Higher Energy-Dense Food Intake is Linked to Cognitive Decline in Schoolchildren: The Moderating Role of Cardiorespiratory Fitness and Emotional Well-Being (PACH study)

Objective. Cognitive skills are essential for learning, problem-solving, and adapting to new information and daily life situations, allowing children to process and retain knowledge efficiently. Well-developed cognitive functions also contribute to emotional regulation, decision-making, and academic achievement, forming the basis for future personal and professional growth. This study aims to examine the effects of dietary habits, emotional status, and cardiorespiratory fitness (CRF) on cognitive functions in schoolchildren.
Materials and methods. Prospective longitudinal study involved 106 pupils aged 8-10 years (53.5% boys and 46.5% girls). Over 3 consecutive years dietary habits and emotional well-being were assessed by food frequency survey and revised children's anxiety and depression scale 25 (RCADS25), accordingly. Cognitive functions were determined by Vienna test system tests – determination test (DT), visual pursuit test (VPT), reaction test (RT). For determination of CRF level pupils performed Kasch Pulse Recovery test. Latent growth curve model was used to test whether changes in cognitive functions over time are linear. Only cognitive function variables with a Comparative fit index of 0.90 or higher were included in the linear mixed model (LMM) analysis to identify influencing factors. Principal component analysis (PCA) was used to reduce food group dimensionality by creating principal components (PC). PCs were included in LMM.
Results. PCA identified 2 PCs, where PC 1 represented energy dense foods, PC 2 – nutrient dense foods. LMM showed that PC2 had no effect on cognitive functions, while PC1 represented by food rich in carbohydrates showed to have an association. The increase of PC 1 score was associated with decreased correct responses in DT (mean estimate -5.72), but there was no effect on RT motor time (p>0.005). RCADS25 score played a moderating role between PC1 and DT correct responses, and between PC1 and RT motor time. The increase of PC1 score was associated with decrease in VPT score (mean estimate -1.70). CRF was identified as moderator between PC1 and VPT score.
Conclusions. Higher consumption of energy-dense foods was associated with poorer results in most of the cognitive function tests and a decline in cognitive functions. CRF level and emotional well-being played a moderating role in relationship between PC1 and cognitive functions. Findings highlight the importance of prudent eating habits, CRF and emotional health management in early childhood to support cognitive development.