There's been concern over the years about the possible health issues with aluminum cookware as it pertains to Alzheimers. I use my pressure cooker often and today realized it's aluminum. I haven't seen any recent stories around- does anyone have any current info or data on the safety of aluminum cookware? Have there been any reliable new studies to back up the old concerns or debunk them? Thought I'd do some research before I go out and invest in a stainless pressure cooker.