As with polyunsaturated fats, the brain is rich in monounsaturated fats, which form the brain’s myelin sheath. This is the protective coating that insulates neurons and allows for speedy neurotransmission. However, unlike polyunsaturated fats, monounsaturated fats are chemically stable. Oils composed primarily of these fats not only are safe to consume but seem to have a number of positive effects in the body. Some common sources of monounsaturated fat include avocados, avocado oil, and macadamia nuts, and the fat content of wild salmon and beef is nearly 50 percent monounsaturated. But perhaps the
most famous source of monounsaturated fat is extra-virgin olive oil.
In Mediterranean countries such as Greece, southern Italy, and Spain
where rates of neurodegenerative diseases like Parkinson’s and Alzheimer’s are lower—extra-virgin olive oil is the ultimate sauce, used liberally on steak, beans, vegetables, bread, pizza, pasta, and seafood, in soups, and even in desserts. My friend Nicholas Coleman, chief oenologist at New York City’s Eataly, painted the picture for me: “They don’t drizzle olive oil; they pour it on.” Mediterranean’s even cook with it—contrary to popular belief, EVOO retains much of its nutritional value even under extreme conditions.
That being said, it’s still better to save high-heat cooking
For saturated fats, which are the most chemically stable—and which we’ll cover next.) The so-called Mediterranean diet is often cited by epidemiologists (scientists who study health and disease in large populations and make associations based on the data that they collect) as being the most protective large-scale dietary pattern against cardiovascular disease and neurodegeneration, and it’s been shown that higher adherence to the Mediterranean style of eating leads to not only better long-term health outcomes (including a robust risk reduction for developing dementia), but bigger brains as well.
But as I’ve mentioned, the major limitation of epidemiological studies is that they are based on observation, making it impossible to pinpoint which aspects of the diet are causally involved in such benefits. To bridge this gap and look specifically at the effect of foods rich in monounsaturated fat on cognitive performance, scientists in Barcelona began a trial that pitted a low-fat diet (still widely recommended) against two versions of the higher-fat Mediterranean diet.
One of the two experimental Mediterranean diets
Was supplemented with tree nuts like almonds, hazelnuts, and walnuts—all great sources of monounsaturated fat. The other experimental diet was supplemented with even more extra-virgin olive oil. In the high olive oil group, participants were given a liter to consume per week. Just to put that in perspective, one liter of olive oil contains more than 8,000 calories—more than half a week’s worth of calories for an adult male!
Both groups—those that adhered to the diet supplemented with added nuts and those supplementing with added olive oil—not only retained but improved their cognitive function after six years, with the olive oil group coming out slightly ahead. The low-fat control group exhibited steady decline. Get to know the grassy, peppery taste of a good EVOO (preferably organic) by swooshing it to the back of your throat—and taste it often! Stock your kitchen with extra-virgin olive oil, and use it in low- to medium-heat cooking, as a sauce on eggs, vegetables, and fish, and in all of your salads.