Coffee can give you a kick on a cold morning, and it’s a great donut companion. Now researchers say a cup of joe may also help prevent liver cancer.

A study of more than 90,000 Japanese found that people who drank coffee daily or nearly every day had half the risk of hepatocellular carcinoma, a type of liver cancer, as those who never drank coffee. The study found that the protective effect occurred in people who drank one to two cups of coffee a day and increased at three to four cups.

There’s no word on whether it’s the caffeine that’s having the effect or something else. Decaf is rarely consumed in Japan and wasn’t included in the study. Coffee contains antioxidants, but so does green tea. Researchers found no reduced risk of liver cancer with green tea.

A separate study, conducted by researchers at Brigham and Women’s Hospital in Boston, found no relationship between coffee and colon or rectal cancer.

But it found a 52 percent decline in rectal cancer among people who regularly drank two or more cups of decaf compared to those who didn’t. However, the researchers said the link may be due to differences in lifestyle: Drinkers of decaffeinated coffee might be more health-conscious than those who drink caffeinated coffee.

Both studies appear in Wednesday’s issue of the Journal of the National Cancer Institute.