Supplementation With Rrr- Or All-Rac-Alpha-Tocopherol Differentially Affects The Alpha-Tocopherol Stereoisomer Profile In The Milk And Plasma Of Lactating Women

Background: The naturally occurring alpha-tocopherol stereoisomer RRR-alpha-tocopherol is known to be more bioactive than synthetic alpha-tocopherol (all-rac-alpha-tocopherol). However, the influence of this difference on the a-tocopherol stereoisomer profile of human milk is not understood.Objective: We investigated whether supplemental RRR-alpha-tocopherol or all-rac-alpha-tocopherol differentially affected the distribution of alpha-tocopherol stereoisomers in milk and plasma from lactating women.Methods: Eighty-nine lactatingwomen aged 19-40 y andwith a body mass index (in kg/m(2))<= 30 were randomly assigned at 4-6 wk postpartum to receive a daily supplement containing 45.5 mg all-rac-alpha-tocopherol acetate (ARAC), 22.8 mg all-rac-alpha-tocopherol acetate + 20.1 mg RRR-alpha-tocopherol (MIX), or 40.2 mg RRR-alpha-tocopherol (RRR). Milk and plasma were analyzed for alpha-tocopherol structural isomers and alpha-tocopherol stereoisomers at baseline and after 6 wk supplementation with the use of chiral HPLC.Results: There were no significant treatment group or time-dependent changes in milk or plasma alpha, gamma, or delta-tocopherol. RRR-alpha-tocopherol was the most abundant stereoisomer in both milk and plasma in each group. Supplementation changed both milk and plasma percentage RRR-alpha-tocopherol (RRR > MIX > ARAC) (P < 0.05) and percentage non-RRR-alpha- tocopherol (ARAC > MIX > RRR) (P < 0.05). In the RRR group, percentage RRR-alpha-tocopherol increased in milk (mean +/- SEM: 78% +/- 2.3% compared with 82% +/- 1.7%) (P < 0.05) and plasma (mean +/- SEM: 77% +/- 1.8% compared with 87% +/- 1%) (P < 0.05). In contrast, the percentage RRR-alpha-tocopherol decreased in the MIX and ARAC groups (MIX, P < 0.05; ARAC, P < 0.0001), and percentage non-RRR-alpha-tocopherol stereoisomers increased (MIX, P < 0.05; ARAC, P < 0.0001) commensurate with an accumulation of 2S-alpha-tocopherol stereoisomers (P < 0.05) in bothmilk and plasma. Milk and plasma RRR-alpha-tocopherol was positively correlated at baseline (r = 0.67; P < 0.0001) and 6 wk (r = 0.80; P < 0.0001).Conclusion: The alpha-tocopherol supplementation strategy differentially affected the alpha-tocopherol milk and plasma stereoisomer profile in lactating women. RRR-alpha-tocopherol increased milk and plasma percentage RRR-alpha-tocopherol, whereas all-rac-alpha-tocopherol acetate reduced these percentages. Because RRR-alpha-tocopherol is the most bioactive stereoisomer, investigating the impact of supplement-driven changes in the milk alpha-tocopherol stereoisomer profile on the alpha-tocopherol status of breastfed infants is warranted.