Extra virgin olive oil also forms an essential part of the Mediterranean diet, which has been shown to boost brain health.
One study published in the journal Neurology, found that older people who followed a Mediterranean diet retained more brain volume over a three-year period than those who did not follow the diet as closely.
In addition to olive oil, the Mediterranean diet includes large amounts of fruits, vegetables, beans and cereal grains such as wheat and rice, moderate amounts of fish, dairy and wine, and limited red meat and poultry.
Researchers gathered information on the eating habits of 967 Scottish people around age 70 who did not have dementia. Of those people, 562 had an MRI brain scan around age 73 to measure overall brain volume, gray matter volume and thickness of the cortex, which is the outer layer of the brain.