Researchers have found that caffeine changes the levels of estrogens in younger women.
This research has been published online in February issue of The American Journal of Clinical Nutrition.
Researchers have worked on more than 250 women in the age range of 18-44 for one to three times a week over two menstrual cycles. They took blood samples along with information about other behaviors like eating, exercise and smoking. On average, they consumed one cup of coffee daily.
Researchers have found that the caffeinated beverages can alter the levels of estrogen, after controlling a number of variables such as age and diet. However, the impact of caffeine on the level of estrogen changes with ethnic groups i.e. in white women, the level of estrogen lowered with caffeine while in Asian women the level of hormone increased with caffeine. In black women, researchers have not found any significant effect. This difference in the affect is still to work on.
Researchers have not worked on older women but the women of child bearing age can bear the effects. Women have not to worry about the level of changes as researchers have not found any affect on ovulation or overall health in short term.
“This is important physiologically because it helps us understand how caffeine is metabolized by different genetic groups,” said Dr. Enrique Schisterman, an author of the study and senior investigator at the National Institutes of Health. “But for women of reproductive age, drinking coffee will not alter their hormonal function in a clinically significant way.”
Karen C Schliep, Enrique F Schisterman, Sunni L Mumford, Anna Z Pollack, Cuilin Zhang, Aijun Ye, Joseph B Stanford, Ahmad O Hammoud, Christina A Porucznik, and Jean Wactawski-Wende, (2012). Caffeinated beverage intake and reproductive hormones among premenopausal women in the BioCycle Study. The American Journal of Clinical Nutrition, doi: 10.3945/ajcn.111.021287