Dietary fiber intake and depressive symptoms in Japanese employees: The Furukawa Nutrition and Health Study

Abstract Objective Dietary fiber may play a favorable role in mood through gut microbiota, but epidemiologic evidence linking mood to dietary fiber intake is scarce in free-living populations. We investigated cross-sectionally the associations of dietary intakes of total, soluble, insoluble, and sources of fiber with depressive symptoms among Japanese workers. Methods Participants were 1977 employees ages 19–69 y. Dietary intake was assessed via a validated, brief self-administered diet history questionnaire. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale. Logistic regression was used to estimate odds ratios of depressive symptoms adjusted for a range of dietary and non-dietary potential confounders. Results Dietary fiber intake from vegetables and fruits was significantly inversely associated with depressive symptoms. The multivariable-adjusted odds ratios (95% confidence intervals) for the lowest through the highest tertile of vegetable and fruit fiber were 1.00 (reference), 0.80 (0.60–1.05), and 0.65 (0.45–0.95), respectively ( P for trend = 0.03). Dietary intake of total, soluble, insoluble, and cereal fiber was not associated with depressive symptoms. Conclusions Higher dietary fiber intake from vegetables and fruits may be associated with lower likelihood of having depressive symptoms.