What Are Microplastics and How Do They Enter the Body?

Apr 14, 2026

Following an EPA and HHS announcement, PolitiFact published an expert-backed guide explaining how microplastics—plastic fragments measuring 5 millimeters or less—enter the human body through food, water, and air, with the tiniest particles passing into the bloodstream and accumulating in organs including livers, kidneys, lungs, brains, and placentas. A 2025 Nature Medicine study found increasing microplastic concentrations in liver and brain tissue of people who died in 2024 versus 2016, with higher levels in dementia patients, while a 2024 study linked microplastics in arterial plaque to increased heart attack and stroke risk. Despite these findings, HHS Secretary Robert F. Kennedy Jr. acknowledged on April 2 that officials do not yet understand how microplastics interact with immune, endocrine, or neurological systems and lack validated removal methods. Researchers use methods costing $10 to $600 per sample to detect microplastics among over 16,000 chemicals in plastic products, while experts recommend reducing exposure by avoiding plastic water bottles and containers, especially when microwaving, though complete plastic elimination remains impossible.

What microplastics are and how they enter the body

▪Microplastics are plastic fragments that measure 5 millimeters long at most.
▪Nanoplastics are microplastics that measure less than 1 micrometer.

Detection and measurement challenges in microplastics research

▪Optical microscopes will not work for particles smaller than 1 micrometer.
▪A Stanford University working group identified seven methods for measuring microplastics costing $10 to $600 per sample.
▪Gas chromatography-mass spectrometry costs about $150 to $400 per sample and destroys the sample during analysis.

Health effects and ongoing scientific research

▪A 2025 Nature Medicine study found more microplastics in the brains of people with dementia diagnoses.
▪A 2024 New England Journal of Medicine study found that people who had microplastics in their carotid artery plaque had a higher risk of heart attack, stroke or death following a surgical procedure to remove plaque than those whose plaque lacked microplastics.
▪A 2025 Nature Medicine study found increasing concentrations of microplastics in the liver and brain tissue of people who died in 2024 compared with people who died in 2016.
▪Health and Human Services Secretary Robert F. Kennedy Jr. stated on April 2 that officials do not yet understand how microplastic particles interact with the immune system, the endocrine system or the neurological system.
▪Health and Human Services Secretary Robert F. Kennedy Jr. stated on April 2 that officials do not have validated methods to remove microplastics safely from the body.

Reducing exposure to microplastics

▪Philip Landrigan stated that it is not possible to completely eliminate plastic from one's life.

Perspective of Health and Human Services Secretary Robert F. Kennedy Jr.

▪Officials do not have validated methods to remove microplastics safely from the body according to Robert F. Kennedy Jr.
▪Officials do not yet understand how microplastic particles interact with the immune system according to Robert F. Kennedy Jr.