Consumption of Aloe to improve health outcomes in adults with irritable bowel syndrome: A systematic review and meta-analysis

Abstract

Study aim: To evaluate the effect of Aloe on symptoms associated with Irritable Bowel Syndrome (IBS) in adults. Study objective: To summarize the existing evidence on the contribution of Aloe to improved health outcomes among adult patients diagnosed with IBS and where possible, identify potential factors that may infl uence this response.

Design: Systematic review and meta-analysis of randomized controlled trials, non-randomised controlled trials, retrospective and prospective cohort studies, and controlled before-and-after (CBA) studies.
Data sources: Medline, Scopus, EBM reviews, Africa-wide, CINAHL, Web of Science, Mednar, Cochrane Library, clinicaltrials. gov, World Health Organization Library Information System (WHOLIS), Ebscohost and Google Scholar up to August 2018.
Review methods: Randomized controlled trials, non-randomised controlled trials, retrospective and prospective cohort studies, and controlled before-and-after (CBA) studies comparing Aloe in different preparations to placebo in adults with irritable bowel syndrome were eligible for inclusion. Minimum duration of therapy considered was two weeks, and studies had to evaluate either a global assessment of cure or improvement in symptoms, or cure, or improvement in abdominal pain, after treatment. A random effects model was used to pool the effect of therapy compared with placebo or no treatment. This was reported as the risk ratio (95% confi dence interval) of those who responded to treatment versus those who responded to placebo.
Results: Compared with placebo, this systematic review found evidence for improvement in symptoms for Aloe-containing preparations in patients with IBS (relative risk (RR), 2.75; 95% confi dence Interval (CI), 1.88 to 4.03, 5 studies, n=325; I2=0%). In sub-group analyses, this fi nding was consistent amongst patients with constipation-predominant IBS (IBS-C) (RR, 3.41; 95% CI, 2.11 to 5.51; 3 studies, n=199. This fi nding was not replicated in the single study comparing Aloe with placebo in patients with diarrhoea-predominant IBS (IBS-D) and mixed-pattern IBS (IBS-M).

Conclusion: Aloe-containing preparations were more effective than placebo in improving symptoms among all IBS sub-types combined. In sub-group analyses, Aloe was more effective than placebo in the treatment of constipation-predominant IBS, however this was not the case with IBS-D and IBS-M sub-types. Given the variation in the formulae of Aloe preparations in the included studies, generalizability of this fi nding may be a challenge. Thus, further research with adequately-powered studies using a standardised formulation for Aloe-containing preparations for IBS is advised.