Biologically active phytoestrogens are present in bourbon.

The nonethanol congeners of bourbon have been found to possess estrogenic activity when tested using an in vivo oophorectomized rat bioassay, as well as an in vivo estrogen receptor assay system. The phytoestrogen, biochanin A, as well as the plant sterol, beta-sitosterol, were identified in the bourbon preparation using gas chromatography/mass spectrometry. These findings, using three methodological approaches, demonstrate that bourbon contains at least one biologically active phytoestrogen and suggest that the effects of alcoholic beverage use or abuse, particularly as they relate to endocrine systems, should not be viewed as resulting solely from exposure to ethanol.