While millions of Americans suffer from heartburn and gastric reflux, only a small number develop more severe ailments that can lead to esophageal cancer. Scientists trying to understand what may protect against these conditions have identified an unlikely agent: wine.

Two studies published this month in the journal Gastroenterology suggest that people who drink wine, white or red, in moderation are less likely to develop conditions that may lead to esophageal adenocarcinoma, an uncommon cancer that has increased sharply in the United States over the past 30 years.

The reports are particularly surprising because alcohol intake is a well-established risk factor for the other main form of esophageal cancer, squamous cell carcinoma. Researchers noted the studies were preliminary.

In one study, researchers at Kaiser Permanente in Oakland, Calif., found that drinking a glass of wine a day was associated with a more than 50 percent reduction in the risk of developing Barrett’s esophagus, though there was no reduction in risk among adults who drank liquor or beer. Barrett’s esophagus, an erosion of the esophageal lining that can be caused by chronic heartburn or acid reflux, increases the odds of developing esophageal adenocarcinoma 30-fold to 40-fold.