Concentration of Lactoferrin in Human Milk and Its Variation during Lactation in Different Chinese Populations

Abstract

Background: Lactoferrin (Lf) is a multifunctional protein and one of the most abundant proteins in human milk. Various factors may affect its concentration in human milk, such as stage of lactation, ethnicity, and diet. Objectives: The objectives of the present study were to examine the dynamic change in milk Lf throughout the course of lactation and explore factors associated with milk Lf concentrations in various Chinese populations. Methods: This investigation was a part of a large cross-sectional study conducted in 11 provinces/autonomous regions/municipalities (Beijing, Gansu, Guangdong, Guangxi, Heilongjiang, Inner Mongolia, Shandong, Shanghai, Xinjiang, Yunnan, and Zhejiang) across China between 2011 and 2013. Lactating women (n = 6481) within 0–330 days postpartum were recruited in the original study. A sub-sample of 824 women was randomly selected, and milk Lf concentrations were determined by UPLC/MS. Results: The Lf concentration in milk from women delivering at term was 3.16 g/L, 1.73 g/L and 0.90 g/L for colostrum, transitional milk, and mature milk, respectively. Lf concentrations differed significantly between stages of lactation (colostrum vs. transitional milk, colostrum vs. mature milk, transitional milk vs. mature milk, all p < 0.001). Maternal BMI, age, mode of delivery, parturition, protein intake, and serum albumin concentration were not correlated with milk Lf concentration. However, milk Lf concentrations varied among different geographical regions (Guangdong (1.91 g/L) vs. Heilongjiang (1.44 g/L), p = 0.037; Guangdong (1.91 g/L) vs. Gansu (1.43 g/L), p = 0.041) and ethnicities (Dai (1.80 g/L) vs. Tibetan (0.99 g/L), p = 0.007; Han (1.62 g/L) vs. Tibetan (0.99 g/L), p = 0.002) in China. Conclusions: The concentration of Lf in human milk changes dynamically throughout lactation. Few maternal characteristics affect the milk Lf concentration, but it varies across different geographical regions and ethnicities in China.

Breast Milk and Saliva Lactoferrin Levels and Postnatal Cytomegalovirus Infection

“…The lactoferrin concentration in breast milk of these mothers of preterm infants was consistent with previous reports. 53,54 We found no correlation between milk CMV load and lactoferrin concentration, consistent with previous findings in small study of 23 preterm infants and their lactating mothers. 55 Finally, we found no major difference in lactoferrin concentration in milk of women that transmitted CMV and those that did not.…”

Lactoferrin in Human Milk of Prolonged Lactation

“…As a continuation of the previous study, lactoferrin changes in prolonged lactation were assessed in this study. During the first month of lactation, Lf decreases and then remains relatively stable [33]. The highest content of Lf is in colostrum at 5.5 g/L, whereas mature milk contains only 1.5–3.0 g/L, dependent on the stage of lactation in the first year postpartum [32,34,35].…”

“…However, this decrease was constant during lactation until one to two months (1.24 g/L), and then stabilized until the eighth month. Changes in Lf content may reflect various biological functions of milk during different stages of newborn and infant development [33].…”

Lactoferrin Reverses Methotrexate Driven Epithelial Barrier Defect by Inhibiting TGF-β Mediated Epithelial to Mesenchymal Transition

“…Among the constituents of milk, lactoferrin has received particular attention because of its antimicrobial properties 14 , immune regulatory properties 15 , and ability to signal through the lactoferrin receptor expressed on epithelial cells 16 . It is an approximately 80 kDa iron binding protein that is present in breast milk at concentrations ranging from 10 to 90 mg/ml μ M) 17 , but may be deactivated during pasteurization 18 . It is also present in cow's milk at the significantly lower concentration of 0.031-0.485 mg/ml 19 .…”

“…We next investigated the specific molecular activity responsible for the effects of expressed breast milk (EBM) on epithelial barrier function. Lactoferrin is present at a concentration of 13-113 µM in breast milk 17 , and it has been hypothesized that it is one of the factors responsible for its barrier-protective effects 41 . We therefore tested whether lactoferrin was sufficient to restore barrier integrity in this assay by titrating cysts with increasing concentrations of human lactoferrin (Supplemental Figure S1C) in combination with methotrexate.…”