Health News: NIH Study Shows Caffeine Consumption Linked to Estrogen Changes

Asian women who consumed an average of 200 mg or more of caffeine a day—the equivalent of roughly two cups of coffee—had elevated estrogen levels when compared to women who consumed less, according to a study of reproductive age women by researchers at the National Institutes of Health.

However, white women who consumed 200 mg of caffeine a day had slightly lower estrogen levels than women who consumed less. Black women who consumed 200 mg or more of caffeine a day were found to have elevated estrogen levels, but this result was not statistically significant.

The changes in estrogen levels among the women who took part in the study did not appear to affect ovulation despite previous studies conducted in animals that had suggested that caffeine might interfere with ovulation.

“The results indicate that caffeine consumption among women of child-bearing age influences estrogen levels,” said Enrique Schisterman, PhD. “Short term, these variations in estrogen levels among different groups do not appear to have any pronounced effects. We know that variations in estrogen level are associated with such disorders as endometriosis, osteoporosis, and endometrial, breast, and ovarian cancers. Because long term caffeine consumption has the potential to influence estrogen levels over a long period of time, it makes sense to take caffeine consumption into account when designing studies to understand these disorders.”