Something to file in the "hmmmmm" folder:

Natural Compound In Extra-virgin Olive Oil -- Oleocanthal -- May Help Prevent, Treat Alzheimer's
ScienceDaily (Sep. 29, 2009)
Oleocanthal, a naturally-occurring compound found in extra-virgin olive oil, alters the structure of neurotoxic proteins believed to contribute to the debilitating effects of Alzheimer's disease. This structural change impedes the proteins' ability to damage brain nerve cells... Also known as beta-amyloid oligomers, ADDLs are structurally different from the amyloid plaques that accumulate in brains of Alzheimer's patients... Oleocanthal and ibuprofen also have similar anti-inflammatory properties, and ibuprofen – like extra virgin olive oils presumably rich in oleocanthal – is associated with a decreased risk of Alzheimer's when used regularly...
http://www.sciencedaily.com/re.../09/090929133123.htm

It seems to come back to the body's response to inflammation.