personal
