Television ads commonly show adults suffering with acid reflux or heartburn, but they seldom, if ever, show an exhausted parent walking the floor with an infant who is screaming, arching his or her back, and spitting up milk only to want to feed again, gulping it down quickly, and then vomiting it up once more. Yet, according to Susan Ornstein, a pediatric endocrinologist in Pittsburgh, five percent or more of babies born in the United States have gastroesophageal reflux disease—or GERD—which is the medical name for what we know as acid reflux or heartburn.
Acid reflux happens when acid, with or without partially digested food, flows backwards from the stomach and into the esophagus and sometimes the mouth. The acid burns when it touches the delicate membranes of these areas. Heartburn is just one symptom of GERD, but it is probably the one with which we are most familiar.
The regurgitation is due to a problem with a valve called the lower esophageal sphincter (LES), a circular muscle found between the esophagus and the upper part of the stomach. Normally, the LES tightens automatically after food and liquid enter the stomach so the contents, along with stomach acid, don't flow backwards into the esophagus. But for various reasons, the valve doesn't shut properly and reflux occurs.