Drinking about two cups of coffee a day is able to raise estrogen levels in Asian women of childbearing age, but not in white and black women, according to scientists whose conclusions were published in the American Journal of Clinical Nutrition.
In the short term, changes in estrogen levels do not have any clear effect. However, the effect of long-term coffee consumption on the level of this hormone should be taken into account when analyzing diseases such as endometriosis, osteoporosis and cancers of the endometrium, breast and ovaries, as they are associated with changes in estrogen levels, says Dr. Enrique Schisterman of the US National Institutes of Health.
Over 250 women aged 18 to 44 participated in the research. Scientists took into account the different phases of the menstrual cycle and factors such as diet, level of physical activity, sleep and smoking.
The results differed slightly depending on the analyzed source of caffeine. Consuming at least 200 milligrams of caffeine from coffee increased the level of estrogen in Asian women, but in white women it translated into a slight reduction in the level of this hormone, and in black women no statistically significant difference was noticed. When soda and tea were the source of caffeine, increases in estrogen levels were seen in all three groups.
Contrary to the results of animal studies, the current analysis did not show that changes in estrogen levels affect ovulation.