SOYBEAN DIET AND BREAST DENSITY

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 与许多亚洲国家一样，食用高水平大豆的人群与典型的西方饮食人群相比，卵巢激素水平较低，乳腺癌发病率较低，乳房X光检查密度也较低。我们发现，在绝经前的女性中，大豆有益地降低了25-45%的卵巢激素。我们建议测试一种错别法，即食用大豆会减少卵巢类固醇激素(雌二醇、雌酮、硫酸盐和黄体酮)，并导致相应的乳房密度降低，并且这些效果可以在不含异黄酮的大豆饮食中实现。目的1确定慢性大豆暴露的潜在不良影响的评估。这些目标将通过进行一项随机的双盲研究来测试，研究对象为两只手臂，每只手臂上有100名绝经前妇女。有50%致密乳房组织的绝经前妇女将被随机分配到不含异黄酮类的豆奶(治疗)或牛奶(安慰剂)作为饮食补充剂，为期两年。这两组妇女的卵巢类固醇、激素和乳房密度的比较水平将在两年的饮食干预之前、期间和之后进行评估。减少乳房密度有望通过两种机制降低乳腺癌风险，即减少癌症发展风险的目标组织体积和提高乳房X光检查早期筛查的敏感性。我们的长期目标之一是确定大豆是否可以作为第二次乳腺癌的替代和补充预防措施。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Populations consuming high levels of soy, as in many Asian countries, have lower levels of ovarian hormones, lower rates of breast cancer, and reduced mammographic density than populations consuming typical Western diets. We found that soy feeding favorably lowered ovarian hormones by 25-45% in premenopausal women. We propose to test the typothesis that consumption of soya reduces ovarian steroid hormones (estradiol, estrone, sulfate, and progesterone) and results in a corresponding reduction in breast density and that these effects can be achieved with a soy diet that does not contain isoflavones. Aim 1 determines the assess potential adverse effects of chronic soy exposure. The aims will be tested by conducting a randomized, double-blind study, with two arms and 100 premenopausal women in each arm. Premenopausal women with 50% of dense breast tissue will randomly allocated to take soymilk without isoflavones (treatment) or cow milk (placebo) as dietary supplements daily for 2 years. The comparative levels of ovarian steroids, hormones and breast density will be assessed before, during and after 2 years of dietary interventions in these two groups of women. Reducing breast density can be expected to reduce breast cancer risk by two mechanisms, i.e., reducing the volume of target tissue at risk for cancer development and improving the sensitivity of mammography for early screening detection. One of our long-term objectives is to determine if soy can be an alternative and complementary preventive measure for a second breast cancer.