Healthy dietary patterns in relation to cognitive performance and Alzheimer's disease mortality.

Background: Dietary factors play a major role in cognitive aging, but few studies have assessed and compared the associations between specific dietary patterns and Alzheimer's disease (AD) mortality.

Methods: We included 27,773 U.S. participants (mean age = 59.8 years, 51.4 % female) from the National Health and Nutrition Examination Survey (NHANES) between 1998 and 2016, with follow-up for AD mortality until December 2019. Five dietary pattern scores were calculated utilizing one (1999-2002) or two repeated (2003-2016) 24hr dietary recalls, including the Healthy Eating Index (HEI-2015), the healthful plant-based diet index (hPDI), the alternate Mediterranean diet (aMED), the Dietary Approach to Stop Hypertension diet (DASH), and the Mediterranean-DASH Intervention for Neurodegeneration Delay diet (MIND) scores. We utilized Cox proportional hazard models to evaluate the associations of these dietary pattern scores with AD mortality.

Results: A total of 260 AD deaths occurred during a median follow-up of 9.8 years. Higher aMED score was associated with a lower risk of AD mortality (HR: 0.72, 95 % CI, 0.52-1.00, p-trend = 0.041). In a sub-sample of 2,713 participants in NHANES 2011-2014, 432 individuals had prevalent psychometric mild cognitive impairment (p-MCI). Higher aMED, MIND, HEI-2015, and hPDI were associated with lower odds of p-MCI. The potential contributors to these associations included higher intake levels of vegetables and nuts, moderate alcohol consumption, and lower intake level of sweets.

Conclusions: The Mediterranean dietary pattern was associated with more favorable cognitive outcomes among middle-aged and older adults, underscoring the importance of a healthy diet for long-term benefits in cognitive and brain health.