Soy Estrogen Alternative Study (SEA)

National Institutes of Health (NIH) logo

National Institutes of Health (NIH)

Status and phase

Phase 2


Menopausal Complaints
Endometrial Hyperplasia
Uterine Diseases
Cardiovascular Diseases
Heart Diseases


Behavioral: dietary supplements
Drug: estrogens, conjugated
Behavioral: diet, soy proteins

Study type


Funder types



P01HL045666 (U.S. NIH Grant/Contract)

Details and patient eligibility


To conduct a three-armed trial assessing the effect of soy phytoestrogens on menopausal complaints, plasma lipids and lipoproteins, vaginal bleeding and endometrial proliferation, and health related quality of life.

Full description

BACKGROUND: The results of many studies indicate that estrogen replacement therapy (ERT) reduces the risk of coronary heart disease (CHD) in postmenopausal women. However, less than 9 percent of these women choose to take ERT because of unwanted side effects and concerns about increased risk of cancer associated with ERT. Therefore, alternative therapies are needed. The isoflavonoids found in soy protein (specifically genistein) have many properties that may reduce the risk of coronary heart disease. These include favorable effects on plasma lipids and coronary artery vasomotion. Furthermore, genistein is a tyrosine kinase (TK) inhibitor with inhibitory effects on thrombin activity and TK receptor-linked mitogens that may be associated with atherogenesis and neointimal formation after angioplasty. DESIGN NARRATIVE: Randomized, double-blind, placebo-controlled. The women were randomized into one of three groups: placebo, conjugated equine estrogens, or soy supplementation. Primary endpoints were the impact on menopausal complaints such as hot flushes, mood lability, anxiety, sleep disturbances; effects on plasma lipids and lipoproteins, including lipoprotein (a); effects on vaginal bleeding and endometrial proliferation; changes in health-related quality of life. Secondary endpoints included: assessment of the impact of these interventions on the progression of carotid artery intimal medial wall thickening as assessed by B-mode ultrasonography; bone density and bone turnover; additional measures to monitor the compliance and safety of the intervention such as mammography, anticipated or known side effects of hormone replacement therapy, blood levels of genistein, and clinical outcomes such as hospitalizations, physician visits, and symptoms. The study ended in December, 1998. The study was a subproject within a program project on coronary atherosclerosis in females, primarily monkeys. Dr. Thomas B. Clarkson was the P.I. The subproject dollars were estimated based on the CRISP dollars assigned to the study which were approximately 12 percent of the total program project dollars and were broken down as follows: FY 1996 - 219,254; FY 1997 - $217,000; FY 1998 - $221,000. The study completion date listed in this record was obtained from the "End Date" entered in the Protocol Registration and Results System (PRS) record.




45 to 55 years old


No Healthy Volunteers

Inclusion and exclusion criteria

Perimenopausal/menopausal women, ages 45 to 55.

Trial contacts and locations



Data sourced from

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