Science Slate Good News: You Probably Don’t Have a Spoon’s Worth of Plastic in Your Brain After All

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Remember hearing that you have a spoon’s worth of plastic in your brain? That’s what a study published last February in Nature Medicine suggested. Researchers at the University of New Mexico analyzed samples of brain tissue from dead people, and found they contained a truly alarming amount of teeny tiny shards and flakes of polyethylene, and other polymers. While the negative effects of such microplastics and nanoplastics on the body were unclear—and the researchers admitted that point—it was still an incredibly jarring discovery. “I certainly don’t feel comfortable with this much plastic in my brain,” said Matthew Campen, a toxicologist who led the study. Plastic made up nearly 0.5 percent of the brain tissue of “normal individuals” that the team examined, an amount that Campen, aware of the size of the brain, characterized to the media as the equivalent of a spoon. Yikes!

Well—now, double yikes. In the weeks after the paper was published, someone spotted that it contained a couple of duplicated images. That itself might have just been a sloppy clerical error. But over the summer a group of scientists wrote to the journal where the study had appeared, highlighting “methodological limitations” in the study, namely that it may have failed to properly root out any “contamination introduced during sampling, sample preparation or detection.”

That is: did the proverbial plastic spoon come from the brain tissue itself, or did some of it come from other sources, like labware or even the air? We just can’t tell. At any rate, as one of the scientists critical of the study put it to the Guardian in a report published Tuesday: “The brain microplastic paper is a joke.”

“There’s a lot of plastic in your body” has become a not-uncommon refrain in headlines in recent years, ever since they were detected in human blood in 2022. But just how much plastic is in your body is up for debate. The issue isn’t even just with that one spoon paper. The 2022 blood-plastic paper received criticism shortly after it was published too, and more recently, a study led by researchers at the University of Queensland assessed the methodology commonly used to detect microplastics in these studies, and found it was prone to false positives (namely, mistaking fats for plastics).

None of this is to say that there affirmatively isn’t any microplastic in your brain, blood, etc—but how much is unclear, and when it comes to toxicity, the dose still makes the poison, even when we’re talking brain plastic. As the Guardian’s environmental editor, Damien Carrignton writes: “the race to publish results, in some cases by groups with limited analytical expertise, has led to rushed results and routine scientific checks sometimes being overlooked.”

So too with the race to publicize them. In fall 2024, many of us were ridding our kitchens of a very common utensil, thanks to a piece in the Atlantic that instructed us to, “Throw Out Your Black Plastic Spatula.” The claim was that they contain chemicals from recycled computer parts—I’m typing, for example, on black computer keys—which were, as we slid our black plastic spatulas across hot cooking surfaces, leaching into our food at alarming rates. I needed a second opinion before tossing mine, so I asked Gideon Meyerowitz-Katz, a regular Slate contributor and epidemiologist for his take. He looked at the alarming research underlying the Atlantic piece, and found no reason for alarm: you’d have to boil your spatula in oil, and then drink the oil, to be exposed to a meaningful level of those iffy computer chemicals. And even then, you might be fine. Further, one of the spatula papers turned out to have contained a math error.

The real problem, I think, isn’t necessarily the sloppy studies themselves. There will always be sloppy studies, because the people who do science are human beings. There’s no evidence, the Guardian points out, of fraud in the microplastics research. Scientists fight all the time about results, methodology—it’s part of the process.

The issue, rather, is our rush to make meaning out of such small scraps—shards? microparticles? if you will—of science. Just this summer, Orlando Bloom revealed he’d had a $10,000 procedure to clean the microplastics from his blood, a procedure which itself relies on plastic components (that could potentially contaminate the blood). This kind of “cleanse” outpaces any science that might suggest it is a meaningfully good use of funds or even simply one’s time. Bryan Johnson, the sallow billionaire who claims he wishes to “never die,” is selling $150 kits where you can draw your own blood, at home, and send it to be evaluated for microplastics; having edited a piece in which a writer tries the kit out, my take is that you might as well consult a tarot deck. Plastic is everywhere, and it’s bad for the environment—we know this. It is also virtually impossible to avoid, and it’s not clear whether trying to avoid it curtails any kind of real health problem.

The other issue—the fear, really—is that squabbles in science can be weaponized; used as an excuse to curtail funding, or to throw out common-sense policies that curtail plastic use. The truth is that we do not know what the future of microplastics research holds. We will have to keep doing it to find out.