Is it harmful to cook or store food in aluminum foil?

We do not recommend cooking or storing food in aluminum foil-even though there is no strong scientific evidence showing these practices to be harmful to your health. We have three reasons for making this recommendation. First, even though research studies don't show the food use of aluminum foil to be harmful, they clearly show migration of small amounts of aluminum from the foil into the food. For example, in one study conducted in Italy about 2-6 milligrams of aluminum was found to move over into food from aluminum foils, cookware, and utensils. Even if this amount has not been show to pose health harm, we don't like our food containing a potentially problematic metal that wasn't naturally supposed to be there.
Second, we believe that the jury is still out on aluminum with respect to chronic long-term health problems. (We're talking here about exposure to aluminum from all sources, including the environment, certain workplace settings, personal care products, etc.) Potential connections have been found between certain cancers and aluminum exposure, and also between aluminum exposure and Alzheimer's disease. Infertility connections have also been found. We don't see any reason to add potential exposure through the use of aluminum foil with food.
Finally, we don't like the consequences of aluminum foil manufacturing for our planet. Aluminum remains on the federal government's list of priority toxins for the United States, and its mining, manufacture, and post-use disposal pose significant problems for our environment. From our perspective, while aluminum foil is definitely lightweight, flexible, and convenient, these upsides don't come close to outweighing the downsides here.

http://whfoods.org/genpage.php?tname=newtip&dbid=8