Phytoestrogens and bone

Practically all plant foods contain small amounts of the diverse phytoestro gen molecules that have the potential to improve health. Phytoestrogens, es pecially the soy-derived isoflavones, are receiving great scrutiny as food supplements for the purposes of both enhancing the health of tissues and pr eventing several common diseases, such as cardiovascular diseases, cancers of reproductive tissues and osteoporosis. Investigations of isoflavones, in particular, have recently become more prominent because of their oestrogen ic activities. These actions may be as either partial oestrogen agonists or antioestrogens (inhibitors of natural oestrogen activity). For example, th e isoflavones of soy, mainly genistein and daidzein, have been shown by at least three different laboratories to conserve bone in ovariectomized roden t models, and they probably have similar conservatory effects in higher mam malian species. Nevertheless, the only positive effects of phytoestrogens o n bone observed so far in post-menopausal women have been small and limited to the lumbar vertebrae. Additional information on human studies currently in progress is needed before the efficacy of these preparations in human s ubjects is known.