Objectives: The aim of this study was to examine the association of dietary protein intake and protein sources with cognitive function in population aged 60 years and older.
Design: Cross-sectional study.
Setting: The National Health and Nutrition Examination Survey (NHANES) 2011-2014.
Participants: Non-institutionalized US adults aged 60 years and older.
Measurements: Cognitive functions were assessed by a series of cognitive tests. Dietary protein intake was assessed by two 24-hour dietary recall interviews. Linear regression analyses were used to assess the associations between quartiles of dietary protein intake and cognitive function.
Results: Protein intake was positively associated with cognitive function. In full-adjusted model, the significant association between dietary protein intake and Recall Test score was observed (quartile (Q) 2 versus Q1, β=0.24, 95%CI: 0.01 to 0.47); the association between protein intake and Animal Fluency test was significant (Q2 versus Q1, β=1.40, 95%CI: 0.51 to 2.29; Q4 versus Q1, β=1.42, 95%CI: 0.37 to 2.48); the positive associations with DSST score and Composite z-score were observed both in Q2 versus Q1 and Q3 versus Q1 of protein intake. Protein intake from total animal, total meat, eggs and legumes were associated with a better performance on certain cognitive tests. However, an adverse association between higher protein intake from milk and milk products and cognitive function was observed.
Conclusions: We found the positive associations of dietary protein intake and protein intake from total animal, total meat, eggs and legumes with cognitive function in adults aged 60 years and older, while higher milk and milk products were negatively associated with cognitive function.
Keywords: Dietary protein; NHANES; cognition; cross-sectional study; protein sources.