Walnuts have been associated with neuroprotective effects against Alzheimer’s disease (AD), as studies have indicated that walnut extract may reduce amyloid beta protein-induced oxidative stress and cell death. New research sought to examine potential neuroprotective effects of walnut consumption using data from the cross-sectional National Health and Nutrition Examination Surveys (NHANES). 

Select participants from the initial NHANES survey (n=5,662) completed central nervous system (CNS) evaluation tests that included three measures of cognitive function: the simple reaction time test (SRTT), the symbol digit substitution test (SDST), and the single digit learning test (SDLT) for those aged 20–59 and the story recall test (SRT) and the digit symbol substitution test (DSST) for those aged ≥60 years. These participants also reported foods and beverages consumed during the past 24 hours at a mobile exam center and those who consumed walnuts were divided into consumption of walnuts with high certainty (WWHC) and walnuts with other nuts (WWON) groups. Compared to the control group, walnut consumption (either WWHC or WWON) had significant and positive associations with cognitive functions as measured by SSRT, SDST, and SDLT among those aged 20–59 and in SRT and DSST in those aged ≥60 years. With the exception of SDST, higher consumption of walnuts was linked to significantly faster response time compared to those who consumed no nuts. WWHC participants had the fastest response time compared to no nut consumers for SRTT and SDLT cognitive outcomes. 

These findings support previous studies that have shown walnuts to have neuroprotective properties and are encouraging for future controlled studies to further evaluate this relationship.