Contaminated Brains: The Invisible Plastic That Could Increase Dementia Risk

Researchers have discovered that the human brain can accumulate microplastics, with higher levels in people with dementia. These particles, which come from air, water and food, can cause inflammation and impair the body’s functioning. To reduce exposure, experts recommend avoiding bottled water, heating food in plastic and consuming less ultra-processed foods. Studies suggest that the body can eliminate some of these particles, but more research is needed to understand the long-term impacts.

A recent study published in Nature Medicine revealed an alarming discovery: the human brain can contain about a spoonful of tiny plastic particles, known as microplastics and nanoplastics (MNPs).

Microplastics and nanoplastics are small plastic particles that result from the degradation of larger plastic products or are intentionally produced for industrial use. Microplastics are less than 5 mm in size, while nanoplastics are less than 1 micrometer in size and can even penetrate human cells.

These particles are present in air, water and food, and are a growing concern due to their potential toxic effects on the environment and human health. 

The researchers analyzed the brains of deceased individuals and found that those diagnosed with dementia had a concentration of microplastics and nanoplastics 3 to 5 times higher than those without the disease.

They also found that the brain accumulates 7 to 30 times more microplastics than other organs, such as the liver and kidneys. Most of these particles were made of polyethylene, a type of plastic commonly found in packaging and bags.

The scientists also observed that the amount of microplastics and nanoplastics in the brain increased by 50% between 2016 and 2024, which coincides with the alarming growth of plastic pollution in the environment.

It is estimated that between 10 and 40 million tons of microplastics are released into nature each year, a number that could double by 2040. These particles are everywhere, in the ocean, in mountains, in soil, and end up reaching us through food, the water we drink and even the air we breathe.

Although it is not yet fully understood how microplastics affect the human body, studies in animals and cells show that they can cause inflammation, oxidative stress, metabolic problems, damage to the immune system and even interfere with brain function.

In recent studies, patients with plaque in their arteries containing microplastics were at higher risk of heart attack and stroke. Another study showed that people with inflammatory bowel disease had 1.5 times more microplastics in their stool than healthy individuals, suggesting a possible link between these plastics and chronic diseases.

Scientists believe that the link between microplastics and dementia may have two explanations:

- Patients with dementia have a weaker brain barrier, allowing more microplastics to enter the brain.

- Microplastics can trigger inflammation in the brain, making it harder for toxic proteins to be eliminated and worsening the progression of the disease.

Since completely eliminating exposure to microplastics is virtually impossible, experts suggest some simple steps to reduce the intake of these particles:

1. Avoid drinking bottled water: Switching to filtered water can reduce your annual intake of microplastics from 90,000 to 4,000 particles. Avoid heating food in plastic containers: Heat releases millions of plastic particles into food. Opt for glass or stainless steel.

   
   

2. Reduce your consumption of ultra-processed foods: Chicken nuggets, for example, contain 30 times more microplastics than natural chicken breast. Reduce your consumption of seafood and alcoholic beverages, which are significant sources of microplastics. Use air filters (HEPA) at home, as inhalation is also an important route of exposure.

In addition to reducing intake, another important question is whether the body can eliminate microplastics. Studies suggest that chemicals found in plastics, such as bisphenol A (BPA), can be excreted in sweat, urine and feces.

One study showed that some people eliminated bisphenol A through sweat, suggesting that exercise and saunas may help reduce the body’s microplastic burden, although more research is needed to confirm this effect.

Future research needs to look more closely at how long microplastics remain in the body and how exactly they affect health.

In studies with fish, it has been observed that the brain can eliminate 75% of accumulated plastic particles in about 70 days, as long as exposure is reduced. If this is also true for humans, lifestyle changes may be effective in reducing the presence of microplastics in the body.

As knowledge on this topic grows, it is essential that governments, companies and society seek ways to reduce the production and consumption of plastics, promoting policies to limit pollution and protect public health.

READ MORE:

Human microplastic removal: what does the evidence tell us?

Nicholas Fabiano, Brandon Luu and David Puder

Brain Medicine. 4 March 2025, Page Range: 1 – 2

DOI: 10.61373/bm025c.0020

Abstract: 

The increased levels of microplastics and nanoplastics (MNPs) found in human brain tissue are alarming, particularly in patients with dementia. Although total avoidance of MNP exposure will likely remain an unattainable endpoint in light of their ubiquity in the environment, new studies indicate feasible pathways by which dietary intake may be decreased or clearances improved. This commentary reviews the evidence on human exposure to MNPs, their tissue penetration, and potential health effects, particularly on neurotoxicity. We will explore evidence-based strategies for reducing exposure through dietary and lifestyle changes while addressing key gaps in our current knowledge calling for additional research.