Dietary fiber is positively associated with cognitive control among prepubertal children

Background: Converging evidence now indicates that aerobic fitness and adiposity are key correlates of childhood cognitive function and brain health. However, the evidence relating dietary intake to executive function/cognitive control remains limited. Objective: The current study assessed cross-sectional associations between performance on an attentional inhibition task and dietary fatty acids (FAs), fiber, and overall diet quality among children aged 7-9 y (n = 65). Methods: Attentional inhibition was assessed by using a modified flanker task. Three-day food records were used to conduct nutrient-level analyses and to calculate diet quality (Healthy Eating Index-2005) scores. Results: Bivariate correlations revealed that socioeconomic status and sex were not related to task performance or diet measures. However, age, intelligence quotient (IQ), pubertal staging, maximal oxygen uptake (VO₂max), and percentage of fat mass (%fat mass) correlated with task accuracy. Hierarchical regression models were used to determine the relation between diet variables and task accuracy and reaction time across both congruent and incongruent trials of the flanker task. After adjustment of confounding variables (age, IQ, pubertal staging, (VO₂max, and %fat mass), congruent accuracy was positively associated with insoluble fiber (ß = 0.26, P = 0.03) and total dietary fiber (ß = 0.23, P = 0.05). Incongruent response accuracy was positively associated with insoluble fiber (ß = 0.35, P < 0.01), pectins (ß = 0.25, P = 0.04), and total dietary fiber (ß = 0.32, P < 0.01). Higher diet quality was related to lower accuracy interference (ß = 20.26, P = 0.03), whereas higher total FA intake was related to greater accuracy interference (ß = 0.24, P = 0.04). No statistically significant associations were observed between diet variables and reaction time measures. Conclusion: These results demonstrate that children's diet quality, specifically dietary fiber, is an important correlate of performance on a cognitive task requiring variable amounts of cognitive control.