A Mediterranean diet consists of fruit, vegetables, whole grains, legumes, nuts, olive oil in order to lower the use of saturated fats and trans fats linked to lowering oxidative stress. A randomized clinical trial published in the journal JAMA Internal Medicine followed volunteers with an average age of 67 over a period of time. Previous studies have associated numerous positive health benefits to the diet.
Cardiovascular disease has been linked to oxidative stress and vascular impairment related to age-related cognitive decline, a strong risk factor for development of dementia. Two research participants for this study consisted of a total of 155 participants who were randomly assigned to follow a Mediterranean diet supplemented with one liter of extra virgin olive oil per week. The second group of participants were assigned to follow a Mediterranean diet supplemented with 30 grams per day of mixed nuts (walnuts, hazelnuts and almonds). The control group consisted of 145 participants who followed a reduced fat diet.
The research findings were based on multiple neuro-psychological tests focusing on memory, global cognition and frontal cognition (attention and executive function). These participants were compared with a control group of 145 participants following a diet where they were advised to reduce dietary fat. Cognitive function was significantly improved with the Mediterranean diet.
“The group with nuts did better compared to the control group in memory tests, memorizing names or words, while the olive oil group did better on tests that require speed of thought, your frontal function, your executive function,” said Dr. Ros.
“Our results suggest that in an older population, a Mediterranean diet supplemented with olive oil or nuts may counteract age-related cognitive decline,” conclude the authors. “The lack of effective treatments for cognitive decline and dementia points to the need of preventive strategies to delay the onset and/or minimize the effects of these devastating conditions.”
Mediterranean diet and age-related cognitive decline, Emilio Ros, et al., JAMA Internal Medicine, doi:10.1001/jamainternmed.2015.1668, published online 11 May 2015, abstract.