Drinking coffee may help reduce the damage to the liver that is associated with too much food and alcohol. The finding is based on a meta-analysis, which is an analysis of combined data from existing studies.
Researchers at the University of Southampton in England and the University of Edinburgh analyzed data from nine published studies. These studies had collected data on more than 430,000 participants. They found that drinking two additional cups of coffee a day was associated with a 44% lower risk of developing liver cirrhosis, which is serious damage to the liver that kills more than one million people each year worldwide. Cirrhosis can be caused by hepatitis infections, excessive alcohol consumption, immune disorders, obesity, and fatty liver disease. The studies included about 1,990 patients with cirrhosis.
The researchers pooled the information about average coffee consumption from the earlier studies to determine the influence of drinking two additional cups of coffee each day on the odds of liver disease.
In eight of the nine studies analyzed, adding two cups of coffee a day was associated with a significant reduction in the risk of cirrhosis. In all but one study, the risk of cirrhosis continued to decline as the number cups of coffee per day increased.
The researchers estimated that drinking one cup of coffee a day was linked with a 22% lower risk of cirrhosis compared to drinking no coffee. The risk dropped by 43% with two cups of coffee a day, by 57% with three cups, and 65% with four cups.
But the meta-analysis raised some questions. One study found a stronger link between consumption of filtered coffee and a reduced risk of cirrhosis than with boiled coffee. Coffee contains many different chemical compounds. It is also not clear what is in coffee that may be protecting the liver.
There are some limitations to these findings. Not all the studies accounted for alcohol consumption, nor did they all account for other cirrhosis risk factors such as obesity and diabetes.
The study was published in the journal Alimentary Pharmacology and Therapeutics. You can read it here.