CHICAGO – Coffee may counteract alcohol's poisonous effects on the liver and help prevent cirrhosis, researchers say. In a study of more than 125,000 people, one cup of coffee per day cut the risk of alcoholic cirrhosis by 20 percent. Four cups per day reduced the risk by 80 percent. The coffee effect held true for women and men of various ethnic backgrounds.
It is unclear whether it is the caffeine or some other ingredient in coffee that provides the protection, said study co-author Dr. Arthur Klatsky of the Kaiser Permanente Division of Research in Oakland, Calif.
"The way to avoid getting ill is not to drink a lot of coffee, but to cut down on the drinking" of alcohol, he said.
The participants ranged from teetotalers, who made up 12 percent of the total, to heavy drinkers, who made up 8 percent. The researchers calculated the risk reductions rate for the whole group, not just the drinkers.
Not all heavy drinkers develop cirrhosis, an irreversible scarring of the liver that hurts the organ's ability to filter toxins from the blood. Klatsky said the new findings may help explain why some people's livers survive heavy alcohol use.
Hepatitis C and some inherited diseases can also cause cirrhosis. But the study found coffee did not protect the liver against those other causes of scarring.
The same study found coffee drinkers had healthier results on blood tests used to measure liver function, whether or not they were heavy alcohol users. Coffee's effect on reducing liver enzymes in the blood was more apparent among the heavy drinkers in the study.
Cirrhosis from all causes kills more than 27,000 Americans a year and sends nearly 400,000 to the hospital.
The findings, published in Monday's Archives of Internal Medicine, build on reports that coffee also may reduce the risk of liver cancer.
The data came from members of a Northern California health plan. Their coffee consumption was noted only at the beginning of the study, which the researchers admitted was a limitation. They were followed for an average of 14 years.
The researchers found no reduced risk of cirrhosis for tea drinkers. Tea has less caffeine than coffee and there were fewer heavy tea drinkers in the study, so if caffeine is the protective ingredient, an effect may not have shown up for tea in the study, Klatsky said.