Your Brain On Microplastics

Myths vs. Facts

Photo by Noppadon Manadee on Unsplash

Hello, everyone. I’m sure you are well aware that the world has a serious plastic problem. By now you have been inundated with reports of the dangers of microplastics—tiny particles (smaller than 5 millimeters) of plastic debris. Not only is plastic accumulating in our oceans and soil, recent studies describe microplastic building up in the body.

Last year the New England Journal of Medicine published data that people with microplastics lodged in coronary arteries were more likely to have a heart attack, stroke, or die. Another group of researchers found them in the olfactory bulb of the brain.

Then, in February, a study published in Nature Medicine really got my attention. Researchers mapped out how microplastics accumulate in the liver, kidneys, and brains. The brains of post-mortem specimens were more likely to harbor microplastics than other organs. Not only that, the brains of people who had dementia accumulated these plastics the most.

What does this mean for brain health? Does microplastic accumulation increase the risk of Alzheimer’s and other dementias? If there is a strong link, is it even possible to significantly reduce microplastic exposure? This is one topic with more questions than answers.

Here’s the good news, though: when it comes to these tiny plastic toxins, a small amount of knowledge goes a long way. For example, it is helpful to know that some plastic sheds less than others. E.g., the plastic in your VitaMix pitcher is not the same as in take-out containers. And, that swearing off plastic water bottles (at least most of the time) goes a long way to reduce exposure.

For today’s newsletter I aim to help you raise your microplastic IQ so you can take action to mitigate risk. We’ll cover:

• Myths vs. Facts. There is a lot of misinformation out there about this topic!

• Microplastics in the brain

• What we know about microplastics and what we don’t

Next time, I’ll give you 8 simple things you can do to reduce exposure in the kitchen.

Before we get into the Nature Medicine brain study, let’s debunk a few of the many myths floating around about microplastics.

This post is the second in our mini-series on the impact of environmental toxins on brain health. In case you missed it, catch up on the link between pesticides and Parkinson’s in this post.

Microplastics: Myths vs. Facts

Photo by Kabir Kotwal on Unsplash

Myth: Our bodies harbor a credit card’s worth of microplastics, or about 5 grams.
Fact: This widely shared statement was based on this study which was subsequently debunked by this one. More accurate estimates are measured in micrograms, or 1/1000 of a gram. The truth is, nobody knows how much plastic debris accumulates in the body. There’s solid data to say, however, that our bodies harbor more microplastic now than they did 20 years ago.

Myth: Most of the microplastics ingested accumulate in the body.
Fact: Your body eliminates 99% of what’s ingested within 24 to 72 hours, mostly through stool but also through urine.

Myth: Shards of plastic from cutting boards are a primary health concern.
Fact: While ingesting large pieces of plastic is gross, these readily pass through the digestive system. It’s the tiny microplastics (smaller than 5 millimeters) and even tinier nanoplastics (smaller than 1 micrometer) that are of concern. (One micrometer is 1/1000 of a millimeter.) Putting a plastic cutting board (or other kitchen utensil) in the dishwasher, however, can shed microplastics onto your dishes.

Myth: Microplastics have been proven to damage organs like kidneys, liver, and brain.
Fact: It’s too early to say, but it is certainly a concern. Diseased organs tend to accumulate microplastics at a higher rate, which may have more to do with their faulty filtration and inflammatory defenses. What we do know is this: there is a strong link to health problems such as infertility, preterm birth, and diabetes from exposure to some of the chemicals in microplastics, such as bisphenols (BPA) and phthalates.

Myth: Microplastics are everywhere so it’s impossible to reduce exposure.
Fact: Exposure comes primarily from the air we breathe, our water, and our food. It is possible to reduce exposure and therefore (hopefully) accumulation in the body. When the team of analysts at Peter Attia crunched the numbers, they came up with an estimate of how much we can put a dent in exposure by modifying habits:

• Limiting plastic in the kitchen, avoiding plastic water bottles, and drinking filtered water probably eliminates 50% of microplastic exposure.

• Also avoiding synthetic clothing, seafood and seaweed, installing a HEPA filtration system in your home probably gets you to 75% reduction in exposure.

(I highly recommend listening to this podcast episode for a deeper dive into this topic, although there may be a paywall.)

Microplastics in the brain

Caption: These graphs show the accumulation of microplastics in liver, kidney and brain over the last 20 years, and how it plots against dementia brains. (NC, MD, MA, NM refers to the state of origin of the specimens.)Source: Nature, 2025.

There’s currently no reliable biomarker for detecting microplastics in live humans so researchers rely on post-mortem specimens. In the Nature study, they looked at microplastic accumulation in kidneys, liver, and brain in people who had passed between 2016 and 2024. Brain tissue accumulated more of these toxins than liver and kidneys, and was on par with what had been described in coronary arteries. Researchers also noticed significantly more accumulation in 2024 than was seen in 2016.

The researchers then asked the question: do people with dementia accumulate more microplastics than those with healthy brains? To find out, they obtained 12 brain samples from another lab, all of which were known to have dementia: 6 with Alzheimer’s, 3 with vascular dementia, and 3 with other dementia. The findings: dementia brains harbored more microplastics than non-dementia brains.

Are microplastics increasing the risk of dementia?

It is impossible to say. Another plausible explanation is that people with dementia accumulate more microplastics because they have impaired blood brain barrier (BBB) integrity. A leaky BBB makes the brain more vulnerable to all sorts of particulate matter that otherwise would not be able to cross.

So, while this study can’t prove cause and effect, scientists are concerned that microplastics are yet another factor to incite inflammation in the brain, a known root cause of dementia. This was shown in coronary arteries, although the sample size of cardiac events was also small (n=8). Based on animal studies in rodents and fish, microplastics are harmful to health due to their inflammatory effects.

Putting microplastics into perspective

With microplastics, there are still more questions than answers. Scientists are still struggling to define the impact of micro- and nanoplastics on human health. And that makes it impossible to determine the brain health benefits of reducing exposure.

Alzheimer’s, as we already know, is not caused by one thing. It’s a multifactorial disease. There are many paths to Alzheimer’s and other dementias, yet all are rooted in having chronic inflammation in the brain over decades.

How I’ve been thinking about brain health lately: diet and exercise are the foundation, along with other proven supporting factors. Where will microplastics and other toxins fit? TBD.

My personal feeling is that these tiny toxins will prove to be yet another insult of modern life that creates neuroinflammation in the brain. But it’s too early to say if they will have as significant an impact as air pollution on dementia (now one of the modifiable risk factors for Alzheimer’s) or pesticides on Parkinson’s.

But that doesn’t mean we should ignore their brain-harming potential.

While scientists are working on defining the microplastic problem, I propose a rationale, doable approach to reduce exposure, and thus hopefully accumulation in our bodies and brains. Why?

• Because it seems prudent to take action on what we already know before waiting for proven brain health risks.

• Because reducing plastic consumption is better for the planet.

• And because working towards less plastic in your home enhances its function and beauty.

I always like to say that brain health starts in the kitchen. And that’s exactly where I’d start to purge plastics, too. Next time I’ll share simple ways to reduce your microplastic exposure without having it take over your life.

I’d love to hear from you. How concerned are you about microplastic exposure?

Thank you for reading, sharing, and above all, for taking the best care of your brain. If you found this post helpful, please tap on the heart, restack, or send it to someone you love.

Love,

Annie

Brain Health Retreats Update

Want to join me on a Brain Health Retreat this year? Your brain will thank you! For detailed information about each trip, click on the links below or tap on RETREATS on the homepage.

BHK Retreat at Rancho La Puerta, Mexico June 7 to 14, 2025. Join me at the Ranch during Brain Health Week for a special retreat within a retreat. To register or submit questions, contact Donna Sher at 858.449.3672 or email her at dsher52@hotmail.com. This retreat is sold out. I’ll host another retreat at Rancho La Puerta November 15 to 22, 2025. Contact Donna for more info.

Sardinia’s Secrets For a Long and Healthy Life, October 12 to 19, 2025. This fall I am headed back to Italy to explore Sardinia’s blue zones. Find all the details here; call 877-298-9677 for more information and to reserve your spot. This Brain Health Retreat was featured in National Geographic Traveller UK.

Costa Rica in February 5 to 10, 2026: Fitness + brain health in the jungle by the beach! This retreat is 100% plant-based and alcohol-free. Learn more and reserve your spot here. 3 cabañas left!