Does Grapefruit Juice Affect Hormone Levels?

Grapefruit juice can affect estrogen hormone levels. Grapefruit may minimally increase a woman's natural estrogen levels. If consumed with drugs containing estrogen, such as birth control pills or drugs prescribed to treat the symptoms of menopause, grapefruit juice may dramatically increase your estrogen hormone levels.

Increased Estrogen and Breast Cancer Link

A joint University of Southern California and University of Hawaii study led by Kristine Monroe showed that grapefruit consumption can slightly increase the levels of the estrogen hormone in a woman's blood. The study, published in July 2007 in the "British Journal of Cancer" also reported that grapefruit consumption can increase a post-menopausal woman's chances of developing breast cancer by 30 percent, due to the association of excess estrogen leading to breast cancer.

Study Refuting Breast Cancer and Grapefruit Link

A follow-up study reported in "Cancer Causes and Control" in August 2009 found no relationship between grapefruit consumption and the risk of breast cancer. The study, led by Elizabeth Spencer of the University of Oxford, found no greater breast cancer risk for premenopausal or postmenopausal women who consumed grapefruit versus those who didn't, despite grapefruit's effect on the estrogen hormone. Catherine Collins, chief dietician at St George's Hospital in London, told "The Daily Telegraph" that grapefruit's ability to elevate estrogen hormone levels may make it beneficial in alleviating symptoms associated with menopause, such as osteoporosis.

Birth Control and Estrogen Increase

If you are take birth control pills, do not consume grapefruit or grapefruit juice. The combination could increase the estrogen hormone in your blood to a dangerous level. The small amount of estrogen slightly increases your risk of developing a blood clot. Grapefruit inhibits your CYP34A enzyme from metabolizing the estrogen in birth control pills. You may end up with a excess of estrogen in your bloodstream, increasing your risk of blood clots, which may cause gangrene, heart attacks and strokes.

Estrogen Drugs for Menopause and Grapefruit

Your doctor may prescribe estrogen to help alleviate some of the symptoms of menopause, including vulvar or vaginal atrophy and osteoporosis. A drug containing estradiol, such as estrace, may reduce your menopausal symptoms. If combined with grapefruit or grapefruit juice, you face an increased risk for blood clots. Before consuming grapefruit or grapefruit juice with any drug, consult a medical professional. Grapefruit adversely interacts with a long list of medications, not just those that contain hormones.