Phytoestrogens are increasingly used as dietary supplements due to their suggested health promoting properties, but also by women for breast enhancement and relief of menopausal symptoms. Generally, phytoestrogens are considered to exert estrogenic activity via estrogen receptors (ERs), but they may also affect estrogen synthesis and metabolism locally in breast, endometrial and ovarian tissues. Considering that accurate regulation of local hormone levels is crucial for normal physiology, it is not surprising that interference with hormonal synthesis and metabolism is associated with a wide variety of women’s health problems, varying from altered menstrual cycle to hormone-dependent cancers. Yet, studies on phytoestrogens have mainly focused on ER-mediated effects of soy-derived phytoestrogens, with less attention for steroid synthesis and metabolism or other phytoestrogens. This review aims to evaluate the potential of phytoestrogens to modulate local estrogen levels and the implications for women’s health. For that, an overview is provided of the effects of commonly used phytoestrogens, i.c. 8-prenylnaringenin, biochanin A, daidzein, genistein, naringenin, resveratrol and quercetin, on estrogen synthesizing and metabolizing enzymes in vitro. The potential implications for women’s health are assessed by comparing the in vitro effect concentrations with blood concentrations that can be found after intake of these phytoestrogens. Based on this evaluation, it can be concluded that high-dose supplements with phytoestrogens might affect breast and endometrial health or fertility in women via modulation of steroid hormone levels. However, more data regarding tissue levels of phytoestrogens and effect data from dedicated, tissue-specific assays is needed for a better understanding of potential risks. At least until more certainty regarding the safety has been established, especially young women would better avoid using supplements containing high doses of phytoestrogens.

中文翻译：

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雌激素在体外对雌激素合成和代谢的调控及其对妇女健康的影响

由于植物雌激素具有促进健康的特性，因此越来越多地被用作膳食补充剂，而且女性也被用来增强乳房和缓解更年期症状。通常，植物雌激素被认为是通过雌激素受体（ER）发挥雌激素活性的，但是它们也可能会影响乳房，子宫内膜和卵巢组织中的雌激素合成和代谢。考虑到准确调节局部激素水平对正常生理至关重要，因此，干扰激素的合成和代谢与妇女的各种健康问题相关联，这不足为奇，从月经周期改变到激素依赖性癌症不等。然而，有关植物雌激素的研究主要集中在ER介导的大豆衍生植物雌激素的作用上，对类固醇合成和代谢或其他植物雌激素的关注较少。这篇综述旨在评估植物雌激素调节局部雌激素水平的潜力及其对妇女健康的影响。为此，概述了常用的植物雌激素，ic 8-异戊烯基柚皮素，生物chanin A，大豆黄酮，染料木黄酮，柚皮素，白藜芦醇和槲皮素对体外雌激素合成和代谢酶的作用。通过将体外效应浓度与摄入这些植物雌激素后的血液浓度进行比较，评估对妇女健康的潜在影响。根据该评估，可以得出结论，大剂量植物雌激素补充剂可能会通过调节类固醇激素水平而影响女性的乳房和子宫内膜健康或生育能力。然而，需要更多有关植物雌激素组织水平的数据以及来自专门的组织特异性测定的作用数据，以更好地了解潜在风险。至少在确定安全性之前，尤其是年轻女性最好避免使用含有高剂量植物雌激素的补品。