Probiotics-containing products can effectively raise stool frequency, enhance stool consistency, and relieve symptoms associated with functional constipation.

This systematic review and meta-analysis sought to examine the usefulness of probiotics-containing products in improving bowel movement and examine alterations in gut microbiota among adult patients suffering from functional constipation (a common functional gastrointestinal disorder).

ClinicalTrials.gov, Cochrane Library, and PubMed were examined for randomized controlled trials (RCTs), encompassing both published studies and grey literature. The intervention involved probiotics-containing products, including synbiotics or probiotics, with a placebo control. Bias risk assessment was performed. Bowel movement efficiency was determined based on stool frequency, consistency, and the Patient Assessment of Constipation Symptom (PAC-SYM) score.

Alterations in gut microbiota were examined through measures like α diversity, β diversity, and alterations in relative abundance. For exploring heterogeneity, subgroup analyses, sensitivity analyses, and random-effects meta-regression were executed. Utilizing the Grading of Recommendations Assessment Development and Evaluation (GRADE) framework, the quality of evidence was examined.

A total of 17 studies involving 1256 subjects were incorporated, showing strong agreement between researchers (kappa statistic=0.797). In comparison with placebo, probiotics-containing products considerably raised the frequency of stool (weighted mean difference [WMD] 0.93, 95% Confidence Interval (CI) 0.47 to 1.40, p=0.000, I²=84.5%, 'low'), enhanced stool consistency (WMD 0.38, 95% CI 0.05 to 0.70, p=0.023, I²=81.6%, 'very low'), and lowered PAC-SYM scores (WMD -0.28, 95% CI: -0.45 to -0.11, p=0.001, I²=55.7%, 'very low').

Subgroup assessment indicated that synbiotics were more efficacious than probiotics alone in raising stool frequency. Probiotics-containing products did not considerably affect α or β diversity but did escalate the relative abundance of specific strains.

Probiotics-containing products demonstrated remarkable improvements in stool frequency, consistency, and functional constipation symptoms while increasing the relative abundance of specific strains in the gut microbiota. Further high-quality RCTs comparing different interventions are warranted.