GUT MICROBIOTA, EATING BEHAVIOR, AND CLINICAL MANIFESTATIONS IN AUTISM SPECTRUM DISORDER: A CASE STUDY

Abstract

Autism Spectrum Disorder (ASD) is a neurodevelopmental condition characterized by persistent deficits in communication and social interaction, associated with restricted and repetitive patterns of behavior, often accompanied by feeding difficulties and gastrointestinal symptoms. Recent evidence suggests that imbalances in the gut microbiota may influence behavioral and cognitive manifestations through the gut–brain axis. This study aimed to investigate the relationship between gut microbiota, feeding behavior, and clinical manifestations of ASD in a child through a case report. This is an observational, descriptive study with a qualitative and quantitative approach, conducted with a nonverbal male child diagnosed with ASD, support level 3, who was followed by a multidisciplinary team for 17 months. Data collection included interviews with caregivers, application of semi-structured questionnaires, anthropometric assessment, and estimation of intestinal dysbiosis risk using the Dysbiosis Frequent Questions Management instrument. At baseline, the child presented marked food selectivity, predominant consumption of ultra-processed foods, aggressive behaviors, and a moderate risk of intestinal dysbiosis. After nutritional intervention combined with sensory and behavioral strategies, an expansion of the food repertoire, reduction in aggressive behaviors, improved therapeutic engagement, and a decrease in dysbiosis risk scores were observed. These findings suggest that nutritional intervention integrated with multidisciplinary follow-up may contribute to modulation of the gut–brain axis and improvements in feeding behavior and behavioral aspects in children with ASD, highlighting the importance of individualized and interdisciplinary approaches in clinical care..