Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA, USA.
J Nutr. 2012 Apr;142(4):655-60. doi: 10.3945/jn.111.150623. Epub 2012 Feb 22.
Dietary analysis predicts that marginal Zn deficiency is common in women of reproductive age. The lack of reliable biomarkers limits the capacity to assess Zn status and consequently understand effects of maternal Zn deficiency. We determined effects of marginal maternal Zn deficiency on mammary gland function, milk secretion, and milk composition in mice. Mice (n = 12/diet) were fed marginal (ZD; 15 mg Zn/kg diet) or adequate (ZA; 30 mg Zn/kg diet) Zn diets for 30 d prior to conception through mid-lactation. Mice fed the ZD had a higher plasma Zn concentration (20%; P < 0.05) but lower milk Zn concentration (15%; P < 0.05) compared with mice fed the ZA. ZnT2 abundance was higher (P < 0.05) in mice fed the ZD compared with mice fed the ZA; no effect on ZnT4 abundance was detected. The Zn concentration of mammary gland mitochondria tended to be 40% greater in mice fed ZD (P = 0.07); this was associated with apoptosis and lower milk secretion (80%; P < 0.01). Total milk protein was ~25% higher (P < 0.05), although the abundance of the major milk proteins (caseins and whey acidic protein) was lower (P < 0.05) in mice fed the ZD. Proteomic analysis of milk proteins revealed an increase (P < 0.05) in four proteins in mice fed the ZD. These findings illustrate that marginal maternal Zn deficiency compromises mammary gland function and milk secretion and alters milk composition. This suggests that lactating women who consume inadequate Zn may not produce and/or secrete an adequate amount of high quality milk to provide optimal nutrition to their developing infant.
膳食分析预测，育龄妇女普遍存在边缘性锌缺乏。缺乏可靠的生物标志物限制了评估锌状况的能力，进而无法理解母体锌缺乏的影响。我们确定了边缘性母体锌缺乏对小鼠乳腺功能、乳汁分泌和乳汁成分的影响。在受孕前至哺乳期中期，将小鼠（n = 12/饮食）用边缘（ZD；饮食中锌 15 毫克/千克）或充足（ZA；饮食中锌 30 毫克/千克）锌饮食喂养 30 天。与 ZA 相比，ZD 喂养的小鼠血浆锌浓度更高（约 20%；P < 0.05），但乳汁锌浓度更低（约 15%；P < 0.05）。与 ZA 相比，ZD 喂养的小鼠 ZnT2 丰度更高（P < 0.05）；ZnT4 丰度没有影响。ZD 喂养的小鼠乳腺线粒体的锌浓度趋于高出约 40%（P = 0.07）；这与细胞凋亡和乳汁分泌减少有关（约 80%；P < 0.01）。总乳蛋白高出约 25%（P < 0.05），尽管 ZD 喂养的小鼠主要乳蛋白（酪蛋白和乳清酸性蛋白）的丰度较低（P < 0.05）。乳汁蛋白的蛋白质组学分析显示，ZD 喂养的小鼠有四种蛋白增加（P < 0.05）。这些发现表明，边缘性母体锌缺乏会损害乳腺功能和乳汁分泌，并改变乳汁成分。这表明摄入不足的锌的哺乳期妇女可能无法产生和/或分泌足够数量的高质量乳汁，以向其发育中的婴儿提供最佳营养。
