People who rely on a cup of coffee to start their day may be lowering their risk of Liver Cancer in the process, Japanese researchers suggest.
The study, based on data from more than 60,000 Japanese adults, bolsters the findings of another study published earlier this year that linked coffee consumption to a lower risk of Liver Cancer.
In the current study, researchers found that men and women who drank at least one cup of coffee a day were less likely to develop liver cancer than those who drank little or none.
Compared with occasional coffee drinkers, habitual drinkers were 29 percent less likely to develop liver cancer over the 7 to 9 years the researchers followed them. And in comparison to their peers who never drank coffee, their liver cancer risk was 42 percent lower, according to findings published in the International Journal of Cancer.
It’s not clear why coffee might help ward off the disease, said Dr. Taichi Shimazu of Tohoku University Graduate School of Medicine in Sendai, Japan.
One compound in the beverage - chlorogenic acid - has been shown in animal research to have potential cancer-fighting effects in the liver, according to Shimazu.
A previous study of people at high risk of liver disease found that it was less common among those who drank coffee or other caffeinated beverages. But, Shimazu’s team notes, caffeine may not be the secret ingredient, as green tea consumption was unrelated to Liver Cancer in this study.
The findings add to a large body of conflicting research on the potential health effects of coffee. Lab research has suggested the beverage can have both cancer-promoting and cancer-inhibiting effects on cells. Meanwhile, some studies of coffee drinkers have linked the habit to a lower risk of Parkinson’s disease, while other research suggests caffeine can send up blood pressure and blood levels of homocysteine, a protein tied to Heart disease.
For the current study, the researchers pooled data from two large studies that included men and women age 40 and older. At the start of the studies, participants completed questionnaires about their diets and other health habits. Over the next 7 to 9 years, 117 men and women developed liver cancer.
Those who said they were regular coffee drinkers at the outset were less likely than abstainers or occasional drinkers to develop liver cancer, even when factors such age, alcohol use and smoking were weighed.
Further analysis showed that the protective effect was strong, in statistical terms, only among people with a history of liver disease. However, liver diseases - particularly chronic infection with the viruses hepatitis B and C - are responsible for most liver cancers worldwide.
The findings, Shimazu told, do not necessarily mean that the potential benefit of coffee would be limited to people with a history of liver disease. Coffee drinkers without liver disease also had a lower cancer risk, but statistical analysis showed that could be a chance finding.
If further research confirms that coffee does indeed offer some protection from liver cancer, Shimazu noted, it will be important to figure out which compounds in the beverage are responsible.
SOURCE: International Journal of Cancer, August 10, 2005.
Revision date: June 21, 2011
Last revised: by Sebastian Scheller, MD, ScD