LiveScience.com Thu Jan 5, 12:00 PM ET Despite what many may have heard, drinking soda does not increase the risk of developing esophageal cancer. In fact it might protect against it, a new study finds.Cases of cancer affecting the esophagus, the muscular tube linking the mouth and stomach, in the United States have more than tripled since the 1970s. And in the past 50 years, Americans have increased their annual consumption of carbonated soft drinks nearly five-fold, from 10.8 gallons in 1946 to a whopping 42.2 gallons in 2000. The two trends are strongly correlated and in 2004, Indian researchers...