Trace element content of human milk during lactation

Area of Science:

• Nutritional Science
• Human Physiology
• Trace Element Analysis

Background:

• Human milk is considered the optimal nutrition source for infants.
• Understanding the dynamic changes in milk composition is crucial for infant health.
• Longitudinal data on trace element concentrations in human milk is limited.

Purpose of the Study:

• To investigate longitudinal changes in key trace elements (Fe, Cu, Zn, Se, Br, Pb, Rb, Sr) in human milk.
• To determine the stability and variability of these elements during the lactation period.
• To establish reference ranges for trace elements in milk over 180 days postpartum.

Main Methods:

• Collection of 140 human milk samples from 26 mothers between day 2 and day 180 postpartum.
• Analysis of trace element concentrations including iron (Fe), copper (Cu), zinc (Zn), selenium (Se), bromine (Br), lead (Pb), rubidium (Rb), and strontium (Sr).
• Statistical evaluation of time-dependent changes and half-life estimations for each element.

Main Results:

• Copper (Cu), zinc (Zn), and selenium (Se) exhibited time-dependent decreases with approximately 10-day half-lives.
• Bromine (Br) and lead (Pb) showed temporal correlations but with very short estimated half-lives (2-3 days).
• Iron (Fe), rubidium (Rb), and strontium (Sr) concentrations remained constant throughout the lactation period. Trace element levels stabilized after approximately one month.

Conclusions:

• Human milk trace element composition is dynamic, particularly in the early lactation phase.
• Specific elements like Cu, Zn, and Se show significant decreases, while Fe, Rb, and Sr are stable.
• These findings provide valuable insights into human milk nutritional dynamics and infant trace element supply.