Coffee consumption reduces risk of hepatocellular carcinoma (HCC), the most common type of liver cancer, by about 40 percent, according to an up-to-date meta-analysis published in Clinical Gastroenterology and Hepatology, the official clinical practice journal of the American Gastroenterological Association. Further, some data indicate that three cups of coffee per day reduce liver cancer risk by more than 50 percent.

"Our research confirms past claims that coffee is good for your health, and particularly the liver," said Carlo La Vecchia, MD, study author from the department of epidemiology, Istituto di Ricerche Farmacologiche "Mario Negri," and department of clinical sciences and community health, Università degli Studi di Milan, Italy. "The favorable effect of coffee on liver cancer might be mediated by coffee's proven prevention of diabetes, a known risk factor for the disease, or for its beneficial effects on cirrhosis and liver enzymes."

Researchers performed a meta-analysis of articles published from 1996 through September 2012, ultimately studying 16 high-quality studies and a total of 3,153 cases. This research fills an important gap as the last meta-analysis was published in 2007, and since then there has been data published on more than 900 cases of HCC.

Despite the consistency of results across studies, time periods and populations, it is difficult to establish whether the association between coffee drinking and HCC is causal, or if this relationship may be partially attributable to the fact that patients with liver and digestive diseases often voluntarily reduce their coffee intake.

"It remains unclear whether coffee drinking has an additional role in liver cancer prevention," added Dr. La Vecchia. "But, in any case, such a role would be limited as compared to what is achievable through the current measures."

Primary liver cancers are largely avoidable through hepatitis B virus vaccination, control of hepatitis C virus transmission and reduction of alcohol drinking. These three measures can, in principle, avoid more than 90 percent of primary liver cancer worldwide.

Liver cancer is the sixth most common cancer in the world, and the third most common cause of cancer death. HCC is the main type of liver cancer, accounting for more than 90 percent of cases worldwide. Chronic infections with hepatitis B and C viruses are the main causes of liver cancer; other relevant risk factors include alcohol, tobacco, obesity and diabetes.