Wellness Learning Center
Women's Health
Phytoestrogens and their Role in Women’s Health
Roger W. Mustalish, MPH, Ph.D.
Sue H. Mustalish, RN, HNC
This year finds an estimated 50 million menopausal women in the United States; with over 8 million employing synthetic hormonal replacement therapy (HRT), despite mounting evidence that HRT significantly elevates risk of endometrial and breast cancers, among other side effects (Laux and Conrad). The monolithic approach to menopause that HRT represents belies, however, the very individual nature of the menopausal experience. Were one to interview 10 menopausal women about their symptoms and their impact on quality of life, likely no one would be surprised if 10 different scenarios were expressed. When one adds to this other corollary conditions that are not strictly menopausal, such as stress, insomnia, diet, weight, and activity level, but which can, in turn, exacerbate menopausal symptoms, one quickly sees that for any given woman, an integrated, holistic approach will most likely provide the greatest degree of individual relief during this life transition. It is in this context that botanical medicines can play a significant role. It must be emphasized, however, that simply substituting a phyto-estrogen (plant estrogen) for a synthetic estrogen misses the entire concept of dealing with the whole person, and is likely to meet with lesser degrees of success and satisfaction.
A growing body of research is establishing the efficacy of phytoestrogens in alleviating typical symptoms of menopause, i.e. hot flashes, anxiety, vaginal dryness, fatigue, and depression, as well as associated risks of osteoporosis and hearth disease. But exactly what are phytoestrogens? There is considerable confusion in the literature regarding the definition. Stansbury explains that some authors reserve the term for plants that specifically contain steroids such as estrone, estradiol, and estriol. However, plants (i.e. pomegranates) containing steroids identical to human steroids are very rare, and the concentration of active compounds very low. Therefore, the term phytoestrogen is also used more broadly to include plant constituents that have estrogenic effects. Estrogenic plants directly stimulate or indirectly influence the hormonal system but do not contain any steroids.
Isoflavonoids and lignans are two of the major food constituents clinically proven to have positive estrogenic activities. They possess a terminal phenolic group, similar to that found on estrogen, that permits them to bind to estrogen receptor sites (Trickey).
- Coumestans. Common in soy products, beans, peas and other legumes. Coumestrol is believed to be the most important, and has substantially greater estrogenic activity than isoflavones, but is about 160 times less powerful than estradiol.
- Isoflavones. Genistein, daidzein, biochanin A, and formononetin are the most important, and are also found in soy and legumes.
- Lignans. Found in fiber-rich foods, they undergo bacterial modification in the bowel into estrogenically active mammalian lignans, of which enterlactone and enterodiol are the most important. Flax seed is particularly rich in lignans (Phipps, et al.).
Although phytoestrogens are weak estrogens, Fugh-Berman notes that in adequate doses they can still stimulate biological activity comparable to endogenous estrogens, and thus have therapeutic benefit.
Reviewing the results of several clinical studies on incorporating soy into one’s diet, Holt concludes that 50-100 mg/day of isoflavones, as supplements or as soy products, can significantly relieve menopausal symptoms, especially frequency and severity of hot flashes. In addition, Fugh-Berman cites two studies demonstrating positive effects on vaginal epithelial cells following incorporation of soy products into the diet. While the beneficial role of soy isoflavones is well documented in the literature, Holt also cautions against excessive doses (well above 100 mg/d) noting extensive studies of undesirable side effects.
For some women, menopausal symptoms that do not respond to integrated modalities including phytoestrogens may find it necessary to consider hormone replacement therapy. But there exists a natural alternative to the synthetic hormones such as Premarin, derived from pregnant horse urine. Lee, Wright and Morgenthaler, and Laux and Conrad describe in detail natural HRT. Under careful laboratory controlled conditions, plant estrogens that are not active in their natural state, such as those found in the Mexican Wild Yam, are chemically modified to be identical to human estrogen. The advantage is estrogen replacement therapy without the side effects associated with synthetic HRT. As the authors caution, however, natural HRT must be carefully conducted in a manner that respects the unique experiences of the woman and her particular constitution.
In addition to menopausal symptoms, other female reproductive conditions have been clinically proven to respond to botanical therapies. A standardized extract of chaste tree berries (Vitex agnus-castus) is commonly used to treat amenorrhea; dysmenorrhea responds to dong quai (Angelica sinensis); and dong quai or shepherd’s purse (Capsella bursa-pastoris) are useful for menorrhagia (Murray). Murray also reports that licorice (Glycyrrhiza glabra) and especially black cohosh (Cimicifuga racemosa) are particularly useful for alleviating premenstrual syndrome (PMS).
Approximately 3,500 women will enter menopause today. Their stories are as individual as they are, and how they choose to respond to the challenge of this transition ought to be similarly individualized. Botanical therapies, not used alone, but in concert with other integrated modalities, hold promise in aiding the woman and her health care practitioner in successfully addressing undesirable symptoms while honoring the process and the woman.
Literature Cited
Fugh-Berman, A. 1998. Phytoestrogens: Natural Hormone Replacement Therapy? Alternative Therapies in Women’s Health. Vol.1(1): 1-8.
Holt, S. Phytoestrogens for a Healthier Menopause. 1997. Alternative and Complementary Therapies. (June):187-193.
Laux, M. and C. Conrad. 1998. Natural Woman, Natural Menopause. New York, NY: Harper Perennial.
Lee, F. 1996. What Your Doctor May Not Tell You About Menopause. New York, NY: Warner Books.
Murray, M. Herbs for Her. 1996. Let’s Live. (May): 35-37.
Phipps, W., et al. 1993. Effect of Flax Seed Ingestion on the Menstrual Cycle. Journal of Clinical Endocrinology and Metabolism. Vol. 7(5): 1215-1219.
Stansbury, J. 1997. Botanical Medicines Acting on the Female Reproductive System. Proceedings of the 8th Annual Symposium of the American Herbalists Guild. Cincinnati, OH. (October 17-20): 166-172.
Trickey, R. 1998. Women, Hormones and the Menstrual Cycle. Australia: Allen Unwin.
Wright, J. and J. Margenthaler. 1997. Natural Hormone Replacement. Petaluma, CA: Smart Publications.
