STUDY ANALYSIS: Microplastics in the Brain Have Increased 50% in Eight Years

This is a very interesting and worrying study

We’ve already know that microplastics are present in the brain. And why wouldn’t they be? They’re present in all the other major organs—liver, kidneys, heart, lungs, placenta…—so why not the brain too?

Like all of those other organs, the brain has a blood flow, and although it has its own defence system—the blood-brain barrier—it’s only a single line of defence and we know that other harmful substances can get across it, from pathogens to toxic chemicals.

In the last couple of years, studies have shown that microplastics fed to mice end up inside their brains within a period of just a few hours, crossing the blood-brain barrier without any great problem at all. It obviously stands to reason that this is happening in humans as well. Many, but not all, microplastic studies—and especially the feeding studies—work on the basis of extrapolation from observed effects in animals. We can’t feed humans microplastics and see where they go.

It’s early days for microplastic studies in general, but especially for studies of microplastics and their effects on our brains. From my knowledge of the literature, as a keen non-specialist, it looks like a great many “common sense” questions aren’t really being posed yet. Or if they are, they aren’t being answered with the kind of urgency the realisation that our brains are filling up with plastic should, in a relatively sane world, demand.

One such question is: How many microplastics end up in the brain relative to other organs? Surely we need to know this!

Another question: Are the amounts of microplastics ending up in our organs, including our brains, increasing over time?

As far as I can see, these are relatively easy questions to answer. You could easily take post-mortem tissue samples and compare them to answer question one. Here’s a liver sample. Here’s a brain sample. Which has the most microplastics in it?

And with regard to question two, there are large quantities of tissues “on ice” that could be used to construct a longitudinal account of exposure. I don’t know exactly how far back tissue samples go, but I’d bet you could find samples that are many years or even decades old. I’d love to know just how much people in the 1980s were exposed to microplastics by comparison with today.

This isn’t a research pitch, but it easily could be. It’s the pitch I would make if I were a biochemist or whatever.

Thankfully, there’s a new preprint study that provides some initial answers to both questions, using the methodology I’ve just laid out.

Researchers looked autopsy samples taken in Albuquerque, New Mexico between 2016 and 2024 and compared microplastic levels between different organs—brain, liver and kidneys—and compared levels over time.

Here’s what they found.