Longitudinal Changes in Crude Protein and Amino Acids in Human Milk in Chinese Population

Abstract

Objective: More than 20% of the world population live in China, which has made significant achievement in human milk research. Part of the data that were published in Chinese were, however, unavailable to non-Chinese speakers. There was also no comprehensive overview of crude protein and amino acid levels in human milk in Chinese population. This systematic review aimed to compile the data on human milk crude protein and amino acid levels in Chinese population. Methods: After searching for and screening original research articles in both English and Chinese, 23 published from 1987 to 2019 were identified (18 in Chinese and 5 in English). The data were pooled into 9 defined lactation stages. Results: Crude protein and amino acids (protein bound plus nonprotein bound) concentrations gradually decreased during the first 60 postpartum days and remained relatively static thereafter. The concentrations and dynamic change of crude protein and amino acids were similar to those in other populations. By contrast, the longitudinal changes in free amino acids (nonprotein bound) were less clear due to the limited data available. Several common weaknesses were identified in these studies. Conclusions: Our study represented the most comprehensive overview on crude protein and amino acid concentrations in human milk in Chinese population, and enhanced the knowledge of protein and amino acid intakes and requirements by Chinese infants.

The Association of Formula Protein Content and Growth in Early Infancy: A Systematic Review and Meta-Analysis

“…The difference in protein concentrations between human milk and infant formulas may explain the faster growth trajectory in formula-fed infants than in breastfed infants. Human milk protein concentrations decrease gradually from 2.13 to 1.14 g/dL in the first 90 days of lactation and remain stable thereafter [ 42 ]. By contrast, formula-fed infants, in the first 6 months of life, consume the same formulas, which typically range from 1.4 to 1.5 g of protein/dL.…”

“…By contrast, formula-fed infants, in the first 6 months of life, consume the same formulas, which typically range from 1.4 to 1.5 g of protein/dL. Accordingly, infant formulas may provide 30% more protein than human milk after the infant is 2 months old [ 42 ]. Because the digestibility, amino acid profile, and protein efficiency of human milk protein are superior to those of other protein sources such as bovine milk, it is rational for infant formula to provide higher concentrations of protein.…”

Longitudinal Changes in the Concentration of Major Human Milk Proteins in the First Six Months of Lactation and Their Effects on Infant Growth

“…The concentrations of HM proteins were expressed as g/100 g. To be consistent with the data in the literature, the concentrations were converted to g/100 mL. When converting, the HM density was regarded as 103.2 g/100 mL [ 25 ].…”

“…Depicting the longitudinal patterns of milk proteins also provides useful information for the manufacture of infant formula, which is an alternative for infants who cannot obtain enough HM. To date, some protein components in HM have been widely investigated, such as total protein [ 25 ] and lactoferrin [ 17 ]. Meanwhile, data on some other components (e.g., osteopontin and casein fractions) remain scarce.…”

Dynamic Changes in Human Milk Oligosaccharides in Chinese Population: A Systematic Review and Meta-Analysis

“…The full texts of the remaining articles were examined by applying the inclusion and exclusion criteria listed in the PICOS table ( Supplementary Table S1 ). Quality of included studies was assessed as previously described [ 22 ]. The literature selection was performed independently by two investigators (Y.Z.…”