First Evidence-Based Dietary Guidelines for Chronic Constipation Released

Chronic constipation affects approximately 10% of the global population, significantly reducing quality of life and imposing substantial costs on healthcare systems. Despite near-universal patient attempts to manage symptoms through dietary changes, over half remain dissatisfied with current treatments. Existing clinical guidelines have been limited, vague, or unsupported by robust evidence, creating a critical need for comprehensive, evidence-based dietary recommendations.

To address this gap, researchers from King's College London and collaborating institutions developed the first dedicated dietary guidelines for chronic constipation in adults under the British Dietetic Association. A seven-member multidisciplinary Guideline Steering Committee oversaw the project, which encompassed four pre-registered systematic reviews and meta-analyses examining dietary supplements (fiber; probiotics and synbiotics; food, vitamin and mineral supplements) and foods, drinks, and whole diets. Only adults with chronic idiopathic constipation were included, and eligible studies were predominantly placebo-controlled RCTs. The GRADE framework was applied to assess evidence quality, and a modified Delphi consensus survey was used to finalize recommendation statements.

Across 75 RCTs, 59 recommendation statements were accepted. For dietary supplements, psyllium fiber emerged as the best-supported fiber supplement. Probiotics received 20 recommendation statements, though effects were strain-specific and outcome-dependent. Magnesium oxide supplements received 5 recommendations, and senna received 2. Kiwifruit supplements generated 3 statements. Among whole foods, kiwifruit (3 statements), prunes (2 statements), and rye bread (2 statements) were recommended for specific constipation outcomes. High-mineral-content water received 5 recommendation statements. Crucially, no recommendations could be made for whole-diet approaches such as increasing overall fiber intake, as insufficient RCT evidence existed in this area.

Evidence quality was predominantly low: 12 statements were graded very low, 39 low, and only 8 moderate. Twenty-seven statements were strong recommendations and 32 were qualified recommendations. The guidelines note that these findings apply specifically to chronic idiopathic constipation and should be applied with caution to secondary constipation populations, such as pregnant women or inpatients.

These guidelines represent a significant advance for clinical practice, providing actionable, specific, and evidence-graded dietary recommendations that healthcare professionals — particularly dietitians and gastroenterologists — can implement immediately to improve patient outcomes and satisfaction.