If you're a man and you're drinking at least two cups of coffee a day, you may be less likely to experience gallbladder problems than if you purposely avoided the java. According to a ten-year study published in early June in the Journal of the American Medical Association, coffee drinking can reduce the risk of gallstones by 40 percent or more. Researchers at the Harvard University School of Public Health studied more than 46,000 male health professionals, all of whom filled out an extensive food-frequency questionnaire. The subjects were aged 40 to 75 and had no histories of gallstone disease when the study was begun in 1986. The beneficial effect on the gallbladder was evident even after the scientists adjusted the results for known gallstone risk factors, such as being overweight. Coffee's potential protective effect was also suggested by an earlier animal study that linked coffee consumption to fewer gallstones.

The Harvard researchers noted that coffee has several metabolic effects that could reduce the risk of gallstones. Caffeine, for example, is known to increase the flow of bile. A liquid that is produced by the liver and then concentrated and stored in the gallbladder, bile is necessary to break down fats in the small intestine during digestion. Gallstones may occur when bile becomes overloaded with cholesterol and the fatty substance begins to accrete around a tiny particle. Gallstones often don't cause any symptoms, but those that get stuck in the duct leading from the gallbladder can cause intense pain and inflame the gallbladder. Caffeine's role was supported by the finding that subjects who drank decaf coffee did not have a decreased risk of gallstones.

Gallstones and gallbladder disease are common conditions among American men and women who eat a high-fat, low-fiber diet. Gallstones affect an estimated 20 million Americans and account for some 800,000 hospitalizations per year. Conventional treatment is to surgically remove the gallbladder. Alternative approaches that may help to prevent or treat gallstones include a high-fiber, whole foods diet; exercise or physical activity; drinking lots of water; and taking lecithin (or other choline-containing supplements) and silymarin (a milk thistle compound).

Reference: Leitzmann, W.F., et al., "A prospective study of coffee consumption and the risk of symptomatic gallstone disease in men," JAMA (1999), 281:2106-12