Supplementation with or -α-Tocopherol Differentially Affects the α-Tocopherol Stereoisomer Profile in the Milk and Plasma of Lactating Women

The naturally occurring α-tocopherol stereoisomer α-tocopherol is known to be more bioactive than synthetic α-tocopherol (-α-tocopherol). However, the influence of this difference on the α-tocopherol stereoisomer profile of human milk is not understood. We investigated whether supplemental α-tocopherol or -α-tocopherol differentially affected the distribution of α-tocopherol stereoisomers in milk and plasma from lactating women. Eighty-nine lactating women aged 19-40 y and with a body mass index (in kg/m) ≤30 were randomly assigned at 4-6 wk postpartum to receive a daily supplement containing 45.5 mg -α-tocopherol acetate (ARAC), 22.8 mg -α-tocopherol acetate + 20.1 mg -α-tocopherol (MIX), or 40.2 mg α-tocopherol (RRR). Milk and plasma were analyzed for α-tocopherol structural isomers and α-tocopherol stereoisomers at baseline and after 6 wk supplementation with the use of chiral HPLC. There were no significant treatment group or time-dependent changes in milk or plasma α, γ, or δ-tocopherol. α-tocopherol was the most abundant stereoisomer in both milk and plasma in each group. Supplementation changed both milk and plasma percentage α-tocopherol (RRR > MIX > ARAC) ( < 0.05) and percentage non-α-tocopherol (ARAC > MIX > RRR) ( < 0.05). In the RRR group, percentage α-tocopherol increased in milk (mean ± SEM: 78% ± 2.3% compared with 82% ± 1.7%) ( 0.05) and plasma (mean ± SEM: 77% ± 1.8% compared with 87% ± 1%) ( 0.05). In contrast, the percentage α-tocopherol decreased in the MIX and ARAC groups (MIX, 0.05; ARAC, 0.0001), and percentage non-α-tocopherol stereoisomers increased (MIX, 0.05; ARAC, 0.0001) commensurate with an accumulation of α-tocopherol stereoisomers ( < 0.05) in both milk and plasma. Milk and plasma α-tocopherol was positively correlated at baseline ( = 0.67; 0.0001) and 6 wk ( = 0.80; 0.0001). The α-tocopherol supplementation strategy differentially affected the α-tocopherol milk and plasma stereoisomer profile in lactating women. α-tocopherol increased milk and plasma percentage α-tocopherol, whereas -α-tocopherol acetate reduced these percentages. Because α-tocopherol is the most bioactive stereoisomer, investigating the impact of supplement-driven changes in the milk α-tocopherol stereoisomer profile on the α-tocopherol status of breastfed infants is warranted.