I am extremely skeptical about this research. Firstly, the "plastic is bad" narrative is too easy to believe, just because plastic is ugly. It's also starting to follow the pattern I have seen in clinical psychology, where many studies find promising initial results, but no one bothers to conduct the real-life randomized controlled study that shows an actual clinical effect. And after a couple of decades of dogma, someone points out that the emperor has no clothes. Suddenly, the whole field looks silly, be it EMDR, classical psychotherapy, mindfulness therapy for severe mental illness, or the abuse craze in the 1990s.

The longer it goes without concrete and clinically significant findings, the larger I think the probability of the findings being wrong becomes. I also find it strange that so few of the studies I have read ever comment on the fact that our system might be fully capable of removing the nanoparticles by itself, just as it removes everything from dust to methylmercury. We do not know if this is the case, but the fact that nobody is addressing this further strengthens my fear that there is a lot of confirmation bias going on.

Every time I post something like this, I get a lot of angry responses, so I can try to preempt some of them by saying: I am not asserting that microplastics are safe. But the pattern of lots of pilot studies, and few studies that significantly prove the theory, is very recognizable to me.

Until someone either conducts a naturalistic experiment with lots of people exposed to large doses of microplastics and compares them to a control group, or we expose some larger animals to microplastics over a long time in a true randomized controlled study, I'm going to remain skeptical.