Eating Mediterranean diet helps delay cognitive decline

Professor of Preventive Medicine at the University of Valencia Dolors Corella is part of the multidisciplinary team conducting the Predimed study, which has found that eating a Mediterranean diet, enriched with olive oil or nuts, helps delay cognitive decline.

The findings of this study led by Dr Emilio Ros, from the Hospital Clínic of Barcelona, have just been published in the journal JAMA Internal Medicine.

The professor of the Faculty of Medicine and Dentistry and researcher at the Spanish biomedical research centre CIBER Physiopathology of Obesity and Nutrition (CIBERobn) has studied the influence of diet on the cognitive function of older adults in the context of Predimed, a study on dietary intervention for various chronic diseases. Participants were 67 years old on average and their progress was monitored over four years.

BETTER MEMORY ABILITIES

"Research has allowed us to verify for the first time ever that people who followed a Mediterranean diet, supplemented with extra virgin olive oil or nuts throughout the follow-up period, had a better cognitive ability than the control group, who didn't follow the diet", argues Corella. In general, it was observed that people in the Mediterranean diet group experienced less loss of global brain function compared with the control group. Also, "the group on the Mediterranean diet supplemented with nuts preserved memory better than any other group", adds the scientist at the University and CIBERobn.

BENEFITS DESPITE THE GENETIC FACTOR

The additional importance of this study is that it has also traced the influence of genetic factors, among which the APOE genotype is especially remarkable. In fact, the University of Valencia analysed the APOE genotype of patients. When genetic influence has been taken into account in statistical analyses, the results suggest that the beneficial effect of Mediterranean diet on cognitive function is independent of the APOE genotype.

Consequently, according to Professor Corella, "we must highlight that people with a higher genetic risk of cognitive disorders and dementia associated with their APOE4 genotype also benefit more by following a Mediterranean diet."

Dolors Corella points out that even if these results were obtained from a relatively small sample of 447 participants, and that it is necessary to replicate them in a larger population, "these findings open the door to preventive strategies based on diet to delay the onset of this cognitive decline", she explains.

One of the problems associated with ageing population is the incidence of cognitive conditions that can be mild, with the onset of functional problems that indicate that daily activities are no longer performed with the same skill. These are followed by memory impairment, which may then progress to more severe forms of dementia, including Alzheimer's disease.

The factors that influence this cognitive decline are currently under investigation and it is already known that there is a significant genetic contribution. Of all the genetic factors known, the APOE gene is the most widely associated with greater cognitive decline and greater risk of Alzheimer's in people carrying the variant called APOE4 (compared with E2 and E3, which are the other forms of the gene).