A new study by IRB CatSud and ISGlobal links teenagers’ nutrition with emotional wellbeing, cognitive performance, and long‑term decision‑making
Adolescence is a key period for brain development, and eating habits play an essential role in this process. A new study led by the Institut de Recerca Biomèdica Catalunya Sud (Southern Catalonia Biomedical Reseach Institute – IRB CatSud, formerly IISPV), includes the participation of the Barcelona Institute for Global Health (ISGlobal), a centre supported by the “la Caixa” Foundation, shows that eating ultra‑processed foods is linked to more emotional and behavioural difficulties. On the other hand, following the Mediterranean diet is associated with better executive function. The study, titled Dietary Patterns and Neuropsychological Function in Adolescents: A Cross-sectional and Longitudinal Study, has been published in BMC Medicine.
The study, carried out by the Clinical and Epidemiological Neuroscience Research Group (NeuroÈpia) at IRB CatSud. The research analyses data from a sample of 653 adolescents aged 12 to 16 from the metropolitan area of Barcelona (Smart-Snack study). It highlights the importance of nutrition during adolescence, a stage where the brain is still developing, especially the prefrontal cortex, which is involved in decision‑making and impulse control.
Eating habits were assessed using food‑frequency questionnaires that measured adherence to the Mediterranean diet and the intake of ultra‑processed foods. Neuropsychological function was evaluated through standardised computerised tests that measured attention, working memory, fluid intelligence, decision‑making, and emotional recognition. Behavioural and emotional outcomes were also assessed using validated questionnaires.
Opposite effects on the teen brain
The results show clear differences between the two eating patterns. According to Alexios Manidis, the lead researcher, a higher intake of ultra‑processed foods—such as sugary drinks, industrial pastries, and ultra-processed meats—is linked to poorer performance in emotional recognition and sustained attention. Teenagers who consume more ultra‑processed foods also report more symptoms of anxiety and depression, as well as more behavioural problems.
In contrast, greater adherence to the Mediterranean diet—rich in fruits, vegetables, legumes, and olive oil—is linked to fewer behavioural problems and better scores in executive attention.
However, in the six-month follow-up, only initial ultra-processed food consumption showed longitudinal associations with internalizing symptoms and decision-making, while Mediterranean diet adherence showed no longitudinal effects. “This may suggest that Mediterranean diet benefits require ongoing adherence, while the effects of ultra-processed foods may be more persistent,” comments Manidis, reinforcing the importance of maintaining healthy habits consistently.
Objective validation through biomarkers
The study also analysed urinary biomarkers in a subsample of 257 participants. The results show that adolescents who consume more ultra‑processed foods have fewer compounds from plant‑based foods and more compounds linked to food processing, confirming the reliability of dietary questionnaires.
Christopher Papandreou, Assistant Professor at the Hellenic Mediterranean University (Crete, Greece) and senior co-author of the study, notes that “teenagers’ diets are shifting towards ultra-processed foods” and warns that this change “may be contributing to the rise in mental health problems among young people”.
Jordi Julvez, head researcher of the NeuroÈpia Research Group at the IRB CatSud and ISGlobal, reminds us that “adolescence is a period of great brain reorganisation” and explains that diet “can influence how teenagers regulate their emotions and make complex decisions”.
The researchers conclude that future strategies, such as replacing processed snacks in schools with nutrient‑dense options like nuts and fresh fruit, could be effective in improving emotional regulation and cognitive function in the long term.
Bibliographic reference of the study
Manidis, A., Ayala-Aldana, N., Bernardo-Castro, S., Pinar-Martí, A., Galkina, P., Fernández-Barrés, S., Ramirez-Carrasco, P., Lamuela-Raventós, R. M., Papandreou, C., & Julvez, J. (2026). Dietary patterns and neuropsychological function in adolescents: a cross-sectional and longitudinal study. BMC Medicine, 10.1186/s12916-026-04658-6. Advance online publication. https://doi.org/10.1186/s12916-026-04658-6
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