Dietary management of chronic constipation: a review of evidence-based strategies and clinical guidelines.

This review comprehensively examines the current evidence on the dietary management of chronic constipation, and the dietary recommendations presented in clinical guidelines for chronic constipation. Several randomised controlled trials (RCT) have investigated the effect of dietary supplements, foods and drinks in chronic constipation. Systematic reviews and meta-analyses of these RCTs have demonstrated that psyllium supplements, specific probiotic supplements, magnesium oxide supplements, kiwifruits, prunes, rye bread and high mineral water content may be effective in the management of constipation. However, despite the plethora of evidence, current clinical guidelines only offer a limited number of dietary recommendations. The most commonly recommended dietary strategy in clinical guidelines is dietary fibre, followed by senna supplements and psyllium supplements. The least commonly recommended dietary strategies are magnesium oxide, Chinese herbal supplements, prunes and high mineral-content water. Several evidence-based dietary strategies are omitted by current clinical guidelines (e.g. kiwifruits), while some strategies that are recommended are not always supported by evidence (e.g. insoluble fibre supplement). Dietary recommendations in clinical guidelines can also be ambiguous, lacking outcome-specific recommendations and information for appropriate implementation. Future RCTs are needed to assess currently under-investigated dietary approaches that are nevertheless commonly recommended, and future clinical guidelines should include dietary recommendations supported by available evidence.