Tim, Essex asked:
Is it dangerous to human health to wrap foods in aluminium foil, knowing that there might be a link between aluminium and Alzheimer's?
Although there is a link between Alzheimer's and aluminium; if you look in the brains of people who have Alzheimer's disease, you find these build ups of protein called Alzheimer plaques or beta amyloid plaques, and if you look inside those, you can find aluminium ions there. Itís not clear whether the aluminium goes there because the plaque is there and therefore the brain is already abnormal or whether the aluminium helps to start the process off in the first place.
What we know is that when you cook things in aluminium foil or aluminium pans, because aluminium is a very reactive metal, the surface of the metal is covered in a very thin layer of an oxide Ė aluminium oxide - and this actually protects the metal from the atmosphere. That's why aluminium doesnít rust like iron does, itís fairly well protected by that oxide layer. This protective layer also means that the aluminium can't actually get into the food in any appreciable amount.
The exception to this is if you cook very, very acidic foods in your aluminium pot, and a good example of this Rhubarb. Rhubarb is extremely acidic and if you make a rhubarb crumble in an aluminium cooking pan, you will find that it needs virtually no cleaning afterwards because the acid attacks the oxide layer and can liberate a small amount of aluminium from the pan and this can get into the food.
Whether that will then produce Alzheimer's disease subsequently is a bone of contention. People say that you're advised not to cook very acidic foods in aluminium rich cooking materials and utensils because there is a small risk that you might get aluminium in the food and it could therefore have health consequences. Some of the interpretation is based on what happened to people in Ė I think it was Castleford in Devon Ė where they accidentally dumped a whole lot of aluminium in a water settling tank. Aluminium is used in swimming pools and at sewage works as a flocculent. It causes small particles to clump together. They accidentally put some aluminium in a tank that people were going to drink from, rather than the tank they wanted to settle out. So people were receiving a very high dose of aluminium and there were some alleged connections with Alzheimer type of changes in people subsequently, but we don't know if those people were just going to get Alzheimer's anyway.
So itís a good question. Itís open to debate. But don't cook acidic things in those sorts of pans. That would be my advice.