Mediterranean Diet Tied to Better Cognitive Function
New research adds to the growing body of evidence showing the cognitive and mental health benefits of eating a Mediterranean diet; one high in vegetables, whole grains, fish, and olive oil.
According to an analysis of data from two major eye disease studies, researchers found that participants who most closely adhered to a Mediterranean diet exhibited better cognitive function. Among these subjects, high fish and vegetable consumption appeared to have the greatest protective effect on cognition.
Researchers at the National Eye Institute (NEI), part of the National Institutes of Health, led the analysis of data from the Age-Related Eye Disease Study (AREDS) and AREDS2. They published their findings in the journal Alzheimer’s and Dementia.
“We do not always pay attention to our diets. We need to explore how nutrition affects the brain and the eye,” said Emily Chew, M.D., director of the NEI Division of Epidemiology and Clinical Applications and lead author of the studies.
The research team looked at the effects of nine components of the Mediterranean diet on cognitive function. The Mediterranean 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 AREDS and AREDS2 studies assessed the effects of vitamins on age-related macular degeneration (AMD), which damages the light-sensitive retina. AREDS included about 4,000 participants with and without age-related macular degeneration, and AREDS2 involved about 4,000 participants with age-related macular degeneration.
The research team evaluated the AREDS and AREDS2 subjects regarding their diet at the start of the studies. The AREDS study tested participants’ cognitive function at five years, while AREDS2 tested cognitive function in subjects at baseline and again two, four, and 10 years later.
The researchers used standardized tests based on the Modified Mini-Mental State Examination to measure participants’ cognitive function as well as other tests. The team evaluated diet with a questionnaire that asked participants their average consumption of each Mediterranean diet component during the previous year.
The findings reveal that participants with the greatest adherence to the Mediterranean diet had the lowest risk of cognitive impairment. High 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.
The numerical differences in cognitive function scores between participants with the highest versus lowest adherence to a Mediterranean diet were relatively small, meaning that individuals likely won’t see a difference in daily function. But at a population level, the effects clearly show that cognition and neural health depend on diet.
The research team 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 greater decline than those without the gene. Alzheimer’s is an irreversible progressive brain disorder.
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’s disease.
Previous studies have shown that eating a Mediterranean diet can slow memory loss and reduce loss of brain volume in older adults.
Source: NIH/ National Eye Institute
Pedersen, T. (2020). Mediterranean Diet Tied to Better Cognitive Function. Psych Central. Retrieved on September 19, 2020, from https://psychcentral.com/news/2020/04/15/mediterranean-diet-tied-to-better-cognitive-function/155744.html