I have read that scratched and pitted aluminum pieces do leach aluminum into food.
That being said, I have also read that aluminum is not readily absorbed into our bloodstream when it is swallowed; it is only absorbed when put directly in the bloodstream (I read this in this Mothering
Here's a quote from that article (by Dr. Sears):
Normally, one wouldn't consider aluminum to be a problem. It's a naturally occurring element that is present everywhere in our environment—in food, water, air, and soil. It's also a main ingredient in over-the-counter antacids. And because the body doesn't absorb aluminum, it's harmless when swallowed.
I cannot find any real answers to why aluminum cookware is reputed to be unsafe. The one fact I found claimed that by using aluminum cookware you may consume up to 4% of the safely recommended allowance:The best heat conductor next to copper, it is very widely used in cooking utensils because of its advantages of great conductivity, lower cost and great strength. Aluminum utensils can either be made by casting or by rolling, and they are easily anodized or covered with a non-stick surface. Aluminum is a reactive metal, and its primary disadvantage is in that acidic foods should not be cooked in it for any length of time.
Because of fears concerning a possible connection between aluminum and Alzheimer's disease, many people are turning away from aluminum cookware. Both the Food and Drug Administration (FDA) and the Alzheimer's Foundation assure us that no link has been found between the use of aluminum utensils and the disease.
The World Health Organization (WHO) estimates that we absorb less than 4% of the maximum safe dosage from cooking in aluminum utensils. Because aluminum is readily absorbed from many foods, it is estimated that we absorb only between 10% and 20% of our daily intake as a result of cooking in aluminum.
Avoid cooking in pitted aluminum pans; aluminum is absorbed into foods much more readily from pitted ones. And avoid storing foods in uncoated aluminum to prevent absorption. Acidic foods and leafy vegetables absorb the most aluminum.
(I'm not sure of the original source of this WHO info...)http://www.cheftalk.com/forums/cooki...um-safety.html