Background/Objectives: Nutritional factors, including β-carotene with antioxidant and anti-inflammatory properties, are increasingly recognized for their role in mental health. However, population-based evidence on micronutrient intake and suicidal ideation among cancer survivors remains limited. This study investigated the association between dietary β-carotene intake and suicidal ideation among cancer survivors using nationally representative data. Methods: We conducted a cross-sectional analysis of 698 adult cancer survivors from the 2014–2020 Korea National Health and Nutrition Examination Survey. Suicidal ideation was assessed using the ninth item of the Patient Health Questionnaire. Dietary β-carotene intake was estimated using a 24-h dietary recall. Multivariable logistic regression models were applied with adjustment for sociodemographic, lifestyle, clinical, and dietary factors. Restricted cubic spline models were used to examine non-linear dose–response relationships. Subgroup analyses were performed by age, sex, and time since diagnosis. Results: Among participants, 6.3% reported suicidal ideation. Higher β-carotene intake was associated with lower odds of suicidal ideation (adjusted OR 0.68 per 1000 µg increase, 95% CI 0.50–0.93). Restricted cubic spline analyses revealed a significant U-shaped association (p for non-linearity = 0.030), indicating that the risk of suicidal ideation was lowest at an intermediate intake level (approximately 6000 µg/day). Stronger associations were observed among younger individuals and those ≥5 years post-diagnosis, with no significant interaction by sex. Conclusions: Dietary β-carotene intake showed a non-linear association with suicidal ideation, suggesting that both insufficient and excessive intake are associated with higher odds of suicidal ideation. These findings suggest the potential importance of optimal micronutrient balance in mental health and suggest that dietary factors may be associated with suicidal ideation among cancer survivors.
Tae et al. (Thu,) studied this question.