Markers of a plant-based diet relate to memory and executive function in older adults
Background: Although it is widely known that consumption of plant-based foods is important for physical health, little is known about the relationship between plant-based foods and cognitive health. Emerging evidence suggests that some macronutrients may exert effects on cognition, but it is unclear which domains of cognition are involved; more importantly, it is unknown how a plant-based dietary pattern relates to cognition.Objective: To examine associations between a plant-based dietary pattern and multiple cognitive functions (i.e., memory and two aspects of executive function).Methods: Participants were 3,039 older adults who participated in the 2011-2014 waves of the National Health and Nutrition Examination Survey (NHANES). The present cross-sectional study used data on macronutrient intake from two 24-hour dietary interviews, as well as performance on tests of long-term memory and executive function (i.e., delayed word recall, digit symbol substitution test, and animal fluency). Principal component analysis was used to extract a dietary pattern consistent with a plant-based diet.Results: Greater adherence to a dietary pattern consistent with a plant-based diet was related to better performance on all cognitive tasks. Secondary analyses indicated that the associations between a plant-based dietary pattern and executive function accounted for the association between a plant-based dietary pattern and memory. Furthermore, this same plant-based dietary pattern was associated with reduced baseline inflammation in a separate dataset.Conclusions: Experimental manipulations are needed to determine the direction and timescale of the observed associations, but these results suggest that a plant-based diet is related to better cognition, especially through improved executive control. Future work should also attempt to extend these results by examining potential mechanisms underlying these associations, such as reduced inflammation.