ObjectiveTo compare the outcomes associated with the use of probiotics, prebiotics, and synbiotics for the treatment of chronic constipation in adults.MethodsWe searched eight electronic databases from database inception to July 11, 2023, to identify randomized controlled trials (RCTs) that report efficacy and safety for the treatment of chronic constipation. The risk of bias in the included RCTs was evaluated according to the Cochrane tool, and the certainty of the evidence was assessed using the Confidence in Network Meta-Analysis framework. The analysis was conducted using R version 4.3.0.ResultsOut of the 37 RCTs, a total of 21 different types of interventions were reported, involving 3,903 patients. This NMA demonstrated that both prebiotics and synbiotics resulted in an increase in frequency of stool movements per week. Compared to placebo, lactulose (Mean difference [MD] = 3.39, 95% Confdence interval [CI] [1.13, 5.65], moderate certainty), mix2 (consisting of Lactulose and Bacillus coagulans) (MD = 3.63, 95% CI [1.37, 5.89], moderate certainty), mix6 (consisting of Lactulose and Bifidobacterium coagulans) (MD = 4.30, 95% CI [1.04, 7.54], low certainty), and mix7 (consisting of Lactulose, Bifidobacterium subtilis, and Enterococcus faecium) (MD = 4.58, 95% CI [1.35, 7.78], moderate certainty) exhibited a significant effect. Notably, mix7 demonstrated the highest probability of being the most effective intervention (94.8%). Furthermore, when compared to L. plantarum, four probiotics and two synbiotics showed significant advantages in the Patient Assessment of Constipation Symptoms (PAC-SYM) score. L. reuteri (MD = -13.74, 95% CI [-22.20, -4.66], very low certainty) exhibited a significant effect in improving the Patient Assessment of Constipation Quality of Life (PAC-QoL) score. In terms of safety, there were no statistically significant differences between the intervention and control groups in all adverse event analyses.ConclusionsModerate to very low evidence supports the use of lactulose and synbiotics to increase the number of weekly stool movements in patients, particularly highlighting the significant impact of synbiotics in increasing the number of weekly stool movements in patients with constipation. The use of L. paracasei showed improvements in PAC-SYM scores, while L. reuteri demonstrated enhancements in PAC-QoL scores.

Probiotic and prebiotic products have shown potential health benefits, including for the prevention of adverse pregnancy outcomes. The incidence of adverse effects in pregnant people and their infants associated with probiotic/prebiotic/synbiotic intake, however, remains unclear. The objectives of this study were to evaluate the evidence on adverse effects of maternal probiotic, prebiotic, and/or synbiotic supplementation during pregnancy and lactation and interpret the findings to help inform clinical decision-making and care of this population. A systematic review was conducted following PRISMA guidelines. Scientific databases were searched using pre-determined terms, and risk of bias assessments were conducted to determine study quality. Inclusion criteria were English language studies, human studies, access to full-text, and probiotic/prebiotic/synbiotic supplementation to the mother and not the infant. In total, 11/100 eligible studies reported adverse effects and were eligible for inclusion in quantitative analysis, and data were visualised in a GOfER diagram. Probiotic and prebiotic products are safe for use during pregnancy and lactation. One study reported increased risk of vaginal discharge and changes in stool consistency (relative risk [95% CI]: 3.67 [1.04, 13.0]) when administering Lactobacillus rhamnosus and L. reuteri. Adverse effects associated with probiotic and prebiotic use do not pose any serious health concerns to mother or infant. Our findings and knowledge translation visualisations provide healthcare professionals and consumers with information to make evidence-informed decisions about the use of pre- and probiotics.