Evolving scientific evidence suggests there’s a relationship between dietary habits and cognitive performance. An article describing a study of the cognitive function of older adults in Spain was published by JAMA Internal Medicine online. This study focused on supplementing the typical plant-based Mediterranean diet with mixed nuts or extra virgin olive oil rich in antioxidants. Researchers found that the supplemented Mediterranean diet was associated with improved cognitive function in the hundreds of individuals involved in the study.
One major factor that plays a role in cognitive decline is oxidative stress, or the body’s ability to correctly detoxify itself. Existing research proposes that a Mediterranean diet may result in better cognitive function as well as a lowered risk of dementia. However, according to the study background, the examination of these associations are not without limitations. Thus, researchers from the Institut d’Investigacions Biomediques August Pi Sunyer, Hospital Clinic, Barcelona, and other institutions designed their study which compares a Mediterranean diet that has been supplemented with olive oil or nuts with a low-fat control diet.
There were 447 cognitively healthy volunteers with high cardiovascular risk that participated in the randomized clinical trial. Researchers gave 155 of these volunteers a supplement of one liter of extra virgin olive oil per week with a Mediterranean diet. Another 147 were assigned to supplement with 30 grams of mixed nuts per day, also with a Mediterranean diet. The rest of the 145 participants were assigned a low-fat control diet to follow. Their cognitive change over time was measured with neuropsychological tests. After a median of four years of the diet intervention, there were 335 participants with available follow-up tests.
The study discovered that those on the low-fat control diet experienced a significant decrease in all composites of cognitive function from baseline. In comparison to the control group, the volunteers from the Mediterranean diet plus nuts diet had significant improvement in the memory composite. Also, the frontal and global cognition composites improved in those who were on the Mediterranean diet plus extra virgin olive oil regime. Overall, the authors state that the changes for the two types of supplemented Mediterranean diets were similar, while there were bigger differences when comparing each individual Mediterranean groups with the low-fat diet control group. The results suggest that supplementing extra virgin olive oil or nuts with a Mediterranean diet may counteract age-related cognitive decline in an older population. Though these findings are encouraging, further investigation is needed.