Acid reflux is a condition in which the stomach contents reflux back up the esophagus, the tube that carries food from the mouth to the stomach. In adults, once food has been swallowed, it is abnormal for it to regurgitate back up the esophagus toward the mouth. If this occurs on a chronic basis, it causes heartburn. This is the term used to describe the pain adults experience with acid reflux.
However, acid reflux is not abnormal in infants. The system used by the body to prevent regurgitation of food from the stomach uo the esophagus is quite sophisticated. It involves the coordination of the swallowing motion of the esophagus, which moves food into the stomach, and a circular band of muscle at the base of the esophagus that acts as a valve to prevent regurgitation of food. This system is immature in infants and does not work well. Hence, babies are spitters. Think about it. Babies often spit up their feeds to one degree or another and we consider it normal. Yet spitting is actually regurgitation of food, a behavior that would be abnormal in an adult.
So, acid reflux, spitting, is quite common and normal in infants during the first several months of life. Unlike adults, infants seem protected from the painful effects of reflux. Some physicians have suggested that perhaps the infant with colic lacks this natural protection and is crying from heartburn, such as Zantac and propulsid.
