Gallstones
Potential mechanisms
A role for caffeine
The majority of the published research* shows that caffeinated coffee reduces the risk of symptomatic gallbladder disease. This would suggest that caffeine is the active component responsible for the preventive role of coffee in the development of the disease.
There is evidence to suggest that caffeine can trigger contraction of the gallbladder. These contractions may be beneficial to the gallbladder when no disease is present, or is asymptomatic, but may lead to more severe symptoms in more advanced gallbladder disease.
This suggests that individuals with symptomatic gallstones may reduce their coffee consumption as a result of their symptoms, rather than developing more severe symptoms because of a reduction in their coffee consumption.
Role of other coffee components
Other components, however, could also play a part. A small trial8 in the US found that coffee consumption raised plasma cholecystokinin** levels and triggered gallbladder contractions, whether it was caffeinated or decaffeinated. This suggests a role for components in coffee other than caffeine.
