> Formaldehyde and its adducts are ubiquitous in living organisms. It is formed in the metabolism of endogenous amino acids and is found in the bloodstream of humans and other primates at concentrations of approximately 0.1 millimolar.
Maybe "people will literally argue that formaldehyde is naturally occurring and exists in our bodies" because, you know, it's true?
Also considering that aluminum is the third most abundant element in the Earth's crust, I'd be very surprised if even ancient people didn't have some aluminum in their bodies. They could ingest more aluminum than we do simply by chewing on food with dirt.