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 the associations between dietary intakes of total,vegetable,fruit,and cereal fiber and depressive symptoms.Methods:Data were from the 2007-2008,2009-2010,2011-2012,and 2013-2014National Health and Nutrition Examination Survey in this cross-sectional study.Adults aged 20 years or older were included.Demographic characteristic,lifestyle,physical information,blood pressure,blood glucose,and history of disease were obtained through questionnaire,physical examination,and laboratory examination.Dietary data were obtained through two 24-h dietary recall interviews.Depressive symptoms were assessed using Patient Health Questionnaire.Student's t-test,chi-square test,and rank-sum test were performed to compare the mean levels of continuous variables or the percentages of categorical variables between subjects with and without depressive symptoms.Univariate,age-and gender-adjusted,and multivariate logistic regression models were conducted to evaluate the associations among dietary intakes of total,vegetable,fruit,and cereal fiber and depressive symptoms.Restricted cubic spline models were applied to evaluate the dose-response relationships.Stratified analyses were performed by age?<45y,45 to 64y and>64y?,gender?male and female?,and total energy intake?low,normal and high level?to assess the above-mentioned associations.Results:A total of 16807 adults aged 20 years or older were included in this study.The prevalence of depressive symptoms was 9.41%.Dietary intakes of total,vegetable,fruit,and cereal fiber were inversely associated with depressive symptoms in univariate logistic regression models,and the corresponding odds ratios?ORs?and 95%confidence intervals?CIs?of depressive symptoms were 0.35?0.28,0.43?,0.42?0.33,0.55?,0.42?0.32,0.56?,and 0.56?0.45,0.70?,respectively.The above-mentioned significant inverse associations were also found in age-and gender-adjusted models,and the corresponding ORs?95%CIs?of depressive symptoms were 0.38?0.30,0.49?,0.43?0.33,0.55?,0.42?0.31,0.56?,and 0.62?0.49,0.78?,respectively.In multivariate-adjusted models adjusting for age,sex,race,marital status,educational level,annual household income,and body mass index,total energy intake,smoking status,alcohol consumption,work physical activity,recreational physical activity,hypertension,and diabetes,dietary intakes of total,vegetable,and fruit fiber were inversely associated with depressive symptoms,and the corresponding ORs?95%CIs?of depressive symptoms were 0.59?0.44,0.79?,0.58?0.45,0.76?,and 0.64?0.45,0.92?,respectively.No significant association of cereal fiber intake with depressive symptoms was found?P=0.46?.In stratified analyses by age,gender,and total energy intake,total fiber intake was inversely associated with depressive symptoms in groups aged less than 45 years and aged 45 to 64 years,male,female,and low and normal total energy intake groups.Vegetable fiber intake was inversely associated with depressive symptoms in groups aged less than 45 years and more than 64 years,male,female,and groups with low and normal total energy intake.Fruit fiber intake was inversely associated with depressive symptoms in groups aged more than 64 years,female,and group with normal total energy intake.Dose-response analyses found that the risk of depressive symptoms was associated with total(P _{for nonlinearity}=0.18),vegetable(P _{for nonlinearity}=0.22)and fruit fiber(P _{for nonlinearity}=0.07)intakes in a linear manner.As total fiber intake increased,the OR of depressive symptoms sharply dropped,reaching a relatively low level approximately in23 g/d[OR=0.43,95%CI:?0.27,0.69?],and then slowly dropped.For vegetable and fruit fiber,the ORs of depressive symptoms sharply decreased as vegetable and fruit fiber intakes increased,reaching a relatively low level with vegetable fiber intake at 6 g/d[OR=0.62,95%CI:?0.49,0.79?]and fruit fiber intake at 5 g/d[OR=0.65,95%CI:?0.47,0.91?].Conclusions:Total fiber,vegetable fiber and fruit fiber intakes may be inversely associated with depressive symptoms.Further prospective studies and experimental studies are needed to confirm our findings.