Association of Dietary Live Microbes and Nondietary Prebiotic/Probiotic Intake With Cognitive Function in Older Adults: Evidence From NHANES.

Background: The current study aims to examine association of dietary live microbes and nondietary prebiotic/probiotic intake with cognitive function among older U.S. adults, examining heterogeneity across demographic characteristics and diseases.

Methods: Participants from the National Health and Nutrition Examination Survey 2011-2014 cycles were selected and administered 3 cognitive function tests: the Consortium to Establish a Registry for Alzheimer's Disease Word Learning subtest (CERAD W-L, including immediate [CERAD-IRT] and delayed [CERAD-DRT] memory), the Animal Fluency Test (AFT), and the Digit Symbol Substitution Test (DSST). Test-specific and global cognition z-score was created. Based on their estimated dietary live microbes intake, participants were categorized into three groups: low, medium, and high. Text mining was employed to identify nondietary prebiotic/probiotic usage by examining the names and ingredients of dietary supplements or drugs.

Results: Participants in the medium (including AFT) and high (including global cognition, AFT, DSST, and CERAD-IRT) dietary live microbes intake group had significantly higher z-score of cognitive function compared to those in the low intake group. Among participants with cardiovascular disease history, nondietary prebiotic intake was associated with higher z-score in global cognition and CERAD-DRT compared to those who did not consume prebiotic. Additionally, probiotic intake was linked to higher z-score in global cognition, AFT, and DSST, particularly in participants with diabetes mellitus or hypertension.

Conclusions: Our study suggests that the intake of dietary live microbes and nondietary probiotic/prebiotic was associated with better cognitive function in older adults, particularly in specific disease states.