Cancer Prevention Program

Equol, Breast, and Bone Study

PI: Johanna Lampe PhD

In relation to human health, some studies have suggested that, compared to people who do not produce equol, equol-producers may have lower circulating concentrations of some hormones, and potentially a lower risk of hormone-dependent diseases such as breast and prostate cancers.

The Equol, Breast, and Bone (EBB) study, funded by the National Cancer Institute, is looking at whether there are differences between equol-producers and equol non-producers in circulating levels of hormones and markers of hormone exposure, including mammographic breast density and bone density.  About 200 premenopausal women, ages 40-45 years, who had recently had a screening mammogram at Group Health Cooperative (GHC), participated in the EBB study.  Women attended a clinic visit, timed to their menstrual cycle during which their bone density was measured and blood and urine samples were taken for measuring hormones.  The women were asked to eat one soy protein bar (in addition to their usual diet) for three days in a row, and to collect a urine sample on the morning of the fourth day.  The urine sample was mailed to the laboratory and analyzed for daidzein and equol for classifying individuals as equol-producers or non-producers.  We will compare hormones and hormone-related markers (breast and bone densities) among equol-producers and non-producers.  Recruitment has been completed for this study.