Adherence to a Mediterranean-type dietary pattern and cognitive decline in a community population

Abstract

Background: Many of the foods abundant in the traditional Mediterranean diet, such as vegetables and fish, have been associated with slower cognitive decline.

Objective: We investigated whether adherence to a Mediterranean dietary pattern or to the Healthy Eating Index-2005 (HEI-2005) is associated with cognitive change in older adults.

Design: This article is based on analyses of data from an ongoing longitudinal study in adults aged ≥65 y known as the Chicago Health and Aging Project (CHAP). CHAP participants (2280 blacks and 1510 whites) with ≥2 cognitive assessments were evaluated for adherence to 1) the Mediterranean dietary pattern (MedDiet; maximum score: 55) and 2) the HEI-2005 (maximum score: 100). For both scoring systems, higher scores connote greater adherence. Cognitive function was assessed at 3-y intervals on the basis of a composite measure of global cognition. Linear mixed models were used to examine the association of dietary scores to change in cognitive function. Mean follow-up time was 7.6 y.

Results: Mean (±SD) scores for participants were 28.2 ± 0.1 for the MedDiet and 61.2 ± 9.6 for the HEI-2005. White participants had higher energy-adjusted MedDiet scores but lower HEI-2005 scores than did black participants. Higher MedDiet scores were associated with slower rates of cognitive decline (β = +0.0014 per 1-point increase, SEE = 0.0004, P = 0.0004) after adjustment for age, sex, race, education, participation in cognitive activities, and energy. No such associations were observed for HEI-2005 scores.

Conclusion: The Mediterranean dietary pattern as captured by the MedDiet scoring system may reduce the rate of cognitive decline with older age.

FIGURE 1.

Rates of changes in global cognitive scores over time as a function of MedDiet score tertiles (left), MedDiet wine score tertiles (middle), and Healthy Eating Index–2005 (HEI-2005) score tertiles (right). The first tertile is represented by dashed lines, the second by solid plus dashed lines, and the third by solid lines. Rates of change among Chicago Health and Aging Project (CHAP) participants were significantly associated with those whose MedDiet scores were in the highest or third tertile (solid lines; β = −0.0171, SEE = 0.0046, P = 0.0002) but not with those whose scores were in the second tertile (β = −0.0079, SEE = 0.0045, P = 0.075). Similarly, those whose MedDiet wine scores were in the third tertile experienced significantly slower rates of cognitive decline (β = −0.0106, SEE = 0.0046, P = 0.021) but not those whose scores were in the second tertile (β = −0.0063, SEE = 0.0045, P = 0.156). There were no significant associations in rates of change in cognitive scores between CHAP persons categorized by HEI-2005 tertiles (for the third tertile: β = −0.0171, SEE =0.0046, P = 0.0002; for the second tertile: β = −0.0021, SEE = 0.0042, P = 0.621).