The nucleotide profile of human milk

Area of Science:

• Human milk composition
• Nutritional biochemistry
• Lactation studies

Background:

• Understanding the nitrogen fraction of human milk is crucial for infant nutrition.
• Previous characterization of human milk's nitrogen components, particularly nucleotides, requires further detail.

Purpose of the Study:

• To identify and characterize nucleotide and total nitrogen content in human milk.
• To analyze changes in nucleotide profiles over the lactation period (2-12 weeks postpartum).

Main Methods:

• High-performance liquid chromatography (HPLC) and Kjeldahl analyses were employed.
• Longitudinal study of five lactating women, collecting milk samples at various times (pre/post-nursing, morning/afternoon) and time points (2, 4, 8, 12 weeks postpartum).

Main Results:

• Nucleotide variance patterns differed from total nitrogen.
• Cytidine 5' monophosphate and adenosine 5' monophosphate levels decreased, while inosine 5' monophosphate increased from week 2 to 12.
• Nucleotide nitrogen constituted 0.1-0.15% of total nitrogen; total milk concentration decreased with lactation, higher in afternoon samples.

Conclusions:

• Human milk nucleotide profiles exhibit distinct changes throughout lactation.
• The nucleotide composition of human milk differs significantly from other infant feeding milks.
• Estimated daily nucleotide nitrogen intake for infants is 1.4-2.1 mg.