Objectives: This study investigates the effect of dietary fiber on the prevention of depressive symptoms.
Methods: In a cohort of 88,826 Korean adults (57,284 men and 31,542 women), we longitudinally evaluated the risk of depressive symptoms according to quartiles of dietary fiber intake for 5.8 years of follow-up. A food frequency questionnaire was used in evaluating dietary fiber intake. Depressive symptoms were assessed by the Center for Epidemiological Studies-Depression (CES-D) scale, in which CES-D ≥ 16 was defined as depressive symptoms. The Cox proportional hazards model was used to calculate the adjusted hazard ratio (HR) and 95% confidence intervals (CI) for depressive symptoms (adjusted HR [95% CI]). Subgroup analysis was performed for gender and BMI (≥25 or <25).
Result: In men, the risk of depressive symptoms significantly decreased with the increase of dietary fiber (quartile 1: reference, quartile 2: 0.93 [0.87-0.99], quartile 3: 0.91 [0.85-0.98] and quartile 4: 0.84 [0.77-0.92]). This association was more prominently observed in men with BMI ≥ 25 (quartile 1: reference, quartile 2: 0.95 [0.86-1.06], quartile 3: 0.88 [0.79-0.99] and quartile 4: 0.84 [0.73-0.97]). Women did not show a significant association between quartile groups of dietary fiber intake and the risk of depressive symptoms across subgroup analysis for BMI.
Conclusion: High intake of dietary fiber is potentially effective in reducing depressive symptoms in Korean men. The protective effect of dietary fiber on depressive symptoms may vary by gender and obesity.
Keywords: Dietary fiber; FFQ; cohort study; depression; depressive symptom; dietary pattern; gender; obesity.