Real-World Fermented Food Consumption and Depression, Anxiety, and Stress Symptoms in a Southeast Asian University Population: A Cross-Sectional Study

Introduction Controlled psychobiotic trials suggest fermented foods may influence mental health via the microbiota-gut-brain axis. However, whether habitual consumption of diverse fermented foods in real-world Southeast Asian settings is associated with psychological symptoms remains unclear. This study examined the association between fermented food intake and depression, anxiety, and stress among Malaysian university students. Methods A cross-sectional online survey was conducted among 212 undergraduates at a public university in Malaysia. Fermented food intake, including traditional and commercial products, was assessed using a culturally adapted food frequency questionnaire and converted to servings/week. Psychological symptoms were measured using the validated Malay DASS-21. Multivariable logistic regression estimated adjusted Odds Ratios (aOR) for moderate-to-extremely severe symptoms per additional serving/week and across intake quartiles, adjusting for sociodemographic and health-related factors. Results Median fermented food intake was 2.0 servings/week. In fully adjusted models, intake was not significantly associated with moderate-to- extremely severe depression (aOR 1.04, 95% CI 0.92-1.16), anxiety (aOR 1.04, 95% CI 0.95-1.13), or stress (aOR 0.87, 95% CI 0.65-1.05). Quartile and spline analyses showed no consistent dose-response relationship. Discussion These findings suggest that typical real-world consumption of heterogeneous fermented foods may not replicate the psychobiotic effects observed in controlled intervention studies. Variability in microbial composition, modest intake levels, and non-clinical population context may limit detectable associations. Conclusion Habitual fermented food intake was not independently associated with psychological symptom severity in this Southeast Asian university sample, highlighting the need for culturally specific and mechanistically informed research in nutritional psychiatry.