Forms of human milk folacin and variation patterns.

Area of Science:

• Nutritional Biochemistry
• Microbiology

Background:

• Folacin (vitamin B9) exists in various forms in human milk.
• Understanding these forms is crucial for infant nutrition.
• Bacterial assays offer a method to differentiate folacin vitamers.

Purpose of the Study:

• To characterize the different forms of folacin in human milk.
• To investigate how lactation stage, time of day, and milk fraction affect folacin content.
• To identify the predominant folacin vitamers in human milk.

Main Methods:

• Human milk samples (n=180) from 16 women were analyzed.
• Microbiological assays using Lactobacillus casei, Streptococcus faecalis, and Pediococcus cerevisiae were employed.
• Samples were treated with pteroylglutamic hydroxylase (conjugase) to differentiate folate forms.

Main Results:

• Mean total folacin activity (L. casei) was 85.3 ng/ml, increasing with lactation duration.
• Folacin activity increased from morning to evening and from foremilk to hindmilk.
• N-5-methyltetrahydrofolate and pteroylpolyglutamates (≥3 glutamic acid) were identified as predominant forms.

Conclusions:

• Folacin content and forms in human milk are influenced by sampling methods.
• Lactation stage, time of day, and milk fraction impact measured folacin levels.
• Differential bacterial growth assays effectively characterize human milk folacin composition.