The Gut Microbiota of Infants Before and After Probiotic and/or Lactose Treatment

Objective: This study aimed to evaluate the effects of Bifidobacterium longum and lactulose in alleviating functional constipation in infants and toddlers and to explore potential mechanisms through gut microbiota analysis.Methods: A 28-day open-label, randomized controlled trial (RCT) was conducted on 84 infants and toddlers aged 0 to 3 years with functional constipation. Participants were randomized into three groups: probiotics (n=38), combination (probiotics and lactulose, n=27), and lactulose group (n=19). Outcomes included bowel movement frequency (BMF), Bristol stool scale (BSS), and defecation difficulty (visual analog scale scores, VAS). Stool samples were collected before and after the intervention for 16S rDNA microbiota analysis, assessing alpha diversity, beta diversity, community bar plot analysis, and species difference analysis.Results: All groups showed significant improvements in BMF, BSS, and VAS compared to baseline (P<0.01). At 28 days, no significant differences in BSS were noted among groups (P>0.05), but significant differences in defecation difficulty were observed. Microbiota analysis revealed no significant changes in alpha diversity and beta diversity (P>0.05), but beneficial bacteria increased while harmful bacteria decreased after the intervention. Streptococcus and Enterococcus abundances varied significantly among groups after the intervention.Conclusions: Combined administration of B. longum and lactulose improved BSS and defecation difficulty in infants and toddlers with functional constipation. While it is challenging to definitively determine greater therapeutic efficacy for the combined group, it exhibited changes in gut microbiota that offer potential benefits in constipation relief.