The therapeutic potential of phytoestrogens

Phytoestrogens, such as the soya isoflavones genistein and daidzein, are cu rrently being extensively investigated through both molecular, preclinical and clinical studies to determine their potential health benefits. Phytoest rogens may protect against chronic diseases such as hormone-dependent cance r (e.g., breast and prostate cancer), cardiovascular disease and osteoporos is. Investigations of phytoestrogen metabolism and bioavailability are also of great relevance. Conversion by gut microflora of daizein to its isoflav an metabolite equol, which is a more potent oestrogen and anti-oxidant, occ urs only in some individuals (about 35% of subjects tested are equol excret ers). This has considerable implications for daidzein bioavailability and a lso for cancer risk. Oxidative damage has been implicated in the developmen t of heart disease and cancer and soya phytoestrogens have been reported to decrease plasma F-2-isoprostane concentrations (biomarker for in vivo lipi d peroxidation) and increase low density lipoprotein oxidation resistance. This anti-oxidant action of phytoestrogens could potentially contribute to their therapeutic efficacy. The findings from the current ongoing studies a re all likely to contribute to determining the potential use of phytoestrog ens as therapeutic agents.