Dr. Edward Giovannucci, a professor of nutrition and epidemiology at the Harvard School of Public Health, said coffee is emerging as a protective agent in cancers that are linked to obesity, estrogen and insulin.
Giovannucci and Youjin Je, a doctoral candidate, and colleagues observed cumulative coffee intake in relation to endometrial cancer in 67,470 women who enrolled in the Nurses' Health Study.
During the course of 26 years of follow-up, researchers documented 672 cases of endometrial cancer.
The study -- published in the journal Cancer Epidemiology, Biomarkers & Prevention -- found drinking more than four cups of coffee per day was linked with a 25 percent reduced risk for endometrial cancer, while drinking between two and three cups per day was linked with a 7 percent reduced risk.
A similar link was seen in decaffeinated coffee. Drinking more than two cups of decaf per day was linked with a 22 percent reduced risk for endometrial cancer.
"Coffee has long been linked with smoking, and if you drink coffee and smoke, the positive effects of coffee are going to be more than outweighed by the negative effects of smoking," Giovannucci said in a statement. "However, laboratory testing has found that coffee has much more antioxidants than most vegetables and fruits."