The purpose of this study is to determine whether soy supplements can reduce hardening of
the arteries in postmenopausal women. This study will also determine the effects of soy
supplements on mental processes, bone mineral density, and breast tissue density.
Heart disease is the leading cause of death among women in the United States.
Atherosclerosis, a primary cause of heart disease, accounts for more than 485,000 heart
attacks and 370,000 strokes each year in American women. Data indicate that a woman's risk
of suffering from an atherosclerosis-related cardiovascular event significantly increases
after menopause; this risk may be due to reduced estrogen production associated with
menopause. Soy isoflavones are plant compounds that are structurally similar to human
estrogen. Evidence suggests that soy supplements may provide the same protection against
heart disease as estrogen in postmenopausal women. This study will determine the effects of
soy supplements on atherosclerosis progression, cognition, bone mineral density, and breast
tissue density changes in postmenopausal women.
This study will last 2.5 years. Participants will be randomly assigned to receive either soy
supplements or placebo daily for the duration of the study.
The active product, which will be given as two divided doses, is 25 g soy protein containing
85 mg aglycone weight naturally-occurring isoflavones (150 mg total isoflavone), genistein
45 mg aglycone weight (80 mg total weight), daidzein 35 mg aglycone weight (60 mg total
weight) and glycitein 5 mg aglycone weight (10 mg total weight). Blood collection, cognitive
tests, and mammograms will be used to assess participants at study entry, at each monthly
visit, and at study completion.
- Postmenopausal, defined as having no vaginal bleeding for at least 1 year and having
a serum estradiol level higher than 20 pg/ml
- Signs or history of cardiovascular disease
- Diabetes mellitus or fasting serum glucose of 140 mg/dL or greater
- Plasma triglyceride levels of 500 mg/dL or greater
- Serum creatinine greater than 2.0 mg/dL
- Uncontrolled hypertension
- Untreated thyroid disease
- Life expectancy less than 5 years
- Current use of hormone replacement therapy (HRT)
- Soy- or nut-related food allergies
- Follow a vegan diet