Estrogenicity Of Soy Formula

染料木素和大豆黄酮是大豆中的雌激素异黄酮。虽然它们的效力远不如雌二醇，但食用大豆配方奶粉的婴儿的血清浓度比雌二醇高4个数量级。在食用大豆的婴儿中，尚未找到雌激素暴露的解剖、超声和其他生化证据。这种广泛使用的产品在婴儿（每公斤接触量最高的群体）中是否具有临床可检测的雌激素活性，在临床上很重要；此外，这可能是一个至关重要的测试，实验室测量雌激素的能力，以预测实际的内分泌反应的人。我们已经进行了实地的初步研究，以检查新生儿雌激素反应生理的自然史，并利用这些结果对大豆配方奶粉对婴儿可能产生的雌激素效应进行了纵向研究。

Genistein and daidzein are estrogenic isoflavones found in soybeans. Although they much less potent as estradiol, infants fed soy formula have serum concentrations that are up to 4 orders of magnitude higher than estradiol. Anatomic, sonographic, and other biochemical evidence of estrogen exposure has not been looked for in infants fed soy. Whether such widely used products do or do not have clinically detectable estrogenic activity in infants, the group with the highest exposure per kilo, is important clinically; in addition, it may be a crucial test of the ability of laboratory measures of estrogenicity to predict actual endocrine response in humans. We have done the field work for pilot studies to examine the natural history of estrogen responsive physiology in the newborn, and have used the results to develop a longitudinal study of the possible estrogenic effects of soy formula on infants. Using samples from this project, we are collaborating with the Centers for Disease Control to see if perchlorate, a contaminant of the US water supply, lowers thyroid hormone levels in infants as it does in adult females. We are currently recontacting families who told us to ask them before analyzing their childs samples for substances other than those in the original study plan. We will use the samples from those who give their consent now, plus those who originally gave consent for general use of their samples, to measure concentrations of perchlorate, iodine, and thiocyanate in infants for whom we have already measured thyroid hormone. We are also using samples from this study to examine the hormonal basis of the relative anesthesia of breast fed infants.