A study from Spain found that adding olive oil and nuts to a Mediterranean diet slowed declines in cognitive function. The benefits were seen among a group of 447 healthy seniors (average age nearly 67) who were considered at high cardiovascular risk and were participating in a larger, ongoing study of the Mediterranean diet. Researchers in Barcelona assigned 155 of the study participants to supplement the diet with five tablespoons a day of extra-virgin olive oil. A second group of 147 participants supplemented with 30 grams (about an ounce) per day of a mixture of walnuts, hazelnuts and almonds. A third group, with 145 participants, was assigned to follow a non-Mediterranean, low-fat diet.
During the four-year study, the researchers looked for cognitive changes by asking the participants to perform a series of neuropsychological tests. They focused on changes in memory, attention and executive function (the ability to plan and execute mental tasks), and global cognition.
Compared to the participants on the low-fat diet, memory declined less in those on the Mediterranean diet plus nuts, while and global cognition benefited in those on the diet with extra olive oil. Over the course of the study the team saw significant decreases in all aspects of cognitive function in participants on the low-fat diet.
Earlier observational studies have shown better cognitive function and a lower-than-normal risk of dementia among people who follow the Mediterranean diet. This new study is the first to show an association between the diet and diminished declines in cognitive function and memory.
Study leader Emilio Ros, M.D., Ph.D. of Spain’s Institut d’Investigacions Biomediques August Pi Sunyer Hospital Clinic in Barcelona suggests that the diminished declines probably stem from the abundance of antioxidants and anti-inflammatory agents in olive oil and nuts.
My anti-inflammatory diet, which is modeled on the Mediterranean diet with added Asian influences, emphasizes the healthy fats from extra virgin olive oil and nuts. You don’t have to choose between the two – I recommend a total of five to seven servings a day of nuts and olive oil.
Bear in mind that the incidence of Alzheimer’s disease is higher than normal among people whose diets are high in saturated fat, which causes free radical damage leading to inflammation of the brain. On the other hand, omega-3 fatty acids found in salmon, sardines and flax seeds appear to be protective. Blueberries also seem to help. The anthocyanin pigments they contain are responsible for their antioxidant potency – one half cup of blueberries packs as much antioxidant power as five servings of peas, carrots, apples, squash, or broccoli. These foods are all compatible with my anti-inflammatory diet and the Mediterranean diet.
Andrew Weil, M.D.
Emilio Ros et al, “Mediterranean Diet and Age-Related Cognitive Decline: A Randomized Clinical Trial.” JAMA Internal Medicine, May 2015, doi: 10.1001/jamainternmed.2015.1668