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

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 (beta = +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. Am J Clin Nutr 2011;93:601-7.