To Örebro University

BACKGROUND: An increasing number of cross-sectional studies suggests that diet may impact memory and cognition in healthy older adults. However, randomized, controlled trials investigating the effects of whole-diet interventions on memory and cognition in healthy older adults are rather rare and conflicting results are often reported.

OBJECTIVE: Therefore, a systematic review was conducted to compile the current evidence regarding the potential effects of whole-diet interventions on 1) memory and, 2) other cognitive outcomes in older adults.

METHODS: Studies that reported on randomized, controlled trials with dietary interventions in healthy older adults (60 yrs. and older) were included. Studies utilizing supplements, single food items or trials in specific patient groups (ie neurodegenerative diagnoses) were excluded.

RESULTS: For the 23 included articles, the main outcomes examined fell into one or more of the following categories: cognitive task-based outcomes related to memory, other cognitive task-based outcomes, and additional outcomes related to cognitive function or disease risk. Three of the studies that investigated dietary interventions alone and two multi-domain study showed positive effects on memory function, whereas five multi-domain interventions and one intervention that focused on diet alone showed positive effects on other cognitive outcomes.

CONCLUSIONS: The effect of randomized, controlled whole-diet interventions on memory and cognitive function in healthy older adults is modest and inconclusive, highlighting the need for more well-designed, sufficiently powered studies. Furthermore, the potential mechanisms by which diet impacts cognition in healthy aging need to be elucidated.

REGISTRY AND REGISTRY NUMBER FOR SYSTEMATIC REVIEWS OR META-ANALYSES: This systematic review is registered in PROSPERO under ID CRD42022329759.