Cancer phytoestrogens

Prostate Cancer. Evidence that phytoestrogens can influence the incidence of male-speciflc diseases is restricted to prostate cancer, and is largely of an observational nature. In the UK, prostate cancer is the most common hormone-related cancer in men. However, like breast cancer in women, it is comparatively rare as a clinically evident disease in men living in Asian countries. 

Thus, it is uncertain to what extent the apparent protective effects of fruit and vegetable consumption on risk of stomach cancer can be attributable to their phytoestrogen content. This appears not to have been studied directly, and other constituents such as ascorbic acid (vitamin C), a-tocopherol (vitamin E) and /1-carotene may be potentially protective. 

Adlercreutz H. 1995. Phytoestrogens Epidemiology and a possible role in cancer protection. Environ Health Perspect 103(Supplement 7) 103-112. 

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. 

There is much interest in the possible hormonal effects of phytoestrogens in both men and women. The majority of studies conducted in women have examined the ability of phytoestrogens to alleviate menopausal symptoms. Whilst hormone replacement therapy is recommended for women experiencing menopausal symptoms, there remains some uncertainty as to whether HRT can increase the risk of breast cancer. As a result of these concerns, investigations into natural alternatives such as phytoestrogens have received considerable attention. 

REiNLi K and BLOCK G (1996), Phytoestrogen content of foods - a compendium of literature values. Nutr Cancer 26, 123-48. 

An inverse correlation between thyroid cancer risk and phytoestrogens was recently proposed as a result of a multi-ethnic population-based case control study conducted in the San Francisco Bay Area (Hom-Ross et al., 2002). In this study, dietary habits and phytoestrogen consumption were assessed by a food-frequency questionnaire and by a nutrient database. The outcome of the study was that soy-based foods and alfalfa sprouts were associated with a reduction of thyroid cancer risk, whereas a Western diet did not influence cancer risk. No difference was observed between American and Asian women or between pre- and postmenopausal women. Furthermore, among the few compounds examined, the isoflavones genistein and daidzein and the lignan secoisolariciresinol were the phytoestrogens most frequently associated with risk reduction (Horn-Ross et al., 2002). 

In order to get recent advances on the effects of phytoestrogens on hormonal-dependent diseases as well as on human supplementation trials, it might be useful to refer to http //www.venus-ca.org/ (EU-funded project on dietary exposure to phytoestrogens and related compounds and effects on skeletal tissues) http //www.phytos.org (EU-funded project on the prevention of osteoporosis by nutritional phytoestrogens) http //www.phytoprevent.org (EU-funded project on the role of phytoestrogens in the prevention of breast and prostate cancer) and http //www.nutrition.tum.de/isoheart.htm (EU-funded project on cardiovascular health of postmenopausal women). 

HORN-Ross p L, HOGGATT K J and LEE M M (2002) Phytoestrogens and thyroid cancer risk the San Francisco Bay Area thyroid cancer study. Cancer Epidemiol Biomarkers Prev. 11 (1) 43-9. 

G A (2000) Assessing the accuracy of a food frequency questionnaire for estimating usual intake of phytoestrogens. Nutr Cancer. 37 (2) 145-54. 

CAG repeat length. Shorter CAG repeat sequences have been found in African Americans. Therefore, the combination of increased testosterone and increased androgen receptor activation may account for the increased risk of prostate cancer for African-American men.2 The Asian diet generally is considered to be low in fat and high in fiber with a high concentration of phytoestrogens, potentially explaining the decreased risk in Asians.4... 

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