Researchers in Barcelona, Spain recently found that when older adults supplemented their Mediterranean style of eating with extra olive oil or nuts, they had better memory and thinking skills than those who ate a low-fat diet.
The study involved nearly 450 older adults divided into three groups. One group ate a Mediterranean diet plus a liter of extra virgin olive oil per week. A second supplemented the Mediterranean diet with 30 grams of nuts per day, including walnuts, hazelnuts and almonds. The remaining participants followed a low-fat diet.
After an average of about four years, the participants took a cognitive assessment. Results showed the two groups who ate the Mediterranean diet had better cognitive function, such as reasoning, attention, memory and language, than the group that ate the low-fat diet.
The study does not show a direct cause-and-effect relationship between what you eat and your brain power. But based on the results, the researchers theorize that in the future, diet could play a role in preventing dementia.
“These findings are novel because, to our knowledge, no prior long-term clinical trial has assessed cognitive changes in response to dietary patterns,” the study says.
How it might work
Scientists believe that oxidative stress – when damaging free radicals outnumber the body’s defenses – and damaged blood vessels in the brain are related to age-related cognitive decline. Age-related cognitive decline is a strong risk factor for development of dementia.
The Mediterranean diet emphasizes fresh fruits and vegetables and whole grains, with olive oil as the primary source of fat. Low- or non-fat dairy, fish and wine are consumed in low to moderate amounts. And total daily fat intake should range from 25 percent to 35 percent of total calories, with saturated fat no more than 7 percent of calories.
The beneficial effect of the Mediterranean diet on cognition likely stems from the abundance of antioxidants and anti-inflammatory agents that the foods provide, the researchers say.
The supplemental foods – extra virgin olive oil and nuts – featured in the study are particularly rich in substances that also might counteract oxidative processes in the brain, says registered dietitian Julia Zumpano, RD, LD.
More evidence of benefit
“The fat from olive oil and the fat from nuts provide monounsaturated fatty acids,” Ms. Zumpano says. “We know those help the heart and now there’s evidence that they may help the brain as well.”
Ms. Zumpano says the study provides even more reasons to consider adopting the Mediterranean diet. The diet is proven to have positive health effects, such as lower cholesterol and blood pressure and weight reduction.
“In general, we’re finding that the Mediterranean diet is just the best way to go,” she says. “It’s a whole-foods-based diet and high in antioxidants because of its abundance of fresh fruits, vegetables and grains.”
Complete findings for the study, Mediterranean Diet and Age-Related Cognitive Decline, appear in the journal JAMA Internal Medicine.