Researchers fed extra virgin olive oil (EVOO) to mice that are genetically engineered to get dementia from the accumulation of toxic proteins (tau proteins) in the brain that lead to alzheimer's. After six months the researchers saw a "60% reduction in toxic tau deposits in the brains of the mice fed the EVOO-enriched diet compared to the mice eating a regular diet," reports Forbes.
The article includes some caveats to this promising news:
While this line of research is promising (along with the list of EVOO studies leading up to the latest), a few limitations apply. Mouse research can point to important directions for human research, but it's not the same as human research and does not demonstrate a cause-and-effect relationship between EVOO and brain-health benefits for humans. The positive results found in this and related studies suggest potential benefits, but they are not "proof" of anything.
Along with that limitation, it's also important to note that the accumulation of tau in the human brain typically occurs over many years, for reasons we're only starting to understand. The mice in this and related studies have been genetically altered to develop a similar condition in a matter of months. While this acceleration provides a useful model for research, it's not nearly the same as what happens in humans over the course of decades.