The following is excerpted from an article published on the website of the U.S. National Library of Medicine, May 11, 2015.

Adding more olive oil or nuts to a Mediterranean diet—one rich in fruits, vegetables, fi sh, and whole grains and low in red meat—may help keep your mind sharper as you age, a new study suggests.

The Spanish researchers found that seniors following such diets had greater improvements in thinking and memory than people who were simply advised to eat a lower-fat diet.

“You can delay the onset of age-related mental decline with a healthy diet rich in foods with a high antioxidant power, such as virgin olive oil and nuts,” said lead researcher Dr. Emilio Ros, director of the lipid clinic at the Hospital Clinic in Barcelona.

“Because the average age of participants was 67 when the trial began, one can say that it is never too late to change your diet to maintain or even improve brain function,” he said.

The report was published online May 11 in the journal JAMA Internal Medicine.

Dr. Sam Gandy, director of the Center for Cognitive Health at Mount Sinai Hospital in New York City, said, “The general heart-healthy and brain-healthy effects of eating less beef and more chicken, fi sh, fruits and vegetables [have] been validated to the point that I now recommend this general Mediterranean diet to all my patients.”

…. Participants were randomly assigned to add a liter (about 33 ounces) of extra virgin olive oil per week to their Mediterranean diet, or to supplement their Mediterranean diet with 30 grams (roughly 1 ounce) per day of a mixture of walnuts, hazelnuts and almonds. Others followed a low-fat diet…. The participants followed the diets for four years, on average, according to the study.

In both groups following a Mediterranean diet, the researchers saw improvements in tests of memory and thinking compared to the group on the low-fat diet, the study showed.

Samantha Heller, a senior clinical nutritionist at New York University Medical Center in New York City, explained that “healthy fats from foods like nuts and olive oil play crucial roles in brain function and health.”

Every one of the nerve cells in the human brain is surrounded by an ultra-thin layer of fat and protein called the myelin sheath, she explained. The myelin sheath protects the nerve structure and helps nerve cell interaction. The brain gets its fats to make and maintain the myelin sheath from the foods people eat. The healthier the foods and fats, the healthier the brain, Heller said.

SOURCES: Emilio Ros, M.D., Ph.D., director, lipid clinic, Hospital Clinic, Barcelona, Spain; Sam Gandy, M.D., Ph.D., director, Center for Cognitive Health, Mount Sinai Hospital, New York City; Samantha Heller, M.S., R.D., senior clinical nutritionist, New York University Medical Center, New York City; Valls-Pedret C, Sala-Vila A, Ros E, et al. Mediterranean diet and agerelated cognitive decline. JAMA Intern Med. 2015;doi:10.1001/jamainternmed.2015.1668. [Epub ahead of print]