The nature and utility of the phytoestrogens: a review of the evidence.

Non-prescription remedies are becoming increasingly popular particularly amongst postmenopausal who in this market are the largest consumers. Phytoestrogens are a large family of plant derived molecules possessing various degrees oestrogen like activity. Food or food supplements containing phytoestrogen are often been advocated as an alternative to hormonal replacement therapy (HRT) in women with contraindications to the use of conventional oestrogen replacement, or simply wanting a more 'natural' alternatives. There have been several studies performed with phytoestrogen in various aspects of the postmenopausal women health. Results have been sometimes conflicting and difficult to interpret. The lack of knowledge of what precisely is the active ingredient, its minimally effective doses, the lack of standardisation of the preparations used as well as the large individual variability of metabolism of precursors introduced with the diet may all have played a role in confusing the issue about effectiveness of these compounds. Phytoestrogen fall in the gray area between food and drugs hence in spite of the vast public interest, there are no interests in company producing these supplements in investing in research from which they will not exclusively benefit from. It is difficult for the physician to know how to advise patients on this matter. In this paper we critically review the clinical data available to date in an attempt to answer some of the most commonly asked questions about dose and type of phytoestrogens supplementation most likely to be effective in different aspects of climacteric woman health.