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EDRI Federal Project Inventory:
66016-01 Effects of Soy Consumption on Estrogen in Women
- Sponsor Organization: NIH/NCI
- Project Title: 66016-01 EFFECTS OF SOY CONSUMPTION ON ESTROGEN IN WOMEN
- Project Focus: EXPOSURE ASSESSMENT
- Description: As the incidence of breast cancer continues to rise in postmenopausal
American women, it becomes more and moreimportant to develop safe,
effective methods of prevention. Numerous epidemiological and animal
studies show lowcancer rates associated with specific dietary
patterns, suggesting that diet may be an important factors in
cancerdevelopment. In fact, substances found in fruits, vegetables,
grains and legumes have been found to act asanticarcinogens via a
number of mechanisms. The purpose of this proposal is to investigate
isoflavones, a class ofphytoestrogens found primarily in soybeans,
that have been shown to act as anticarcinogens in a number of animal
andcell systems. As a result of their known antiestrogenic
properties, it has been proposed that isoflavones act
asanticarcinogens in part due to antiestrogenic effects. On the other
hand, although isoflavones are weak estrogens that arepredicted to
block high levels of endogenous estrogen in premenopausal women, it is
likely that they will actually beestrogenic in postmenopausal women.
It is therefore critical to differentiate the effects of isoflavones
in pre- andpostmenopausal women. The objective of this proposal is to
evaluate estrogen and isoflavone levels and action in pre-and
postmenopausal women after a defined consumption of isoflavone-rich
soy products. The specific objectives are 1)to determine the effects
of soy consumption on estrogen levels and action in pre- and
postmenopausal women; 2) toevaluate isoflavone absorption and
metabolism; and 3) to determine the effect of the menstrual cycle on
isoflavone andestrogen metabolism. Eighteen premenopausal and 18
postmenopausal women will be evaluated. The subjects willconsume 3
diets for about 13 weeks each; their habitual diets, their habitual
diets supplemented with a low level of soymilk (1 mg isoflavones/kg
body weight) and their habitual diets supplemented with a high level
of soy milk (2 mgisoflavone/lg body weight). In order to determine
the estrogenic or antiestogenic effects of the diet, a number of
estrogenendpoints will be measured, reflecting estrogen availability,
metabolism, excretion and action. These include
circulatingconcentrations of estrogens, androgens and SHBG, urinary
estrogen metabolites, fecal estrogens, menstrual cyclefunction,
endometrial histology and vaginal cytology. In addition, isoflavones
will be measured in the diet as well asurine, blood, and feces, for
determination of isoflavone absorption and metabolism. In this study
of premenopausalwomen, urinary isoflavones and estrogen metabolites
will be measured during each phase of the menstrual cycle,
fordetermination of the hormonal effects on estrogen and isoflavone
metabolism. Increased understanding of themechanisms by which dietary
components influence estrogen action may provide critical information
for thedevelopment of cancer preventive dietary recommendations.
- References:
- Category: MODELS
- Subcategory: BASIC RESEARCH
- Keywords for Experimental System/Species: HUMAN, FIELD STUDY
- Keywords for Experimental Endpoints: CARCINOGENESIS, EPIDEMIOLOGY, HORMONAL MEASURES
- Chemical Agents: PHYTOESTROGENS, ISOFLAVONES, ESTROGENS
- Performing Institution: UNIVERSITY OF MINNESOTA TWIN CITIES
- Contact: CONTRACT PERSON: ELAINE C. LEE; BUILDING 31; 11A21; NATIONAL CANCER
INSTITUTE, NIH,BETHESDA, MD 20892-2590; 301-496-5515;
LEEE@OD.NCI.NIH.GOV
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