Non reactive pots?
Is Le Creuset non reactive? what about a stainless that is nonstick? what happens if you use the wrong kind- why do certain recipes note to use a non reactive pot?
The most common examples of reactive pots/pans would be bare (unanodized) aluminium, cast iron, unlined copper (used for candymaking) and bare steel (like woks). Anodized aluminum (like Calphalon and its lookalikes), stainless steel, stainless-lined anything, non-stick coated surfaces, glass/ceramic/pottery are all "non-reactive."
Usually what happens is the metal imparts an off-flavor or color to the food, or acidic and very salty foods can discolor or pit the cookware's surface. I'm not aware of any health issue involved, except with copper, where repeated use for anything but cooking sugar solutions can lead to health problems from copper toxicity. (We need some copper, but a really infinitesmal amount we get from just about any diet; too much, but still tiny amounts, can interfere with some very basic biological processes that keep us healthy and alive.)
For a while aluminum was thought to cause Alzheimer's, but with more research that initial hypothesis proved to be incorrect. (In a way unfortunately, since it would have been relatively easy to avoid. We've learned a lot, but we still don't know for sure why Alzheimer's happens.)
Although you are right that anodized aluminum bills itself as non-reactive, plenty of people could tell you that in reality it pits and discolors after extended exposure to acidic foods (like tomato sauce). Specifically, Calphalon pans in my experience. Can't speak to the health effects.