Role of estrogens, selective estrogen receptor modulators and phytoestrogens in cardiovascular protection

A large body of evidence suggests that estrogen may be of benefit in reducing the risk of heart disease in postmenopausal women. The mechanism by which this benefit is conferred has been the subject of numerous investigations. In addition to the well known effects of estrogen on lipids, estrogen exerts a number of endothelium-dependent effects related to both vasodilation and nitric oxide metabolism that may have a favourable impact on vascular health. However, this benefit has not yet been confirmed in randomized clinical trials. Indeed, the only large trial published to date failed to document a benefit in women with established heart disease. Recent studies have shown that estrogen may also have some prothrombotic or proinflammatory effects that may offset other benefits. The extent to which selective estrogen receptor modulators and phytoestrogens share in the beneficial and potentially harmful effects of estrogen is not yet established.