Microplastics and PFAS ("forever chemicals") accumulate in human tissue. A 2024 NEJM study found microplastics in the carotid plaque of over half of surgery patients, who then had a higher risk of heart attack, stroke or death, and a 2025 study reported plastic in brain tissue. For PFAS, a randomized trial found that regular blood or plasma donation lowered blood levels in firefighters. But how plastics are measured is disputed: some methods can mistake natural fats for polyethylene.
Summary drafted from this entry’s sources; editorial review pending.
01Key questions
Are microplastics linked to heart disease?
In 257 patients having carotid surgery, those with microplastics detected in their plaque had about 4.5 times the risk of heart attack, stroke or death over 34 months (Marfella et al., NEJM 2024). It is one observational study.1
Are there microplastics in the brain?
A 2025 study of decedent tissue reported micro- and nanoplastics in brain, at higher levels in 2024 than in 2016 samples and higher still in people with dementia (Nihart et al., Nature Medicine 2025). An author correction followed, and the measurement method is disputed.2
Can PFAS levels be lowered?
Yes. In a randomized trial in 285 Australian firefighters, regular plasma or blood donation over a year lowered blood PFAS levels compared with observation (Gasiorowski et al., JAMA Netw Open 2022).5
Are the microplastic measurements reliable?
Not fully. Lipids can produce false-positive polyethylene signals in pyrolysis mass spectrometry, the method behind many tissue studies, which matters most for fatty organs such as the brain (Almeida et al., J Hazard Mater 2026).4
Microplastics and nanoplastics (MNPs) are fragments of plastic small enough to enter tissue; PFAS ("forever chemicals") are fluorinated compounds used in non-stick, waterproof and firefighting products that persist in the body for years. Both are now measurable in most people. The research has moved fast since 2024, and so has the hype: detox protocols and binders are being sold on the back of studies that show association, not cause. This entry separates what has been measured, what it is linked to, and the one intervention with randomized evidence for lowering body burden.
02What has been found in human tissue
| Study | Finding | What it does not show |
|---|---|---|
| Marfella et al., NEJM 2024 | Polyethylene was detected in carotid plaque from 150 of 257 surgery patients (58%); those with plastic in their plaque had 4.53 times the risk of heart attack, stroke or death over about 34 months (95% CI 2.00 to 10.27) (PMID 38446676) | Cause. Plastic in plaque may mark other exposures, diet or poverty; the study was observational and the confidence interval is wide. |
| Nihart et al., Nature Medicine 2025 | MNPs, mostly polyethylene shards at nanoscale, in decedent liver, kidney and brain; concentrations higher in 2024 than 2016 samples, and higher still in brains of people with dementia (PMID 39901044) | That plastics cause dementia (dementia may impair clearance), or the precise mass in a brain. An Author Correction was published (PMID 40164728), and lipids are a recognized source of false-positive polyethylene signals in pyrolysis mass spectrometry, which matters for a fat-rich organ like the brain (PMID 41352016). |
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The widely shared claim that a human brain holds "a spoon" or about 7 g of plastic comes from extrapolating the brain concentrations in this study. It should be treated as an overstatement of an uncertain measurement, not a fact.
03What lowers body burden: the evidence
Only one intervention has randomized evidence, and it is for PFAS, not microplastics. In 285 Australian firefighters with elevated blood PFOS, donating plasma every 6 weeks for a year cut mean PFOS by 2.9 ng/mL and PFHxS by 1.1 ng/mL; whole-blood donation every 12 weeks cut PFOS by 1.1 ng/mL; the observation group did not change (PMID 35394514). This works because PFAS bind to blood proteins, so removing plasma removes the chemical. Whether it changes health outcomes was not tested. Therapeutic plasma exchange (see Therapeutic plasma exchange) uses the same principle at larger scale, but no randomized trial has tested it for plastics.
No randomized trial has shown that any supplement, sauna protocol, binder or chelator lowers microplastic levels in human tissue. Reducing exposure (heated plastic food containers, PFAS-treated textiles and cookware, contaminated water) is plausible but has not been tested against health outcomes either. For heavy metals, where chelation does have a trial record, see Heavy metal burden and chelation.
04Where it sits on the Heretic scale
Early. Body burden is real and rising, and the cardiovascular association in the NEJM study is large, but harm in humans has not been shown to be causal and measurement methods are still maturing. The one bright spot, PFAS reduction by plasma or blood donation, is a single randomized trial with a lab endpoint. What would move it: replication of the plaque finding with exposure measured before disease, and intervention trials that track clinical outcomes.
Further reading: detailed protocols
- NIEHS: PFAS research and exposure niehs.nih.gov
05Connections
06Sources
- Marfella R, et al. (2024). "Microplastics and Nanoplastics in Atheromas and Cardiovascular Events." N Engl J Med 390(10):900-910. PMID 38446676 . DOI 10.1056/NEJMoa2309822PubMed 38446676 · DOI 10.1056/NEJMoa2309822
- Nihart AJ, et al. (2025). "Bioaccumulation of microplastics in decedent human brains." Nat Med 31(4):1114-1119. PMID 39901044 . DOI 10.1038/s41591-024-03453-1PubMed 39901044 · DOI 10.1038/s41591-024-03453-1
- Nihart AJ, et al. (2025). "Author Correction: Bioaccumulation of microplastics in decedent human brains." Nat Med 31(4):1367. PMID 40164728 . DOI 10.1038/s41591-025-03675-xPubMed 40164728 · DOI 10.1038/s41591-025-03675-x
- Almeida FN, et al. (2026). "Py-GC-MS/MS quantification of microplastics in vertebrate tissues: Addressing false positives of polyethylene." J Hazard Mater . PMID 41352016 . DOI 10.1016/j.jhazmat.2025.140658PubMed 41352016 · DOI 10.1016/j.jhazmat.2025.140658
- Gasiorowski R, et al. (2022). "Effect of Plasma and Blood Donations on Levels of Perfluoroalkyl and Polyfluoroalkyl Substances in Firefighters in Australia: A Randomized Clinical Trial." JAMA Netw Open 5(4):e226257. PMID 35394514 . DOI 10.1001/jamanetworkopen.2022.6257PubMed 35394514 · DOI 10.1001/jamanetworkopen.2022.6257
07Entry history
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Heretic informs and never prescribes. Where amounts appear, they describe what published studies used. Talk to a qualified clinician before acting on anything here.