Phytoestrogens: The Food of the Menopause?

Abstract

Objectives: to provide an overview of the literature on the subject of phytoestrogens, with particular emphasis on their role in menopause, and to a lesser extent, on women’s health.Data Sources: a ten-year Medline search using phytoestrogens as both a subject and a textword. The author’s personal files and the reference lists from selected articles were explored. The Internet was selectively explored.Study Selection: review articles and those dealing with women’s health or menopausal issues were selected as were other studies if they shed light on the primary objective.Data Extraction: data were heterogeneous and not appropriate for formal analysis.Results: the phytoestrogens are non-steroidal, diphenolic compounds that occur naturally in plants. Soybeans and flaxseed both contain large amounts of isoflavones and lignans, which are metabolized in the gut to compounds which bind to the estrogen receptor and have weak estrogenic or anti-estrogenic activity. Epidemiological evidence of a lower incidence of menopausal symptoms, breast, endometrial and prostate cancer, and of a lower rate of cardiovascular disease in populations consuming large amounts of the phytoestrogens in their diet, has led to interest in their preventive benefits. Phytoestrogens appear to increase sex hormone binding globulin levels, compete for aromatase and inhibit tyrosine kinase. Individuals vary greatly in how they metabolize and absorb these substances. Clinically, such substances may reduce the severity of menopausal flushing.Conclusions: physicians seeing menopausal women should be aware of these compounds and of the type and amount of dietary supplements their patients may be taking.