Entrepreneurs sell creams and pills made from extracts of yams, wheat or soybeans as a “natural replacement” for estrogen for postmenopausal women, advertising that they will help to prevent heart attacks, strokes, osteoporosis, hot flushes, vaginal dryness, lowered I.Q or depression. Several scientific papers show that these products cannot be used to replace estrogen.
There are several ways to measure whether a product contains enough of the female hormone, estrogen, to affect a woman’s body. Estrogen thickens and lubricates vaginal tissue. A study in Fertility and Sterility showed that soybean estrogen does not thicken or lubricate vaginal cells (1).
The most sensitive test to see if a woman has estrogen is to measure the brain hormone called FSH that controls estrogen levels in the body. An article in the Journal of Endocrinology and Metabolism showed that soybean estrogen does not raise blood levels of estrogen and it does not lower blood levels of the brain hormone, FSH (2). Over-the-counter estrogenic creams and pills are not approved by the FDA for estrogen replacement, and cannot be guaranteed as safe. However, eating lots of plants may provide enough phytoestrogens to help prevent cancer. There are 17 animal studies that show that the phytoestrogens in soybeans, yams, wheat and other grasses may help to prevent cancer, and there is evidence that people who eat a lot of soybeans or yams have a reduced incidence of cancers of the prostate, breast and colon. (3,4)
By Gabe Mirkin, M.D., for CBS Radio News
1) JM Cline, JC Paschold, MS Anthony, IO Obasanjo, MR Adams. Effects of hormonal therapies and dietary soy phytoestrogens on vaginal cytology in surgically postmenopausal macaques. Fertility and Sterility 65: 5 (MAY 1996):1031-1035.
2) DD Baird, DM Umbach, L Lansdell, CL Hughes, KDR Setchell, CR Weinberg, AF Haney, AJ Wilcox, JA Mclachlan. Dietary intervention study to assess estrogenicity of dietary soy among postmenopausal women. Journal of Clinical Endocrinology and Metabolism 80: 5(MAY 1995):1685- 1690.
3) MJ Messina, V Persky, KDR Setchell, S Barnes. Soy Intake and Cancer Risk – A Review of the in Vitro and in Vivo Data. Nutrition and Cancer – an International Journal 1994;21(2):113-131.
4) MK Sung, CWC Kendall, MM Koo, AV Rao. Effect of soybean saponins and gypsophilla saponin on growth and viability of colon carcinoma cells in culture. Nutrition and Cancer – an International Journal 23: 3(1995):259-270.
5) Mirkin, G. Estrogens in Yams. JAMA, 1991(Feb 20);265(7):912.
6) JT Dwyer, BR Goldin, N Saul, L Gualtieri, S Barakat, H Adlercreutz. Tofu and Soy Drinks Contain Phytoestrogens.(in variable amounts) Journal of the American Dietetic Association 94: 7:JUL 1994:739-743.
7) AM Hutchins, JL Slavin, JW Lampe. Urinary isoflavonoid phytoestrogen and lignan excretion after consumption of fermented and unfermented soy products. Journal of the American Dietetic Association 95: 5(MAY 1995):545-551. Fermentation of soy decreased the isoflavone content of the product fed but increased the urinary isoflavonoid recovery. This finding suggests that fermentation increases availability of isoflavones in soy.
8) AL Murkies, C Lombard, BJG Strauss, G Wilcox, HG Burger, MS Morton. Dietary flour supplementation decreases post-menopausal hot flushes: Effect of soy and wheat. Maturitas 21: 3 (APR 1995):189-195.