Messina Mark J, Wood Charles E
Nutrition Matters, Inc, 439 Calhoun Street, Port Townsend, WA 98368, USA.
Nutr J. 2008 Jun 3;7:17. doi: 10.1186/1475-2891-7-17.
There has been considerable investigation of the potential for soyfoods to reduce risk of cancer, and in particular cancer of the breast. Most interest in this relationship is because soyfoods are essentially a unique dietary source of isoflavones, compounds which bind to estrogen receptors and exhibit weak estrogen-like effects under certain experimental conditions. In recent years the relationship between soyfoods and breast cancer has become controversial because of concerns--based mostly on in vitro and rodent data--that isoflavones may stimulate the growth of existing estrogen-sensitive breast tumors. This controversy carries considerable public health significance because of the increasing popularity of soyfoods and the commercial availability of isoflavone supplements. In this analysis and commentary we attempt to outline current concerns regarding the estrogen-like effects of isoflavones in the breast focusing primarily on the clinical trial data and place these concerns in the context of recent evidence regarding estrogen therapy use in postmenopausal women. Overall, there is little clinical evidence to suggest that isoflavones will increase breast cancer risk in healthy women or worsen the prognosis of breast cancer patients. Although relatively limited research has been conducted, and the clinical trials often involved small numbers of subjects, there is no evidence that isoflavone intake increases breast tissue density in pre- or postmenopausal women or increases breast cell proliferation in postmenopausal women with or without a history of breast cancer. The epidemiologic data are generally consistent with the clinical data, showing no indication of increased risk. Furthermore, these clinical and epidemiologic data are consistent with what appears to be a low overall breast cancer risk associated with pharmacologic unopposed estrogen exposure in postmenopausal women. While more research is required to definitively allay concerns, the existing data should provide some degree of assurance that isoflavone exposure at levels consistent with historical Asian soyfood intake does not result in adverse stimulatory effects on breast tissue.
关于大豆食品降低癌症风险，尤其是乳腺癌风险的可能性，已经有了大量研究。人们对这种关系的极大兴趣主要源于大豆食品是异黄酮的独特饮食来源，异黄酮是一种能与雌激素受体结合并在某些实验条件下表现出微弱雌激素样作用的化合物。近年来，大豆食品与乳腺癌之间的关系引发了争议，这主要是基于体外和啮齿动物实验数据的担忧，即异黄酮可能会刺激现有的雌激素敏感型乳腺肿瘤生长。由于大豆食品越来越受欢迎以及异黄酮补充剂在市场上可得，这场争议具有相当重要的公共卫生意义。在本分析与评论中，我们试图概述当前对异黄酮在乳腺中的雌激素样作用的担忧，主要聚焦于临床试验数据，并将这些担忧置于绝经后女性雌激素治疗使用的最新证据背景下。总体而言，几乎没有临床证据表明异黄酮会增加健康女性患乳腺癌的风险或恶化乳腺癌患者的预后。尽管相关研究相对有限，且临床试验通常涉及的受试者数量较少，但没有证据表明摄入异黄酮会增加绝经前或绝经后女性的乳腺组织密度，也不会增加有或没有乳腺癌病史的绝经后女性的乳腺细胞增殖。流行病学数据总体上与临床数据一致，未显示出风险增加的迹象。此外，这些临床和流行病学数据与绝经后女性因无对抗的雌激素暴露而总体乳腺癌风险较低的情况相符。虽然需要更多研究来彻底消除担忧，但现有数据应能提供一定程度的保证，即与亚洲人历史上大豆食品摄入量相当的异黄酮暴露水平不会对乳腺组织产生不良刺激作用。
