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Soy foods contain trypsin inhibitors that inhibit protein digestion and affect pancreatic function. In test animals, diets high in trypsin inhibitors led to stunted growth and pancreatic disorders. Soy foods increase the body?s requirement for vitamin D, needed for strong bones and normal growth. Phytic acid in soy foods results in reduced bioavailabilty of iron and zinc which are required for the health and development of the brain and nervous system. Soy also lacks cholesterol, likewise essential for the development of the brain and nervous system. Megadoses of phytoestrogens in soy formula have been implicated in the current trend toward increasingly premature sexual development in girls and delayed or retarded sexual development in boys.
Soy isoflavones are phyto-endocrine disrupters. At dietary levels, they can prevent ovulation and may stimulate the growth of cancer cells. Eating as little as 30 grams (about 4 tablespoons) of soy per day can result in hypothyroidism with symptoms of lethargy, constipation, weight gain and fatigue.
Soy foods may stimulate the growth of estrogen-dependent tumors and cause thyroid problems. Low thyroid function is associated with difficulties in menopause.
Numerous animal studies show that soy foods cause infertility in animals. Soy consumption enhances hair growth in middle-aged men, indicating lowered testosterone levels. Japanese housewives feed tofu to their husbands frequently when they want to reduce his virility.
source: Soy on line
Soy can also mimic and potentate the effects of estrogen:
Interaction of Estrogenic Chemicals and Phytoestrogens with Estrogen Receptor ?
George G. J. M. Kuiper1, Josephine G. Lemmen, Bo Carlsson, J. Christopher Corton, Stephen H. Safe, Paul T. van der Saag, Bart van der Burg2 and Jan-?ke Gustafsson3
Center for Biotechnology and Department of Medical Nutrition (G.G.J.M.K., J.-?.G.), Karolinska Institute and KaroBio AB (B.C.) Huddinge, Sweden; Hubrecht Laboratory, Netherlands Institute for Developmental Biology (B.v.d.B., P.T.v.d.S., J.G.L.) Utrecht, The Netherlands; Chemical Industry Institute of Toxicology (J.C.C.), Research Triangle Park, North Carolina; Department of Veterinary Physiology and Pharmacology (S.H.S.), Texas A&M University, College Station, Texas 77843-4466
Address all correspondence and requests for reprints to: Dr. George Kuiper, Center for Biotechnology, NOVUM, S-14186 Huddinge, Sweden. E-mail: [email protected].
The rat, mouse and human estrogen receptor (ER) exists as two subtypes, ER{alpha} and ER?, which differ in the C-terminal ligand-binding domain and in the N-terminal transactivation domain. In this study, we investigated the estrogenic activity of environmental chemicals and phytoestrogens in competition binding assays with ER{alpha} or ER? protein, and in a transient gene expression assay using cells in which an acute estrogenic response is created by cotransfecting cultures with recombinant human ER{alpha} or ER? complementary DNA (cDNA) in the presence of an estrogen-dependent reporter plasmid.
Saturation ligand-binding analysis of human ER{alpha} and ER? protein revealed a single binding component for [3H]-17?-estradiol (E2) with high affinity [dissociation constant (Kd) = 0.05 - 0.1 nM]. All environmental estrogenic chemicals [polychlorinated hydroxybiphenyls, dichlorodiphenyltrichloroethane (DDT) and derivatives, alkylphenols, bisphenol A, methoxychlor and chlordecone] compete with E2 for binding to both ER subtypes with a similar preference and degree. In most instances the relative binding affinities (RBA) are at least 1000-fold lower than that of E2. Some phytoestrogens such as coumestrol, genistein, apigenin, naringenin, and kaempferol compete stronger with E2 for binding to ER? than to ER{alpha}. Estrogenic chemicals, as for instance nonylphenol, bisphenol A, o, p'-DDT and 2',4',6'-trichloro-4-biphenylol stimulate the transcriptional activity of ER{alpha} and ER? at concentrations of 100-1000 nM. Phytoestrogens, including genistein, coumestrol and zearalenone stimulate the transcriptional activity of both ER subtypes at concentrations of 1?10 nM. The ranking of the estrogenic potency of phytoestrogens for both ER subtypes in the transactivation assay is different; that is, E2 >> zearalenone = coumestrol > genistein > daidzein > apigenin = phloretin > biochanin A = kaempferol = naringenin > formononetin = ipriflavone = quercetin = chrysin for ER{alpha} and E2 >> genistein = coumestrol > zearalenone > daidzein > biochanin A = apigenin = kaempferol = naringenin > phloretin = quercetin = ipriflavone = formononetin = chrysin for ER?. Antiestrogenic activity of the phytoestrogens could not be detected, except for zearalenone which is a full agonist for ER{alpha} and a mixed agonist-antagonist for ER?. In summary, while the estrogenic potency of industrial-derived estrogenic chemicals is very limited, the estrogenic potency of phytoestrogens is significant, especially for ER?, and they may trigger many of the biological responses that are evoked by the physiological estrogens.
This article has been cited by other articles:
Home page
EndocrinologyHome page
B. R. Bhavnani, S.-P. Tam, and X. Lu
Structure Activity Relationships and Differential Interactions and Functional Activity of Various Equine Estrogens Mediated via Estrogen Receptors (ERs) ER{alpha} and ER{beta}
Endocrinology, October 1, 2008; 149(10): 4857 - 4870.
[Abstract] [Full Text] [PDF]
Soy isoflavones are phyto-endocrine disrupters. At dietary levels, they can prevent ovulation and may stimulate the growth of cancer cells. Eating as little as 30 grams (about 4 tablespoons) of soy per day can result in hypothyroidism with symptoms of lethargy, constipation, weight gain and fatigue.
Soy foods may stimulate the growth of estrogen-dependent tumors and cause thyroid problems. Low thyroid function is associated with difficulties in menopause.
Numerous animal studies show that soy foods cause infertility in animals. Soy consumption enhances hair growth in middle-aged men, indicating lowered testosterone levels. Japanese housewives feed tofu to their husbands frequently when they want to reduce his virility.
source: Soy on line
Soy can also mimic and potentate the effects of estrogen:
Interaction of Estrogenic Chemicals and Phytoestrogens with Estrogen Receptor ?
George G. J. M. Kuiper1, Josephine G. Lemmen, Bo Carlsson, J. Christopher Corton, Stephen H. Safe, Paul T. van der Saag, Bart van der Burg2 and Jan-?ke Gustafsson3
Center for Biotechnology and Department of Medical Nutrition (G.G.J.M.K., J.-?.G.), Karolinska Institute and KaroBio AB (B.C.) Huddinge, Sweden; Hubrecht Laboratory, Netherlands Institute for Developmental Biology (B.v.d.B., P.T.v.d.S., J.G.L.) Utrecht, The Netherlands; Chemical Industry Institute of Toxicology (J.C.C.), Research Triangle Park, North Carolina; Department of Veterinary Physiology and Pharmacology (S.H.S.), Texas A&M University, College Station, Texas 77843-4466
Address all correspondence and requests for reprints to: Dr. George Kuiper, Center for Biotechnology, NOVUM, S-14186 Huddinge, Sweden. E-mail: [email protected].
The rat, mouse and human estrogen receptor (ER) exists as two subtypes, ER{alpha} and ER?, which differ in the C-terminal ligand-binding domain and in the N-terminal transactivation domain. In this study, we investigated the estrogenic activity of environmental chemicals and phytoestrogens in competition binding assays with ER{alpha} or ER? protein, and in a transient gene expression assay using cells in which an acute estrogenic response is created by cotransfecting cultures with recombinant human ER{alpha} or ER? complementary DNA (cDNA) in the presence of an estrogen-dependent reporter plasmid.
Saturation ligand-binding analysis of human ER{alpha} and ER? protein revealed a single binding component for [3H]-17?-estradiol (E2) with high affinity [dissociation constant (Kd) = 0.05 - 0.1 nM]. All environmental estrogenic chemicals [polychlorinated hydroxybiphenyls, dichlorodiphenyltrichloroethane (DDT) and derivatives, alkylphenols, bisphenol A, methoxychlor and chlordecone] compete with E2 for binding to both ER subtypes with a similar preference and degree. In most instances the relative binding affinities (RBA) are at least 1000-fold lower than that of E2. Some phytoestrogens such as coumestrol, genistein, apigenin, naringenin, and kaempferol compete stronger with E2 for binding to ER? than to ER{alpha}. Estrogenic chemicals, as for instance nonylphenol, bisphenol A, o, p'-DDT and 2',4',6'-trichloro-4-biphenylol stimulate the transcriptional activity of ER{alpha} and ER? at concentrations of 100-1000 nM. Phytoestrogens, including genistein, coumestrol and zearalenone stimulate the transcriptional activity of both ER subtypes at concentrations of 1?10 nM. The ranking of the estrogenic potency of phytoestrogens for both ER subtypes in the transactivation assay is different; that is, E2 >> zearalenone = coumestrol > genistein > daidzein > apigenin = phloretin > biochanin A = kaempferol = naringenin > formononetin = ipriflavone = quercetin = chrysin for ER{alpha} and E2 >> genistein = coumestrol > zearalenone > daidzein > biochanin A = apigenin = kaempferol = naringenin > phloretin = quercetin = ipriflavone = formononetin = chrysin for ER?. Antiestrogenic activity of the phytoestrogens could not be detected, except for zearalenone which is a full agonist for ER{alpha} and a mixed agonist-antagonist for ER?. In summary, while the estrogenic potency of industrial-derived estrogenic chemicals is very limited, the estrogenic potency of phytoestrogens is significant, especially for ER?, and they may trigger many of the biological responses that are evoked by the physiological estrogens.
This article has been cited by other articles:
Home page
EndocrinologyHome page
B. R. Bhavnani, S.-P. Tam, and X. Lu
Structure Activity Relationships and Differential Interactions and Functional Activity of Various Equine Estrogens Mediated via Estrogen Receptors (ERs) ER{alpha} and ER{beta}
Endocrinology, October 1, 2008; 149(10): 4857 - 4870.
[Abstract] [Full Text] [PDF]
