Introduction: Malnutrition and cognitive decline are prevalent and interrelated conditions in older adults, both contributing to increased disability, frailty, and mortality. Evidence suggests that poor nutritional status may accelerate cognitive deterioration, particularly in domains related to executive function and memory. However, longitudinal data in community-dwelling populations remain limited. This study aimed to examine both the cross-sectional and longitudinal associations between malnutrition and cognitive performance in a large sample of older adults.

Methods: Data were drawn from the TOLEDO Study of Ageing, involving 963 community-dwelling older adults. Malnutrition was defined according to the Global Leadership Initiative on Malnutrition (GLIM) criteria. Cognitive performance was assessed using a comprehensive neuropsychological battery including the Mini-Mental State Examination, the Short- and Long-Term Memory Recalling Test, the Boston Naming Test, a Verbal Fluency Test, Digit Span Forward, the Go/No-Go Test, the Edinburgh Handedness Inventory, the Luria Orders Test, a Clock Drawing Test, and a Serial Word Learning Test.

Results: In the cross-sectional analyses, malnutrition was significantly associated with a poorer performance in tests assessing frontal lobe function, including the Luria and Go/No-Go tasks. Longitudinally, malnutrition at the baseline predicted lower scores over time in frontal lobe tasks, the Boston Naming Test (BNT), and global cognitive functioning.

Conclusion: Malnutrition is associated with a poorer cognitive performance, particularly in executive function and naming tasks, both at the baseline and over time. These findings underscore the importance of early nutritional screening and intervention to support cognitive health in aging populations.