The influence of maternal factors on the concentration of vitamin A in mature breast milk.

BACKGROUND & AIMS: This study evaluated the relationship between vitamin A concentration in maternal milk and the characteristics of the donors of a Brazilian human milk bank.
MATERIAL AND METHODS: A total of 136 donors were selected in 2003-2004 for micronutrient determinations in breast milk and blood, anthropometric measurements and investigation of obstetric, socioeconomic-demographic factors, and life style. Maternal serum/milk samples were obtained for vitamin A, iron, copper, and zinc determinations. Vitamin A concentrations in breast milk and blood were assessed by high-performance liquid chromatography. Copper, zinc and iron concentrations in breast milk, and copper and zinc concentrations in blood were detected by atomic emission spectrophotometry. Serum ceruloplasmin and serum iron were determined, respectively, by nephelometry and colorimetry. A linear regression model assessed the associations between milk concentrations of vitamin A and maternal factors.
RESULTS: Vitamin A in milk presented positive associations with iron in milk (p<0.001), serum retinol (p=0.03), maternal work (p=0.02), maternal age (p=0.02), and oral contraceptive use (p=0.01), and a negative association with % body fat (p=0.01) (R(2)=0.47).
CONCLUSION: These results suggest that some nutritional, obstetric, and socioeconomic-demographic factors may have an effect on mature breast milk concentrations of vitamin A in apparently healthy Brazilian mothers.