Laboratory Medicine, University Medical Center Groningen, The Netherlands.
Prostaglandins Leukot Essent Fatty Acids. 2011 Dec;85(6):369-79. doi: 10.1016/j.plefa.2011.08.001. Epub 2011 Sep 7.
The hormonal milieus of pregnancy and lactation are driving forces of nutrient fluxes supporting infant growth and development. The decrease of insulin sensitivity with compensatory hyperinsulinemia with advancing gestation, causes adipose tissue lipolysis and hepatic de novo lipogenesis (DNL).
We compared fatty acid (FA) contents and FA-indices for enzyme activities between preterm (28-36 weeks) and term (37-42) milks, and between colostrum (2-5 days), transitional (6-15) and mature (16-56) milks. We interpreted FA differences between preterm and term milks, and their changes with lactation, in terms of the well known decrease of insulin sensitivity during gestation and its subsequent postpartum restoration, respectively.
Compared with term colostrum, preterm colostrum contained higher indices of DNL in the breast (DNL-breast) and medium chain saturated-FA (MCSAFA), and lower DNL-liver and monounsaturated-FA (MUFA). Preterm milk also had higher docosahexaenoic acid (DHA) in colostrum and transitional milk and higher arachidonic acid (AA) in mature milk. Most preterm-term differences vanished with advancing lactation. In both preterm and term milks, DNL-breast and MCSAFA increased with advancing lactation, while DNL-liver, MUFA, long chain SAFA and AA decreased. DHA decreased in term milk. MUFA was inversely related to MCSAFA in all samples, correlated inversely with PUFA in colostrum and transitional milks, but positively in mature milk. MCSAFA correlated inversely with PUFA in mature milk.
Higher maternal insulin sensitivity at preterm birth may be the cause of lower MUFA (a proxy for DNL-liver) and higher MCSAFA (a proxy for DNL-breast) in preterm colostrum, compared with term colostrum. Restoring insulin sensitivity after delivery may be an important driving force for milk FA-changes in early lactation.
妊娠和哺乳的激素环境是支持婴儿生长和发育的营养物质通量的驱动力。随着妊娠的进展，胰岛素敏感性下降伴代偿性高胰岛素血症，导致脂肪组织脂肪分解和肝从头合成脂肪（DNL）。
我们比较了早产儿（28-36 周）和足月儿（37-42 周）奶、初乳（2-5 天）、过渡乳（6-15 天）和成熟乳（16-56 天）之间的脂肪酸（FA）含量和 FA 指数的酶活性。我们根据妊娠期间胰岛素敏感性的降低及其随后的产后恢复，分别解释了早产儿和足月儿奶之间的 FA 差异及其随泌乳的变化。
与足月初乳相比，早产儿初乳中的 DNL-乳腺（DNL-breast）和中链饱和 FA（MCSAFA）指数较高，而 DNL-肝和单不饱和 FA（MUFA）较低。早产儿奶中的二十二碳六烯酸（DHA）在初乳和过渡乳中较高，花生四烯酸（AA）在成熟乳中较高。随着泌乳的进展，大多数早产儿-足月儿差异消失。在早产儿和足月儿奶中，DNL-乳腺和 MCSAFA 随着泌乳的进展而增加，而 DNL-肝、MUFA、长链饱和 FA 和 AA 减少。足月奶中的 DHA 减少。MUFA 在所有样本中与 MCSAFA 呈负相关，与初乳和过渡乳中的 PUFA 呈负相关，而与成熟乳中的 PUFA 呈正相关。MCSAFA 与成熟奶中的 PUFA 呈负相关。
与足月初乳相比，早产儿初乳中 MUFA（DNL-肝的替代物）较低和 MCSAFA（DNL-乳腺的替代物）较高，可能是由于出生时母亲的胰岛素敏感性较高。产后恢复胰岛素敏感性可能是早期泌乳中乳 FA 变化的重要驱动力。
