The effects of breast milk storage and freezing procedure on interleukine-10 levels and total antioxidant activity.

Objective: To compare interleukine-10 (IL-10) and total antioxidant capacity (TAC) levels after breast milk storage by studying premature and term mothers’ colostrum and mature milk and by analyzing those levels relative to gestational week.

Methods: Fifty-four colostrum and mature breast milk samples were collected from both premature and term mothers. The samples were divided into three groups based on the time of analysis: fresh milk, at +4 °C for 72 h, and at -20 °C for 14 d. The IL-10 and TAC levels were measured quantitatively.

Results: Fresh colostrum and mature milk had similar IL-10 levels. Term mothers’ fresh-colostrum TAC levels were higher than their mature milk. The mature milk of the premature mothers’ had higher TAC levels than that of term mothers. Storage did not affect the IL-10 levels of breast milk, but fresh milk antioxidant capacity halved after 72 h and 14 d. Colostrum IL-10 and TAC levels did not correlate with gestational week. Mature milk IL-10 levels did not correlate with gestational week, but TAC levels negatively correlated with gestational week (r: -0.61: p < 0.01).

Conclusions: The milk stored for 72 h at +4 °C and for 14 d at -20 °C did not maintain the same TAC levels as the fresh samples. This should be considered especially for sick infants who need more antioxidant capability in neonatal units.