Ouwehand, Arthur C.Ibarra, AlvinMiller, Larry E.Background Probiotics are commonly recommended for the alleviation of constipation symptoms. The aim of this research was to determine the effects of probiotic-containing products on stool frequency and intestinal transit time (ITT) in constipated adults and to determine the factors that influence the efficacy of these products.Methods We conducted a systematic review of randomized controlled trials that measured weekly stool frequency or ITT in constipated adults receiving probiotic-containing supplements. A random effects meta-analysis was performed; stool frequency was summarized by the mean difference statistic and ITT was summarized by the standardized mean difference (SMD) statistic. Meta-regression and diagnostic model performance testing were used to identify publication bias and sources of heterogeneity.Results A total of 21 studies (23 comparisons) comprising 2656 subjects were included. All studies utilized probiotics containing Lactobacillus or Bifidobacterium species. Probiotic-containing products resulted in a mean increase in weekly stool frequency of 0.83 (95% confidence interval [CI] 0.53-1.14, P<0.001). There was high heterogeneity among the studies (I2=85%, P<0.001) and evidence of significant publication bias (Egger's P-value <0.01). After adjustment for publication bias, the mean difference in weekly stool frequency was reduced from 0.83 to 0.30. The effects on stool frequency were greater in studies where functional constipation was diagnosed using Rome III (P<0.01), or Rome II or III criteria (P<0.05), compared to non-Rome diagnosis techniques. Probiotic-containing products were also efficacious in reducing ITT (SMD=0.65, 95%CI 0.33-0.97, P<0.001). There was high heterogeneity among studies (I2=66%, P<0.01), but no evidence of publication bias (Egger's P-value=0.52). A larger total sample size was associated with greater efficacy as regards ITT (P=0.03). The probiotic species, the number of probiotic strains and the daily probiotic dosage had no influence on the outcomes.Conclusion Supplementation with products containing Lactobacillus or Bifidobacterium species increases stool frequency and reduces ITT in constipated adults. However, since significant heterogeneity in outcomes was detected among the studies analyzed, the results should be interpreted with caution.Keywords Constipation, meta-analysis, probiotic, stool frequency, transit timeAnn Gastroenterol 2017; 30 (6): 629-639text/htmlapplication/pdfimage/jpegimage/tiffapplication/vnd.openxmlformats-officedocument.wordprocessingml.documenthttp://www.annalsgastro.gr/index.php/annalsgastro/article/view/3346engHellenic Society of Gastroenterology1792-74631108-7471Annals of Gastroenterology; Volume 30, No 6 (2017); 629Effects of probiotic-containing products on stool frequency and intestinal transit in constipated adults: systematic review and meta-analysis of randomized controlled trialsinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersion2017-11-02Δημοσίευση σε περιοδικόPublication in journalΓαστροεντερολογίαGastroenterologyisi -Gastroenterology & Hepatology covers resources on the anatomy, physiology, biochemistry, and pathology of the digestive system. This category includes specific resources on the prognosis and treatment of digestive diseases; stomach ulcers; metabolic, genetic, infectious and chemically induced diseases of the liver; colitis; diseases of the pancreas and diseases of the rectum.Επιστημονικό άρθροScientific articleΕλληνική Γαστροεντερολογική ΕταιρίαGreek Aggregator OpenArchives.gr | National Documentation Centre (EKT)other