Pediatrics and Neonatology (2014) 55, 421e422
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EDITORIAL
Factors Affecting Human Milk Composition Exclusive human milk feeding for the first 6 months of life followed by human milk with complementary foods for 1e2 years or longer is the normative standard for infant feeding and nutrition recommended by the American Academy of Pediatrics and World Health Organization. However, unlike infant formula which is standardized within a very narrow range of composition, the composition of human milk is dynamic and variable within a feeding, diurnally, over lactation, between mothers, and with treatment of expressed milk including storage and pasteurization. Therefore, understanding these variables is important for feeding infants, especially for those at high-risk and with a very low birth weight. The stage of lactation and preterm delivery are known to be major factors affecting the composition of human milk. In this issue of Pediatrics and Neonatology, Hsu et al1 analyzed the composition of preterm human milk collected longitudinally for 4e6 weeks to investigate changes in composition. With the progress of lactation, there were significant increases in lactose, lipids, calories, and phosphate concentration. With regard to preterm delivery, they found no significant differences in most components of human milk between the term and preterm mothers. These results are compatible with Paul et al’s study,2 and, similarly, the changes with lactation were more pronounced in preterm than in term milk. Generally, the colostrum is rich in growth factors and immunologic components such as secretory immunoglobulin A (sIgA), lactoferrin, and leukocytes, and contains relatively low concentrations of lactose, lipids, and energy. This indicates that the primary function of colostrum is trophic and immunologic rather than nutritional. In Ronayne de Ferrer et al’s study,3 the lactoferrin levels in preterm human milk seemed to remain higher and rather constant in the 1st week as in Hsu et al’s study.1 However, Hsu et al1 found a significant decrease of secretory immunoglobulin concentration, and no differences in calcium, lactoferrin, leptin, and lysozyme levels with lactation stage, which is discordant with Mehta and Petrova’s study.4 Charpak et al5 reported that calcium/ phosphorus ratios were stable with lactation stage at close to 2:1, and that the content of both was similar in samples of different postconceptional age and postnatal age, which
is also different from the increased phosphate level with lactation in Hsu et al’s study.1 Bauer and Gerss 6 reported that carbohydrate, fat, protein, and energy concentrations were significantly higher in preterm than in term human milk. In particular, the protein levels were significantly higher in extremely preterm milk (
Available online at www.sciencedirect.com
ScienceDirect journal homepage: http://www.pediatr-neonatol.com
EDITORIAL
Factors Affecting Human Milk Composition Exclusive human milk feeding for the first 6 months of life followed by human milk with complementary foods for 1e2 years or longer is the normative standard for infant feeding and nutrition recommended by the American Academy of Pediatrics and World Health Organization. However, unlike infant formula which is standardized within a very narrow range of composition, the composition of human milk is dynamic and variable within a feeding, diurnally, over lactation, between mothers, and with treatment of expressed milk including storage and pasteurization. Therefore, understanding these variables is important for feeding infants, especially for those at high-risk and with a very low birth weight. The stage of lactation and preterm delivery are known to be major factors affecting the composition of human milk. In this issue of Pediatrics and Neonatology, Hsu et al1 analyzed the composition of preterm human milk collected longitudinally for 4e6 weeks to investigate changes in composition. With the progress of lactation, there were significant increases in lactose, lipids, calories, and phosphate concentration. With regard to preterm delivery, they found no significant differences in most components of human milk between the term and preterm mothers. These results are compatible with Paul et al’s study,2 and, similarly, the changes with lactation were more pronounced in preterm than in term milk. Generally, the colostrum is rich in growth factors and immunologic components such as secretory immunoglobulin A (sIgA), lactoferrin, and leukocytes, and contains relatively low concentrations of lactose, lipids, and energy. This indicates that the primary function of colostrum is trophic and immunologic rather than nutritional. In Ronayne de Ferrer et al’s study,3 the lactoferrin levels in preterm human milk seemed to remain higher and rather constant in the 1st week as in Hsu et al’s study.1 However, Hsu et al1 found a significant decrease of secretory immunoglobulin concentration, and no differences in calcium, lactoferrin, leptin, and lysozyme levels with lactation stage, which is discordant with Mehta and Petrova’s study.4 Charpak et al5 reported that calcium/ phosphorus ratios were stable with lactation stage at close to 2:1, and that the content of both was similar in samples of different postconceptional age and postnatal age, which
is also different from the increased phosphate level with lactation in Hsu et al’s study.1 Bauer and Gerss 6 reported that carbohydrate, fat, protein, and energy concentrations were significantly higher in preterm than in term human milk. In particular, the protein levels were significantly higher in extremely preterm milk (
