Retinol, β-carotene, and lutein + zeaxanthin in the milk of Brazilian nursing women: associations with plasma concentrations and influences of maternal characteristics

The objectives of the present study were to determine the concentration of vitamin A (retinol), provitamin A (β-carotene), and non-provitamin A (lutein + zeaxanthin) carotenoids in mature breast milk of Brazilian women (n = 49; 30-120 days postpartum), and to evaluate their associations with plasma levels and with maternal characteristics (parity and body mass index). Nutrient concentrations (mean ± SE) in plasma and milk were, respectively, as follows: retinol, 2.5 ± 0.1 and 1.4 ± 0.1 μmol/L; β-carotene, 0.3 ± 0.04 and 0.018 ± 0.002 μmol/L; lutein + zeaxanthin, 0.06 ± 0.01 and 0.006 ± 0.001 μmol/L. The milk/plasma molar ratio was 10 times higher for retinol than for carotenoids, and twice as high for the more polar xanthophylls (lutein + zeaxanthin) than for the less polar β-carotene. Associations (P < .05) between milk and plasma levels were observed for β-carotene (r = 0.35) and lutein + zeaxanthin (r = 0.37), but not for retinol. Multiparous women presented higher (P < .05) levels of retinol in plasma and in milk than primiparous women. Plasma levels of retinol, β-carotene, and lutein + zeaxanthin, but not milk levels, were significantly associated with body mass index (r = 0.32, 0.45, and 0.41, respectively).