Study Links Coffee, Cancer

Researchers at the Harvard School of Public Health recently published evidence linking coffee with a decrease in risk of developing endometrial cancer after observing that women who drank more than four cups of coffee per day over the course of many years were less likely to develop cancer in the lining of their uterus.

These results follow a series of studies released in recent years indicating that coffee may have a number of long-term health benefits including decreased risk of Parkinson’s disease, depression, and type 2 diabetes.

Researchers examined cumulative coffee intake in relation to endometrial cancer in 67,470 women between the ages of 34 and 59. Over the course of 26 years, they documented 672 cases of endometrial cancer among the participants.

The researchers found that drinking more than four cups of coffee per day was linked with a 25 percent reduced risk for endometrial cancer and that drinking between two and three cups per day was linked with a 7 percent reduced risk.

The results may stem from the fact that coffee appears to reduce insulin levels and free estrogen levels, which are both risk factors associated with endometrial cancer, according to Edward L. Giovannucci ’80, lead author of the study and a professor at the School of Public Health.

A similar link was seen in decaffeinated coffee, where drinking more than two cups per day was linked with a 22 percent reduced risk for endometrial cancer, according to Giovannucci.

Giovannucci said that he would not recommend that women drink more coffee solely to lower the risk of endometrial cancer.

“However, women consuming coffee should feel some reassurance that coffee in general is not a harmful substance, and may even offer some health benefits,” Giovannucci said.

Researchers warn that drinking too much caffeine, or using substantial sugar and cream with the coffee, may offset any health benefits.

The added calories and fat could contribute to weight gain and insulin resistance.

“While coffee may play a role, maintaining a normal body weight and being physically active are most important,” Giovannucci said.

Other experts in the field said that coffee-drinking may be associated with other behaviors that would lead to reduced cancer risk.

“Maybe caffeine drinkers are also smokers or have a lower BMI ... both of which would contribute to lower risk of endometrial cancer,” Elena S. Ratner, assistant professor of Obstetrics, Gynecology, and Reproductive Sciences at the Yale School of Medicine, wrote in an email.

Coffee-drinkers might also forgo other, more harmful beverages.

“Maybe women who drink lots of coffee are not drinking sugared beverages that lead to weight gain,” Thomas J. Herzog, director of the Division of Gynecologic Oncology at Columbia University, wrote in an email.

“I hope this study will lead to further inquiries about the effect of coffee on cancer because in this and similar studies, coffee intake is self-selected and not randomized,” said Giovannucci.