Vitamin A and E content of human milk at early stages of lactation

Abstract

The influence of gestational age and lactational stage on carotene, retinol ester, alpha-tocopherol and gamma-tocopherol content of early human milk was studied. These nutrients were analyzed simultaneously using normal phase high-performance liquid chromatography. Serial samples of colostrum and early milk representative of complete early morning expressions were obtained during the first 6 weeks post-partum from mothers giving birth prematurely (PT) and at term (FT). Colostrum carotene content declined significantly during the first week of lactation. There was no apparent gestational age effect on milk carotene levels. The longitudinal pattern of change observed for milk retinol ester and alpha-tocopherol content was however, significantly different between PT and FT milk. Retinol ester levels were similar on days 1-2 postpartum reaching a maximal level on days 3-4 postpartum in FT milk. For PT milk the maximum retinol ester concentration occurred on days 6-7 postpartum. Retinol ester content decreased throughout lactation. The rate of decline was more marked for FT milk. The concentration of alpha-tocopherol in colostrum was higher in FT milk. On all subsequent days examined the level of alpha-tocopherol was greater in PT milk. For both FT and PT milk the alpha-tocopherol concentration was higher during the first week of lactation when compared with following weeks. gamma-Tocopherol levels were not influenced by gestational age or lactational stage. Levels of milk vitamin A and E did not appear to correlate with maternal intake. Colostrum levels of vitamin A and E may imply active sequestration by the mammary gland in compensation for limited placental transport. Early milk content of vitamin A and E appears to parallel mammary gland lipid synthesis.