But hold the decaf. The study found that men who drank two to three cups of caffeinated coffee a day had a 40 percent lower risk of developing gallstones than those who did not drink regular coffee. Men who drank four or more cups a day had a 45 percent lower risk.
But what coffee does to the gallbladder -- stimulating contractions and lowering cholesterol in the bile that can form painful gallstones -- it does only if it has caffeine in it, the researchers reported in Wednesday's edition of The Journal of the American Medical Association. Decaffeinated coffee and caffeinated tea and soda didn't help, the researchers said.
"I wouldn't actually say we would recommend that people take up coffee just to prevent gallstones," said Dr. Michael F. Leitzmann of the Harvard University School of Public Health, the lead researcher. "But it's OK to continue drinking it."
He added: "Coffee doesn't cause any other major diseases."
Gallstones are painful deposits of cholesterol in the gallbladder, the organ under the liver that stores bile. They affect about 20 million Americans and cause 800,000 hospitalizations each year, researchers said.
Leitzmann said lack of physical activity and being overweight are the two main causes.
The researchers followed 46,008 men from 1986 through 1996. The men, who were aged 40 to 75 in 1986, were members of the Health Professionals Follow-up Study, which is looking at dietary and lifestyle factors and their effect on diseases. Their caffeine intake was assessed several times in the course of the study.
Leitzmann said there was no theoretical reason the results would not translate to women, but that a separate study would look at women.
An expert not involved in the study said it was well done and convincingly showed a link between coffee consumption and gallstones.
"But further research needs to be done to see what that link is and what it is in coffee that causes that relationship," said Dr. Thomas Magnuson, an associate professor of surgery at Johns Hopkins University who has conducted animal research that reached similar conclusions.
Written By Eric Fidler