Drinking coffee could help protect women over 50 from an aggressive form of breast cancer, Swedish scientists said Wednesday.
Researchers at the Karolinska Institute found that regular coffee drinkers were less likely to develop estrogen-receptor negative tumors -- a form of cancer that is resistant to a wide range of drugs.
Those who consume five or more cups a day are 57 percent less likely to develop the cancer, according to the study.
The team presented their findings after studying data from almost 6,000 women over the age of 50.
"A high daily intake of coffee was found to be associated with a significant decrease in ER-negative breast cancer among postmenopausal women," the researchers wrote in the journal Breast Cancer Research.
They said that coffee could contain compounds that affect various types of breast cancer in different ways and further study was needed.
"We believe that this may have something to do with the way the coffee was prepared, or the type of bean preferred," said lead author Dr. Jingmei Li. "It is unlikely that the protective effect is due to phytoestrogens present in coffee since there was no reduction in the incidence of ER-positive cancer in this study."
Cancer charities greeted the findings with caution and pointed out that other research has suggested coffee could increase the risk of some types of cancers.