Relation of DASH- and Mediterranean-like dietary patterns to cognitive decline in older persons

We examined whether accordance to the DASH (Dietary Approach to Stop Hypertension) and Mediterranean diets is associated with slower cognitive decline in a prospective Chicago cohort study of older persons, the Memory and Aging Project.

The sample comprised 826 Memory and Aging Project participants (aged 81.5 ± 7.1 years) who completed a 144-item food frequency questionnaire at baseline and 2 or more cognitive assessments over 4.1 years. Dietary scores were computed for accordance to the DASH diet (0-10) and the Mediterranean diet (MedDietScore) (0-55). For both, higher scores reflect greater accordance. Both patterns share at least 3 common food components. Cognitive function was assessed annually with 19 cognitive tests from which global cognitive scores and summary measures are computed.

The mean global cognitive score at baseline was 0.12 (range, -3.23 to 1.60) with an overall mean annual change in score of -0.08 standardized units. Only 13 participants had possible dementia. The mean DASH score was 4.1 (range, 1.0-8.5) and the MedDietScore was 31.3 (range, 18-46). In mixed models adjusted for covariates, a 1-unit difference in DASH score was associated with a slower rate of global cognitive decline by 0.007 standardized units (standard error of estimate = 0.003, p = 0.03). Similarly, a 1-unit-higher MedDietScore was associated with a slower rate of global cognitive decline by 0.002 standardized units (standard error of estimate = 0.001, p = 0.01).

These findings support the hypothesis that both the DASH and Mediterranean diet patterns are associated with slower rates of cognitive decline in the same cohort of older persons.