Could Nuts and Olive Oil Protect Cognitive Function?

Following a Mediterranean diet including extra portions of mixed nuts or extra virgin olive oil rich in antioxidants could protect older adults from cognitive decline, according to new research.

“Oxidative stress and vascular impairment are believed to partly mediate age-related cognitive decline, a strong risk factor for development of dementia,” explained the study’s authors.
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“Epidemiologic studies suggest that a Mediterranean diet, an antioxidant-rich cardio protective dietary pattern, delays cognitive decline, but clinical trial evidence is lacking,” they said.

For the randomized, clinical trial, 447 cognitively healthy participants who exhibited high cardiovascular risk underwent neuropsychological assessment. The participants were randomly divided to 1 of 3 groups: those eating a Mediterranean diet supplemented with extra virgin olive oil (1L per week), those eating a Mediterranean diet supplemented with 30 g per day of mixed nuts, or those eating a control diet who were asked to reduce dietary fat.

Cognitive change was measured in participants using various neuropsychological tests, which focused on global and frontal lobe cognition, and memory.

After a median 4-year follow-up, cognitive test results were available from 334 patients.

There were 37 cases of mild cognitive impairment among all participants. Mild cognitive impairment was present among 13.4% (17) in the extra olive oil supplement group, 7.1% (8) in the mixed nuts supplement group, and 12.6% (12) in the control dietary group.

Researchers found that individuals in the control group showed major decreases in each measured component of cognitive function. However, researchers discovered that both Mediterranean diet groups in the study demonstrated different cognitive function improvements.

Compared to the control groups, those who had additional nuts as a dietary supplement scored better in memory tests, and those with the olive oil supplement performed better on tests requiring frontal and executive function.

The complete study is published in the May issue of JAMA Internal Medicine.

-Michelle Canales Butcher

Reference:
Valls-Pedret C, Sala-Vila A, Serra-Mir M, et al. Mediterranean diet and age-related cognitive decline. JAMA Intern Med. 2015 May [epub ahead of print] doi: 10.1001/jamainternmed.2015.1668.