Phyto-oestrogens: a potential role in the prevention of CHD?

CHD is a major cause of morbidity and mortality in women. The incidence of CHD in premenopausal women is low but increases substantially after the men opause, and this difference suggests that endogenous oestrogens are cardiop rotective. Observational prospective studies have consistently shown that e xogenous oestrogens also lower CHD risk. The biological mechanisms by which endogenous and exogenous oestrogens exert their protective effect are mult ifactorial, affecting lipids, carbohydrate metabolism, body fat distributio n and blood pressure. The prevention of CHD with oestrogen therapy is there fore aimed both at correction of the traditional risk factors and at direct control of vessel structure and function. The wide international variation in rates of CHD together with the lower mortality in sub-groups of the pop ulation suggests that a considerable proportion of CHD may be prevented by dietary modification. Since phytooestrogens are structually similar to oest rogen, they have the potential to mimic its effects in vivo. The hypocholes terolaemic effects of soyabean protein (rich in phyto-oestrogen precursors) are well established, but the underlying mechanism and atherogenic potenti al of these changes are unknown. One isoflavone, genistein, has been shown in vitro to exert effects which may slow the development of atherosclerotic disease. However, further studies are required to determine the dose-relat ed changes induced by phyto-oestrogens on serum lipoproteins, haemostasis a nd vascular function.