We all love news that stimulants like coffee and chocolate are good for us. It turns out that drinking as much as four cups of coffee a day may reduce the risk of uterine cancer (also known as endometrial cancer) by almost 20 percent, according to a 2015 study.
The researchers analyzed data about a large pool of women — more than 450,000 — in two ongoing studies, including about 2,800 women who developed uterine cancer. The research team looked into their diets over time, following more than 80 foods, including drinks. Although one study seemed to show that women who ate more fat, carbohydrates, butter, yogurt, cheese, or potatoes were at more risk, those leads weren’t confirmed by the second study. However, drinking coffee was a clear plus.
The result made sense because coffee affects how much estrogen a women produces. Estrogen and progesterone are two hormones that regulate female reproduction. A surfeit of estrogen over progesterone can increase your risk of uterine cancer.
Many women take estrogen to make their menopause more comfortable — reducing hot flashes and vaginal dryness. But the extra estrogen can increase the risk of uterine cancer, so often women take progesterone or something like it alongside the estrogen, an approach called “combination hormone therapy.”
A history of no pregnancies or having many menstrual periods — usually because your menstrual cycle both began early and ended later in life — are both risk factors. More body fat can increase estrogen levels. As a result, uterine cancer is twice as common in women who are overweight, and more than three times as common in those who are obese, the American Cancer Society reports.
So if you’re an overweight childless woman who got her period early in life, you have reason to feel good about drinking that java! More than 50,000 American women are diagnosed every year with uterine cancer and about 8,000 die. Symptoms include pelvic pain, pain during sexual intercourse, and bleeding in between periods.
On the other hand, if you use birth control pills, your risk of uterine cancer is lower, especially if you take them for a long time. A history of many pregnancies helps, too.
Extra fat also can go along with type 2 diabetes, and, interestingly, coffee may also protect us against diabetes, another meta-analysis found. Evidence from more than a million participants and more than 45,000 cases of type 2 diabetes has suggested that drinking six cups of java a day is associated with a reduction in risk by a third, compared to drinking no coffee at all. The researchers argued that the effect was true for coffee, rather than just caffeine. One possible reason: chlorogenic acid, which is plentiful in coffee, seems to reduce the absorption of glucose in the intestines.
Other research suggests genetic differences in the effect of coffee on the body. A study of 250 premenopausal women who drank an average of one cup of coffee a day found that the coffee reduced estrogen levels slightly in white women, but increased it in Asians. However, caffeinated cola and green tea reduced estrogen regardless of race. The estrogen level changes did not affect ovulation.
Many people find that coffee is rough on their stomachs. If you tend to get acid reflux or gastritis, you’ll be warned against coffee. If you want to drink coffee, try low-acid types like Mexican and Sumatran, and dark-roasted beans. Some research suggests that roasting beans produces a component that blocks stomach-acid production; the darker the roast the more stomach-friendly your coffee may be.
April 20, 2015
Christopher Nystuen, MD, MBA