New Orleans, Louisiana – Two studies unveiled Monday as part of Digestive Disease Week 2004 revealed that soda drinkers are at increased risk of developing esophageal cancer, while those who drink coffee and caffeinated beverages may in fact be at lower risk for developing liver problems such as liver injury due to hepatitis B or C, alcoholism, obesity, or impaired glucose metabolism.
One of the studies, conducted by Dr. Constance E. Ruhl and Dr. James E. Everhart at Social and Scientific Systems, examined the effects of caffeine on liver function. The researchers found that liver injury was less prevalent in coffee drinkers, and that at-risk study participants who drank two cups of coffee a day were less likely to have elevated levels of ALT, a chemical released by the liver when it is in distress.
The national, population-based study had 5,944 adult participants, and due to the size and geographical range of the study, Dr. Ruhl and Dr. Everhart feel their findings are very significant to researchers of chronic liver disease.
"Among persons at risk for liver injury, coffee drinking and caffeine consumption from beverages were associated with lower risk of injury," the doctors wrote of their discovery. "These possible beneficial effects deserve further investigation."
Another study, conducted by Dr. Mohandas K. Mallath of Tata Memorial Hospital in India, found that consumption of carbonated soft drinks is correlated with increased rates of esophageal adenocarcinoma, or cancer of the esophagus.
Data on dietary practices of people in the United States from the U.S. Department of Agriculture shows that over a period of 55 years, annual per-capita consumption of carbonated soft drinks rose at an alarming rate, from 10.8 gallons in 1946 to 49.2 gallons in 2000.
Drinking carbonated soft drinks triggers reflux symptoms, and in turn increases the exposure of the esophagus to acid. One can of soda can cause a dramatic increase in acid exposure for the hour or so following consumption, and when this number is multiplied by several cans per day, and several days of the week during the course of a year, the increase in acid exposure is dramatic.
"The linear association between per-capita consumption of [carbonated soft drinks]… and the incidence of [esophageal adenocarcinoma] is very strong," wrote Dr. Mallath. "These findings are strong enough to initiate good epidemiological studies to establish the true association."