RESUMO
OBJECTIVE: Chronic functional constipation is a frequent condition. The aim of the study was to evaluate the efficacy of the probiotic Lactobacillus (L.) reuteri DSM 17938 and magnesium oxide (MgO) for relieving chronic functional constipation in children. STUDY DESIGN: A prospective, double-blind, placebo-controlled, randomized, and parallel-group trial was conducted in five pediatric outpatient clinics in Japan. Sixty patients who were more than six months old and under six years of age with a diagnosis of functional constipation according to Rome IV criteria were randomly divided into three groups: group A (n = 20) received L. reuteri DSM 17938 and lactose hydrate as a placebo of MgO; group B (n = 19) received L. reuteri DSM 17938 and MgO; and group C (n = 21) received a placebo of L. reuteri DSM 17938 and MgO. RESULTS: All three groups exhibited significant improvement in defecation frequency in the fourth week compared with the baseline condition (group A: p < 0.05; group B: p < 0.05; group C: p < 0.05). The MgO group and combination group showed a significant decrease in stool consistency, but the L. reuteri DSM 17938 group did not (group A: p = 0.079; group B: p < 0.05; group C: p < 0.05). MgO significantly suppressed the presence of the genus Dialister. Defecation frequency negatively correlated with the frequency of Clostridiales-belonging bacteria among the gut microbiome. CONCLUSIONS: L. rueteri DSM 17938 and MgO were both effective in the management of functional constipation in young children. MgO caused an imbalance in the gastrointestinal microbiome, which was not the case in the probiotic group.