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Re: "Natural Estrogens"From: John Hellriegel (jhellrie@pce.net)Fri Jan 24 22:13:07 1997
Regarding “natural estrogens” and plant phytoestrogens, Bryan Jick wrote: Also, there are some food products which contain estradiol itself. In fact Estrace (pure 17-beta estradiol) is extracted from soybeans. Therefore TOFU can provide some degree of pure estradiol. Yams contain pure natural estrogen and progesterone, and yam extract is available in health-food stores as well (as creams or capsules). I would expect that if patients see reduction in H.F. from plant-derived estrogen sources, then reduction in total Chol, reduction in LDL, and improved HDL (all known properties of estrogen) would also occur. I agree that standardization would be helpful, since there is the risk that patients could self-medicate themselves into endometrial hyperplasia/carcinoma if they try hard enough! Comment: The assumption that because a substance exhibits estrogenic activity in one biological system or cell type or tissue, it will act as an estrogen in all biological systems or cell types or tissue is incorrect. Steroid hormones produce cellular responses by regulating gene activity. This involves a rather complex process mediated by an intracellular receptor(s) that affects gene transcription and also regulates post- transcription events and non-genomic events. Thus, an “estrogenic” substance my activate or inhibit some or all of these events in different cells (different tissues). An example of such a substance is tamoxifen which acts as an anti- estrogen on proliferating breast carcinoma cells, but as a weak estrogen on endometrial cells. Thus, while tamoxifen helps to prevent breast cancer, it is a cause of endometrial cancer. We do not know if a substance has estrogenic activity, anti-estrogenic activity, a mix of both, or no estrogenic activity until it is studied in each tissue. Hence, the only natural estrogens in man are estradiol, estriol and estrone. “Natural” estrogenic substances in plants and other animals may be most un-natural for man and cause undesirable effects. They may act as estrogens in one tissue and anti-estrogens in another. Theoretically, a substance could exhibit estrogenic activity by alleviating hot flushes and anti-estrogenic activity on bone exacerbating osteoporosis. I worry about the use of “natural estrogenic substances” because we know very little about their actions in various tissues in man. The activity (function) of these estrogenic substances should be investigated. We might find one which prevents breast and endometrial cancer as well as preventing heart disease and osteoporosis. Miracles happen from time to time.
-- John Hellriegel, Jr., MD, PhD Buffalo, NY jhellrie@pce.net
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