Plastic Particles in the Brain: The Amount Just Keeps Growing

We are living in the age of plastics. They are fantastically useful.  Their properties can be tailored by tuning the chemical content to provide desired attributes.  They are generally inexpensive to produce.  Some products can be recycled, but the process is more expensive than producing fresh material, so the only economic benefit is derived from public relations gestures.  They have become ubiquitous.  Initially, we worried that they were such long-lasting products that they would be permanent eyesores as they collected on roadsides and beaches.  We now know that they are far from robust materials.  They contain dangerous chemicals that can leach from their surfaces.  Particles can cleave from their surfaces as they interact with the environment.  These particles can then fragment into even smaller particles producing more surface area from which chemicals can leach.  If the particles become small enough, they can enter our blood stream via our lungs or our intestines.  At that point, they can find a home for themselves and the chemicals they bear in all of our organs and body parts.

There is no place on earth that has been found safe from plastic pollution.  It has only been a few years since scientists began to realize these tiny plastic particles can be a threat to human health.  The article, Study Finds Hundreds of Thousands of Plastic Particles in Bottled Water, provides a perspective on current findings with a focus on the common plastic water bottle.

“Plastic water bottles, a long-known enemy of our Earth, are finding their way into human bodies in huge quantities—well, pieces of them are. A study published this week shows just how much plastic we drink with bottled water: Researchers from Columbia University and Rutgers have found at least 240,000 plastic particles in the average liter of bottled water, a major health concern.”

“Most of the plastic particles found by the researchers were extremely small nanoplastics, which have a diameter of less than one micrometer—making them invisible to the naked eye. Nanoplastics have been historically challenging to study due to their extremely small size, but as technology has improved, scientists are now finding them almost everywhere—including in the environment, plants, animals, beverages, foods, and our human bodies.”

“While the full range of health effects of nanoplastics and microplastics in our bodies is not yet fully understood, what experts do know is already very concerning. Like all plastics, microplastics and nanoplastics are known to contain any mix of additive chemicals.  More than 16,000 such chemicals have been counted in plastics, and none have been classified as ‘safe.’ At least 25% are already officially classified as hazardous. A few concerning plastic chemicals include hormone-disrupting and cancer-causing phthalates, PFAS, and bisphenols; asbestos and toxic heavy metals such as lead and arsenic; and much more. Additionally, microplastics can absorb and accumulate toxic chemicals in the environment, which leach into living bodies, waters, soils, and plants.”

“Most plastic water bottles are made of PET (polyethylene terephthalate) plastic. At least 150 chemicals are known to leach from PET plastic beverage bottles into the liquid inside, including heavy metals like antimony and lead, and hormone-disruptors like BPA. Plastic PET bottles are even more likely to leach toxic chemicals if they are recycled, or are kept in warm environments, are exposed to sunlight, or are reused. Single-use plastic bottles also contain PFAS, a class of chemicals that are particularly dangerous to human and environmental health.”

A recent article (March,2025), Human microplastic removal: what does the evidence tell us?, provides a glimpse at what might be happening when these tiny particles accumulate in our bodies.  The focus is on our plastic-laden brains as determined by measurements taken from deceased subjects.

“A recent paper in Nature Medicine by Nihart et al. found that the human brain contains approximately a spoon’s worth of microplastics and nanoplastics (MNPs), with levels 3–5 times higher in those with a cohort of decedent brains with a documented dementia diagnosis (with notable deposition in cerebrovascular walls and immune cells).  Particularly, brain tissues were found to have 7–30 times higher amounts of MNPs than other organs such as the liver or kidney. Also of note, the microplastics in the brain were of a smaller size (<200 nm) and most often polyethylene.”

“This aligns with the observed exponential increase in MNP environmental concentrations over the past half-century. Particularly, 10 to 40 million tonnes of emissions of microplastics to the environment are estimated per year, with this figure expected to double by 2040.”

Little is known about what all this means.

“The current evidence base (largely based upon animal and cell culture studies) suggests that MNP exposure can lead to adverse health impacts via oxidative stress, inflammation, immune dysfunction, altered biochemical/energy metabolism, impaired cell proliferation, abnormal organ development, disrupted metabolic pathways, and carcinogenicity.  These can lead to direct or indirect consequences to various organ systems, including respiratory, gastrointestinal, cardiovascular, hepatic, renal, nervous, reproductive, immune, endocrine, and muscular.”

And don’t forget, people diagnosed with dementia tend to have 3-5 times the plastic particle concentrations in their brains when they die.  That has to mean something, but it is not yet known whether plastic concentration is a cause or an effect.

The most interesting findings presented in the article are summarized here.

“Although MNP [microplastic and nanoplastic] concentration was not influenced by factors such as age, sex, race, or cause of death, there was a worrisome 50% increase in MNP concentration based on the time of death (2016 versus 2024).” 

If plastic particles were simply accumulating in our bodies, one would expect older persons to have accumulated higher concentrations.  This suggests that the body has some mechanism by which it can excrete plastics, either as particles or by first breaking them down into component chemicals.  There is little to no evidence yet for any such process in humans, but the authors do make the following observation.

“In fish models, it takes approximately 70 days to clear 75% of accumulated brain microplastics, suggesting that decreased inputs and increased outputs must both be maintained for long enough durations to see measurable changes.”

The authors also state that plastic particle concentrations increased by 50% between the years 2016 and 2024, an eight-year period.  They also predict an increase in the rate of plastic loading of the environment of about 100% over the period 2024 to 2040, a sixteen-year period.  Does that mean we will likely have three spoonful of tiny plastic particles in our brains in 2040, or could it be much higher?

The fact that plastic concentrations increased over the eight-year period means the plastic sources are exceeding any plastic sink mechanisms in the body.  There should then have been some level of age effect. The sample of deceased may have been too similar in age to detect a difference, or the ratio of plastic particle source to sink may have only recently exceeded 1.0.

It is scary to combine how little we know of what is happening to us now with the knowledge that whatever it is, it will get much worse in the near future. 

There are many ways in which small plastic particles enter the environment and proceed to enter our bodies.  Limiting the use of plastics seems to be the only solution.  It is probably too much right now to ask people to stop wearing and washing plastic clothing, but immediately stopping the use of those damn plastic bottles would be a good first step.

  

You can learn a little about a lot of things or you can learn a lot about a very few things. Guess which is the most fun.

Source: http://letstalkbooksandpolitics.blogspot.com/2025/03/plastic-particles-in-brain-amount-just.html