The increased frequency of age-related diseases such as Alzheimer disease, and other types of dementia, makes that finding simple strategies that may prevent or delay its onset has become a public health priority. Several studies suggest a link between eating habits and cognitive performance and that oxidative stress (the inability of the body to detoxify itself) plays a key role in the onset of neurodegenerative diseases. Thus, a diet containing anti-oxidant foods may provide protection against these diseases.
The study involved 447 cognitively healthy volunteers but at high cardiovascular risk, both women and men, with an average age of 67 years and who participated in the PREDIMED study, a multicenter clinical trial of nutritional intervention with Mediterranean diet in 7447 participants. The volunteers were told a Mediterranean diet supplemented with extra virgin olive oil, Mediterranean diet with extra nuts or a low-fat control diet. In this sub-study an assessment of cognitive function through different neuropsychological tests was carried out at the beginning and end of the follow-up period.
After a 4 years follow-up, researchers found that there was an improvement of cognitive function in participants who followed the Mediterranean diet supplemented with respect to the control diet, in which a cognitive impairment was found, and that this improvement was independent of variables such as age or sex. The diet with nuts was more effective in improving memory, while the olive oil favorably influenced the frontal cognition (executive function). "These beneficial effects of the Mediterranean diet are probably due to the large number of anti-inflammatory and antioxidant agents that provides" explains Dr. Emili Ros, coordinator of the study.
This is the first clinical trial of this kind in finding a relationship between changes in cognitive impairment and dietary habits. This study provides strong evidence of the potential of the Mediterranean diet in helping to maintain good cognitive performance, despite aging, and to eventually reduce the incidence of neurodegenerative diseases like Alzheimer disease.
Cinta Valls-Pedret, Aleix Sala-Vila, Mercè Serra-Mir, Dolores Corella, Rafael de la Torre, Miguel Ángel Martínez-González, Elena H. Martínez-Lapiscina, Montserrat Fitó, Ana Pérez-Heras, Jordi Salas-Salvadó, Ramon Estruch, Emilio Ros.
JAMA Intern Med. Published online May 11, 2015. doi:10.1001/jamainternmed.2015.1668