Introduction

Increased fiber intake has been associated with decreased breast cancer risk, while increased animal protein intake with increased risk. The objective of this study is to examine the relationship of dietary fiber and protein intake to estrogen and sex hormone–binding globulin (SHBG) concentrations at puberty onset.

Methods

These analyses were conducted using the Cincinnati puberty cohort of the Breast Cancer and the Environment Research Program, with girls followed every 6 months from ages 6 and 7. The analyses included serum measurements at 6-month intervals for estrogen and SHBG concentrations, from 18 months prior to breast stage 2 (onset of puberty). Dietary intake was documented via 24-hour dietary recalls every 3 months. Dietary factors of interest included total energy intake; total and animal protein; total, soluble, and insoluble fiber; and lignan and flavanol intake.

Results

This study included 260 participants who generated 871 serum specimens and 3,000 days of diet intake. In longitudinal models, estradiol was associated inversely with insoluble fiber intake; estrone positively with animal protein intake; SHBG with greater insoluble fiber and lower total protein intake; and ratio of estrone to SHBG, a measure of bioavailable estrogen, positively with animal protein.

Conclusions

Greater protein intake, especially animal protein, led to greater estrogen concentrations and lower SHBG; greater animal protein and greater caloric intake led to increased bioavailable estrogen. This relationship may have served an evolutionary advantage in the past for greater fertility with adequate high-quality protein; in contemporary women, a modest decrease in animal protein may be beneficial in reducing breast cancer risk.

中文翻译：

---

大量营养素摄入对青春期开始时性类固醇的影响

介绍

纤维摄入量增加与乳腺癌风险降低有关，而动物蛋白摄入量增加则风险增加。本研究的目的是检查膳食纤维和蛋白质摄入量与青春期开始时雌激素和性激素结合球蛋白 (SHBG) 浓度之间的关系。

方法

这些分析是使用乳腺癌和环境研究计划的辛辛那提青春期队列进行的，女孩从 6 岁和 7 岁起每 6 个月随访一次。分析包括从 18 个月开始每 6 个月测量一次血清雌激素和 SHBG 浓度在乳房第 2 阶段（青春期开始）之前。每 3 个月通过 24 小时饮食回顾记录饮食摄入量。感兴趣的饮食因素包括总能量摄入；总蛋白和动物蛋白；总纤维、可溶性和不溶性纤维；以及木酚素和黄烷醇的摄入量。

结果

这项研究包括 260 名参与者，他们生成了 871 份血清样本和 3,000 天的饮食摄入量。在纵向模型中，雌二醇与不溶性纤维摄入量呈负相关；雌酮与动物蛋白摄入呈正相关；SHBG 具有更高的不溶性纤维和更低的总蛋白质摄入量；雌酮与 SHBG 的比率，一种生物可利用雌激素的量度，与动物蛋白呈正相关。

结论

更多的蛋白质摄入，尤其是动物蛋白，会导致更高的雌激素浓度和更低的 SHBG；更多的动物蛋白和更多的热量摄入导致生物可利用的雌激素增加。这种关系在过去可能具有进化优势，可以通过提供足够的优质蛋白质来提高生育能力。在当代女性中，适度减少动物蛋白可能有助于降低患乳腺癌的风险。