If you are at risk for liver disease, drinking caffeinated coffee and soda may help protect you from getting it, a new study shows.

According to research presented at the Digestive Disease Week meeting in New Orleans, a researcher from the National Institute of Diabetes and Digestive and Kidney Diseases found people at high risk for liver problems can reduce their risk by drinking coffee and other caffeinated beverages.

There have been other studies that have shown this effect from caffeine, said lead researcher Dr. James E. Everhart. However, why caffeine protects against liver disease is not known.

"Caffeine blocks one receptor found in the brain and liver. This may have immunological effects, but this is really speculative," he added.

In their study, Everhart and his colleague, Dr. Constance E. Ruhl from Social and Scientific Systems in Silver Spring, Md., collected data on 5,944 men and women who were at high risk for liver injury.

The subject's risk came from excessive drinking, hepatitis B or C, iron overload, obesity or impaired sugar metabolism.

All the subjects participated in the third U.S. National Health and Nutrition Examination Survey.

As part of the study, the subjects were asked to report how much coffee, tea and soft drinks they consumed.

Everhart and Ruhl found the more coffee and caffeine these people drank, the less likely they were to develop liver injury. This finding was the same for all age, gender and ethnic groups.

In addition, the protective effect was stronger for caffeine than for coffee.

Laboratory work is needed to figure out why caffeine has this effect, Everhart said. "More importantly, this finding should stimulate more clinical research in people with liver disease to see whether either drinking coffee or consuming caffeine has an effect," he added.

Dr. Jonathan A. Dranoff, an assistant professor of internal medicine at Yale University, said the finding is "provocative and worthy of further investigation."

Dranoff noted that findings in population-based studies do not necessarily confirm that caffeine causes any change in liver health. At this point, he said, "it is impossible to say that increasing coffee consumption would cause one to have less advanced liver injury."

The next step, Dranoff said, is to do a study of patients and randomize them into caffeine or no-caffeine groups. "This is the best way to test if this hypothesis is true," he added.

"These findings are so shocking that they deserve much more intense investigation before you can draw any conclusion," Dranoff said.