Many people are fans of the Mediterranean diet. The Mediterranean diet is basically a diet high in vegetables and olive oil and low on animal protein. A recent study published in JAMA Internal Medicine seems to validate the benefits of this diet, especially when supplemented with nuts and olive oil.
The study was a small one done in Spain. The average age of the participants was 67. Most of the participants were overweight and had hypertension and/or elevated cholesterol levels. They were divided into three groups. One group followed a low-fat diet. Another group followed a Mediterranean diet supplemented with nuts. The third group followed a Mediterranean diet and supplemented with 5 teaspoons of olive oil a day.
Each group underwent memory testing and cognitive function testing before the diet and at 4 years. The group following a Mediterranean diet with supplemental nuts had significant improvements in memory, while the group adding extra virgin olive oil experienced significantly better cognitive function.
The study was small and definitive answers cannot be given concerning the benefits of olive oil and walnuts on memory and cognition. I do think it is safe to consume both olive oil and nuts such as walnuts or almonds and I believe that they can offer some benefits for brain health.
Olive oil and nuts have antioxidant effects and have long been advocated for brain health. They can reduce intravascular inflammation, which is a major cause of vascular damage. There are no bad side effects from these foods but do watch out for calories. (Nuts in general have about 10 calories per nut.)
So the next time you have a salad, add some olive oil and walnuts!