The health effects of phytoestrogens cancer

Breast cancer is one of the most common forms of cancer affecting women and, in Western countries, the incidence is rising. The risk of breast cancer increases markedly with age, although a decrease in the rate occurs after the menopause, suggesting that development is hormone-dependent. To date, a number of hormone-related risk factors have been identified (Bingham et al, 1998). Countries such as Japan have relatively low rates of breast cancer, which have been associated with consumption of a diet high in soy foods. Currently, however, the data from epidemiological studies is inconclusive. 

The pattern of hormonal risk factors involved in the development of endometrial cancer is similar to those associated with the development of breast cancer. In addition, there is substantial evidence to suggest that HRT can increase the risk (Beral et al, 1999 Bingham et al, 1998). Compared to the UK, the incidence of endometrial cancer in countries such as Japan is relatively low (Bingham et al, 1998). It has been suggested that dietary factors may be responsible for the reduced incidence, and there is indirect evidence from epidemiology studies which suggests that increased consumption of soy products may lower the risk of endometrial cancer. However, these data are not conclusive. To date, no studies have demonstrated a link between consumption of phytoestrogens and an increased risk of endometrial cancer. 

In countries such as Japan, although the incidence of latent, small or non-infiltrative prostate cancer is similar to that found in Western countries, the incidence of invasive cancer and associated mortality is far lower (Adlercreutz and Mazur, 1997). In Japan, diets have traditionally included large amounts of soy, and it has been proposed that this may be responsible for the protective effect. To date, however, the results are inconsistent, although there may be an inverse correlation with non-fermented soy foods. The active component 

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