(PTFS12-03-25) Effects of Soluble Corn Fiber Consumption on Cognitive Function and Gastrointestinal Microbiota

Objectives: This study evaluated the effects of soluble corn fiber (SCF) on cognition, gastrointestinal (GI) microbiota composition, and fermentation end-products, with pre-defined aims to investigate GI microbiota-dependent mechanisms by which SCF consumption may underpin cognitive performance.

Methods: This randomized, double-blind, crossover trial included 42 healthy adults (45-75 yr) asked to consume maltodextrin (CON, 22 g/d) or SCF (18 g/d fiber) for 4 weeks, separated by a 4-week washout in a counterbalanced order. Outcome assessments included cognitive control (flanker task), GI microbiota and metabolome, and GI tolerance symptoms. Additional exploratory in vitro and genomic analyses characterized microbial species and genes facilitating SCF fermentation in the full cohort and in select responders (n=3) and non-responders (n=3).

Results: SCF consumption improved reaction times (RT) for congruent (P = 0.002) and incongruent (P < 0.001) task conditions of the flanker task, compared to CON. Faster congruent RT was correlated with greater fecal concentrations of acetate (ρ = -0.33, P = 0.048) and propionate (ρ = -0.36, P = 0.03). Parabacteroides relative abundance was enriched with SCF (FDR-adj P < 0.001) and correlated with acetate (ρ = 0.34, P = 0.04) and propionate (ρ = 0.27, P = 0.1). In vitro culturing confirmed P. distasonis (Pd) growth on SCF after an extended lag phase, with a comparable growth rate (µ, log OD₆₀₀/hr) to glucose and maltodextrin. PICRUSt2 differential analysis using LinDA identified enrichment of carbohydrate metabolism KEGG metabolic pathways following SCF consumption (FDR-adj P < 0.05), while MaAsLin2 analysis revealed 2,701 differentially associated KEGG Orthologs (KOs), including carbohydrate-active (CA) KOs (FDR-adj P < 0.05). Shotgun metagenomic analysis of responders confirmed the presence of CA genes linked to Pd.

Conclusions: SCF consumption improved attentional inhibition and increased Parabacteroides relative abundance. In vitro culturing confirmed Pd utilization of SCF. Acetate and propionate concentrations were correlated with Parabacteroides abundance and inversely correlated with flanker response times, suggesting a link between GI microbial activity and cognitive performance.

Funding Sources: Tate & Lyle Ingredients Americas LLC