Protein Evolution of Human Milk

Abstract

Given the documented short- and long-term advantages of breastfeeding, human milk (HM) as a sole source of nutrition for the first few months of newborn life is considered a normative standard. Each macroconstituent of HM plays a crucial role in the growth and development of the baby. Lipids are largely responsible for providing more than 50% of the energy as well as providing essential fatty acids and minor lipids that are integral to all cell membranes. Carbohydrates can be broadly divided into lactose and oligosaccharides, which are a readily digestible source of glucose and indigestible nonnutritive components, respectively. Proteins in HM provide essential amino acids indispensable for the growth of infants. What is more interesting is that protein concentration profoundly changes from colostrum to mature milk. In this report, we share data from an observatory, single-center, longitudinal trial assessing the constituents of HM collected 30, 60 and 120 days postpartum from 50 mothers (singleton deliveries: 25 male and 25 female infants). The protein content decreased with evolving stages of lactation from an average of 1.45 to 1.38 g/100 ml. The data did not show any gender differences as it was reported for lipid content at 120 days postpartum by our group. Additionally, we also share consolidated literature data on protein evolution of HM during the first year of lactation.

Feasibility of Standardized Human Milk Collection in Neonatal Care Units

“…Collection rates between A and B showed to be different, but only due to the collection at day 3, where most samples were missed. This confirms that HM collection can be especially problematic during the first few days after birth, when its production is not abundant 31 . As a result, the greatest obstacle to collecting HM samples in the present cohort was represented by the difficulty in establishing milk supply, which underpinned nearly half of the missed samples (Fig.…”

Longitudinal Variation of Amino Acid Levels in Human Milk and Their Associations with Infant Gender

“…Milk for girls was associated with higher levels of protein and TAAs, whereas milk for boys showed a trend towards higher levels of free glutamine when evaluated over the first 3 months of lactation. Interestingly, Thakkar et al also demonstrated that the protein content in milk for girls was slightly higher than that in milk for boys in, at least, the first 60 days of lactation [ 41 ]. They, however, did not report significant differences, possibly due to them analyzing gender differences per time point measured, in contrast to our statistical method which includes the first 3 months of lactation simultaneously.…”