Soya phytoestrogen

Clarke, D.B., Barnes, K.A. and Lloyd, A.S. (2004) Determination of unusual soya and non-soya phytoestrogen sources in beer, fish products and other foods. FoodAddit. Contam., 21,949-962. 

Thus, it is apparent that soya, some soya products and linseed oil influence blood lipid levels, particularly cholesterol and LDL cholesterol. While the extent of the reduction appears to largely depend on an individual s initial serum cholesterol level, the maximum reductions observed are of the order of 10-15%. For hyperlipidemic individuals this may not be a marked reduction, but such an effect on the general population may well have a beneficial effect on the overall incidence of cardiovascular disease and atherosclerosis. The possibility that non-phytoestrogenic dietary components may contribute to the hypocholes-terolemic properties cannot, however, be discounted. Indeed, certain types of dietary fibre have been shown to have a hypolipidemic effect via their ability to increase faecal excretion rates. 

BARNES, K.A., SMITH, R.A., WILLIAMS, K., DAMANT, A.P., SHEPHERD, MJ.A., Microbore high performance liquid chromatography/electrospray ionization mass spectrometry method for the determination of the phytoestrogens genistein and daidzein in comminuted baby foods and soya flour, Rapid Comm. Mass Spectrom., 1998,12,130-138. 

Tsangalis D, Wilcox G, Shah NP, Stojanovska L. 2005. Bioavailability of isoflavone phytoestrogens in postmenopausal women consuming soya milk fermented with probiotic bifidobacteria. Br J Nutr 93 867-877. 

Calculation of the dietary intakes of estrogenic pesticides compared to the intakes of natural phytoestrogens present in soya and other legumes clearly shows that pesticides represent a drop in the ocean of dietary xenoestrogen intake (Table 10.3) (Shaw and McCully, 2000). 

Phytoestrogens (dietary sources such as cereals/seeds, linseed/pulses, particularly soya/vegetables) may help to reduce most symptoms. 

Isoflavones are derivatives of the parent compound isoflavone (3-phenylc,hromone 3-phenylbenzopyran-4-one). The dietary isoflavone phytoestrogens (notably from soya bean) that bind to the oestrogen receptor are the best known, namely daidzein (7,4 -dihydroxy-isoflavone), genistein (5,7,4 -trihydroxyisoflavone) and glycitein (7-hydroxy-6-methoxy-isoflavone) and their respective pro-phytoestrogen 7-0-glucoside precursors daidzin,... 

High consumption of legumes, especially soya beans, which are rich sources of phytoestrogens, is associated with lower incidence of breast and uterine cancer, as well as a lower incidence of osteoporosis. The estrogenic action is probably responsible for the effects on the development of osteoporosis, whereas three factors may be involved in the effect on hormone-dependent cancer ... 

Hutabarat, L.S., Mulholland, M., and Greenfield, H. (1998) Development and validation of an isocratic high-performance liquid chromatographic method for quantitative determination of phytoestrogens in soya bean. Journal of Chromatography A 795, 377-382. 

Isoflavones have been found in higher concentrations only in the legume family of plants (Fabaceae) and occur in significant amounts only in soybeans and soya bean products. Isoflavones exhibit oestrogenic activity, but also further toxic effects, and are often classified, together with other active compounds, as phytoestrogens (see Section 10.4). 

Wang, G., Kuan, S.S., and Francis, O.J., A simplified HPLC method for the determination of phytoestrogens in soya bean and its processed products, J. Agric. Food. Chem., 38, 185-190, 1990. 

The probable beneficial effects of phytoestrogens against breast cancer are likely to be mediated via numerous mechanisms. However, it has not been fully established whether the protective effects of soya and cereals result from their phytoestrogen content or from some other effect. 

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