Donor human milk (DHM) is the preferred alternative for preterm infants when mother’s own milk is unavailable, though its nutrient composition varies with lactation stage. This study evaluated temporal changes in vitamin concentrations in DHM. A total of 189 raw milk samples were collected from 72 donating mothers at three postpartum periods: 2–12, 13–16, and 17–24 weeks. Thirteen vitamins, including B-group vitamers, vitamin C, and vitamin D, were quantified using LC-MS. Significant time-dependent variations were found for several B vitamins. Thiamine increased markedly from 29.5 ng/mL at 2–12 weeks to 45.2 ng/mL at 17–24 weeks (p=3.5E-09), while thiamine monophosphate decreased from 404 to 240 ng/mL (p=5E-04). Pyridoxal levels rose from 77.3 to 97.8 ng/mL (p=3.4E-02). In contrast, vitamin C (22.6 µg/mL) and vitamin D (0.9 ng/mL) remained stable throughout lactation. These results demonstrate measurable shifts in vitamin composition of DHM, particularly in thiamine-related compounds and selected B vitamins, while vitamins C and D show temporal stability. Continuous monitoring of DHM’s nutritional profile is recommended, as such variations may influence its ability to meet preterm infants’ nutritional needs. Further studies should address the clinical significance of these findings. • Vitamins levels in donor milk change significantly across lactation stages. • Thiamine increases while thiamine monophosphate decreases over time. • Vitamins C and D remain stable throughout lactation. • LC-MS enables sensitive multi-vitamin profiling in human milk.
Radkiewicz et al. (Fri,) studied this question.