Adherence to the EAT-Lancet diet and change in cognitive functioning in older adults

Adherence to higher-quality diets has been linked to better cognitive function in older adults. Limited research exists on the EAT-Lancet diet, a healthy reference diet aligned with sustainability goals. This study examined the association between adherence to the EAT-Lancet diet and cognitive function and decline in older adults. Data from 1,371 participants aged 55–99 years from the Longitudinal Aging Study Amsterdam were analyzed. Adherence to the EAT-Lancet diet was assessed in 2014–2015 using a diet quality index based on a 238-item food frequency questionnaire. Cognitive domains—global cognition (MMSE), information processing speed (Coding task), episodic memory (15-Word Test), and executive function (Word Fluency)—were measured every three years (2011–2021) and converted to z-scores. Linear mixed models assessed associations between quintiles of adherence and cognitive function and decline (testing interaction with age), adjusting for demographic and lifestyle factors. Interaction by sex was tested. Higher adherence to the EAT-Lancet diet was associated with better executive function (Q5 vs. Q1, β = 0.19 (0.07;0.30), P-trend 0.002), but not with episodic memory, information processing speed or global cognition. Higher adherence was associated with slower decline in information processing speed (Q5, Q3 vs. Q1, β = 0.01 (0.00;0.02), P trend 0.005), with no associations for other domains. Higher adherence to the EAT-Lancet diet is associated with better executive function and slower decline in information processing speed in Dutch older adults.