"New research indicates that dietary soy products are safe and even beneficial for women diagnosed with breast cancer. Published early online in CANCER a peerreviewed journal of the American Cancer Society the findings may help resolve controversies over soys potential link to breast cancer outcomes. Soy foods are considered among the healthiest for human consumption but their estrogenlike properties have raised concerns of a potential increased risk of breast cancer. This is because in hormone receptorpositive cancer the most common form of the disease there are some concerns that high estrogen levels help cancer cells grow and spread though this remains controversial. Isoflavonesthe component of soy that has estrogenlike propertieshave been shown to slow the growth of breast cancer cells in laboratory studies and epidemiological analyses in East Asian women with breast cancer found links between higher isoflavone intake and reduced mortality however other research has suggested that the estrogenlike effects of isoflavones may reduce the effectiveness of hormone therapies used to treat breast cancer explained Fang Fang Zhang MD PhD of the Friedman School of Nutrition Science and Policy at Tufts University. Because of this disparity it remains unknown whether isoflavone consumption should be encouraged or avoided for breast cancer patients. To provide some clarity Dr. Zhang and her colleagues looked at the relationship between dietary intake of isoflavones and death from any cause in  American and Canadian women diagnosed with breast cancer. Over a median followup of nine years women with breast cancer who consumed high amounts of isoflavones had a  percent lower risk of dying than women who consumed low amounts. This decrease was largely confined to women with hormone receptornegative tumors and women who were not treated with antiestrogen therapy such as tamoxifen which blocks the effects of estrogen. In contrast to some previous research high levels of isoflavone intake were not associated with greater mortality among women receiving hormonal therapy. Based on our results we do not see a detrimental effect of soy food intake among women who were treated with endocrine therapy said Dr. Zhang. For women with hormone receptornegative breast cancer soy food products may potentially have a protective effect. Women who did not receive endocrine therapy as a treatment for their breast cancer had a weaker but still statistically significant association. More than  percent of all new breast cancer cases with known estrogen and progesterone receptor status are receptornegative and they have poorer survival rates than hormone receptorpositive cases. Whether lifestyle factors can improve survival after diagnosis is an important question for women diagnosed with this more aggressive type of breast cancer. Our findings suggest that survival may be better in patients with a higher consumption of isoflavones said senior author Esther John PhD of the Cancer Prevention Institute of California. The investigators noted that they examined only naturally occurring dietary isoflavones not isoflavones from supplements. How isoflavones from foods interact with breast cancer cells is unclear but research has shown that they have antioxidant antiinflammatory antiangiogenic and other effects that could influence tumor survival and growth.  In an accompanying editorial Omer Kucuk MD of the Winship Cancer Institute of Emory University noted that the United States is the number  soy producer in the world and is in a great position to initiate changes in health policy encouraging soy intake. We now have evidence that soy foods not only prevent breast cancer but also benefit women who have breast cancer. Therefore we can recommend women to consume soy foods because of soys many health benefits he wrote.  Additional information NOTE The information contained in this release is protected by copyright. Please include journal attribution in all coverage. A free abstract of this article will be available via the Cancer News Room upon online publication. For more information or to obtain a PDF of any study please contact Dawn Peters US    sciencenewsroomwiley.com mailtosciencenewsroomwiley.com  Follow us on Twitter WileyNews httpstwitter.comWileyNews Full Citation Dietary Isoflavone Intake and AllCause Mortality in Breast Cancer Survivors the Breast Cancer Family Registry. Fang Fang Zhang Danielle E. Haslam Mary Beth Terry Julia A. Knight Irene L. Andrulis Mary Daly Saundra S. Buys and Esther M. John. CANCER Published Online March   DOI .cncr..  URL Upon Publication httpdoi.wiley.com.cncr. Author Contact Siobhan Gallagher of the Tufts University Public Relations Office at Siobhan.gallaghertufts.edu mailtoSiobhan.gallaghertufts.edu or . Editorial Soy Foods Isoflavones and Breast Cancer. Omer Kucuk. CANCER Published Online March   DOI .cncr.. URL Upon Publication httpdoi.wiley.com.cncr. About the Journal  CANCER is a peerreviewed publication of the American Cancer Society integrating scientific information from worldwide sources for all oncologic specialties. The objective of CANCER is to provide an interdisciplinary forum for the exchange of information among oncologic disciplines concerned with the etiology course and treatment of human cancer. CANCER is published on behalf of the American Cancer Society by Wiley and can be accessed online at httpwileyonlinelibrary.comjournalcancer.  Follow us on Twitter JournalCancer httpstwitter.comJournalCancer and Facebook https About Wiley  Wiley a global company helps people and organizations develop the skills and knowledge they need to succeed. Our online scientific technical medical and scholarly journals combined with our digital learning assessment and certification solutions help universities learned societies businesses governments and individuals increase the academic and professional impact of their work. 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