Health benefits of drinking coffee: protects women from uterine endometrial cancer

An interesting and useful piece of cancer research information discovered recently is that drinking coffee decreases the risk of endometrial cancer, the most frequent cancer of the uterus. The risk can fall by as much as 25% depending on how much coffee is consumed.

Researching for his PhD thesis, Youjin Je, under the supervision of Edward Giovannucci at the Harvard School of Public Health, analyzed a very large data set and confirmed coffee protects women from endometrial cancer.

Previous studies had shown that the risk of endometrial cancer is increased in women, who have high levels of estrogen and insulin in the blood. Estrogen in particular is thought to be important because it stimulates the endometrial cells which line the uterus to grow and divide. One of the effects of coffee is to lower the levels of both insulin and estrogen in the circulation. There were already suggestions from some epidemiological studies that coffee could be beneficial in reducing womens' cancer risk, but no definitive evidence.

The data used by Youjin Je came from the Nurses’ Health Study. This is a massive project, originally established at Harvard in 1976. It collects data at regular intervals by sending out questionnaires to a defined group of female registered nurses in order to obtain information about women’s health.

The coffee study used data collected from a food questionnaire answered in 1980 by 67,470 nurses between the ages of 34 and 59 years. During a follow-up period that lasted until 2006 (26 years), 672 of these women were diagnosed with endometrial cancer.

After accounting for all other factors that could potentially have an influence, Youjin Je found that women who said they consumed four or more cups of coffee a day were 25% less likely to get endometrial cancer than those who reported drinking less than one cup per day.

Translated into hard figures this means that the number of cases of endometrial cancer that will occur in a group of 100,000 women decreases from 35 cases in women who drink more than four cups of coffee daily are compared to 56 cases in those who drink less than one cup.

Drinking two or three cups each day was possibly associated with a slight decrease in risk of 7%. However, this result was not “statistically significant”, which means it could just as easily have been due to random coincidence as to a real effect.

The reduction in risk was slightly greater when only coffee with caffeine was taken into account, and somewhat lower when only decaffeinated coffee was taken into account. Although tea also contains some caffeine, it was not found to have any effect whatsoever..

The risk of endometrial cancer is greatly increased in obese women. Thus it is not surprising that these women gained the most benefit from the protective effect of coffee.This was explained by the researchers as probably being due to the fact that obese women have higher blood levels of insulin and estrogen. These are the specific risk factors for endometrial cancer that are decreased by drinking coffee.

In addition, by combating high levels of insulin and estrogen, coffee will have beneficial effects against health conditions that are associated with obesity, such as diabetes.

The fact that coffee protects against endometrial cancer is a further addition to the increasing body of evidence for the health benefits of drinking coffee. Female coffee lovers will no doubt be delighted that this cancer research information provides further encouragement for them to delight in their favorite beverage. However, before you celebrate the fact with a coffee, remember that, as pointed out by the researchers, adding excessive cream and/or sugar to coffee could well negate its potential benefits to your health.

Reference:
Youjin Je, et al.
A Prospective Cohort Study of Coffee Consumption and Risk of Endometrial Cancer over a 26-Year Follow-Up
published in: Cancer Epidemiology, Biomarkers and Prevention; vol. 20(no.12); pages 1–9, November 2011