Phytoestrogens and cardiovascular health.

Coronary artery disease is the leading overall cause of mortality for women and increases dramatically after menopause. Estrogen has many beneficial cardiovascular actions although concerns have been raised about its effects on the progression of breast and uterine neoplasms and its tendency to increase coagulability. Selective estrogen agonists may be superior to conventional estrogens. A dietary source of a partial estrogen agonist is the plant-based group of phytoestrogens, which include isoflavones, lignans and coumestans. Phytoestrogens have a similar structure to estradiol and have weak affinity for the estrogen receptor. Epidemiologic data indicate that women ingesting high amounts of phytoestrogens, particularly as isoflavones in soy products, have less cardiovascular disease, breast and uterine cancer and menopausal symptoms than those eating Western diets. Preclinical and clinical studies have found that isoflavones have lipid-lowering effects as well as the ability to inhibit low-density lipoprotein oxidation. They have been shown to normalize vascular reactivity in estrogen-deprived primates. Furthermore, phytoestrogens have antineoplastic effects with inhibition of cellular proliferation as well as angiogenesis, properties that could be protective against cancer development. Finally, menopausal symptoms and bone density may be favorably influenced by phytoestrogens. In summary, phytoestrogens, in the form of dietary isoflavones, represent a new area to explore in pursuit of nutritional approaches to cardiovascular protection.