Effects of 2-year dietary and physical activity intervention on cognition in children-a nonrandomized controlled trial

Background and objective: We investigated the effects of a combined dietary and PA intervention on cognition in children and whether changes in diet quality, PA, sedentary behavior (SB), and sedentary time (ST) are associated with changes in cognition.

Methods: We conducted a 2-year nonrandomized controlled trial in 504 children aged 6-9 years at baseline. The children were allocated to a combined dietary and PA intervention group (n = 237) or a control group (n = 160) without blinding.

Interventions: The children and their parents allocated to the intervention group had six dietary counseling sessions of 30-45 min and six PA counseling sessions of 30-45 min during the 2-year intervention period. The children were also encouraged to participate in after-school exercise clubs. Cognition was assessed by the Raven's Colored Progressive Matrices. We assessed dietary factors by 4 days food records and computed the Baltic Sea Diet Score (BSDS) as a measure of diet quality. PA and ST were assessed by a combined heart rate and body movement monitor, types of PA and SB by a questionnaire.

Results: The intervention had no effect on cognition. Increased BSDS and consumption of low-fat milk and decreased consumption of red meat and sausages were associated with improved cognition over 2 years. Increased organized sports, ST, and reading were positively, while unsupervised PA, computer use, and writing were negatively associated with cognition.

Conclusion: Combined dietary and PA intervention had no effect on cognition. Improved diet quality and increased organized sports and reading were associated with improved cognition.