Effect of Probiotics on the Intestinal Microbiota of Pediatric Patients

Numerous studies have described an altered gut microbiota composition (dysbiosis) in patients with neurodevelopmental disorders that can be correlated with their symptoms, especially gastrointestinal symptoms. An interventional, randomised, double-blind, placebo-controlled study will be conducted to investigate the effect of a probiotic supplement on the microbiota composition of children aged 3-7 years with neurodevelopmental issues. The duration of the study will be of 6 months approximately, including 6 months of product intake. Participants will be randomly assigned to one of the two study groups: control group with placebo administration or probiotic administration group.

Inclusion Criteria: * Children aged 3 to 7 years old. * Diagnosed with autism spectrum disorder, according to the clinical criteria of the "Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5)" and who meet criteria for ASD according to the ADOS-2 classification. * Presenting one or more gastrointestinal symptoms (constipation, diarrhoea, abnormal stools, painful defecation, abdominal pain, reflux, bloating, flatulence). * Written informed consent signed by the parent or legal guardian with express or tacit consent of the other parent. Exclusion Criteria: * With intake of antibiotics in the last month. * With intake of probiotics in the last two weeks. * Diagnosed with short bowel syndrome or has undergone relevant surgery on the gastrointestinal tract. * Exhibiting a defect in the intestinal epithelial barrier (e.g. inflammatory bowel disease (IBD)). * Diagnosed with endocrinological diseases such as diabetes mellitus, hypo- and hyperthyroidism, Cushing's disease, Addison's disease, etc. * Having heart failure and a cardiac medical history (e.g. artificial heart valve, medical history of infective endocarditis, rheumatic fever, or cardiac malformation). * Congenital or acquired immunodeficiency. * Immunocompromised (e.g., cancer and/or transplant patients taking certain immunosuppressive drugs, patients with inherited diseases that affect or may affect the immune system). * Uncertainty on the part of the investigator about the willingness or ability of the minor's parents or legal guardian to comply with the requirements of the protocol. * With oral hyper sensitivity impairments that prevent the uptake of the study product.