Even though:
These data are associative and do not establish a causal role for such particles affecting health
I still don't feel so nonchalant about the idea of microplastics lodging on my brain. While the effect on human brains is very difficult to directly measure, we do have a lot of data on mice that suggest that having plastic in the brain is bad for the brain.
When quickly looking into EU food regulations it seems like microplastic content is not regulated in food, and the logic appears to be along the lines that not enough data is available to assess the actual risk. This makes some sense in that measurement, control, and enforcing limits is likely to be difficult, expensive, and might create some economic challenges, and so regulators might not want to go this route unless proven absolutely necessary.
At the same time, data does exist showing that the plastic levels are increasing in our brains, and we have very good reasons to believe that this is not a good thing. It is not that we are completely in the dark - I am sure some smart people would be able to come up with reasonable limits and methods of control by now.
My not-very-informed suspicion is that there is pressure from wealthy and powerful lobbyists that would significantly suffer from microplastics regulations, because 'plastic in the brain' has seemed like an obvious thing to address for some years now.
I have never been educated about how to avoid ingesting / breathing microplastics. Do any of you know some habits or diets that reduce or increase exposure to microplastics?