Systematic review and meta-analysis: Foods, drinks and diets and their effect on chronic constipation in adults.

BACKGROUND: Dietary approaches are recommended for the management of chronic constipation. Until now, there has been no systematic review and meta-analysis on foods, drinks and diets in constipation. AIMS: To investigate the effect of foods, drinks and diets on response to treatment, stool output, gut transit time, symptoms, quality of life, adverse events and compliance in adults with chronic constipation via a systematic review and meta-analysis. METHODS: Studies were identified using electronic databases (12th July 2023). Intervention trials (randomised controlled trials [RCTs], non-randomised, uncontrolled) were included. Risk of bias was assessed using Cochrane 2.0 (RCTs) or JBI Critical Appraisal (uncontrolled trials). Data from RCTs only were synthesised using risk ratios (RRs), mean differences (MDs), standardised mean differences (95% CI) using random-effects. RESULTS: We included 23 studies (17 RCTs, 6 uncontrolled; 1714 participants): kiwifruit (n = 7), high-mineral water (n = 4), prunes (n = 2), rye bread (n = 2), mango, fig, cereal, oat bran, yoghurt, water supplementation, prune juice, high-fibre diet, no-fibre diet (n = 1). Fruits resulted in higher stool frequency than psyllium (MD: +0.36 bowel movements [BM]/week, [0.25-0.48], n = 232), kiwifruits in particular (MD: +0.36 BM/week, [0.24-0.48], n = 192); there was no difference for prunes compared with psyllium. Rye bread resulted in higher stool frequency than white bread (MD: +0.43 BM/week, [0.03-0.83], n = 48). High-mineral water resulted in higher response to treatment than low-mineral water (RR: 1.47, [1.20-1.81], n = 539). CONCLUSIONS: Fruits and rye bread may improve certain constipation-related outcomes. There is a scarcity of evidence on foods, drinks and diets in constipation and further RCTs are needed.