Micro/nanoplastics (MNPs) have been measured in blood, placenta, breast milk, urine, lung, testis and semen, gut, brain, liver, kidney, and cardiac and carotid atherosclerotic plaque. Once released into nature, plastics are susceptible to degradation, leading to the formation of microplastics (defined as particles smaller than 5 mm) and nanoplastics (particles smaller than 1000 nanometers). Both types of particles trigger a range of toxicologic effects.
We are just at the beginning of trying to understand the deleterious effects of MNPs on the human body, so most of the data is observational.
The strongest adverse outcomes signal to date is in patients undergoing carotid endarterectomy (surgical procedure to remove plaque buildup from the carotid arteries in the neck). Investigators detected MNPs in atherosclerotic plaque and reported higher risk of MI, stroke, or death over follow-up among those with detected MNPs. https://pmc.ncbi.nlm.nih.gov/articles/PMC11009876/
In a recent study published in Nature Medicine, a team led by toxicologist Matthew Campen, PhD, Distinguished and Regents’ Professor in the UNM College of Pharmacy, reported that plastic concentrations in the brain appeared higher than in the liver or kidney, and higher than previous reports for placentas and testes. Brain tissue from people who had been diagnosed with dementia prior to their death had up to 10 times as much plastic in their brains as those who did not have dementia. https://hsc.unm.edu/news/2025/_media/41591_2024_article_3453.pdf
Campen suspects that most of the microplastics in the body are ingested through food – particularly meat, because commercial meat production tends to concentrate plastics in the food chain.
So what can we do as individuals to reduce plastic exposure?
- Don’t heat food in plastic; use glass/ceramic/stainless for hot foods.
- Reduce bottled water/tea-bag plastics; prefer filtered tap + non-plastic contact where feasible.
- Indoor air: HEPA filtration + wet-mopping/dusting (reduces resuspended fibers).
- Prefer natural textiles where practical; synthetic shedding is a major indoor source.
- Consider decreasing meat intake
- Use a water filter to remove MNPs. Consumerlab.com does 3rd party testing on supplements and other products, including water filters. Their top pick for removing MNPs without adding carbon particles was the Aquagear Water Filter Pitcher.