The researchers examined the effects of nine components of the Mediterranean diet on cognition. AREDS and AREDS2 assessed the effect of vitamins on age-related macular degeneration (AMD), which damages the retina. AREDS included around 4,000 people with and without AMD; AREDS2 included around 4,000 people with AMD.
The results: Participants with the greatest adherence to the Mediterranean diet had the lowest risk of cognitive impairment. Fish and vegetable consumption appeared to have the greatest protective effect; at 10 years, AREDS2 participants with the highest fish consumption had the slowest rate of cognitive decline.
Furthermore, participants with the ApoE gene—putting them at high risk for Alzheimer’s disease—saw similar benefits of close adherence to a Mediterranean diet, suggesting that the effects of diet on cognition are independent of genetic risk for Alzheimer’s.
Related: Making Mediterranean a Lifestyle Mediterranean-Keto Could Reduce Risk of Alzheimer’s, Study Suggests It’s Not the “Bad Food” that Kills UsA press release on the study notes that the difference in cognitive function scores between participants with the highest adherence to the diet and participants with the lowest was relatively small; individuals likely would not see a difference in daily function. However, at a population level, the results show that cognition and neural health depend on diet.
“We do not always pay attention to our diets,” said Emily Chew, M.D., Director of the NEI Division of Epidemiology and Clinical Applications. “We need to explore how nutrition affects the brain and the eye.”