Effect of Pasteurization on Ghrelin and Resistin Hormone Concentrations in Human Breast Milk

Background: Donor breast milk (DBM) is often used to supplement maternal milk, especially for very low birth weight infants, a population vulnerable to suboptimal postnatal growth. The Holder pasteurization process used to ensure DBM safety reduces bioactive components, with unclear impact on preterm infant growth. Ghrelin and resistin are two hormones found in breast milk that may play roles in infant growth. This study aimed to evaluate changes in ghrelin and resistin concentrations in breast milk following pasteurization. Methods: Forty frozen, deidentified pooled expressed breast milk samples were heated to 63°C for 30 minutes and then rapidly cooled. Ghrelin and resistin were measured using enzyme-linked immunosorbent assays. Wilcoxon signed-rank tests assessed differences in hormone levels before and after pasteurization. Macronutrient composition was measured using a mid-infrared human milk analyzer, and associations with hormone levels were assessed using linear regression. Results: One paired sample was excluded due to unquantifiable assay results. Among the remaining 39 pairs, median prepasteurization concentrations were 11.05 pg/mL for ghrelin and 311 pg/mL for resistin. Pasteurization significantly reduced hormone levels, with median decreases of 36.7% for ghrelin and 24.3% for resistin (both p < 0.001). A moderate association was observed between resistin and protein content (R² 0.3399, p < 0.0001). Conclusions: Pasteurization significantly reduces ghrelin and resistin concentrations in breast milk. Further investigation is warranted to determine the clinical relevance of these hormonal changes, particularly in relation to growth outcomes in preterm infants.