Soy Estrogen Alternative Study (SEA)

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.