Functional constipation is very common and causes many anxiety disorders of the gastrointestinal tract. Treating constipation is always a difficult task. Recently, the use of probiotics for this problem has been the subject of in-depth studies.

The purpose of the systematic review and meta-analysis was to study the effect of probiotics on the passage of food through the intestines, the presence of stools and the symptoms of constipation in adults suffering from functional constipation.

A systematic review and meta-analysis included randomized controlled trials that examined the administration of probiotics to adults with functional constipation. The search was searched in 4 electronic databases, bibliographies and by manual search in the summaries presented during the conferences. Two experts independently selected the studies, extracted the data and assessed the relevance of the studies to be included in a systematic review.

All 660 studies were identified, of which 14 with a total number of patients 1182 people could be included in the meta-analysis. Probiotics have been shown to significantly reduce the passage of food through the intestines by 12.4 hours (95% CI -22.3 to -2.5 hours) and increased the frequency of bowel movements. 1.3 times the colon cleanse per week (95% CI 0.7-1.9 intestinal cleanses per week). These differences were statistically significant for Bifidobacterium lactis (1.5 intestinal cleanses per week, 95% CI 0.7-2.3), but not for Lactobacillus casei Shirota (-0.2 intestinal cleansing per week, 95% CI -0.8 to 0.9). The use of probiotics improves stool consistency, and this change was statistically significant for B. lactis but not for L. casei strain Shirota. No serious adverse events were noted.

In this way, probiotics can improve the overall passage of food through the intestines, increase the frequency of bowel movements, and improve the consistency of bowel movements. In a subgroup analysis, it turned out that a statistically significant positive effect was only observed with B. lactis but not when using L. casei of the Shirota strain. For the final conclusions and to determine the most effective type or specific strain of probiotic, dose and duration of use, large-scale, well-organized randomized controlled trials are needed.