Women who drink at least four cups of coffee a day may be lowering their risk of getting endometrial cancer, a cancer of the lining of the uterus, researchers say.
That's the finding of a study at the Imperial College London on how foods impact the risk of endometriosis, a study that looked at 84 different foods and nutrients in women's diets before zeroing in on coffee, finding heavy coffee drinkers had an 18 percent reduced risk compared to women whose daily intake was just one or two cups.
"For most other dietary factors, there was no consistent association with endometrial cancer risk," says lead researcher Melissa Merritt.
Previous studies led to the focus on coffee, the researchers said.
"We were not surprised by the results that a high versus low intake of coffee was associated with a reduced risk for endometrial cancer, because they were consistent with what has been observed in previous studies," Merritt says.
The American Cancer Society says around 55,000 new cases of new cases of endometrial cancer can be expected in the United States this year and around 10,000 women will die from the disease.
The researchers were quick to point out their study demonstrated a link, not a cause-and-effect relationship, between the consumption of coffee and a reduced risk of endometriosis.
And because the study did not attempt to differentiate effects between regular and decaffeinated coffee, Merritt said she could offer guidance as to which one might be better than the other.
The exact mechanism by which coffee might impact endometrial cancer risk is unknown, but researchers note coffee is known to be a good source of antioxidants, which prevent or slow the rate of cell damage from free radicals that ultimately age the body but can also result in cancers.
It's probably not the caffeine in coffee that's involved, experts point out, because other foods containing caffeine, such as chocolate, have not demonstrated any similar link to a lower risk of endometrial cancer.
Still, the new study is valuable because it is "validating other studies showing coffee has a beneficial effect in decreasing endometrial cancer," says Dr. Robert Morgan, a professor of medical oncology at the City of Hope Comprehensive Cancer Center in Duarte, Calif.
However, since some other studies have failed to find a link, "the jury is still out," says Morgan, who was not involved in the British study.