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RRR-?-Tocopherol Is the Predominant Stereoisomer of ?-Tocopherol in Human Milk.

ABSTRACT: Background:The naturally occurring ?-tocopherol (?-T) stereoisomer, RRR-?-tocopherol (RRR-?-T), is known to be more bioactive than all-rac-?-tocopherol (all-rac-?-T), a synthetic racemic mixture of 8 stereoisomers. There is widespread use of all-rac-?-T in maternal supplements. Objective:The aim of the study was to thoroughly describe the ?-T stereoisomer profile of human milk. Methods:We measured the ?-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-?-T was the predominant stereoisomer (P < 0.0001) in all samples in both studies despite a large intrasubject range in total ?-T (0.7-22 ?g/mL). On average, RRR-?-T comprised 73-76% of total ?-T, but average values for the synthetic stereoisomers were RRS, 8-14%; RSR, 6-8%; RSS, 5-6%; and the sum of 2S stereoisomers (?2S), 3-5%. Despite the predominance of RRR-?-T, the sum of the synthetic stereoisomers comprised as much as 48% of total ?-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 ?-T concentration, but both components of the ratio did. Conclusions:RRR-?-T is the predominant stereoisomer in human milk, concentrations of synthetic 2R stereoisomers were notable, and the relation between milk total ?-T and stereoisomer profile is complex. Due to the wide range found in milk ?-T stereoisomer profile, investigation into its impact on ?-T status and functional outcomes in breastfed infants is warranted.

SUBMITTER: Kuchan MJ

PROVIDER: S-EPMC6101621 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature

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<i>RRR</i>-α-Tocopherol Is the Predominant Stereoisomer of α-Tocopherol in Human Milk.

Kuchan Matthew J MJ Moulton Christopher J CJ Dyer Roger A RA Jensen Soren K SK Schimpf Karen J KJ Innis Sheila M SM

Current developments in nutrition 20180615 8

<h4>Background</h4>The naturally occurring α-tocopherol (α-T) stereoisomer, <i>RRR</i>-α-tocopherol (<i>RRR</i>-α-T), is known to be more bioactive than <i>all-rac</i>-α-tocopherol (<i>all-rac</i>-α-T), a synthetic racemic mixture of 8 stereoisomers. There is widespread use of <i>all-rac</i>-α-T in maternal supplements.<h4>Objective</h4>The aim of the study was to thoroughly describe the α-T stereoisomer profile of human milk.<h4>Methods</h4>We measured the α-T stereoisomer profile in milk from ...[more]

PMID: 30140787

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Project description:Backgroundα-Tocopherol (αT) is essential for fetal development. One study has shown that the human placenta preferentially transfers the natural stereoisomer, RRR-αT. But prenatal supplements generally contain synthetic αT (S-αT).ObjectivesWe aimed to determine if umbilical cord plasma is enriched for RRR-αT in racially diverse neonates from both uncomplicated and complicated pregnancies and if cord RRR-αT enrichment is impacted by maternal αT stereoisomer profile.MethodsWe measured αT and αT stereoisomers in plasma from a randomly selected subset of 66 predominantly black and Hispanic maternal-fetal pairs from the Camden Study involving control (n = 28) and complicated pregnancies (n = 38). We collected maternal plasma at study entry (week 16 gestation; w16) and week 28 gestation (w28) and cord plasma at birth.ResultsRRR-αT was the predominant stereoisomer in all maternal and cord plasma samples, but S-αT stereoisomers were found in most samples and comprised a high percentage of αT in some maternal-neonate pairs. Cord plasma had a higher percentage RRR-αT (P < 0.05) and lower percentage S-αT (P < 0.0001) than w28 plasma. Pregnancy status did not impact maternal or cord plasma concentrations of αT, RRR-αT, or S-αT; except plasma from complicated pregnancies was higher in S-αT at w28 than at w16 (P < 0.05). Maternal w28 αT did not correlate with cord αT. However, both maternal w28 αT and S-αT positively correlated with both cord S-αT (r = 0.340, P = 0.0049; r = 0.538, P < 0.00001) and percentage S-αT (r = 0.399, P = 0.001; r = 0.786, P < 0.00001) but negatively correlated with cord percentage RRR-αT (r = -0.399, P = 0.0009; r = -0.786, P < 0.00001).ConclusionsThe proportion of RRR-αT was higher in cord compared with maternal plasma in both uncomplicated and complicated pregnancies. Our data suggest that maternal S-αT raises cord S-αT and decreases the proportion of RRR-αT in the neonatal circulation. Because the bioactivities of RRR-αT and S-αT differ, this warrants future research to determine the importance of our observations to neonatal αT status.

Project description:Backgroundα-Tocopherol (αT) in its natural form [2'R, 4'R, 8'R αT (RRR-αT)] is more bioactive than synthetic α-tocopherol (all rac-αT). All rac-αT is widely used in infant formulas, but its accretion in formula-fed infant brain is unknown.ObjectiveWe sought to compare αT and stereoisomer status in infant rhesus macaques (Macaca mulatta) fed infant formula (RRR-αT or all rac-αT) with a reference group fed a mixed diet of breast milk and maternal diet.MethodsFrom 1 d after birth until 6 mo of age, infants (n = 23) were either nursery reared and exclusively fed 1 of 2 formulas by staff personnel or were community housed with their mothers and consumed a mixed reference diet of breast milk (69 mL/d at 6 mo) transitioning to monkey diet at ∼2 mo (MF; n = 8). Formulas contained either 21 μmol RRR-αT/L (NAT-F; n = 8) or 30 μmol all rac-αT/L (SYN-F; n = 7). Total αT and αT stereoisomers were analyzed in breast milk at 2, 4, and 6 mo and in monkey plasma and liver and 6 brain regions at 6 mo of age. α-Tocopherol transfer protein (α-TTP), lipoprotein αT, and urinary α-carboxyethyl-hydroxychroman (α-CEHC) were measured. One-way ANOVA with Tukey's post-hoc test was used for analysis.ResultsAt study termination, plasma, liver, lipoprotein, and brain total αT did not differ between groups. However, the NAT-F-fed group had higher RRR-αT than the SYN-F-fed group (P < 0.01) and the MF group (P < 0.0001) in plasma (1.7- and 2.7-fold) and brain (1.5- and 2.5-fold). Synthetic αT 2R stereoisomers (SYNTH-2R) were generally 3- and 7-fold lower in brain regions of the NAT-F group compared with those of the SYN-F and MF groups (P < 0.05). SYNTH-2R stereoisomers were 2-fold higher in MF than SYN-F (P < 0.0001). The plasma percentage of SYNTH-2R was negatively correlated with the brain percentage of RRR-αT (r = -0.99, P < 0.0001). Brain αT profiles were not explained by α-TTP mRNA or protein expression. Urine α-CEHC was 3 times higher in the NAT-F than in the MF group (P < 0.01).ConclusionsConsumption of infant formulas with natural (NAT-F) compared with synthetic (SYN-F) αT differentially impacted brain αT stereoisomer profiles in infant rhesus macaques. Future studies should assess the functional implications of αT stereoisomer profiles on brain health.

Dataset Information

RRR-?-Tocopherol Is the Predominant Stereoisomer of ?-Tocopherol in Human Milk.

Publications

<i>RRR</i>-α-Tocopherol Is the Predominant Stereoisomer of α-Tocopherol in Human Milk.

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