According to a recent analysis of the data from two studies on eye diseases, adherence to the Mediterranean Diet, rich in vegetables, whole grains, fish and extra virgin olive oil, is correlated with greater cognitive function, so that dietary factors they also seem to play a role in decreasing cognitive decline.
Researchers from the National Eye Institute (NEI) , part of the National Institutes of Health, led data analysis from the Age-Related Eye Diseases Study (AREDS) and AREDS2; and they published their results in Alzheimer's and Dementia: The Journal of the Alzheimer's Association.
"We don't always pay attention to our diets. We need to explore how nutrition affects the brain and eyes,” said Emily Chew, director of NEI's Division of Epidemiology and Clinical Applications and lead author of the studies.
The researchers examined the effects of nine components of the Mediterranean Diet on cognition, characterized by the consumption of whole fruits, vegetables, whole grains, nuts, legumes, fish and extra virgin olive oil, as well as reduced consumption of red meat. and alcohol.
Thus, AREDS and AREDS2 evaluated for years the effect of vitamins on age-related macular degeneration (AMD), which damages the light-sensitive retina. AREDS included approximately 4,000 participants with and without DMA, and AREDS2 included approximately 4,000 participants with DMAE.
The researchers evaluated the AREDS and AREDS2 participants for diet at the beginning of the studies. The AREDS study assessed participants 'cognitive function at five years, while AREDS2 analyzed participants' cognitive function at the start of the study and again two, four, and 10 years later.
They also used standardized tests based on the modified mini-mental state test to assess cognitive function, as well as other tests. They evaluated the diet with a questionnaire that asked the participants their average consumption of each component of the Mediterranean Diet during the previous year.
Participants with the highest adherence to the Mediterranean Diet had the lowest risk of cognitive decline. The high consumption of fish and vegetables seems to have the greatest protective effect. At 10 years, AREDS2 participants with the highest fish consumption had the slowest rate of cognitive decline.
The numerical differences in cognitive function scores between the participants with the highest versus lowest adherence to a Mediterranean Diet were relatively small, meaning that people likely would not see a difference in daily function. But at the population level, the effects clearly show that cognition and neural health depend on diet.
The researchers also found that participants with the ApoE gene, which puts them at high risk for Alzheimer's disease, on average had lower cognitive function scores and a greater decline than those without the gene. The benefits of close adherence to a Mediterranean Diet were similar for people with and without the ApoE gene, meaning that the effects of the diet on cognition are independent of the genetic risk of Alzheimer's disease.