The researchers examined the effects of 9 components of the Mediterranean diet on cognition.
Adherence to the Mediterranean diet correlates with higher cognitive function according to a recent analysis from 2 major eye disease studies at the National Eye Institute. The analysis showed that dietary factors also seem to play a role in slowing cognitive decline.
The researchers examined the effects of 9 components of the Mediterranean diet on cognition, since the diet emphasizes consumption of whole fruits, vegetables, whole grains, nuts, legumes, fish, and olive oil, as well as reduced consumption of red meat, and alcohol.
The Age-Related Eye Disease Study (AREDS) and AREDS2 examined the effect of years of vitamins on age-related macular degeneration (AMD), which damages the light-sensitive retina. AREDS included approximately 4000 participants with and without AMD, while AREDS2 included approximately 4000 participants with AMD.
The participants in each study were assessed for diet at the start of the studies. AREDS participants were tested for cognitive function at 5 years, while AREDS2 tested cognitive function in participants at baseline and again at 2,4, and 10 years.
The researchers used standardized tests based on the Modified Mini-Mental State Examination to further evaluate cognitive function as well as other tests, assessing diet with a questionnaire that asked participants their average consumption of each Mediterranean diet component over the previous year.
The data found that participants with the greatest adherence to the Mediterranean diet had the lowest risk of cognitive impairment, with high fish and vegetable consumption appear to have the greatest protective effect. AREDS2 participants with the highest fish consumption had the slowest rate of cognitive decline at 10 years.
The numerical differences in cognitive function scores between participants with the highest versus lowest adherence to a Mediterranean diet were relatively small, and individuals most likely will not see a difference in daily function, according to the study authors. At a population level, the effects clearly show that cognition and neural health depend on diet.
Participants with the ApoE gene, which puts individuals at a high risk for Alzheimer disease, on average had lower cognitive function scores and greater decline than those without the gene, according to the study authors. The benefits of close adherence to a Mediterranean diet were similar for people with and without the ApoE gene, meaning that the effects of diet on cognition are independent of genetic risk for Alzheimer disease.
Diet may help preserve cognitive function. NIH.https://www.nih.gov/news-events/news-releases/diet-may-help-preserve-cognitive-function. Published April 14, 2020. Accessed April 14, 2020.