Improved method for quantifying vitamin D in proprietary infants' formulas and in breast milk

Area of Science:

• Nutritional Biochemistry
• Analytical Chemistry

Background:

• Accurate quantification of vitamin D is crucial for infant nutrition and health.
• Existing methods for vitamin D analysis in milk-based products can be time-consuming and require larger sample volumes.

Purpose of the Study:

• To develop and validate a novel, efficient method for quantifying vitamin D in infant formulas and human breast milk.
• To establish a less time-consuming assay suitable for routine nutritional analysis.

Main Methods:

• Samples undergo repeated lipid extraction and purification using Sep-Pak cartridges.
• Liquid chromatography is employed for sample separation.
• Quantification is performed using a competitive protein-binding assay, with analytical recovery assessed using 3H-labeled vitamin D.

Main Results:

• Assays of powdered and liquid infant formulas showed results consistent with labeled vitamin D content.
• Vitamin D concentrations in breast milk from different maternal groups were determined (2.3 ± 1.4 µg/L and 2.0 ± 1.7 µg/L).
• Overall recoveries ranged from 65% to 75%, with only 2 mL of milk required per sample.

Conclusions:

• The developed method provides accurate and reliable quantification of vitamin D in infant formulas and breast milk.
• The assay's efficiency, minimal sample requirement, and speed make it a valuable tool for nutritional assessment.