# Variability in the Composition and Antioxidant Status of Milk of Polish Women Breastfeeding up to 2 Years

**Authors:** Agnieszka Chrustek, Elena Sinkiewicz-Darol, Katarzyna Łubiech, Dorota Olszewska-Słonina, Agnieszka Dombrowska-Pali

PMC · DOI: 10.3390/nu18020314 · 2026-01-19

## TL;DR

This study examines how the composition and antioxidant properties of breast milk change in Polish women who breastfeed for up to two years.

## Contribution

The study provides new insights into the nutritional and antioxidant changes in breast milk beyond the first year of lactation.

## Key findings

- Breast milk from mothers nursing past 12 months has higher fat and magnesium levels.
- Leptin, iron, and iron-reducing capacity decrease in milk from long-term breastfeeding.
- Milk from extended breastfeeding remains nutritious and protective against free radicals.

## Abstract

Background/Objectives: Breastfeeding has accompanied women since the beginning of time and, according to anthropological research, naturally ends between the age of 2 and 6. WHO (World Health Organization) recommends exclusive breastfeeding for about the first 6 months, with continued breastfeeding along with introducing appropriate complementary foods for up to 2 years of age or longer. Despite the increasing promotion of breastfeeding, women do not comply with the WHO guidelines and give up exclusive breastfeeding quickly, and long-term breastfeeding mothers still struggle with a lack of understanding in society. Methods: This work aims to expand the knowledge on the composition and antioxidant status of the milk of mothers breastfeeding past 12 months. Results: The basic composition of human milk changes depending on the stage of lactation. In women breastfeeding for more than a year, an increase in fat (p < 0.001) and magnesium (p < 0.001) was observed. A decreased concentration of leptin (p = 0.001), iron (p < 0.001), and iron-reducing capacity (p < 0.001) was also observed compared to milk from the initial stage of lactation. Conclusions: The milk of women breastfeeding for more than 12 months is a valuable food for the baby, maintaining its protection against free radicals and providing adequate nutrients.

## Full-text entities

- **Genes:** LEP (leptin) [NCBI Gene 3952] {aka LEPD, OB, OBS}
- **Chemicals:** iron (MESH:D007501), magnesium (MESH:D008274)
- **Species:** Homo sapiens (human, species) [taxon 9606]

## Figures

4 figures with captions in the complete paper: https://tomesphere.com/paper/PMC12845316/full.md

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Source: https://tomesphere.com/paper/PMC12845316