The benefits of a Mediterranean diet are widely chronicled, but new research shows extra-virgin olive oil, a key part of the diet, may protect “against cognitive decline.”
Specifically, researchers at Temple University in Philadelphia say extra-virgin olive oil “protects memory and learning ability and reduces the formation of amyloid-beta plaques and neurofibrillary tangles in the brain – classic markers of Alzheimer's disease.”
Researcher say olive oil reduced inflammation and triggers a process called autophagy, which helps broken down cells to flush intracellular debris and toxins. This includes amyloid plaques and tau tangles, the latter of which is associated with memory loss in Alzheimer’s.
“Brain cells from mice fed diets enriched with extra-virgin olive oil had higher levels of autophagy and reduced levels of amyloid plaques and phosphorylated tau,” said senior investigator Domenico Praticò.
For their study, the researchers looked at mice with three traits of Alzheimer’s: memory impairment, amyloid plaques, and neurofibrillary tangles. The mice were put into two groups, one group got a diet enriched with extra-virgin olive oil, while the other group received a normal diet.
The olive oil was given to the mice when they were only six months old and before any symptoms of Alzheimer’s set in. While there was no difference in the appearance of the mice, at age 9 months and 12 months, the mice in the olive oil group “performed significantly better on tests designed to evaluate working memory, spatial memory, and learning abilities.”
An analysis of the brain tissue of the mice revealed more differences.
“One thing that stood out immediately was synaptic integrity,” Praticò said. The integrity of the connections between neurons, known as synapses, were preserved in animals on the extra-virgin olive oil diet. In addition, compared to mice on a regular diet, brain cells from animals in the olive oil group showed a dramatic increase in nerve-cell autophagy activation, which ultimately was responsible for the reduction in levels of amyloid plaques and phosphorylated tau.”
Next, researchers plan to see what happens to mice who are given olive oil at 12 months, when they are already showing symptoms.
“Usually when a patient sees a doctor for suspected symptoms of dementia, the disease is already present,” Praticò added. “We want to know whether olive oil added at a later time point in the diet can stop or reverse the disease.”
The study was published online June 21 in the Annals of Clinical and Translational Neurology.