Estrogen is used as a component of birth control pills, as well as for preventing osteoporosis and heart disease in menopausal women.
Some estrogen products contain the hormone in different forms. For example, certain products such as Ortho Dienestrol Vaginal Cream contain estrogen as dienestrol. Medications containing a form of estrogen called estradiol include:
Premarin, Cenestin, Prempro, and Premphase contain another form of estrogen called conjugated estrogens. Other forms of estrogen and some of their brand names include diethylstilbestrol diphosphate (Stilphostrol), estrone (Kestrone-5), esterified estrogens (Estratab, Menest), estropipate (Ogen, Ortho-Est), and ethinyl estradiol (Estinyl) among others.
Potential Benefits and Risks
When the two are taken together, ipriflavone may increase estrogen's ability to protect bone.2-6 This may allow you to use a lower dose of estrogen and still receive its beneficial effects.
However, there may be risks involved. Although ipriflavone itself probably does not affect tissues other than bone, some evidence suggests that when it is combined with estrogen, estrogen's effects on the uterus are increased.7,8 This might mean that risk of uterine cancer would be elevated by the combination.
It should be possible to overcome this risk by taking progesterone along with estrogen, which is standard medical practice. However, this finding does make one wonder whether ipriflavone-estrogen combinations raise the risk of breast cancer as well, an estrogen side effect that has no easy solution. At present, there is no available information on this important subject.
Possible Harmful Interaction
The supplement resveratrol has a chemical structure similar to that of the synthetic estrogen diethylstilbestrol and produces estrogenic-like effects.14 For this reason, it should not be combined with prescription estrogen products.
Theoretical Harmful Interaction
Indole-3-carbinol (I3C) is a substance found in broccoli that is thought to have cancer preventive effects. One of its mechanisms of action is thought to involve facilitating the inactivation of estrogen, as well as blocking its effects on cells.13,17-18 The net result could be decreased effectiveness of medications containing estrogen.
Theoretical Harmful Interaction
Because of its effects on the pituitary gland, chasteberry might unpredictably alter the effects of estrogen-replacement therapy.
Interaction Unlikely or Probably Insignificant
The herb dong quai (Angelica sinensis) is used for menstrual disorders.
Because dong quai contains beta-sitosterol, a phytoestrogen,15 there have been concerns that taking the herb with estrogen might add to estrogen-related side effects. However, a 24-week, placebo-controlled study of 74 postmenopausal women found no estrogen-like effects or reduction of menopausal symptoms associated with taking dong quai.16
Therefore, dong quai seems unlikely to increase estrogen-related side effects.
1. Roe D and Campbell T. Drugs and nutrients: The interactive effects. New York, NY: Marcel Dekker; 1984: 479.
2. Choi YK, Han IK, and Yoon HK. Ipriflavone for the treatment of osteoporosis. Osteoporos Int. 1997;7(Suppl 3):S174-S178.
3. de Aloysio D, Gambacciani M, Altieri P, et al. Bone density changes in postmenopausal women with the administration of ipriflavone alone or in association with low-dose ERT. Gynecol Endocrinol 1997;11: 289-293.
4. Gambacciani M, Ciaponi M, Cappagli B, et al. Effects of combined low dose of the isoflavone derivative ipriflavone and estrogen replacement on bone mineral density and metabolism in postmenopausal women. Maturitas. 1997;28:75-81.
5. Melis GB, Paoletti AM, Bartolini R, et al. Ipriflavone and low doses of estrogen in the prevention of bone mineral loss in climacterium. Bone Miner. 1992;19:S49-S56.
6. Nozaki M, Hashimoto K, et al. Treatment of bone loss in oophorectomized women with a combination of ipriflavone and conjugated equine estrogen. Int J Gyn Ob. 1998;62:69-75.
7. Petilli M, et al. Interactions between ipriflavone and the estrogen receptor. Calcif Tissue Int. 1995;56:160-165.
8. Cecchini MG, et al. Ipriflavone inhibits bone resorption in intact and ovariectomized rats. Calcif Tissue Int. 1997;61:S9-S11.
9. Rivers JM and Devine M. Plasma ascorbic acid concentrations and oral contraceptives. Am J Clin Nutr. 1972;25:684-689.
10. Pronsky Z, ed. Powers and Moore's food medication interactions. 10th ed. Pottstown, PA: Food-Medication Interactions; 1997: 99.
11. Nielsen FH, Hunt CD, Mullen LM, Hunt JR. Effect of dietary boron on mineral, estrogen, and testosterone metabolism in postmenopausal women. FASEB J 1987;1:394-397.
12. Naghii and Samman S. The effect of boron supplementation on its urinary excretion and selected cardiovascular risk factors in healthy male subjects. Biol Trace Elem Res 1997;56:273-286.
13. Meng Q, Yuan F, Goldberg ID, et al. Indole-3-carbinol is a negative regulator of estrogen receptor-alpha signaling in human tumor cells. J Nutr. 2000;130:2927-293l.
14. Gehm BD, McAndrews JM, Chien PY, et al. Resveratrol, a polyphenolic compound found in grapes and wine, is an agonist for the estrogen receptor. Proc Natl Acad Sci USA. 1997;94:14138-14143.
15. Wilbur P. The phyto-oestrogen debate. Eur J Herbal Med. 1196;2:20-26.
16. Hirata JD, Swiersz LM, Zell B, et al. Does dong quai have estrogenic effects in postmenopausal women? A double-blind, placebo-controlled trial. Fertil Steril. 1997;68:981-986.
17. Michnovicz JJ. Increased estrogen 2-hydroxylation in obese women using oral indole-3-carbinol. Int J Obes Relat Metab Disord. 1998;22:227-229.
18. Bradlow HL, Sepkovic DW, Telang NT, et al. Multifunctional aspects of the action of indole-3-carbinol as an antitumor agent. Ann N Y Acad Sci. 1999;889:204-213.
19. Yuan F, Chen DZ, Liu K, et al. Anti-estrogenic activities of indole-3-carbinol in cervical cells: implication for prevention of cervical cancer. Anticancer Res. 1999;19:1673-1680.
20. Zhu BT, Loder DP, Cai MX et al. Dietary administration of an extract from rosemary leaves enhances the liver microsomal metabolism of endogenous estrogens and decreases their uterotropic action in CD-1 mice. Carcinogenesis. 1998;19:1821-1827.
Last reviewed December 2015 by EBSCO CAM Review Board
Last Updated: 12/15/2015
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