What if you were unknowingly eating a credit card’s worth of plastic every week? Microplastics, tiny plastic particles smaller than a sesame seed, have invaded our food, water and even the air we breathe. Now, alarming new research shows they’re not just in our bodies, they’re in our brains. Found in everything from seafood to bottled water to fresh produce, these particles may be linked to serious health issues like hormonal disruption, organ damage and cognitive decline.

As a dietitian or health and wellness professional, you’re on the front lines of this unfolding public health crisis. Understanding where microplastics are hiding and how to help your clients reduce exposure is crucial.

A growing concern

Microplastics, plastic particles under five millimeters in length, have infiltrated virtually every ecosystem on our planet. These tiny fragments originate from larger plastic waste that breaks down over time (secondary microplastics) or are intentionally manufactured at microscopic sizes for use in consumer products like cosmetics (primary microplastics).

The EPA defines microplastics as particles ranging from 5 millimeters (about the size of a pencil eraser) down to 1 nanometer — over 80,000 times smaller than a human hair. These tiny particles can be further broken down into nanoplastics through chemical weathering, mechanical breakdown and even digestive processes.

The pervasiveness of microplastics has reached concerning levels. According to the World Economic Forum’s Global Risks Report 2025, plastic pollution ranks among the top 10 threats facing our world. Research shows microplastics have been detected throughout the environment across land, sea and air, and throughout the human body, including blood, lungs, liver and lower limb joints.

Microplastics in our food and water

The contamination of our food supply is extensive and affects nearly all food categories. Evidence suggests they are entering the food supply primarily through the environment:

Seafood: Marine organisms are particularly susceptible to microplastic accumulation, which is concerning as these species are otherwise valuable sources of nutrients for the human body. The contamination of seafood with microplastics represents a danger both for these nutritious species and for the health of consumers who eat contaminated species.
Beverages: Recent research has confirmed widespread contamination of microplastics in basic and life-essential foods and beverages. Even ordinary actions like opening plastic packaging, cutting or tearing sealing tape, twisting open a bottle or steeping a single plastic teabag at brewing temperature can release vast amounts of microplastic particles.
Staple foods: Microplastics have been found in honey, tea, sugar, fruit and vegetables. They’re also making their way onto farmland through sewage sludge used as fertilizer, which can then end up in waterways as runoff from the top layer of soil.
Water: A study published by the American Chemical Society indicated that individuals who consume bottled water may ingest approximately 90,000 additional microplastics annually compared to those who do not. Collectively, Americans ingest and inhale up to 121,000 microplastic particles yearly — the equivalent weight of a plastic credit card every week.

Health implications

While research on the full health impacts is still evolving, evidence suggests several concerning effects:

Systemic effects

Data from animal studies have shown that once absorbed, plastic micro- and nanoparticles can distribute to the liver, spleen, heart, lungs, thymus, reproductive organs, kidneys and even cross the blood-brain barrier to enter the brain. After ingestion, the additives and monomers in microplastics can interfere with important biological processes and potentially cause disruption of the endocrine and immune systems, negatively impact mobility, reproduction and development and possibly cause carcinogenesis.

Research has documented that microplastics can cause toxic effects in experimental models including oxidative stress, DNA damage organ dysfunction, metabolic disorders, immune responses, neurotoxicity and reproductive and developmental toxicity.

Recent research points to potentially serious issues from microplastic exposure, including vascular disease, cancers, respiratory disorders, inflammatory bowel disease, as well as dizziness and neurological symptoms.

Brain effects

Recent research has revealed particularly concerning findings about microplastics in the brain and potential links to cognitive decline. A 2025 study published in Nature Medicine confirmed the presence of microplastics and nanoplastics (MNPs) in the human brain, kidney and liver tissue using advanced detection methods including pyrolysis gas chromatography-mass spectrometry. The microplastics in these organs primarily consisted of polyethylene, with brain tissues harboring higher proportions compared to liver or kidney.

Human brains contain approximately a spoon’s worth of microplastics and nanoplastics, with levels 3-5 times higher in individuals with documented dementia diagnoses. More concerning still, brain tissues showed 7-30 times higher concentrations of MNPs compared to other organs like the liver or kidney.

To make matters worse, brain tissue from people diagnosed with dementia had up to 10 times as much plastic in their brains as everyone else. While there is a clear correlation, the study design cannot show whether higher levels of plastic in the brain caused dementia symptoms; they may simply accumulate more due to the disease process itself. The amount of microplastics in human brains appears to be increasing over time, with concentrations rising by roughly 50 percent between 2016 and 2024. Researchers found much higher levels of microplastics in brain tissue than in liver and kidney tissue.

Regulatory status and scientific consensus

According to the FDA, current scientific evidence does not demonstrate that levels of microplastics or nanoplastics detected in foods pose a risk to human health. The agency continues to monitor research while working to advance the science through analysis of testing methodologies and participation in government initiatives addressing plastic pollution.

What can you tell shoppers?

As dietitians and health and wellness professionals, you can help clients reduce their microplastic exposure through these evidence-based recommendations:

1. Water consumption practices

Switching from bottled to filtered tap water alone could reduce microplastic intake from 90,000 to 4,000 particles per year. Bottled water can expose people to nearly as many microplastic particles annually as all ingested and inhaled sources combined, while switching to tap water could reduce this exposure by almost 90%.

2. Food storage and preparation

Exposure to environmental conditions such as heat causes plastic to break into smaller fragments that can migrate into food. Heating food in plastic packaging, long storage times and certain types of plastic packaging all affect the amount of microplastics and harmful chemicals that migrate into food.

Use glass, stainless steel or ceramic containers for food storage.
Avoid heating food in plastic containers, especially in microwaves.
Transfer takeout food from plastic containers before reheating.
Minimize use of plastic wrap in direct contact with food.

3. Food choices and preparation

Research links consumption of highly processed foods such as hamburgers, ready-to-eat convenience meals, French fries, ice cream, soda and canned foods with higher levels of phthalates, which are used to make plastics softer and can leach into the foods themselves. Studies have confirmed that beverage consumption can be considered one of the main pathways for microplastics ingestion by humans.

While research on microplastics continues to evolve, the evidence points to a significant emerging health threat that requires your attention as healthcare professionals. By educating yourselves, your retail buyers, merchandisers and our shoppers about microplastic exposure and implementing practical strategies to reduce consumption, you can play a crucial role in mitigating potential health risks.

The recent findings of microplastic accumulation in the brain and potential connections to dementia add urgency to these interventions. Through client education, policy advocacy and continued research engagement, dietitians can be at the forefront of addressing this growing public health challenge.