Drinking more than two cups of coffee daily may boost estrogen levels in women and could exacerbate conditions such as endometriosis and breast pain, study findings from Brigham and Women's Hospital in Boston, Massachusetts suggest.
Women who drank the most coffee had higher levels of estradiol, a naturally occurring form of estrogen, during days 1 to 5 of the menstrual cycle. Higher estrogen levels would not be beneficial for women who have estrogen sensitive health conditions such as endometriosis, breast pain and family histories of breast or ovarian cancer, especially arising premenopausally.
The study included nearly 500 women aged 36 to 45 who were not pregnant, breast-feeding or taking hormones. All women answered questions about their diets, smoking habits, height and weight. Researchers measured the women's hormone levels during days 1 to 5 of their menstrual cycle. Women who consumed the most cholesterol and alcohol, and those who consumed more than one cup of coffee a day had significantly higher levels of estrogen during the early follicular phase of their menstrual cycle.
Women who consumed at least 500 milligrams of caffeine daily, the equivalent of four or five cups of coffee, had nearly 70% more estrogen during the early follicular phase than women consuming no more than 100 mg of caffeine daily, or less than one cup of coffee.
Women aged 40 and older and those who smoked had higher levels of follicle stimulating hormone (FSH), which reflects the number of eggs remaining in a woman's ovaries. FSH tends to increase with age, and high levels of the hormone correspond with fewer eggs. Therefore, the observation that smokers have higher FSH levels suggests that their ovaries are "older" than their chronological age, Cramer explained.
The researchers advise women to drink no more than two cups of coffee per day.
All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.