Lactoferrin levels in term and preterm milk

Objective: Even though there is no doubt that human milk is the best nouris hment for the neonate, there is still controversy regarding its suitability for preterm infants. The aim of this study was to contribute to the knowle dge of the anti-infective properties of preterm milk, measuring lactoferrin levels, which are a non-specific protective factor. Methods: Samples from 26 preterm and 20 term mothers (mean gestational age/-standard deviation, 30.9+/-2.6 and 39.5+/-1.1 weeks, respectively) were c ollected during the first month post-partum. Milk samples were obtained by total expression of one breast between 10 am. and noon. An aliquot was kept at -20 degrees C until analyzed by SDS-PAGE (sodium dodecyl sulfate-polyac rylamide gel electrophoresis). Each sample was run in duplicate. Results: Lactoferrin levels (X+/-SD) in colostrum and mature milk varied fr om 575.0+/-218.2 mg/dL to 459.4+/-190.7 mg/dL in preterm samples and from 9 70.6+/-288.6 mg/dL to 292.0+/-167.4 mg/dL in term samples. No significant d ifferences were observed between preterm and term groups, in spite of the t rend observed in colostrum, where term milk tended to show higher levels th an preterm milk. Decreasing values were observed in both groups along time (ANOVA, p<0.05). However, in the preterm group, lactoferrin levels seemed t o maintain rather constant values from the eighth post-partum day onwards. Conclusions: The trend to higher levels of lactoferrin in preterm mature mi lk would allow maintenance of the protective effect of human milk in preter m infants in spite of the small volumes ingested by these neonates. These f indings support the practice of feeding premature infants with their own mo thers' milk at a time when their immune systems have not completely develop ed.