Polyamine levels in breast milk are associated with mothers' dietary intake and are higher in preterm than full-term human milk and formulas.

BACKGROUND: Polyamine intake from milk is considered essential for post-natal maturation of the immune system and small intestine. The present study aimed to determine polyamine content in human milk after preterm delivery and the association with mothers' dietary intake. In comparison, the polyamine levels were compared with those in term breast milk and some corresponding formulas. METHODS: Transitional breast milk was collected from 40 mothers delivering after 24-36 weeks of gestation, and from 12 mothers delivering after full term. Food intake was assessed in mothers delivering preterm babies using a 3-day diary. Polyamines were analysed by high-performance liquid chromatography. RESULTS: The dietary intake of polyamines was significantly associated with breast milk content but weaker for spermine than for spermidine and putrescine. Total polyamine level was higher in preterm than term milk and lower in the corresponding formulas. Putrescine, spermidine and spermine contents [mean (SEM)] in preterm milk were 165.6 (25), 615.5 (80) and 167.7 (16) nmol dL⁻¹, respectively, with the levels of putrescine and spermidine being 50% and 25% higher than in term milk. The content of spermine did not differ. CONCLUSIONS: Dietary intake of polyamines has an impact on the content in breast milk. The difference between human milk after preterm and term delivery might be considered when using donor human milk for preterm infants. The corresponding formulas had lower contents. Further studies are important for determining the relationship between tissue growth and maturation and optimal intake.