Clinical Chemistry and Biochemistry, Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland.
Lipids Health Dis. 2013 Jun 15;12:89. doi: 10.1186/1476-511X-12-89.
The fatty acid mixture of human milk is ideal for the newborn but little is known about its composition in the first few weeks of lactation. Of special interest are the levels of long-chain PUFAs (LCPUFAs), since these are essential for the newborn's development. Additionally, the LCPUFAs arachidonic acid (AA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are precursors for lipid mediators which regulate inflammation.
We determined the composition of 94 human milk samples from 30 mothers over the first month of lactation for fatty acids using GC-MS and quantified lipid mediators using HPLC-MS/MS.
Over the four weeks period, DHA levels decreased, while levels of γC18:3 and αC18:3 steadily increased. Intriguingly, we found high concentrations of lipid mediators and their hydroxy fatty acid precursors in human milk, including pro-inflammatory leukotriene B4 (LTB4) and anti-inflammatory and pro-resolving lipoxin A4 (LXA4), resolvin D1 (RvD1) and resolvin E1 (RvE1). Lipid mediator levels were stable with the exception of two direct precursors.
Elevated levels of DHA right after birth might represent higher requirements of the newborn and the high content of anti-inflammatory and pro-resolving lipid mediators and their precursors may indicate their role in neonatal immunity and may be one of the reasons for the advantage of human milk over infant formula.
母乳中的脂肪酸混合物非常适合新生儿，但人们对哺乳期最初几周母乳的成分知之甚少。特别值得关注的是长链多不饱和脂肪酸（LCPUFAs）的水平，因为这些对新生儿的发育至关重要。此外，LCPUFAs 花生四烯酸（AA）、二十碳五烯酸（EPA）和二十二碳六烯酸（DHA）是调节炎症的脂质介质的前体。
我们使用 GC-MS 测定了 30 位母亲在哺乳期第一个月的 94 个人乳样本中的脂肪酸组成，并使用 HPLC-MS/MS 定量了脂质介质。
在四周的时间里，DHA 水平下降，而 γC18:3 和 αC18:3 的水平稳步上升。有趣的是，我们在人乳中发现了高浓度的脂质介质及其羟基脂肪酸前体，包括促炎的白三烯 B4（LTB4）和抗炎、促解决的脂氧素 A4（LXA4）、消退素 D1（RvD1）和消退素 E1（RvE1）。除了两种直接前体外，脂质介质水平稳定。
新生儿出生后 DHA 水平升高可能代表了新生儿更高的需求，而抗炎和促解决的脂质介质及其前体含量高可能表明它们在新生儿免疫中的作用，这可能也是人乳优于婴儿配方奶粉的原因之一。
