Last year, we wrote about how a decimal-point error and selective framing turned black plastic spatulas into a public-health scare. Now Netflix’s The Plastic Detox is amplifying another over-the-top claim: that the human brain may contain enough microplastic to make a plastic spoon. That line traces to a February 2025 Nature Medicine paper from researchers at the University of New Mexico. In postmortem frontal cortex samples collected in 2024, the authors reported a median microplastic concentration of 4,917 µg/g, or roughly 0.49% by weight. Scale that to an average brain and you get a visually irresistible metaphor.
…. A disposable plastic spoon weighs around 7 grams. That’s how the line was born.
By November of 2025, the findings had been formally challenged in a letter published in the same journal. The critics noted that the diagnostic markers needed to distinguish polyethylene from brain fat were absent from the data ….
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Nature Medicine is not the only one to face scrutiny in this area. In January, The Guardian reported that seven major microplastics-in-humans studies have been formally challenged in their respective journals, with one environmental chemist calling the reported concentrations ‘completely unrealistic.’
