Exploration of the association between dietary fiber intake and depressive symptoms in adults.

OBJECTIVE
Current evidence on the association between dietary fiber intake and the risk of depressive symptoms is inconsistent. Thus, the purpose of the present study was to explore their association.

METHODS
Data from the National Health and Nutrition Examination Survey 2007 to 2014 were used in this cross-sectional study. Dietary data were obtained through two 24-h dietary recall interviews. Depressive symptoms were assessed using Patient Health Questionnaire. Logistic regression models and restricted cubic spline models were applied to evaluate the associations among dietary intakes of total, cereal, vegetable, and fruit fiber and depressive symptoms.

RESULTS
A total of 16 807 adults ages 20 y or older were included in this study. Dietary intakes of total, cereal, vegetable, and fruit fiber were inversely associated with depressive symptoms in unadjusted model and multivariate-adjusted model 1. In multivariate-adjusted model 2, the odds ratios (95% confidence intervals) of depressive symptoms were 0.59 (0.44-0.79), 0.90 (0.69-1.19), 0.58 (0.45-0.76), and 0.64 (0.45-0.92) for the highest versus lowest quartile of total, cereal, vegetable, and fruit fiber intakes, respectively. Dose-response analyses found that the risk of depressive symptoms was associated with total fiber intake in a nonlinear manner, whereas the relationships were linear with cereal, vegetable, and fruit fiber intakes.

CONCLUSIONS
Our study suggested that intakes of total fiber, vegetable fiber, and fruit fiber were inversely associated with depressive symptoms. Further larger prospective studies are needed to confirm our findings.