Results of a study conducted in China indicate that drinking tea reduces the risk of bile stones and cancer, especially among women.
Bile stones, which are often seen in women and have been linked to obesity, occur in the ducts that transfer bile from the liver to the small intestine.
If the stones block the opening of the gallbladder, they can cause discomfort and pain, typically located just below the rib cage on the right side of the abdomen.
At this stage, gallbladder removal, or "cholecystectomy," is often required. Serious complications from bile stones are uncommon.
By contrast, "biliary tract cancers are rare but highly fatal," Dr Ann W Hsing of the National Cancer Institute, Bethesda, Maryland, and colleagues write in the International Journal of Cancer.
"Apart from gallstones, (causative) factors for biliary tract cancer are not clearly defined," they note. Several studies "have suggested that consumption of tea, especially green tea, is protective against a variety of cancers."
In the new study, the researchers examined the effects of tea consumption on the risk of biliary tract cancers and biliary stones.
Included in the study were 627 patients with biliary tract cancer, 1,037 with biliary stones, and 959 comparison subjects.
The team obtained data on demographics, medical and dietary factors, and tea consumption. Tea drinkers were defined as those who drank at least one cup of tea per day for at least 6 months. Of the 959 control subjects, 394 (41 per cent) were tea drinkers.
In women, drinking at least one cup of tea per day for at least 6 months seemed to cut the risks of bile stones by 27 per cent, gallbladder cancer by 44 per cent, and bile duct cancer by 35 per cent.
In men, tea drinking had a similar effect, but not of the magnitude seen in women.
Certain chemicals in tea may prevent cells from growing abnormally and may have antiinflammatory effects that reduce the risk of these bile tract diseases, Hsing's team explains. Further studies are needed to see if these findings can be duplicated.