Coffee May Protect Liver

< June 14, 2006 > -- Drinking coffee seems to protect alcohol drinkers from liver disease, a new study suggests.

A daily cup of coffee reduced the incidence of alcohol-related cirrhosis, a condition that destroys liver tissue, by 22 percent, according to researchers at the Kaiser Permanente Medical Care Program in Oakland, Calif.

Two to three cups of coffee reduced risk by 40 percent, and four or more cups cut the risk by 80 percent.

Researchers did not find a similar protection for non-alcoholic cirrhosis. Tea drinkers also did not demonstrate a protective effect against alcoholic cirrhosis.

The new study findings appear in the Archives of Internal Medicine.

Cirrhosis is a disease that causes progressive damage, and impaired function of the liver. There are numerous causes, including alcohol, viruses, obesity, or genetic problems.

According to the National Center for Health Statistics, there are more than 5 million cases of chronic liver disease and cirrhosis in the US, and nearly 28,000 people die of chronic liver disease every year.

New Study Reinforces Previous Results

The study finding was no surprise to Dr. Constance E. Ruhl, co-author of a study published last December in the journal Gastroenterology.

Data from the National Health and Nutritional Survey (NHANES) showed that people at high risk of liver disease had half the likelihood of being hospitalized for cirrhosis if they were coffee drinkers.

"The thing that is different about their [the Kaiser Permanente] study is that they were able to look at different causes of cirrhosis and the relationship of coffee with those different types, which we were not able to do because we did not have data on what caused the cirrhosis," Dr. Ruhl says. "Also, their study was larger."

The Kaiser Permanente researchers analyzed data from more than 125,000 people who were free of liver disease when they had examinations between 1978 and 1985 and who gave information about their alcohol, tea, and coffee consumption.

Participants included in the final analysis were those at risk for alcohol-related cirrhosis.

By the end of 2001, there were 330 cases of cirrhosis in the group, 199 caused by alcohol consumption. For each cup of coffee they drank per day, participants were 22 percent less likely to develop cirrhosis caused by alcohol.

"It's encouraging to me that they found something similar," says Dr. Ruhl. "It's additional evidence that there might be a relationship there."

Dr. Ruhl works at Social and Scientific Systems Inc., a for-profit organization that does research on public health. Her study was funded by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and was done in collaboration with Dr. James E. Everhart of the NIDDK.

Coffee's Protective Means Unknown

The mechanism by which coffee might protect the liver "is pretty speculative at this time," Dr. Ruhl says.

One possible mechanism has been suggested by Dr. Bruce N. Cronstein, director of the division of clinical pharmacology at New York University School of Medicine.

Dr. Cronstein's research has found that caffeine induces the release of adenosine, a molecule that prevents the inflammation that leads to kidney damage.

Still, the picture of caffeine's potential protective effect is far from complete, Dr. Ruhl says.

"The next step is to do clinical trials to look at the relationship between coffee and liver disease," she says. "Also, we need laboratory-type studies because it is not clear what components of coffee might have a direct effect on the liver."

Alcohol in Moderation Still Advised

Dr. Arthur L. Klatsky, lead author of the Kaiser Permanente study and an associate in Kaiser Permanente's research division, says the results "should not be interpreted as giving a license to drink without worry, because of all the other problems connected with drinking."

Liver damage is just one of the "multiple medical and social problems caused by heavy drinking," Dr. Klatsky says, adding, "the only proper advice is to drink less." Three drinks a day should be the limit for most people, he says.

Always consult your physician for more information.