Microplastics can wiggle across the brain’s protections and wreak havoc in our lives.

Environmental and health science researchers have identified microplastics as one of the most concerning discoveries in their field. These tiny plastic fragments are invisible in our daily lives, yet they are present throughout all food sources, water supplies, the air we breathe, household dust, human breast milk, bloodstream samples, and brain tissue. This is highly disturbing when you consider how ubiquitous their presence is in our environment and our bodies.

Research shows that people ingest or inhale over 100,000 microplastic particles each year. How can the body sustain such a continuous onslaught without experiencing some damage? Scientists have found that although most microplastics are excreted, they can remain in tissues for long periods. We have to ask ourselves what a “long period” might be and whether some of this material never leaves. I would think, unfortunately, that some remain forever.

The sources of microplastics include weathered food packaging, synthetic clothing fibers, tire dust, personal care products, and indoor airborne particles. I wrote an article on how going out hiking can damage our environment because the materials we use for our clothing and shoes leave microplastics behind.

Scientists have spent years studying the effects of microplastics on ocean ecosystems, and many of their findings have been extremely concerning. Currently, the scientific community is focusing on different aspects of microplastic research, especially how these particles transfer between ecosystems and human bodies. It’s a question everyone would ask: How are plastics getting into our bodies?

The Path Microplastics Take to Reach Brain Tissue

Research shows that microplastics are present in human organs, including the lungs, liver, kidneys, and blood. Scientists have found microplastic fragments in the frontal cortex of the brain, which controls decision-making, personality development, and attention span. The body retains microplastics in these areas that regulate our identity and mental processes.

The blood–brain barrier acts as a protective shield, controlling which substances can enter the brain. As the barrier allows microplastics to pass through, small particles can begin to cross cell membranes directly, whereas larger particles must use the same transport systems that cells use for nutrient absorption. Our body’s defenses in this regard, however, are not stable in their ability to ward off destructive materials.

As we age or experience strokes, head injuries, vascular diseases, or chronic inflammation related to our aging, the blood–brain barrier becomes more permeable. We see this also in people who drink excessive amounts of alcohol where the blood-brain barrier is broached. As a result, the brain is more vulnerable to the entry of microplastics. This is a fact of life, and one with which we must all contend, but the presence of plastics in the environment is something we do have control over. Look at the label on the jeans you may be wearing today. Is it 100% cotton or does it have some other filament in it that may be derived from oil which means plastic?

I remember working with a woman who wanted carpeting for her living room and insisted that it be 100% cotton. It was impossible to find carpet that was 100% cotton and she had to settle for some combination of fibers, but no plastic. What are the materials in the carpeting that you have in your home or in your car? Take a good look around you and begin to read labels.

The Effects of Microplastic Entry into the Body

The brain reacts to microplastic exposure by initiating its immune response because it recognizes these particles as foreign invaders. The brain’s immune cells, called microglia, detect foreign substances and begin releasing defensive chemicals to combat them. Repeated activation of these cells, however, causes neuronal damage rather than protection. In other words, the defenders become destroyers.

Even the energy production centers in brain cells, called mitochondria, experience disruption when microplastics enter the system. Because mitochondria fail, neurons lose their ability to communicate, repair, and maintain structure. This then causes the brain to undergo a slowdown in energy production, which resembles the early stages of Alzheimer’s and Parkinson’s disease development. It’s almost as though microscopic tumbleweeds are coming into our “town” and making it unlivable.

Multiple scientific studies show that microplastics promote the formation of amyloid protein clumps related to Alzheimer’s disease. These materials (microplastics) create conditions that lead to protein misfolding, which is believed to cause Parkinson’s disease. Additionally, research suggests that microplastics cause brain irritation and may accelerate the progression of degenerative diseases.

If we consider “irritation” to also mean inflammation, then we can see that there is a possible connection between microplastic invasion of the brain and psychiatric disorders such as depression and anxiety. Sufficient research exists to show a relationship between brain or neurologic inflammation and psychiatric disorder.

The Gut–Brain Connection Functions

The story of microplastics extends beyond neurological effects because these particles create damage to gut linings and modify bacterial populations in the gut, which results in dysbiosis. The brain and gut maintain continuous communication through nerve pathways, hormones, and immune system messengers.

The first signs of Parkinson’s disease may develop in the gut before patients show any symptoms. The brain signaling pathways that control neurodegeneration and its disruption could be affected by microplastic-induced gut inflammation.

The particles from microplastics absorb various substances, including pesticides, metals, and endocrine-disrupting compounds, which enhance their biological effects. Those in the scientific community believe these “hitchhiking toxins” create additional stress for brain and body systems.

Although it has yet to be established that there is a direct link between dementia development and microplastics, scientists are finding this an increasingly interesting prospect. The blood–brain barrier, as previously noted, becomes more permeable with age while mitochondrial function declines and inflammation levels increase. The long-term exposure to microplastics could create additional stress on aging systems, which might affect cognitive performance throughout life.

It would seem therefore that the longer we live, the greater exposure we will receive to these toxic materials. In fact, children would probably experience it at a greater rate because they will have been born into a toxic environment, whereas older adults were in that environment later in life. What is being given to children today is a toxic legacy.

Microplastics function as active agents that interact with biological systems. The accumulation of microplastics throughout time will increase their potential to cause harm. The good news is that people can decrease their contact with these substances. What can we do?

We can reduce daily plastic exposure by using stainless steel or glass water bottles, by improving indoor air quality, washing new synthetic clothing and by avoiding plastic container use in the microwave, and selecting products with minimal packaging. The protection of public health will require both individual actions and government policies that work to decrease plastic manufacturing and create new material designs.

The discovery of worldwide microplastics demonstrates that environmental contamination has reached our present day, as they are found in distant ocean waters. These substances exist within our human bodies today. The decisions people make about plastic manufacturing and waste management now determine how well their bodies will function as a whole.

The protection of cognitive health requires people to take action against microplastic exposure because it has become a fundamental environmental duty. Research indicates that the hidden plastic threat exists nearby, and scientists need to act swiftly to understand its effects on human health. But it’s not just its effect on human health but on the health of the planet in general.