A new mouse study suggests another reason why extra virgin olive oil (EVOO) may improve brain health and decrease risk of cognitive decline. A few caveats apply, as they do with all research of this kind, and we’ll circle back to those in a moment.
As one of the main components of the Mediterranean Diet, EVOO has already earned an impressive health reputation. A wide range of research showing benefits of the Mediterranean Diet points to EVOO as one of its likely brain- and heart-health boosters, with the potential for improving the elasticity of blood vessels and hedging against age-related memory decline. Previous animal research has also pointed to its potential for decreasing risk of Alzheimer’s disease.
The latest study went a step further to find out if an EVOO-enriched diet could fight the build-up of toxic tau proteins that are found in the brains of Alzheimer’s patients and those with frontotemporal dementia. Symptoms of this form of dementia, which primarily affects the frontal and temporal lobes of the brain and can manifest as early as 40, include difficulties with language and eventual deterioration of memory.
Researchers put a group of mice genetically engineered to develop tauopathy (accumulation of tau proteins in their brains) on a diet supplemented with a significant amount of EVOO. All of the mice in this group were relatively young, the equivalent to ages 30-40 in humans. Other mice of the same age were fed a normal diet without EVOO.
When the researchers evaluated the mice six months later, they found 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. The EVOO group also performed better on learning and memory tests.
The researchers reported that the brain tissue of mice in the EVOO group showed especially high levels of a protein called complexin-1, thought to play a role in maintaining the health of neuron synapses – the junction points between brain cells. An increase in this protein may counterbalance the accumulation of tau, though the exact relationship isn’t entirely clear.
“EVOO has been a part of the human diet for a very long time and has many benefits for health, for reasons that we do not yet fully understand,” said the study’s senior investigator Domenico Praticò, MD, in a press statement. “The realization that EVOO can protect the brain against different forms of dementia gives us an opportunity to learn more about the mechanisms through which it acts to support brain health.”
Next, the researchers plan to conduct research into the effects of feeding EVOO to older mice that already have advanced tau deposits in their brains. “We are particularly interested in knowing whether EVOO can reverse tau damage and ultimately treat tauopathy in older mice,” Dr. Praticò added.
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.
Having said that, these results add to a body of findings suggesting that EVOO has the potential for improving both brain and heart health. As part of the Mediterranean Diet, which boasts a variety of possible benefits, this ancient oil has earned the attention it’s getting.
The study was published in the journal Aging Cell.