Tocopherols in human milk: Change during lactation, stability during frozen storage, and impact of maternal diet

Tocopherols in human milk samples collected from 103 healthy mothers from China were determined. Samples were obtained at 1-7 d, 8-14 d and after 15 d postpartum. The maternal dietary intake of 24 h dietary recall was collected. Four tocopherol isomers (α-, β-, γ-, and δ-tocopherol) were measured by HPLC. The total tocopherol concentrations significantly decreased from 7.5 ± 2.1 mg L−1 in colostrum to 3.8 ± 1.4 mg L−1 in transitional milk and 3.1 ± 1.4 mg L−1 in mature milk. The similar results were found for α- and γ-tocopherols. However, the content of β- and δ-tocopherols was almost constant. The four tocopherol isomers did not degrade during frozen storage (−20 °C and −80 °C) for 180 d. Total tocopherol content was significantly raised with the increase of fat intake in the maternal diet.