Efficacy of dietary interventions for functional constipation: a systematic review and network meta-analysis

The efficacy of dietary intervention in the treatment of functional constipation (FC) varies substantially across different studies.

This study aimed to compare the relative efficacy of various dietary interventions in patients with FC through network meta-analysis (NMA).

From the inception of the database until 20 August 2025, a systematic search was conducted in PubMed, Embase, Cochrane Library, and Web of Science. Randomized controlled trials (RCTs) were included to evaluate the efficacy of different dietary interventions on FC. A Bayesian framework was used for NMA, and surface under the cumulative ranking curve was employed for cumulative ranking; additionally, network regression, sensitivity, and subgroup analyses were conducted to explore the sources of between-study heterogeneity.

A total of 19 RCTs were included, with 73.7% of the studies having low risk of bias. For defecation frequency, fruit-based foods (category 1) were better than fiber supplements (moderate certainty), mineral water (low certainty), and placebo (moderate certainty). Multicomponent foods (category 1) were better than fiber supplements (low certainty), medicine (moderate certainty), and placebo (low certainty). Subgroup analyses suggested that mineral water may show relatively greater efficacy in studies with longer intervention duration. In terms of improving stool consistency, multicomponent foods (category 1) were superior to medicine (high certainty), vegetables with whole grains (moderate certainty), fiber supplements (moderate certainty), and placebo (high certainty). Fruit-based foods (category 1) were superior to vegetables with whole grains (moderate certainty) and placebo (high certainty). Regarding the severity of constipation, fruit-based foods (category 1) ranked first, superior to fiber supplements (moderate certainty) and placebo (moderate certainty).

Multicomponent foods and fruit-based foods appear to be among the more effective dietary intervention options for managing FC. Intervention duration may influence observed treatment effects. Future studies need to further integrate objective mechanistic biomarkers, in addition to standard clinical outcomes, to explore the potential mechanisms of dietary interventions for FC. This study was registered at PROSPERO as CRD420251134853.