Infant Colic Symptoms and Amino Acid Formula: Insights from a Prospective Cohort Study

<b>Background/Objectives:</b> Infant functional disorders, including colic, irritability, and sleep disturbances, often overlap with symptoms of cow's milk protein allergy (CMPA). While extensively hydrolyzed formulas are commonly used to address these issues, the short-term efficacy of amino acid formulas (AAF) for managing colic remains understudied. This secondary analysis of a previously published prospective cohort, the largest of its kind in the United States, evaluated the short-term impact of AAF in improving colic and associated symptoms in infants under six months of age with suspected CMPA. <b>Methods:</b> This real-world prospective cohort study analyzed data from 138 infants with suspected CMPA initiated on AAF at Visit 1. After excluding 34 infants due to incomplete data or treatment changes, 104 infants were included in the final analysis. Symptom severity and resolution were assessed through outcomes across two visits, with care provided by general pediatricians (82%) and pediatric gastroenterologists (18%). <b>Results:</b> At baseline, the most common symptoms were colic (<i>n =</i> 83), gassiness (<i>n =</i> 72), fussiness (<i>n =</i> 66), and sleep disturbances (<i>n =</i> 58). By the next follow-up visit (Visit 2), parents reported symptom improvements in colic (94%), gassiness (81%), fussiness (83%), and sleep disturbances (86%). Complete symptom resolution was observed in 73% of infants with colic, 68% with gassiness, 65% with fussiness, and 81% with sleep difficulties. By Visit 2, no infants had severe symptoms, with only mild residual symptoms reported. <b>Conclusions:</b> AAF was associated with significant short-term improvements in colic and related symptoms in infants with suspected CMPA. These preliminary findings highlight AAF as a promising dietary intervention during early infancy. Larger controlled studies are necessary to confirm these results and explore long-term outcomes.