A recent article on micro / nano plastics made me pause to consider how we are putting ourselves at higher risk without realizing it. Microplastics are everywhere!
What they are: Microplastics (MPs, <5 mm) and nanoplastics (NPs, <1 μm) are shed from everyday plastics. They’re now turning up in human blood, placentas, and even inside atherosclerotic plaques—where their presence has been linked to higher rates of heart attack, stroke, or death over ~3 years. Mechanisms include inflammation, oxidative stress, and the ability of some particles to breach biological barriers (gut, blood–brain barrier). PMC
Where exposure is most common (ranked by everyday impact)
Drinking water—especially bottled. A 2024 study found ~110,000–370,000 plastic particles per liter in U.S. bottled water; ~90% were nanoplastics. Tap water varies by city, but good treatment and point-of-use filters can remove a lot.
Indoor air & dust. We spend ~90% of time indoors; fibers from textiles, carpets, and dryers plus fragments from furnishings dominate inhalation exposure. New assessments estimate tens of thousands of particles inhaled daily indoors. PMC
Food contact & kitchen gear. Plastic tea bags can shed billions of micro- and nanoparticles into a single cup. Plastic cutting boards release 100–300 particles per cut, and worn nonstick/PTFE or plastic cookware releases micro-/nanoplastics under heat and abrasion. ACS
Laundry & dryers. Synthetic clothing sheds fibers during washing and drying; airborne dryer lint is a major indoor source. PMC
Seafood (especially bivalves), and some salts. Because oysters/mussels are eaten whole, their MPs transfer to us; depuration (purging) reduces load. Sea salts commonly carry MPs too (typically low absolute amounts per serving, but persistent). PMC
Traffic (tire/brake wear). Tire and road-wear particles are a dominant environmental MP source and contribute to airborne exposure near busy roads. ScienceDirect
Why APOE4 should care a bit more
Vascular signal: Micro/nanoplastics have been detected in human carotid plaques; their presence was associated with ~4–5× higher risk of major cardiovascular events or death at follow-up (association, not proof of causation). That matters for anyone managing residual CV risk. New England Journal of Medicine
Brain access: NPs can cross the blood–brain barrier (in models), a pathway relevant to neuroinflammation. PMC
APOE4 context: Separate literature shows that fine particulates from air pollution interact with APOE4 to magnify neurodegenerative risk—suggesting heightened vulnerability to small particle exposures in general. This doesn’t prove microplastics do the same, but it’s a prudent caution signal for E4 carriers. PMC
Reduce exposure: an APOE4-smart, practical plan
Water
Prefer well-treated filtered tap over bottled. A high-quality activated-carbon + sub-micron filter (or ultrafiltration / nanofiltration) helps; maintain cartridges on schedule. If you use RO, service it regularly so the membrane and post-filters don’t shed or re-contaminate. WHO
Hot drinks & kitchen
Use loose-leaf tea in a stainless or paper filter; avoid plastic mesh tea bags, or buy a brand using abaca and cellulose for the teabag. ACS Publications
Swap plastic cutting boards for wood or bamboo; retire gouged boards. ScienceDirect
Favor stainless, cast iron, or glass over worn plastic/nonstick for hot cooking and storage; don’t scrape pans hard, and avoid high heat on aging nonstick. ScienceDirect A caveat: Keep an eye on iron blood levels if using cast iron cooking!
Never microwave or pour very hot liquids into plastic; let foods cool before any plastic contact (or just use glass).
Air & dust
Run a HEPA air purifier in main living/sleep areas; vacuum with a sealed HEPA machine; damp-dust surfaces.
Wash synthetics on cold, full loads, shorter cycles; add a microfiber filter or capture bag to the washer; line-dry or low-heat dry to cut airborne lint. PMC
In traffic, use recirculate plus a good cabin filter when stuck near heavy roads. ScienceDirect
Seafood & salt
Prefer gutted fish; if eating bivalves, buy from trusted sources and allow depuration i.e. placed into a clean water environment for a period of time. Sea salt does contain MPs; amounts are usually small—pick reputable brands and rotate with mined salts.
Infant/fragile health
If preparing infant formula, use glass for mixing and cooling before transferring; heat dramatically increases MP release from plastic bottles. Nature
What’s not proven (yet), and what is
We do not have definitive causal proof that microplastics cause dementia or cardiovascular disease.
We do have human-tissue detections (blood, placenta, plaques) and mechanistic plausibility (inflammation, barrier penetration). One large clinical study linked plastic-containing plaques with substantially higher CV event risk—again, association but concerning. For E4 carriers already optimizing vascular and neuro health, reducing exposure is a sensible part of risk-management. ScienceDirect
Bottom line for APOE4
Think “lower the particle load.” Prioritize water, indoor air/dust, and hot-food plastic contact—these yield the biggest, easiest exposure wins without lifestyle contortions.