Human breast milk is one of the key early postnatal biological exposures for the developing child. It includes bioactive compounds, such as cortisol and fatty acids, which may be linked via the mother’s lipid metabolism. This study investigated the associations between cortisol and lipids in human milk at the infant age of 2.5 months. Human milk cortisol concentrations were measured using luminescence immunoassay, and two groups of milks (n = 50 each) were formed based on either high (> 10 nmol/L) or low (< 3 nmol/L) cortisol levels. Lipids, as fatty acid content and composition of neutral (triacylglycerol-rich) and polar (phospholipid-rich) lipids, were measured with gas chromatography. The samples originated from the FinnBrain Birth Cohort Study. The percentage of phospholipid-rich lipids of total lipids was 33.08% ± 1.33%. In triacylglycerol-rich lipids, high cortisol level in milk was associated with higher lauric (12:0, mass % and mg/mL), myristic (14:0, mass % and mg/mL), eicosenoic (20:1n − 9, mass %), docosenoic (22:1n − 9, mass %, and mg/mL) acids, and to lower palmitic acid (16:0, mass %) compared with low cortisol levels in milk. In phospholipid-rich lipids, high cortisol level was associated with higher myristic (14:0, mass %) and docosenoic (22:1n − 9, mass %) acids. After adjusting for pre-pregnancy BMI and sampling time by linear regression, the milk cortisol remained a significant predictor for lauric and myristic acids in triacylglycerol-rich lipids, and myristic and docosenoic acid in phospholipid-rich lipids (β = 0.23 to 0.38 and p < 0.05 for each). This study revealed certain significant associations between milk cortisol and the fatty acid composition of human milk, indicating that cortisol might be one of the factors affecting the origin of the lipids in human milk.

中文翻译：

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皮质醇和人乳中脂质之间的相互作用。

母乳是发育中儿童的重要早期产后生物暴露之一。它包括生物活性化合物，例如皮质醇和脂肪酸，它们可能通过母亲的脂质代谢联系在一起。这项研究调查了婴儿在2.5个月大时皮质醇和人乳中脂质之间的关系。使用发光免疫测定法测量人乳中皮质醇的浓度，并根据高（> 10 nmol / L）或低（<3 nmol / L）皮质醇水平形成两组牛奶（每组n = 50）。用气相色谱法测定脂质的脂肪酸含量和中性（富含三酰甘油）和极性（富含磷脂）脂质的组成。样本来自FinnBrain出生队列研究。富含磷脂的脂质在总脂质中的百分比为33.08％±1.33％。在富含三酰甘油的脂质中，牛奶中的高皮质醇水平与较高的月桂酸（12：0，质量％和mg / mL），肉豆蔻酸（14：0，质量％和mg / mL），二十碳五烯酸（20：1n-9 （质量百分比），二十二烯酸（22：1n-9，质量百分比和mg / mL），以及低牛奶中的棕榈酸（16：0，质量％），而牛奶中的皮质醇水平较低。在富含磷脂的脂质中，高皮质醇水平与较高的肉豆蔻酸（14：0，质量％）和二十二烯酸（22：1n-9，质量％）有关。在通过线性回归调整孕前BMI和采样时间后，牛奶皮质醇仍然是富含三酰甘油的脂质中月桂酸和肉豆蔻酸以及富含磷脂的脂质中的肉豆蔻酸和二十二烯酸的重要预测因子（β= 0.23至0.38和p均<0.05）。