Dietary fiber intake, depression, and anxiety: a systematic review and meta-analysis of epidemiologic studies

ABSTRACT

Background

Findings of previous studies on relationship between dietary fiber intake and depression were inconsistent. We performed a meta-analysis on the association of dietary fiber intake with depression and anxiety in epidemiologic studies.

Methods

We conducted a systematic search of electronic databases, up to May 2021. Data from 18 publications (12 cross-sectional, five cohort and one case–control studies) on dietary fiber consumption in relation to depression or anxiety were included. For depression, fifteen studies were conducted on adults and three others on adolescents. Anxiety was not included in the analysis, due to insufficient eligible studies.

Results

Total dietary fiber intake was associated with a 10% lower odds of depression (OR = 0.90; 95% confidence interval [CI]: 0.86, 0.95) in adults and a 57% lower odds (OR = 0.43, 95% CI: 0.32, 0.59) in adolescents. Dose–response meta-analysis revealed an inverse linear association between total dietary fiber intake and odd of depression in adults; such that each 5-g increase in total dietary fiber intake was associated with a 5% reduction in risk of depression (OR = 0.95; 95% CI: 0.94, 0.97). An inverse significant association was observed between intake of fiber from vegetables (OR = 0.73; 95% CI: 0.66, 0.82) and soluble fiber (OR = 0.80, 95% CI: 0.71, 0.91) and odds of depression. However, cereal fiber, fiber from fruits and insoluble fiber were marginally associated with a reduction in having depression.

Conclusions

High intake of dietary fiber was protectively associated with depression in adults, in a dose–response fashion.

KEYWORDS:

• Fiber
• depression
• systematic review
• meta-analysis
• anxiety
• dose–response
• cereal fiber
• fiber from vegetables

Acknowledgments

We wish to thank Dr. Khayyatzadeh who kindly responded to our request and sent the PDF of his study.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available on request from the corresponding author (Dr. Parvane Saneei). The data are not publicly available due to (some of containing information has not been still published).

Additional information

Funding

The financial support for conception, design, data analysis, and manuscript drafting comes from Isfahan University of Medical Sciences, Isfahan, Iran.

Notes on contributors

Faezeh Saghafian

FS contributed in conception, design, statistical analyses, data interpretation, and manuscript drafting. All authors approved the final manuscript for submission.

Maryam Hajishafiee

MH contributed in conception, design, statistical analyses, data interpretation, and manuscript drafting. All authors approved the final manuscript for submission.

Parisa Rouhani

PR contributed in conception, design, statistical analyses, data interpretation, and manuscript drafting. All authors approved the final manuscript for submission.

Parvane Saneei

PS contributed in conception, design, statistical analyses, data interpretation, and manuscript drafting. All authors approved the final manuscript for submission.