Lactose quantification in human breast milk by gas chromatography - mass spectrometry

Mammary gland development is a complex process that begins in utero and continues to evolve after birth and throughout life. During and after pregnancy, this gland responds to stimuli to prepare for reproduction, undergoing several cycles of growth, maturation, milk production and secretion, and finally involution. Lactation is a high-energy-consuming process that, over a limited period, becomes one of the major energy expenditures for mothers, which is essential for the offspring's survival. The mammary epithelium produces and secretes the different milk constituents, consisting of protein, lipids, and carbohydrates (lactose). Lactose represents one of the most abundant nutrients present in milk, being of the utmost importance for newborns. Here, we present a new methodology to perform quantitative measurement of lactose by gas chromatography - mass spectrometry. The method is simple and allows high recovery of lactose (>95%), along with a high reproducibility between batches at physiologically relevant concentrations. It thus represents a new tool to further study milk biology.•A novel protocol to measure lactose by mass spectrometry in milk is described.