Autopsies in early 2024 found more plastic fragments in human brains compared to samples from eight years ago.
It’s important to note that this study is not yet peer-reviewed and comes from a May pre-print. It is something to keep an eye on as we learn more about microplastics in the human body and how they may be impacting human health.
Key Findings from the Study
The study, conducted by researchers at the University of New Mexico, analyzed microplastics in human brain tissues, comparing samples collected in 2016 and 2024. Here’s what they found:
- ~50% Increase in Microplastics Over Time: The concentration of microplastics in the brain tissue of individuals aged 45 to 50 years increased by approximately 50% over the eight-year period.
- The Brain is About 0.5% Plastic by Weight: In 2016, the average concentration was 3,057 micrograms per gram, while in 2024, it rose to 4,806 micrograms per gram, equating to 0.5% of the brain tissue’s weight.
- Higher Plastic Levels Found in the Brain Compared to Other Organs: The study revealed that the brain had significantly higher levels of microplastics compared to other organs like the liver and kidneys. For instance, in 2024, the brain tissue had 7 to 30 times more microplastics than the kidneys and liver.
- Predominant Plastic Type: The most common type of plastic found in the brain was polyethylene, a widely used plastic in products such as packaging, plastic bags, and containers. This type of plastic was found in greater quantities in the brain than in other organs.
How Microplastics Enter the Brain
Microplastics can enter the body through various routes, including ingestion (food) and inhalation (air).
Once in the bloodstream, these tiny particles can cross the blood-brain barrier, which normally protects the brain from harmful substances.
This study suggests that smaller nanoplastics, particularly those less than 200 nanometers in size, are most likely to accumulate in the brain due to their ability to penetrate cellular membranes.
“Based on our observations, we think the brain is pulling in the very smallest nanostructures, like 100 to 200 nanometers in length, whereas some of the larger particles that are a micrometer to five micrometers go into the liver and kidneys,” said Matthew Campen, lead author of the study and a regents’ professor of pharmaceutical sciences at the University of New Mexico in Albuquerque.
One theory is that microplastics “hijack” their way into the brain by binding with fats, which are abundant in the brain. The human brain is about 60% fat by weight, making it particularly susceptible to these plastic particles.
Potential Health Implications
While the study provides clear evidence that microplastics are accumulating in human brains, the health implications remain uncertain. Unfortunately, there is still very little research on the direct impact that microplastics may have on human health.
However, there are concerns that microplastics could contribute to various health concerns:
- Neurological Impact: The study’s authors noted that the brain areas most affected by microplastics are also those associated with frontotemporal dementia and later stages of Alzheimer’s disease. This raises the question of whether or not microplastics could be linked to the development or exacerbation of these conditions.
- Inflammation and Toxicity: Previous studies have shown that microplastics can cause inflammation and other toxic effects in various tissues. If microplastics are similarly toxic to brain cells, they could potentially disrupt normal brain function.
- Chemical Contaminants: It’s not just the microplastic particles themselves that are of concern, but also what they carry with them. Microplastics are known to be “carriers” of harmful chemicals such as bisphenols, phthalates, flame retardants, and heavy metals, which can then be absorbed through the skin. These chemicals could further contribute to health issues, including reproductive problems and cancer.
What You Can Do
Given the pervasive nature of microplastics, you cannot avoid them completely. However, here are some practical steps you can take to reduce your exposure:
- Reduce Plastic Use When You Can: Minimize the use of single-use plastics like plastic bags, bottles, and packaging. Opt for reusable alternatives made of glass or stainless steel, especially when it comes to your food and drinks.
- Avoid Heating Food in Plastic: When possible, avoid heating food in plastic containers, as heat can cause microplastics to leach into your food. Transfer food to glass or ceramic containers before microwaving or cooking.
- Filter Your Water: Use a water filter that is designed to reduce microplastics.
- Be Mindful of Clothing Choices: Synthetic fabrics like polyester can shed microplastics during washing. Choose natural fibers like cotton or wool when possible and consider using a microfiber filter in your washing machine.
- Swap Our Products Gradually: As the products in your home need to be replaced, swap them out for safer ones. For example, toothbrushes, yoga mats, coffee makers, baby bottles, Ziploc baggies, etc.
- Support Environmental Efforts: Advocate for policies that reduce plastic production and pollution. Consider getting involved with organizations such as Beyond Plastics, which are working to reduce plastic waste, transition away from the single-use economy, and clean up plastic pollution.
Considering how ubiquitous microplastics are in our environment, we absolutely need to continue researching the potential health impacts.
While we may not yet fully understand the risks, we do know that plastic is not good for anyone. So taking small steps to reduce plastic use and exposure can help protect your health and the environment. As the scientific community continues to explore this emerging issue, it’s clear that microplastics are an unfortunate part of our modern world—with consequences that are just beginning to be understood.