Impact of prebiotics and postbiotics in the management of constipation: Analysis of their differentiated modulation of intestinal microbiota.

Chronic constipation represents a burden in the modern world and is most prevalent in the elderly. Constipation has been linked to alterations in the gut microbiota, especially to an increase in methanogenic microorganisms. Prebiotics and some probiotics have already shown beneficial effects in constipation through improving stool consistency and modulating the gut microbiota. In the current double-blind, randomized and parallel-arm clinical study, 24 subjects with constipation were supplemented with NextDext™, a dextran prebiotic, or ABB C24, a prebiotic-postbiotic combination of NextDext™ and ABB C22®, for two weeks to evaluate their effects on stool consistency (Bristol Stool Form Scale) and gut microbiome. The results showed a significant improvement in stool consistency after taking NextDext™ from constipated to normal (Bristol Scale) and a trend to improvement after ABB C24 supplementation. Consumption of NextDext™ increased the presence of some beneficial bacterial groups, such as Bifidobacterium longum and Roseburia hominis, and reduced the presence of microorganisms associated with constipation, such as Blautia obeum, Escherichia coli and Collinsella aerofaciens. Consumption of ABB C24 reduced the presence of Blautia obeum and the methanogenic bacteria Methanobrevibacter smithii, while increased beneficial Clostridium leptum and Coprococcus spp. There were no significant alterations in gut diversity indexes of richness and evenness, even if ABB C24 seemed to increase diversity in a greater number of volunteers. Although NextDext™ influenced more microbial groups and restored microbial groups associated with opioid use, the species modulated by ABB C24 reverted microbial alterations consistently reported in constipation, suggesting an added value of the postbiotic ABB C22®. Both could benefit different profiles of constipation sufferers. This study was registered in ClinicalTrials.gov: NCT06738433.