J. R. Walton at University of New South Wales Faculty of Medicine in Sydney, Australia published a paper in the Journal of Alzheimer's disease to suggest that chronic aluminum intake causes Alzheimer's disease.

People can ingest aluminum through their drinking water and processed foods.  Aluminum additives are used in various processed foods and alum (aluminum sulfate or aluminum potassium sulfate) is used to treat drinking water. 

The study was intended to determine the extent to which the routine, chronic intake and metabolism of aluminum chemicals can account for Alzheimer's disease.

The author found that Alzheimer's disease "is a human form of chronic aluminum neurotoxicity." and "The causality analysis demonstrates that chronic aluminum intake causes AD (Alzheimer's disease)."

The risk of chronic intake of aluminum is associated with aluminum's absorption rates, which make people mistakenly believe that aluminum is safe to consume and safe to use as an additive in food and drinking water, aluminum's slow progressive uptake into the brain and interference with iron ion and affects iron dependent cells responsible for memory.

Aluminum is found in baking powder and some other food ingredients.  (David Liu)