A new study from the University of Agder in Norway, published in the journal Nutrients, suggests that what young children eat may significantly influence their mental health. The research, which examined data from 363 four-year-olds and their mothers, found that children who consumed fruits and vegetables more often exhibited fewer internalised behavioural issues — including anxiety, depression, and withdrawal — while those who ate more sweet and salty snacks showed greater difficulties with externalised problems like aggression and inattention.
“Mental health challenges are increasing worldwide. Identifying preventable factors for such challenges is important and will have the greatest impact if identified in young children,” the researchers wrote. The study underscores that early childhood mental health is critical for future school performance, social skills, and educational attainment, which in turn shape lifelong health and socioeconomic outcomes.
Diet and Behaviour: A Clear Link
The analysis drew on data from the Early Food for Future Health study in Norway, a randomised controlled trial originally designed to improve diet in infants aged six to 12 months. The researchers controlled for maternal education, financial difficulties, and maternal symptoms of depression and anxiety, yet the association between diet and child behaviour remained robust.
Specifically, children who ate vegetables and fruit more often showed lower levels of internalised problems, independent of these socioeconomic and parental factors. Conversely, a more frequent intake of sweet and salty snacks was linked to higher levels of “acting-out” behaviours, such as aggression and oppositional conduct.
Externalising behaviour problems are among the most common childhood adjustment issues and are the primary reason for referral to child and adolescent mental health services. The authors note that these behaviours often begin before age five and, if left unaddressed, can persist: around two-thirds of children who exhibit externalising problems between ages two and three continue to show high levels of similar challenges into school age.
“This shows the importance of identifying factors relevant to mental health early in life,” the study concluded.
The findings add to a growing body of research linking diet to mental health across Europe. For instance, a separate Spanish study recently found that the Mediterranean diet is associated with improved vaginal microbiome and fertility outcomes, highlighting the broad health benefits of whole foods. Meanwhile, the rising prevalence of mental health issues among young people has prompted policymakers to explore preventive measures, including dietary interventions.
The researchers emphasise that while the study does not prove causation, the strength of the association and the consistency with prior research suggest that improving children’s diets could be a cost-effective strategy for supporting mental well-being. As mental health problems continue to rise globally, identifying modifiable factors like diet becomes increasingly urgent.
The study’s authors call for further research to confirm these findings and to explore the mechanisms through which diet may influence behaviour, such as gut-brain interactions or nutrient effects on brain development. For now, they recommend that parents and caregivers prioritise fruits and vegetables while limiting sweet and salty snacks, particularly in early childhood.
