In 2003, scientists concluded that three cups of coffee a day may reduce the risk of cirrhosis by 40%. The following year, the U.S. National Institute of Diabetes and Digestive and Kidney Diseases found a direct relationship between the amount of coffee consumed and reduced risk for liver injury in those with hepatitis B and C, iron overload, obesity, impaired sugar metabolism and excessive alcohol consumption.
In Japan, a 2005 study reached findings that coffee drinkers are half as likely to develop liver cancer as non-drinkers. Italian researchers later focused on those with livers challenged by excessive alcohol consumption, and found that at four cups of coffee a day, the subjects were five times less likely to develop cirrhosis. That outcome was later repeated in a U.S. study, where scientists found a 22% reduction in cirrhosis risk for each cup of coffee, reaching 80% at four cups.
In 2012, French researchers concluded that coffee may protect the liver against fibrosis (essentially, excessive scar tissue) – adding a protective factor of 25% in patients with significant fibroses due to non-alcoholic fatty liver disease.
Turkish scientists later that year issued findings linking coffee consumption to reduction of the risk of non-alcoholic fatty liver disease (NAFLD). French scientists in 2013 linked coffee with a reduction in liver inflammation in patients with both HIV and Hepatitis C infections, with risk reduction averaging about 50% for each of the two marker blood enzymes, with protection increasing with consumption volume. In 2014, Turkish scientists again linked coffee with a reduction of risk for mortality from non-viral liver damage, including cirrhosis and NAFLD, pointing to coffee’s anti-inflammatory properties.1
Like the research documenting coffee’s potential link with a decreased risk of type 2 diabetes, the individual source and mechanism for liver protection is still under examination. In some cases, the same antioxidant compound suggested to provide diabetes protection – chlorogenic acid – is cited; in others, it’s caffeine or a class of antioxidants known as polyphenols.