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Macronutrients in human milk at 2, 12, and 16 weeks postpartum
A M Ferris1, M A Dotts, R M Clark
1Department of Nutritional Sciences, University of Connecticut, Storrs.
Journal of the American Dietetic Association
|June 1, 1988
Summary
Human milk composition changes significantly postpartum. Lipid and energy content increase, while nitrogen decreases, highlighting variability between mothers and over time. Relying on single samples is not recommended.
Area of Science:
- Human milk composition
- Postpartum nutrition
- Lactation physiology
Background:
- Human milk is crucial for infant nutrition.
- Understanding changes in milk composition is vital for assessing infant intake.
- Variability in milk composition can impact nutritional delivery.
Purpose of the Study:
- To evaluate changes in human milk composition from 2 to 16 weeks postpartum.
- To analyze lipid, lactose, nitrogen, and energy content over time.
- To determine inter-individual variability in milk composition.
Main Methods:
- Analysis of milk from 12 mothers using modified Folch for lipids, enzymatic hydrolysis for lactose, and semi-micro Kjeldahl for nitrogen.
- Energy calculated via fractional analysis and bomb calorimetry.
- Standardized collection procedures and well-defined subjects were used.
Main Results:
- Significant inter-individual differences in milk lipid, total nitrogen, and energy content were observed.
- Lipid and energy content increased significantly from 2 to 16 weeks postpartum.
- Nitrogen content significantly decreased, while lactose remained relatively stable during the study period.
Conclusions:
- Human milk composition exhibits significant changes and variability between mothers postpartum.
- Fractional analysis of macronutrients underestimated energy content, particularly early postpartum.
- Single milk sample values should not be relied upon to represent mature milk composition for individuals or groups.