Phytoestrogen use in menopausal patients: Current clinical approach

Menopause is associated with adverse changes in a woman's body, due to a new hormonal profile of reduced estrogen level. These "unfavorable" changes were found to contribute to the development of vasomotor symptoms, psychological disturbances, decreased cognitive functions, cardiovascular diseases, urogenital problems and osteoporosis. Although hormone replacement therapy (HRT), containing synthetic/animal estrogens, has confirmed to exert beneficial effects, it was found to produce numerous potentially dangerous adverse effects, which urged us to search for alternative estrogen-based treatments. Phytoestrogens are naturally occuring polycyclic phenols found in certain plants, that may, when ingested and metabolized, have weak estrogenic effects. Therefore, they can be used as an alternative to HRT in treating menopausal symptoms. They can be classified into two main groups: isoflavones (genistein, daidzein, formononetin, biochanin A, glycitein, puerarin and coumestrol) and lignans (matairesinol and secoisolariciresinol). Phytoestrogens are nowadays extracted from mostly soy and red clover, but can be obtained also from black cohosh, kudzu and other less common plants. Standardized dietary supplements of isoflavones contain at least 40 mg daily which is recognized as minimal dose delivering therapeutic benefit. Still, daily doses can have up to 120 milligrams of isoflavones with a positive safety profile. Frequency and expression level of hot flashes and night sweats can be decreased by isoflavone administration. However, total reduction is observed only in cases with mild vasomotor symptoms. The evidence has been somewhat less convincing, although promising, regarding the use of phytoestrogens for improving cognitive abilities and lowering the risk for dementia. Nevertheless, further studied to assess the clinical significance of these promising findings are needed. Isoflavones have shown their greatest effect for lowering plasma lipid concentrations. Therefore, their use may ultimately result in a reduced risk of heart disease. Isoflavone intake has also proven to have beneficial effect on increasing bone mass density, reducing bone loss and inhibiting the reduction of bone strength. The higher affinity to estrogen receptors (ER) beta compared to ER alpha, as well as the antioxidant activity, have been used as an explanation why phytoestrogens may reduce risk of breast and endometrial cancer. Currently there are no results that could support a biologically significant estrogenic influence of isoflavone on coagulation and fibrinolysis in postmenopausal women. Throughout a period of more than two decades no side effects from phytoestrogens use were detected so far; therefore they can be considered as both safe and reliable even for longer usage. Regarding the above mentioned phytoestrogens appear to have a positive health effect and consequently could be recommended for estrogen substitution for menopause disturbances and disorders.