Phytoestrogens are polyphenolic nonsteroidal plant compounds with have estrogen-like biological activity. According to their chemical structures, phytoestrogens might be organised into three central groups: flavonoids, lignans and stilbenes. Isoflavonoids, a subgroup of flavonoids, are the most studied ones for their biological activities, and they are present in many foods, such as soybeans. The most representative isoflavonoids are genistein and daidzein. Due to the fact that phytoestrogens are considerably similar in structure to estrogen17β-estradiol, they may display selective estrogen receptors (ERs) modulating activities; having a higher affinity for ERβ than for ERα. Several studies conducted in animals and humans have indicated that one of the main functions of phytoestrogens involves having a protective effect on certain conditions which are estrogen-dependent, such as symptoms related to menopause, and on estrogen-dependent diseases including prostate and breast cancer, osteoporosis and heart disease. However, phytoestrogens have also anti-estrogenic properties, which have raised concerns since they might cause adverse health effects. At the moment, the existing data are not enough to support a more sophisticated semiquantitative risk-benefit analysis. Hence, phytoestrogens are currently being studied for their role in human health.
Keywords: 17β-Estradiol, Apoptosis, Bone Tissue, Daidzein, Estrogen Receptors, Genistein, Hormonal Replacement Therapy, Hormone-Dependent Cancer, Isoflavones, Menopause, Osteoporosis, Phytoestrogens, Postmenopausal Women, Proliferation Cell, Protective Effects, Sarcopenia, Skeletal Muscle, Soybeans.