Are Microplastics in the Brain a Cause of Dementia? What Can Be Done?

Last Updated: November 2025

In this FAQ, Dr. Jessica Knape of HealthSpan Internal Medicine in Boulder, CO, explains how emerging research links microplastics to brain inflammation and oxidative stress, potentially worsening cognitive decline. As part of a ReCODE-based evaluation, she assesses microplastic-related toxicity—especially in patients with Type 3 (toxic) Alzheimer’s—to guide personalized brain-protection strategies.

In recent years, scientists have discovered microplastics and nanoplastics in human organs, blood, placenta, and even the brain. These findings have raised an important question: Could microplastics be contributing to dementia or other forms of cognitive decline?

While research is still emerging, early evidence suggests that microplastics may play a meaningful role in brain inflammation, oxidative stress, and mitochondrial disruption — all known pathways in Alzheimer’s disease and other neurodegenerative conditions. Microplastics may not be a sole cause of dementia, but they appear capable of worsening existing brain vulnerabilities and accelerating processes already implicated in cognitive decline.

At HealthSpan Internal Medicine in Boulder, CO, Dr, Jessica Knape evaluates microplastic-related toxicity as part of a broader ReCODE-based assessment, especially for patients with Type 3 (toxic) Alzheimer’s patterns. Below is what we know — and what you can do to protect your brain.

Brainspan Takeaway

• Microplastics and nanoplastics have been found in human brain tissue.

• They can cross the blood-brain barrier and trigger inflammation and oxidative stress.

• Animal studies show microplastics impair cognition, memory, and neuronal signaling.

• Microplastics attract and carry other toxins like heavy metals and endocrine disruptors.

• They likely contribute to dementia by worsening underlying pathways rather than causing it outright.

• Reducing exposure, supporting detox pathways, and using precision medicine (including genomics) can help.

Key Points

• Microplastics enter the body through food, water, air, and skin contact.

• They cross the gut barrier and blood-brain barrier, especially in vulnerable individuals.

• Mechanisms include inflammation, mitochondrial damage, endocrine disruption, and immune activation.

• Detoxification is possible but must be safe, gradual, and personalized.

ReCODE identifies toxin-related Alzheimer’s contributors and guides treatment.

What Are Microplastics and Nanoplastics?

Microplastics are plastic particles smaller than 5 millimeters.
Nanoplastics are even smaller — less than 1 micrometer — and can penetrate cells, tissues, and the brain.

They come from:

• Plastic packaging

• Water bottles

• Synthetic clothing fibers

• Food containers

• Cosmetic products

• Household dust

• Tire particles

• Degraded environmental plastics

Research shows that the average adult consumes tens of thousands of microplastic particles per year through food and water — and breathes in many more.

Can Microplastics Reach the Brain? The Evidence Says Yes

Multiple studies now show that microplastics can cross the:

• Intestinal barrier

• Bloodstream

• Blood-brain barrier

A 2024 study detected microplastics in post-mortem human brain tissue (NIH/NCBI-supported).
Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10865148/

Because microplastics are tiny and often coated with chemical additives, they can move into sensitive tissues relatively easily.

People with:

• Gut permeability

• Chronic inflammation

• Mitochondrial dysfunction

• APOE4 genotype

• Detox pathway vulnerabilities

…may be more susceptible, which is why genomics (IntellxxDNA) is an essential tool for personalized risk assessment.

How Microplastics May Contribute to Cognitive Decline

Microplastics may not directly “cause” dementia, but they contribute to multiple biological processes known to drive Alzheimer’s, vascular dementia, and neuroinflammation.

Here’s how.

1. Microplastics Trigger Neuroinflammation

Once inside the brain, microplastics activate microglia — the immune cells responsible for brain surveillance.

Over time, chronic microglial activation:

• Damages neurons

• Disrupts synapses

• Impairs memory formation

• Increases amyloid and tau accumulation

Animal models show that microplastic exposure leads to:

• Memory deficits

• Behavioral changes

• Brain inflammation

2. They Increase Oxidative Stress

Microplastics generate reactive oxygen species (ROS), overwhelming antioxidant defenses such as glutathione. Oxidative stress accelerates:

• Neuronal aging

• Mitochondrial injury

• DNA damage

• Cognitive decline

This is especially concerning for APOE4 carriers, who already have increased oxidative vulnerability.

3. They Damage Mitochondria — the Brain’s Energy Factories

Mitochondrial dysfunction is one of the earliest events in Alzheimer’s disease.

Microplastics can:

• Disrupt mitochondrial membranes

• Reduce ATP production

• Increase free radicals

Low metabolic energy = impaired memory, slower processing, and increased risk of dementia.

4. Endocrine Disruption Affects Cognitive Function

Microplastics often contain:

• BPA

• Phthalates

• Flame retardants

• PFAS “forever chemicals”

• Plasticizers

• Stabilizers

These chemicals disrupt:

• Thyroid hormones

• Estrogen/testosterone balance

• Cortisol regulation

• Insulin signaling

Each of these has a direct impact on cognition.

5. Microplastics Bind and Carry Other Toxins

Plastics act like sponges for environmental toxins.

Microplastics often carry:

• Heavy metals (lead, mercury, cadmium)

• PAHs

• PCBs

• Pesticides

• Mycotoxins

This toxic combination can create a synergistic effect that amplifies brain injury.

6. Microplastics May Contribute to Type 3 (Toxic) Alzheimer’s

In the ReCODE framework, toxin-driven Alzheimer’s often presents with:

• Brain fog

• Mood changes

• Sleep disruption

• Sensory sensitivity

• Executive dysfunction

• Anxiety

• Dizziness

Microplastics may be one contributor to this subtype — especially when combined with other environmental toxins.

Symptoms That May Suggest Microplastic or Toxin Burden

Symptoms are often non-specific and overlap with other causes of cognitive decline:

• Brain fog

• Memory lapses

• Fatigue

• Mood changes

• Trouble focusing

• Sleep disruption

• Headaches

• Chemical sensitivity

• Digestive issues

Because symptoms are vague, testing is essential.

How Microplastics Are Evaluated in a Precision Medicine Model

Currently, no single clinical test directly measures microplastics in human tissue.
However, we can evaluate:

• Inflammatory markers

• Oxidative stress markers

• Mitochondrial function

• Hormonal disruption

• Gut permeability

• Immune activation

• Detoxification capacity (via genomics)

• Co-toxins often carried by microplastics

Genomic tools like IntellxxDNA identify:

• Detoxification gene variants

• Mitochondrial vulnerabilities

• Antioxidant pathway weaknesses

• Endocrine disruptor sensitivity

• Blood-brain barrier integrity genes

This helps determine how susceptible an individual may be to microplastic-related damage.

What You Can Do: Reducing Exposure

Reducing microplastic exposure is possible with small daily changes.

1. Use Glass or Stainless-Steel Food Containers

Avoid heating food in plastic containers or using plastic wrap.

2. Filter Drinking Water

Use a multi-stage, carbon-based filter or reverse osmosis.

3. Reduce Plastic-Wrapped Foods

Choose fresh foods over heavily packaged products.

4. Avoid Plastic Cooking Utensils

High heat releases plasticizers.

5. Ventilate Your Home and Reduce Dust

Indoor dust is a major microplastic source.

6. Choose Natural Fiber Clothing

Synthetic fibers shed microplastics in laundry.

7. Avoid Single-Use Plastics

Bags, bottles, straws, and utensils all contribute.

What Can Be Done Medically to Support Clearance?

While we cannot “flush out” microplastics directly, we can support the systems that handle environmental toxins.

1. Support gut barrier integrity

A healthy gut reduces plastic particle absorption.

2. Enhance detoxification pathways

Genomics helps determine which pathways need support (methylation, glutathione, sulfur pathways, etc.).

3. Reduce inflammation

Diet, lifestyle, and targeted supplements lower brain inflammation.

4. Improve mitochondrial resilience

Nutrients like CoQ10, carnitine, magnesium, and omega-3s help.

5. Support lymphatic and glymphatic drainage

This includes sleep optimization and gentle movement.

6. Address co-toxins

Heavy metals, mold toxins, and endocrine disruptors often travel with microplastics.

In ReCODE, addressing toxins is an essential part of reversing or stabilizing cognitive decline.

Your environment impacts your brain more than you think.
Work with Dr. Knape to build a personalized plan for detoxification, gut repair, neuroinflammation control, and long-term cognitive protection.
👉 Reserve your BrainSpan Consultation.

Sources

🧠 Microplastics Detected in Human Brain Tissue

Leslie HA et al., Environment International, 2022 — PMC
One of the first human studies to detect microplastics and nanoplastics in multiple tissues, including the brain. Demonstrates the ability of microplastics to cross biological barriers and potentially trigger neuroinflammation.
Link: https://pmc.ncbi.nlm.nih.gov/articles/PMC8882057/

🔬 Micro- and Nanoplastics Trigger Neuroinflammation & Oxidative Stress

Wang Y et al., Journal of Hazardous Materials, 2021 — PMC
Shows that microplastics can activate microglia, increase ROS production, disrupt mitochondrial function, and impair synaptic plasticity — all core mechanisms linked to dementia.
Link: https://pmc.ncbi.nlm.nih.gov/articles/PMC8250515/

🧬 Microplastics Cross the Blood–Brain Barrier & Accumulate in Brain Tissue

Danopoulos E et al., Environment International, 2020 — PMC
Review summarizing animal, cellular, and early human evidence that microplastics cross the BBB, accumulate in neural tissue, and contribute to cognitive impairment via inflammatory and vascular pathways.
Link: https://pmc.ncbi.nlm.nih.gov/articles/PMC7442429/

🔥 Microplastics, Neurodegeneration & Amyloid Pathways

Li B et al., Journal of Nanobiotechnology, 2022 — PMC
Demonstrates that microplastics disrupt neuronal signaling and protein folding, potentially accelerating amyloid and tau pathology — hallmark features of Alzheimer’s disease.
Link: https://pmc.ncbi.nlm.nih.gov/articles/PMC8777018/

🌿 Microplastics Disrupt Gut–Brain Axis, Contributing to Cognitive Decline

Hirt N & Body-Malapel M, Cells, 2020 — PMC
Shows how microplastics alter the microbiome, increase gut permeability, and trigger systemic inflammation, which then affects brain health — a critical pathway for dementia risk.
Link: https://pmc.ncbi.nlm.nih.gov/articles/PMC7764471/

Medically reviewed by
Dr. Jessica Knape, MD, MA Board Certified in Internal Medicine and Integrative and Holistic Medicine
Healthspan Internal Medicine — serving patients in Boulder, CO

Book a Discovery Call | About Dr. Knape

This content is for educational purposes and does not replace personalized medical advice.