# Breast Milk Proteome: Changes in the Different Stages of Lactation and Impacts of Gestational Diabetes Mellitus and Body Mass Index

## TL;DR

This study shows how breast milk proteins change from colostrum to mature milk and how maternal health conditions like gestational diabetes and BMI affect these changes.

## Contribution

The study identifies specific proteomic changes in breast milk across lactation stages and reveals the impact of maternal metabolic conditions.

## Key findings

- Colostrum is enriched in immune-related proteins, while mature milk contains more proteins involved in biosynthesis and growth.
- GDM and higher BMI are associated with altered protein profiles in mature milk, including increased HDL-related proteins.
- The breast milk proteome shows measurable differences influenced by maternal metabolic health.

## Abstract

Breast milk proteome comprises hundreds of bioactive proteins supporting infant development. The extent to which maternal metabolic conditions modify the proteome is poorly known. This study investigates proteome evolution from colostrum to mature milk and examines the impacts of maternal gestational diabetes mellitus (GDM) and BMI on the proteome. We analyzed the proteome by data‐independent acquisition (DIA)‐based LC‐MS/MS from colostrum and mature milk samples collected from mothers (n = 47) with varying BMI values and with (n = 11) or without (n = 36) GDM. We identified 3496 proteins, of which 1055 were differentially abundant between colostrum and mature milk. Colostrum was enriched in proteins related to MHC II antigen response, intestinal IgA, adhesion, and glycosylation, while mature milk showed enrichment in lipid biosynthesis, protein translation, and degradation. In mature milk, mothers with both GDM and higher BMI had increased levels of proteins related to HDL formation. Proteins supporting the maturation of the naive gut immune system were prevalent in colostrum, while those prevalent in mature milk reflected the mammary gland's effort in biosynthesis. Both BMI and GDM have measurable effects on the breast milk proteome. The clinical significance of these findings on a child's future health needs to be clarified.

We analyzed colostrum and breast milk from 47 mothers to see how proteins change over time and with maternal health. Colostrum had more immune proteins, while mature milk had proteins linked to growth support. Gestational diabetes and higher BMI altered the protein composition.