The value of phytoestrogens as a possible therapeutic option in postmenopausal women with coronary heart disease

Abstract

Large epidemiological studies have proved that the risk of coronary heart disease in postmenopausal women can be decreased by oestrogen replacement therapy. The effect is triggered by metabolic processes in the liver (decrease of LDL-cholesterol, increase of HDL-cholesterol) as well as by direct impact on the arterial wall (anti-oxidation, relaxation, anti-proliferation). The therapeutical usage of oestrogens is limited by an increased incidence of breast and endometrial cancer. Cyclic application of progestogens virtually eliminates the risk. Unfortunately, progestogens may antagonise the atheroprotective effect of oestrogens. Structurally modified oestrogens as well as selective oestrogen receptor modulators were investigated in clinical trials. They might provide the desired atheroprotective effects of oestrogen without negative side effects on the mammary gland or the endometrium. In this respect isoflavones also known as phytoestrogens, were analysed. They are widespread and occur naturally in many plants, especially in soy products. Cell culture and animal experiments as well as clinical studies revealed that phytoestrogens such as genistein and daidzein act atheroprotectively in the same way as oestrogen. Effects on the mammary gland or the endometrium could not be detected, but positive side effects on the bone metabolism and the decrease of certain types of cancer could be observed. In total, the therapeutical application of phytoestrogens in postmenopausal women seems to be of real and great benefit. We conclude that in women the risk of death from coronary heart disease increases after the onset of menopause. Recently discovered properties of phyto-oestrogens seem to be of great benefit as they do not seem to have any side effects on the mammary gland and the endometrium which are limiting factors for oestrogen replacement therapy.