In recent years, multiple studies have claimed that micro- and nanoplastics have been found in, among other places, the brain, blood vessels, and testicles.
A study published in Nature Medicine drew particular attention by suggesting that the average brain could contain an amount of plastic equivalent to the weight of a plastic spoon.
According to a review in Fortune, this very study has since been challenged by other researchers.
They pointed to a lack of contamination controls and insufficient validation of the results.
Also read: Traveling with a vape? Here it could lead to prison
This has sparked a broader debate about how reliable the conclusions really are.
Problems with the method
The disagreement mainly concerns the method used to measure plastic in tissue.
The method is called Py-GC-MS and involves heating samples to identify substances based on their molecular weight.
Fortune reports that environmental chemist Cassandra Rauert believes the method may confuse plastic with fats in the body.
Also read: Your daily diet may increase the risk of heart attack by 47 percent
She has identified 18 studies in which the risk of erroneous results was not sufficiently addressed.
Other researchers also emphasize that it seems biologically unlikely that plastic particles of the mentioned size could easily penetrate and accumulate in internal organs.
Immature field and rapid publication
The debate has implications for how the public perceives the risks associated with microplastics.
According to Fortune, researcher Frederic Béen describes the field as immature and characterized by rapid publication.
Also read: Robert F. Kennedy Jr. says keto can cure schizophrenia - psychiatrist rejects the claim
At the same time, some researchers point out that lifestyle factors such as obesity may play a greater role in certain diseases than plastic in the body.
However, critics still believe that plastic particles are likely present in humans. They merely stress that better and more standardized methods are needed before firm conclusions can be drawn about the health risks.
Sources: Fortune, and Nature Medicine.
Also read: This happens in your body when you often eat avocado toast