Association between moderate consumption of ultra-processed foods and elevated hair cortisol levels: A cross-sectional analysis from the ELSA-Brasil cohort

BACKGROUND: Ultra-processed foods (UPFs) are associated with metabolic disorders, mental health and stress-related behaviors. Chronic stress, marked by sustained cortisol elevation, may influence UPF intake. Hair cortisol is a reliable biomarker of long-term stress and enables a deeper understanding of this bidirectional association. OBJECTIVE: This study aimed to investigate the association between hair cortisol, a biomarker of chronic stress, and UPF consumption in the ELSA-Brasil cohort. METHODS: A cross-sectional analysis was performed on 2525 participants from the ELSA-Brasil cohort. Hair cortisol levels were categorized as low, normal, and high, and UPF consumption was expressed as the percentage of the total energy intake divided into tertiles. Multinomial logistic regression was performed to examine the association between cortisol levels and UPF consumption after adjusting for sociodemographic and behavioral factors. RESULTS: Individuals with high hair cortisol levels were 61 % more likely to be in the second tertile of UPF consumption (13.78-21.60 % of total energy intake) compared with the lowest tertile, even after adjustment for confounders. No significant association was observed between high cortisol levels and the highest UPF consumption in any tertile. These findings suggest a non-linear association, in which moderate UPF consumption may provoke a stronger physiological stress response than excessive intake. CONCLUSION: Moderate UPF consumption is significantly associated with elevated hair cortisol levels, emphasizing the importance of dietary and behavioral interventions to mitigate chronic stress. Reducing UPF intake, promoting increased consumption of unprocessed or minimally processed foods, and stress management strategies can be essential in addressing stress-related health outcomes.