The possible association of dietary fiber intake with the incidence of depressive symptoms in the Korean population.

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.