Ferris A M, Dotts M A, Clark R M, Ezrin M, Jensen R G
Department of Nutritional Sciences, University of Connecticut, Storrs.
J Am Diet Assoc. 1988 Jun;88(6):694-7.
This study evaluated changes in human milk composition from 2 to 16 weeks postpartum. Milk from 12 mothers was analyzed for lipid (utilizing a modified Folch), lactose (enzymatic hydrolysis), and nitrogen (semi-micro Kjeldahl). Energy was calculated by fractional analysis and bomb calorimetry. All samples were from well-defined subjects, and uniform collection procedures were used. Milk lipid, total nitrogen, and energy content differed significantly from one woman to another. Lipid and energy content increased from 3.98 +/- 1.0 to 5.50 +/- 1.1 gm/100 ml and 68.5 +/- 9.8 to 83.0 +/- 11.1 kcal/100 ml, respectively, and nitrogen content decreased significantly from 0.24 +/- 0.05 to 0.16 +/- 0.02 gm/100 ml from 2 to 16 weeks postpartum. Lactose remained statistically stable, increasing from 6.3 +/- 0.7 to 7.0 +/- 0.7 gm/100 ml. Estimates of energy from fractional analysis of macronutrients produced lower caloric estimates, especially at 2 weeks postpartum. Statistical differences over time and between and among mothers were found at all periods studied; therefore, on the basis of these data, we caution against reliance on single sample values as representative of mature milk either for individuals or for groups.
本研究评估了产后2至16周母乳成分的变化。对12位母亲的乳汁进行了脂质（采用改良的Folch法）、乳糖（酶水解法）和氮（半微量凯氏定氮法）分析。通过成分分析和弹式量热法计算能量。所有样本均来自明确界定的受试者，并采用了统一的采集程序。不同女性的乳汁脂质、总氮和能量含量存在显著差异。脂质和能量含量分别从3.98±1.0克/100毫升和68.5±9.8千卡/100毫升增加至5.50±1.1克/100毫升和83.0±11.1千卡/100毫升，产后2至16周氮含量从0.24±0.05克/100毫升显著降至0.16±0.02克/100毫升。乳糖在统计学上保持稳定，从6.3±0.7克/100毫升增加至7.0±0.7克/100毫升。通过对常量营养素的成分分析估算的能量产生的热量估算值较低，尤其是在产后2周时。在所研究的所有时间段均发现了随时间以及母亲之间和母亲内部的统计差异；因此，基于这些数据，我们提醒不要依赖单个样本值来代表个体或群体的成熟乳汁。
