不同阶段母乳中唾液酸和铁水平分析

CHANGES OF SIALIC ACID AND IRON LEVELS IN HUMAN MILK AT DIFFERENT STAGES

目的研究不同阶段母乳中唾液酸(sialic acid,SA)和铁的含量,为乳儿喂养和辅食添加及其神经发育评估提供科学依据。方法收集473份母乳(初乳191份,过渡乳115份,成熟乳109份和晚乳58份),母乳SA水平检测采用神经氨酸苷酶法,铁检测采用亚铁嗪法。组间SA水平比较采用方差分析,铁的比较采用非参数检验,相关性采用Pearson相关分析法。结果初乳SA平均浓度(1671.8±641.6)mg/L;过渡乳(1398.1±390.8)mg/L;成熟乳(419.5±292.0)mg/L,晩乳(262.8±80.9)mg/L,初乳SA水平显著高于过渡乳,过渡乳SA水平显著高于成熟乳,后者又显著高于晩乳(F=5.55,P=0.001)。初乳铁含量中位数0.07 mg/L,过渡乳0.09mg/L,成熟乳0.17 mg/L,晩乳0.21mg/L,初乳铁含量显著低于过渡乳(Z=2.61,P=0.009),过渡乳又显著低于成熟乳(Z=6.30,P<0.001),后者又显著低于晩乳(Z=2.87,P=0.004)。母乳中SA含量与月龄负相关(r=-0.677,P<0.001),铁含量与月龄正相关(r=0.333,P<0.001)。结论母乳中SA浓度随着月龄的增加逐渐下降,而铁的含量随着日龄的增加逐渐增高。

Objective To study the levels of sialic acid（SA） and iron in human milks at different stages, and provide scientific basis for breast-milk feeding, supplementary food addition and neural development evaluation. Methods A total of 473 human milk samples, including 191 colostrum, 115 transition, 109 mature and 58 late milk samples, were collected. SA level was measured by neuraminidase assay method, while iron level was determined by ferrozine method. Analysis of variance was used to compare the differences in SA level and non-parametric test was used to compare the differences in iron level among different groups. Pearson correlation analysis method was used to analyze the correlation between the SA or iron levels and the stages. Results The SA levels in colostrum, transition, mature and late milks were（1671.8±641.6） mg/L,（1398.1±390.8） mg/L,（419.5±292.0） mg/L and（262.8±80.9） mg/L respectively, showing a progressive decreasing trend from colostrums to late milk. The medians of iron levels in colostrum, transition, mature and late milks were 0.07 mg/L 0.09 mg/L, 0.17mg/L and 0.21 mg/L, respectively, showing anincreasing trend from colostrum, late milk. A strong negative correlation between the SA level and the infant＇s age was identified（r=-0.677,P〈0.001）, while a positive correlation was identified between the iron level and the infant＇s age（r=0.333,P〈0.001）. Conclusion With the increase of age, the SA level in human milk was decreased gradually, while the iron content increased.