Neuroprotective Dietary Patterns and Longitudinal Changes in Cognitive Function in Older Adults

Background: Numerous studies have examined the association between neuroprotective diets and cognitive function during aging; however, these studies have produced divergent findings. Some studies find that greater adherence to these dietary patterns is associated with preserved cognition, whereas others find no effect.

Objective: The aim of this study was to examine the association of the Mediterranean, the Dietary Approach to Stop Hypertension (DASH), and Mediterranean-DASH Intervention for Neurodegeneration Delay (MIND) dietary patterns with global cognition over 4 waves of data from the Health and Retirement Study, a longitudinal panel study conducted at the University of Michigan.

Design: This is a longitudinal secondary data analysis using Health and Retirement Study data drawn from the Food Frequency Questionnaire completed as part of the Health Care and Nutrition Survey administered in 2013 to 2014, neuropsychological assessment data obtained from the Core questionnaire in 2014, 2016, 2018, and 2020, and demographic data from the Core questionnaire in 2014.

Participants/setting: Participants with total daily energy intake below 600 or 800 kcal and above 6000 and 8000 kcal for women and men, respectively, were excluded based on criteria from a similar study using the same dataset. In addition, participants with a diagnosis of dementia, Alzheimer disease, or stroke as of 2014 were excluded. There were 6154 participants in the Mediterranean diet and DASH diet analyses and 5143 participants in the MIND diet analyses.

Main outcome measure: A global cognitive measure incorporating immediate and delayed recall, serial 7s, and backward counting scores was calculated for each participant at each wave.

Statistical analysis: The primary analyses examined the association between each diet type and cognition over 4 waves using separate multilevel models that controlled for age, gender, self-rated health, years of education, total energy intake, weekly exercise, and body mass index.

Results: Mediterranean and DASH diet adherence were positively and significantly associated with baseline cognition and were associated with slower cognitive decline over a 6-year period. MIND diet adherence was positively and significantly correlated with baseline cognition but was not significantly associated with slower cognitive decline over a 6-year period. Cross-level interactions for adherence to each dietary pattern and cognitive change over time, computed with standardized diet scores, were as follows: Mediterranean diet (β = .03; P = .002), DASH diet (β = .04; P = .004), and MIND diet (β = .02; P = .094).

Conclusions: The Mediterranean, DASH, and MIND dietary patterns are associated with better cognitive performance at baseline and the Mediterranean and DASH diets were associated with slower cognitive decline over time. Adherence to the DASH diet had the greatest magnitude of association with baseline cognition and rate of cognitive change.