Abstract
Soy isoflavones such as genistein and daidzein are naturally occurring phytochemicals and exert estrogen-like activities through binding to two isoforms of the estrogen receptor (ER), ERα and ERβ. Estrogens including 17β-estradiol (E2) function not only in reproductive tissues, but also in peripheral tissues. Both ERα and ERβ are expressed in skeletal muscle. E2 decreases skeletal muscle mass in young females. These findings suggest that soy isoflavones and E2 have physiological roles in skeletal muscle. In this paper, we discuss the mechanism of E2-induced decrease in skeletal muscle mass as well as the beneficial effect of daidzein on skeletal muscle mass through ERα and ERβ in young females. Furthermore, we briefly review the present situation about the effects of isoflavones on the quantity and quality of skeletal muscle in postmenopausal females.
