Greater ultra-processed/unhealthy dietary pattern adherence and lower healthy/traditional dietary pattern adherence were associated with a higher prevalence of an adverse mental health indicator among school-attending Brazilian adolescents in both 2015 and 2019 PeNSE surveys.
Key Findings
Results
Lower adherence to an ultra-processed/unhealthy dietary pattern was associated with a lower prevalence of adverse mental health indicators in both survey years.
In 2015, the lowest adherence quartile (Q1) of the ultra-processed/unhealthy pattern had an adjusted PR of 0.85 (95% CI: 0.73–0.98) compared with the highest quartile (Q4).
In 2019, the lowest adherence quartile (Q1) of the ultra-processed/unhealthy pattern had an adjusted PR of 0.81 (95% CI: 0.76–0.86) compared with Q4.
No between-survey heterogeneity was detected for the ultra-processed/unhealthy pattern, indicating consistency across survey editions.
Sensitivity analyses including continuous, ordinal, alternative-outcome, weighted-PCA, and E-value analyses were directionally consistent with the primary results.
Results
Lower adherence to a healthy/traditional dietary pattern was associated with a higher prevalence of adverse mental health indicators in both survey years.
In 2015, the lowest adherence quartile (Q1) of the healthy/traditional pattern had an adjusted PR of 1.75 (95% CI: 1.45–2.10) compared with Q4.
In 2019, the lowest adherence quartile (Q1) of the healthy/traditional pattern had an adjusted PR of 1.34 (95% CI: 1.26–1.42) compared with Q4.
The healthy/traditional pattern estimates differed in magnitude between the two survey years, indicating between-survey heterogeneity for this pattern.
Despite differing magnitudes, sensitivity analyses remained directionally consistent across both surveys.
Methods
Principal component analysis yielded two dietary patterns in each survey edition: an ultra-processed/unhealthy pattern and a healthy/traditional pattern.
The study analyzed two independent cross-sectional surveys from the Brazilian National Survey of School Health (PeNSE) conducted in 2015 and 2019.
The sample was restricted to school-attending adolescents aged 13–17 years, with the 2015 analysis restricted to Sample 2.
Two dietary patterns were empirically derived using principal component analysis in each survey edition independently.
The primary outcome was membership in the highest category of a non-diagnostic, survey-specific composite score of adverse mental health-related indicators based on weighted distribution.
Methods
Survey-weighted modified Poisson regression was used to estimate adjusted prevalence ratios, with multiple sensitivity analyses conducted to assess robustness.
Adjusted prevalence ratios (PRs) were estimated using survey-weighted modified Poisson regression.
Robustness was assessed through continuous, ordinal, between-survey heterogeneity, alternative-outcome, weighted-PCA, and E-value analyses.
Between-survey heterogeneity was formally tested, revealing no heterogeneity for the ultra-processed/unhealthy pattern but heterogeneity in magnitude for the healthy/traditional pattern.
The two surveys were analyzed separately because they were independent cross-sectional surveys with edition-specific measures.
Discussion
The study's cross-sectional design and use of edition-specific measures preclude conclusions about temporality, causality, or temporal change in invariant constructs.
The authors explicitly state: 'Because the surveys were cross-sectional and used edition-specific measures, these findings do not establish temporality, causality, or temporal change in invariant constructs.'
The mental health outcome was described as a 'non-diagnostic, survey-specific composite score of adverse mental health-related indicators,' limiting generalizability of the mental health measure.
The dietary patterns were derived independently in each survey edition, meaning the patterns themselves may not be directly comparable across years.
The study was limited to school-attending adolescents, which may not represent all Brazilian adolescents in that age group.
What This Means
This research examined the relationship between eating habits and mental health among Brazilian teenagers using data from two large national school health surveys conducted in 2015 and 2019. The researchers identified two main dietary patterns among adolescents aged 13–17: one characterized by ultra-processed and unhealthy foods, and another characterized by healthy and traditional foods. They then looked at how closely following each pattern related to a composite measure of adverse mental health indicators.
The findings suggest that teenagers who ate more ultra-processed and unhealthy foods had a higher likelihood of experiencing adverse mental health indicators, while those who ate more healthy and traditional foods had a lower likelihood. These associations were found in both survey years and held up across multiple additional statistical tests designed to check whether the results were robust. The link between the unhealthy dietary pattern and mental health was consistent in size across both years, while the link for the healthy/traditional pattern was in the same direction but varied somewhat in strength between 2015 and 2019.
This research suggests that dietary patterns may be meaningfully connected to adolescent mental health at a population level in Brazil, and that this connection appeared consistently across two separate surveys spanning several years. However, because both surveys captured information at a single point in time, it is not possible to determine whether diet influenced mental health, mental health influenced diet, or some other factor influenced both. The mental health measure used was also a survey-specific composite score rather than a clinical diagnosis, so these findings should be interpreted as highlighting a potential association worth further investigation rather than establishing a definitive causal link.
Vasconcellos L, Costa W, Sena A, Grippa W, Neto L, Valenti V, et al.. (2026). Dietary Patterns and an Adverse Mental Health Indicator Among School-Attending Brazilian Adolescents: Analyses of the 2015 and 2019 PeNSE Surveys.. Nutrients. https://doi.org/10.3390/nu18172781