The relationship between unhealthy snacking at school and academic outcomes: a population study in Chilean schoolchildren.

OBJECTIVE We examined the association between unhealthy snacking at school and academic outcomes in students from the Santiago Metropolitan Region (Chile). DESIGN Cross-sectional population-based study. SETTING We measured the nutritional quality of snacks at school using an FFQ, and accounting for the amounts of saturated fat, fibre, sugar and salt in the foods, and academic outcomes using national standardized test scores in Language and Mathematics. Multivariate regression analyses modelled the relationship between unhealthy snacking at school (exposure), potential confounders and performance in Mathematics and Language (outcomes). SUBJECTS Random sample of 1073 students (13.1 (SD 2.3) years old) attending public, partially subsidized and private schools. RESULTS Fifty-six per cent of students ate items at snack time that were high in fat, sugar, salt and energy, and thus were considered to have unhealthy snaking. Thirty-six per cent and 8% were considered to have poor-to-fair and healthy snacking, respectively. Unhealthy snacking significantly lowered the odds of good academic performance in both domains. Students having unhealthy snacks were 56% less likely to pass in Language (fully adjusted OR = 0.44; 95% CI 0.23, 0.85) and 66% less likely to pass in Mathematics (fully adjusted OR = 0.34; 95% CI 0.19, 0.64) compared with students having healthy snack items. CONCLUSIONS Schoolchildren eating unhealthy foods at snack time had worse academic performance in Language and Mathematics, as measured by a standardized test. Although association does not imply causation, these findings support the notion that academic and health-related behaviours are linked. More research is needed on the effect of school health programmes on educational outcomes.