Adolescents who consume a greater amount of ultra-processed foods and drinks have more difficulties in terms of mental health, according to new research carried out by the Institute of Environmental Science and Technology of the Universitat Autònoma de Barcelona (ICTA-UAB) and the Girona Biomedical Research Institute (IDIBGI), which analyses the habits of five hundred Spanish adolescents aged between 13 and 18.
The purchase of ultra-processed foods and drinks has tripled in Spain in recent decades, with adolescents being the biggest consumers of these types of industrial products characterized by their low nutrient content (e.g., proteins and fibre), high energy densities (e.g. saturated fats and added sugars), and the presence of additives (e.g. colourings, flavour enhancers) that make them very attractive, tasty and addictive.
The study, which also involves the Faculty of Medicine and the Institut de Neurociències, both at the UAB, and the Barcelona Public Health Agency, analyses the relationship between the intake of ultra-processed foods and psychosocial difficulties - such as low mood, feelings of anxiety, attentional problems - and other behavioral symptoms, taking into account the daily consumption of fruit and vegetables and the weekly physical activity of the participants, variables that have proven to have positive effects on mental health.
The research showed a direct association between high consumption of ultra-processed foods and beverages, emotional distress and behavioral problems, with the association with low mood reported by adolescent participants being most significant.
Adolescents reported an average consumption of 7.7 ultra-processed foods on the previous day, with higher consumption among teenage boys (8.6 ultra-processed foods for boys compared to 7 ultra-processed foods for girls). Most participants reported consuming sausages, biscuits and processed meats (50-60%), chocolate products, snacks, chocolate drinks and sauces (40-50%), and flavoured yoghurts, processed breads and pastries, sugary cereals, soft drinks, packaged fruit juices and processed crisps (30-40%).
Regarding fruit and vegetable consumption, adolescents reported an average consumption of 1.93 servings per day, far from the recommended five servings per day, and reported physical activity on an average of 2.9 days per week. While consumption of fruit and vegetables was higher among adolescent girls (2 servings compared to 1.7 servings for boys), boys reported higher levels of physical activity (3.6 days compared to 2.3 days for girls).
In addition, 26.2% of the participants presented some kind of psychosocial problem, 33.9% related to emotional distress, mainly depression or anxiety, 9.5% related to attentional problems, and 3.9% related to behavioural problems. By gender, girls showed greater psychosocial problems in all areas (26.4% vs. 22.2%), especially in relation to low mood and feelings of anxiety, except for behavioural problems which were similar between the sexes.
"The association between the consumption of ultra-processed foods and mood and anxiety problems in adolescents is consistent with previous studies carried out on similar samples", explains Pietro Tonini, ICTA-UAB researcher and first author of the study together with Marta Reales from IDIBGI, and adds that the results obtained indicate that the relationship between the consumption of these products and attentional and behavioural problems should be studied more in depth.
The relationship between ultra-processed products and psychosocial problems is more marked among adolescent boys; this could be due to the hypothesis that they consume a greater amount of certain types of ultra-processed products, such as sugary and sweetened beverages (soft and energy drinks and packaged fruit juices) and processed meats, as well as the fact that they eat less fruit and vegetables."
Pietro Tonini, ICTA-UAB researcher and first author of the study
New insights on the association between genes, gut microbiota, and mental health