NIE study finds diet may help preserve cognitive function

Adherence to the Mediterranean diet – high in vegetables, whole grains, fish, and olive oil – is associated with higher cognitive function, and specific aspects of that diet may play a role in slowing cognitive decline, according to a study conducted by the National Eye Institute (NEI), part of the National Institutes of Health (NIH). The findings were epublished on April 13 by Alzheimers & Dementia.

NIE researchers led the analysis of data from two major eye disease studies, the Age-Related Eye Disease Study (AREDS) and AREDS2, which looked at the effect of vitamins over time on age-related macular degeneration (AMD), which damages the light-sensitive retina. AREDS included about 4,000 participants, and AREDS2 included about 4,000 participants with AMD.

The researchers assessed diet with a questionnaire that asked participants their average consumption of each Mediterranean diet component over the previous year. Participants with the greatest adherence to the Mediterranean diet had the lowest risk of cognitive impairment, which was assessed using standardized cognitive tests. 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 over time.

“We do not always pay attention to our diets. We need to explore how nutrition affects the brain and the eye” said Emily Chew, MD, director of the NEI Division of Epidemiology and Clinical Applications and lead author of the studies.

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 diet-related difference in daily function. But at a population level, the effects clearly suggest that cognition and neural health are associated with 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 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 diet on cognition are independent of genetic risk for Alzheimer’s disease.

The AREDS and AREDS2 studies were supported by the NEI Intramural Research Program. Additional research funds were provided by the NIH Office of Dietary Supplements, the National Center for Complementary and Integrative Health, the National Institute on Aging, the National Heart, Lung, and Blood Institute, and the National Institute of Neurological Disorders and Stroke.

Read more: https://www.nei.nih.gov/about/news-and-events/news/diet-may-help-preserv...

Read the study abstract: https://alz-journals.onlinelibrary.wiley.com/doi/abs/10.1002/alz.12077