Consumption of olive oil has been found to reduce the risk of Alzheimer's disease.

Oleocanthal has many healthy characteristics and is loaded with antioxidants that aid the immune system. Olive oil can be protective against heart disease as well.
A study conducted in 2009 found that oleocanthal could alter the cell structure in a manner which could fight Alzheimer's. The study found that consumption of extra-virgin olive oil helps in beta-amyloid clearance from the brain.
"Extra-virgin olive oil-derived oleocanthal associated with the consumption of Mediterranean diet has the potential to reduce the risk of Alzheimer's disease or related neurodegenerative dementias," researchers concluded.
Source-Medindia