Aluminum is unusually abundant in the neurofibrillary tangles of Alzheimer’s disease. For years, rumors have circulated that aluminum cookware contributed to the disease. And for just as long, most scientists have scoffed at this notion because aluminum is one of the most abundant elements on earth and everyone is exposed to a great deal of it.

Over the last decade several studies have explored the issue of aluminum–especially Aluminum in drinking water–and Alzheimer’s risk. Some show that as the aluminum concentration in water increases beyond about 11 micrograms per liter, so does Alzheimer’s risk. Others show no association.

Studies showing an aluminum-Alzheimer’s link suggest that aluminum alone is not the sole culprit. Other substances, notably acids, must be present in the water to enable aluminum absorption in the gut.

Scientists who suspect that aluminum exposure may be a risk factor for Alzheimer’s warn against drinking carbonated beverages from aluminum cans. The carbonation makes the drink acidic, which increases aluminumn absorption in the gut.

The issue of aluminumn as a possible risk factor for Alzheimer’s is extremely controversial.

If you’re concerned enough about aluminum to spend about $100 to have your water tested, the National Testing Laboratory of Cleveland includes aluminum in a 74-item test of water quality.

They send you sampling test tubes. You fill them with your water, and send then to the lab in a special styrofoam-lined box. A week or so later, the lab sends you a report detailing what’s in your water. For more information, call 1-800-458-3330.

— By Matthew Naythons MD and Michael Castleman