RRR-α-Tocopherol Is the Predominant Stereoisomer of α-Tocopherol in Human Milk

Abstract

BackgroundThe naturally occurring α-tocopherol (α-T) stereoisomer, RRR-α-tocopherol (RRR-α-T), is known to be more bioactive than all-rac-α-tocopherol (all-rac-α-T), a synthetic racemic mixture of 8 stereoisomers. There is widespread use of all-rac-α-T in maternal supplements.ObjectiveThe aim of the study was to thoroughly describe the α-T stereoisomer profile of human milk.MethodsWe measured the α-T stereoisomer profile in milk from 2 cohorts of women: a cohort of 121 women who provided milk on days 30 and 60 of lactation (study 1) and a separate cohort of 51 women who provided milk on days 10, 21, 71, and 120 of lactation (study 2).Results RRR-α-T was the predominant stereoisomer (P < 0.0001) in all samples in both studies despite a large intrasubject range in total α-T (0.7–22 μg/mL). On average, RRR-α-T comprised 73–76% of total α-T, but average values for the synthetic stereoisomers were RRS, 8–14%; RSR, 6–8%; RSS, 5–6%; and the sum of 2S stereoisomers (Σ2S), 3–5%. Despite the predominance of RRR-α-T, the sum of the synthetic stereoisomers comprised as much as 48% of total α-T. We calculated the ratio of RRR to the sum of the synthetic 2R (RRS + RSR + RSS) stereoisomers (s2R) to assess the degree to which RRR is favored in milk. Consistent with discrimination among 2R stereoisomers in mammary tissue, RRR/s2R values ranged from 2.8 to 3.6, as opposed to the expected ratio of 0.33 if there was no discrimination. However, the RRR to s2R ratio did not correlate with milk α-T concentration, but both components of the ratio did.Conclusions RRR-α-T is the predominant stereoisomer in human milk, concentrations of synthetic 2R stereoisomers were notable, and the relation between milk total α-T and stereoisomer profile is complex. Due to the wide range found in milk α-T stereoisomer profile, investigation into its impact on α-T status and functional outcomes in breastfed infants is warranted.

Breeder Diet Strategies for Generating Ttpa-Null and Wild-Type Mice with Low Vitamin E Status to Assess Neurological Outcomes

“…Synthetic α-T is commonly used in rodent diets, and lactating animals transfer synthetic α-T stereoisomers to their offspring. This has previously been demonstrated in lactating humans ( 33 , 34 ). Importantly, tissue stereoisomer profiles in mouse weanlings could influence the results of later studies that use these animals.…”

Infant Rhesus Macaque Brain α-tocopherol Stereoisomer Profile Is Differentially Impacted by the Source of α-tocopherol in Infant Formula

“…After birth, infants acquire αT from human milk or infant formula, which commonly contains all rac -αT. Human milk αT concentrations vary widely between women, commonly ranging from 2 to 50 μM, with an average of about 10 μM after 1 mo of lactation ( 10 ), and also decrease with stage of lactation ( 11 , 12 ). Infant formula manufacturers generally provide at least 7 μM RRR -αT or at least 12 μM all rac -αT in order to meet prevailing regulations.…”

Increased Breastfeeding Proportion Is Associated with Improved Gross Motor Skills at 3–5 Years of Age: A Pilot Study

“…After being received by the study team, the breastmilk was frozen at −80 °C until analysis. Tocopherol analysis and concentrations of lutein and zeaxanthin were obtained using high-performance liquid chromatography (carotenoids: Agilent 1290 series ultra high performance liquid chromatography autosampler pump and diode array detector (Agilent Technologies, Inc., Santa Clara, CA, USA); YMC American C30 analytical column (YMC America, Inc., Devens, MA, USA); total tocopherols: Agilent 1100 series high performance liquid chromatography autosampler and binary pump (Agilent Technologies, Inc., Santa Clara, CA, USA; Thermo Scientific BETASIL Silica-100 analytical column (Thermo Fisher Scientific, Waltham, MA, USA); Shimadzu RF-10AXL fluorescence detector (Shimadzu, Columbia, MD, USA); chiral tocopherols: Waters Acquity H class ultra performance liquid chromatography pump and autosampler (Waters, Milford, MA, USA); Diacel Chemical Industries Chiracel OD-H analytical column, (Daicel, Sakai, Osaka, Japan); Shimadzu RF-20AXS fluorescence detector (Shimadzu, Columbia, MD, USA)) [ 10 , 11 ]. For enantiomers of α-tocopherol, the proportion of the enantiomer with regard to total α-tocopherol was calculated.…”