Being overweight or obese, or consuming three or more alcoholic drinks a day, increases the risk of liver cancer, but researchers say there's "strong evidence" that drinking coffee can lower that risk.
That's the suggestion of a report from the World Cancer Research Fund International, which analyzed data from 34 worldwide studies involving more than 8 million people, 24,5000 of whom had liver cancer.
A team of researchers at Imperial College London gathered and reviewed the studies to try to determine what effect diet, physical activity and weight had on the risk levels for liver cancer.
An independent panel of international experts reviewed their findings, which were then released in the WCRF report.
Liver cancer now joins some other diseases that have seen their risk levels lowered by coffee consumption, including Alzheimer's disease, multiple sclerosis and Parkinson's disease, the researchers say.
The exact mechanism by which coffee can reduce the risk of liver cancer is unknown, they acknowledge, but their data showed coffee drinkers' risk of cancer was 29 percent lower.
That echoes earlier findings, they say.
"Mechanisms that support a protective effect of coffee on liver cancer relate largely to studies in animals, although some human studies contribute to the evidence," they wrote in their report. "Both coffee and coffee extracts have also been shown to reduce the expression of genes involved in inflammation, and the effects appear to be most pronounced in the liver."
Despite the positive findings about coffee consumption, there is still the fact that both obesity and alcohol consumption remain significant risk factors, the researchers' analysis showed.
Liver cancer, the second-leading cause of cancer deaths worldwide, is increasing in the United States where 69 percent of the population is obese or overweight, according to the Centers for Disease Control and Prevention.
And the new analysis suggests consuming more than 45 grams of alcohol — about three drinks — a day is a "convincing cause" of liver cancer.
So less alcohol, weight control and a cup of coffee is something many people might want to consider, researchers said.
"This is the first time there's been such a clear signal from a rigorous, systematic review on the links between obesity increasing risk of liver cancer and coffee decreasing risk," says Stephen Hursting, a researcher at the University of North Carolina at Chapel Hill.
The risk of liver cancer can be reduced by maintaining a healthy weight and by either abstaining from alcohol or limiting it to the recommended maximum of two drinks per day for men and one per day for women, the report authors said.
And a morning cup of java or two, it now appears.
