Re: “classic column”
http://www.straightdope.com/classics/a1_121a.html
What I want to know is, is it safe to eat the “grayish-black mush of aluminum oxide” that results when aluminum foil surrenders its electrons to ketchup?
(Naturally, this leads into the questions: Is it safe to eat x amount of aluminum? Is it safe to cook in aluminum pots and pans?)
Cecil has discussed the health consequences of aluminum a couple of times, most recently in What’s the latest on the link between aluminum and Alzheimer’s disease?"
Minute traces of aluminum oxide are probably not important. On the other hand, I probably wouldn’t eat a big lump of the stuff in the ketchup, if nothing else for aesthetic reasons. It probably won’t kill you, but it might not be that tasty either. And why risk it?
There’s a chance that reduced (elemental) aluminum might be harmful, but if aluminum oxide were poisonous, we’d all be dead by now. Aluminum is the third most abundant element in the Earth’s crust, appearing primarily in its oxide form, so the stuff’s all over the place. And it’s very difficult to get elemental aluminum from the oxide, so there’s no real risk of your body separating out the (possibly) harmful element.
But it is certainly gross.