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Background: α-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)., Objectives: We 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., Methods: We 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., Results: RRR -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)., Conclusions: The 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., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition.)

Background: Alpha-tocopherol (αT), the bioactive constituent of vitamin E, is essential for fertility and neurological development. Synthetic αT (8 stereoisomers; all rac-αT) is added to infant formula at higher concentrations than natural αT (RRR-αT only) to adjust for bio-potency differences, but its effects on brain development are poorly understood., Objectives: The objective was to determine the impact of bio-potency-adjusted dietary all rac-αT versus RRR-αT, fed to dams, on the hippocampal gene expression in weanling mice., Methods: Male/female pairs of C57BL/6J mice were fed AIN 93-G containing RRR-αT (NAT) or all rac-αT (SYN) at 37.5 or 75 IU/kg (n = 10/group) throughout gestation and lactation. Male pups were euthanized at 21 days. Half the brain was evaluated for the αT concentration and stereoisomer distribution. The hippocampus was dissected from the other half, and RNA was extracted and sequenced. Milk αT was analyzed in separate dams., Results: A total of 797 differentially expressed genes (DEGs) were identified in the hippocampi across the 4 dietary groups, at a false discovery rate of 10%. Comparing the NAT-37.5 group to the NAT-75 group or the SYN-37.5 group to the SYN-75 group, small differences in brain αT concentrations (10%; P < 0.05) led to subtle changes (<10%) in gene expression of 600 (NAT) or 487 genes (SYN), which were statistically significant. Marked differences in brain αT stereoisomer profiles (P < 0.0001) had a small effect on fewer genes (NAT-37.5 vs. SYN-37.5, 179; NAT-75 vs. SYN-75, 182). Most of the DEGs were involved in transcription regulation and synapse formation. A network analysis constructed around known vitamin E interacting proteins (VIPs) revealed a group of 32 DEGs between NAT-37.5 vs. SYN-37.5, explained by expression of the gene for the VIP, protein kinase C zeta (Pkcz)., Conclusions: In weanling mouse hippocampi, a network of genes involved in transcription regulation and synapse formation was differentially affected by dam diet αT concentration and source: all rac-αT or RRR-αT., (Copyright © The Author(s) on behalf of the American Society for Nutrition 2020.)

Background: α-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., Objective: We 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., Methods: From 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., Results: At 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)., Conclusions: Consumption 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., (Copyright © The Author(s) on behalf of the American Society for Nutrition 2020.)

A multilaboratory study was completed with AOAC INTERNATIONAL First Action Official Method SM 2015.09, "Determination of trans and Total ( cis+trans ) Vitamin K 1 in Infant, Pediatric, and Adult Nutritionals by HPLC with Post Column Reduction and Fluorescence Detection." Eight laboratories from six countries participated in the multilaboratory study. Each laboratory analyzed 19 infant, pediatric, and adult nutritionals in duplicate. The product matrixes analyzed included milk, soy, partially hydrolyzed milk, partially hydrolyzed soy, and elemental-based infant formula powders; milk-based infant formula ready-to-feed liquids; pediatric powders; adult low- and high-fat powders; and high-protein ready-to-drink nutritionals. Vitamin K 1 was extracted from product matrixes with isooctane after precipitation of proteins and the release of lipids with methanol. Prepared samples were injected onto a silica HPLC column in which cis and trans vitamin K 1 were separated with an isooctane-isopropanol mobile phase. The column eluent was mixed with a dilute ethanolic solution of zinc chloride, sodium acetate, and acetic acid, and cis and trans vitamin K 1 were reduced to fluorescent derivatives in a zinc reactor column. Overall, trans vitamin K 1 repeatability averaged 3.06% relative standard deviation (RSD) with a range of 0.99-7.16% RSD and reproducibility averaged 6.36% RSD with a range of 3.15-16.1% RSD. Repeatability Standard Method Performance Requirements (SMPR ® ) were met for all 19 matrixes, and reproducibility SMPRs were met for 18 of the 19 product matrixes analyzed. Repeatability and reproducibility for total ( cis + trans ) vitamin K 1 averaged 3.15% RSD with a range of 1.06-6.87% RSD and 6.11% RSD with a range of 2.94-16.7% RSD, respectively.

Background: The 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., Objective: The aim of the study was to thoroughly describe the α-T stereoisomer profile of human milk., Methods: We 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 (Σ 2S ), 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 (s 2R ) to assess the degree to which RRR is favored in milk . Consistent with discrimination among 2 R stereoisomers in mammary tissue, RRR /s2 R 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 s 2R 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 2 R 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.

This reversed-phase HPLC method uses C30 chromatography and UV-Vis spectroscopy to determine cis and trans isomers of lutein, β-carotene, and lycopene in infant, pediatric, and adult nutritionals. Samples are saponified with a mixture of potassium hydroxide, tetrahydrofuran, and methanol, and carotenoids are extracted from saponified samples with 75 + 25 hexane-methyl tertiary butyl ether (MtBE). After extraction, a portion of the organic layer is evaporated to dryness, and the residue is dissolved in 75 + 25 10% butylated hydroxytoluene in methanol-MtBE. Prepared samples are injected into a C30 HPLC column where cis and trans isomers of lutein, β-carotene, and lycopene are separated with a methanol-MtBE gradient and detected with UV-Vis spectroscopy at 445 nm. Total carotenoid concentrations are calculated by comparison of sample peak areas with the areas of trans carotenoid standards of known concentration. During a single-laboratory validation of this method, total lutein repeatability and intermediate precision ranged from 1.89 to 14.9 and 1.93 to 14.0%, respectively, in infant and adult nutritional matrixes with concentrations >1 μg/100 g. Total β-carotene repeatability and intermediate precision ranged from 1.81 to 6.77 and 3.07 to 16.2%, respectively, in infant and adult nutritional matrixes with concentrations >1 μg/100 g, and total lycopene repeatability and intermediate precision ranged from 3.01 to 6.37 and 4.29 to 10.3%, respectively, in infant and adult nutritional matrixes with concentrations >1 μg/100 g. Mean overspike recoveries ranged from 90.3 to 95.3, 89.3 to 108, and 97.3 to 109% for lutein, β-carotene, and lycopene, respectively. The method also demonstrated good linearity. For lutein, r averaged 0.99991 over a standard range of approximately 10-250 µg/L trans-lutein. with average calibration errors of <1%. For β-carotene and lycopene, r averaged 0.99993 and 0.9998 over standard ranges of approximately 25-500 and 5-100 µg/L with calibration errors of <1 and <1.5%, respectively. Lutein, β-carotene, and lycopene LOQs in ready-to-feed nutritionals were estimated to be 0.4, 0.1, and 0.3 µg/100 g, respectively. This method met AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals Standard Method Performance Requirements and was approved as a First Action Official Method at the AOAC INTERNATIONAL 2017 midyear meeting.

A reversed-phase HPLC method with postcolumn protein conjugation and fluorescence detection for the quantitative determination of biotin in infant, pediatric, and adult nutritionals was developed and evaluated in a single-laboratory validation (SLV). Sample of appropriate size is mixed with 2% metaphosphoric acid to precipitate out the protein. The filtrate is injected onto a C18 HPLC column in which biotin and riboflavin are separated with an appropriate mobile phase. The biotin, after eluting from the column, binds with the streptavidin fluorescein to become a fluorescent conjugate. The conjugate is then detected by fluorescence at λex = 495 nm and λem = 518 nm. A column switch is used in the method as an option to shorten the run time from 30 to 15 min, by eluting out riboflavin at a higher flow rate. In this SLV, a total of 19 AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals matrixes representing a range of infant, pediatric, and adult formulas were evaluated for their biotin content. The analytical range was 1.66-142 μg/100 g reconstituted final product. The repeatability and intermediate precision ranged from 0.5 to 3.0% RSDr and from 1.3 to 4.5% RSDiR, respectively. Recovery from spiked matrixes varied from 95 to 111%, and accuracy of quantification using Standard Reference Material 1849a ranged from 99 to 105%. The LOQ in reconstituted product was estimated to be 0.8 μg/100 g. The method was approved by the Expert Review Panel as First Action at the 2016 AOAC INTERNATIONAL Mid-Year Meeting.

AOAC First Action Method 2011.10, Vitamin B12 in Infant and Pediatric Formulas and Adult Nutritionals, was collaboratively studied. This method uses a pH 4.5 sodium acetate buffer and potassium cyanide at 105°C to extract and convert all biologically active forms of vitamin B12 present to cyanocobalamin; octylsilyl (C8) or C18 SPE cartridges to purify and concentrate cyanocobalamin; a combination of size-exclusion and RPLC to isolate cyanocobalamin; and visible absorbance at 550 nm to detect and quantitate cyanocobalamin in infant, pediatric, and adult nutritionals with vitamin B12 concentrations greater than 0.025 μg/100 g ready-to-feed (RTF) liquid. During this collaborative study, nine to 11 laboratories from eight different countries analyzed blind duplicates of 12 infant, pediatric, and adult nutritional formulas. Per the AOAC Expert Review Panel (ERP) on Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) Nutrient Methods the method demonstrated acceptable repeatability and reproducibility and met SPIFAN Standard Method Performance Requirements (SMPRs®) for the majority of product matrixes analyzed. Vitamin B12 SPIFAN SMPRs for repeatability were ≤15% RSD at vitamin B12 concentrations of 0.01 μg/100 g RTF liquid and ≤7% RSD at vitamin B12 concentrations of 0.2-5.0 μg/100 g RTF liquid. Vitamin B12 SPIFAN SMPRs for reproducibility were ≤11% RSD in products with vitamin B12 concentrations ranging from 0.3 to 5.0 μg/100 g RTF liquid. During this collaborative study, the RSDr ranged from 2.98 to 9.77%, and the RSDR ranged from 3.54 to 19.5%. During previous single-laboratory validation studies, the method LOQ was estimated to be 0.025 μg/100 g RTF liquid.

Inositol is a six-carbon sugar alcohol and is one of nine biologically significant isomers of hexahydroxycyclohexane. Myo-inositol is the primary biologically active form and is present in higher concentrations in the fetus and newborn than in adults. It is currently being examined for the prevention of retinopathy of prematurity in newborn preterm infants. A robust method for quantifying myo-inositol (MI), D-chiro-inositol (DCI) and 1,5-anhydro- D-sorbitol (ADS) in very small-volume (25 μL) urine, blood serum and/or plasma samples was developed. Using a multiple-column, multiple mobile phase liquid chromatographic system with electrochemical detection, the method was validated with respect to (a) selectivity, (b) accuracy/recovery, (c) precision/reproducibility, (d) sensitivity, (e) stability and (f) ruggedness. The standard curve was linear and ranged from 0.5 to 30 mg/L for each of the three analytes. Above-mentioned performance measures were within acceptable limits described in the Food and Drug Administration's Guidance for Industry: Bioanalytical Method Validation. The method was validated using blood serum and plasma collected using four common anticoagulants, and also by quantifying the accuracy and sensitivity of MI measured in simulated urine samples recovered from preterm infant diaper systems. The method performs satisfactorily measuring the three most common inositol isomers on 25 μL clinical samples of serum, plasma, milk, and/or urine. Similar performance is seen testing larger volume samples of infant formulas and infant formula ingredients. MI, ADS and DCI may be accurately tested in urine samples collected from five different preterm infant diapers if the urine volume is greater than 2-5 mL., (Copyright © 2015 John Wiley & Sons, Ltd.)

AOAC First Action Method 2011.18, Myo-Inositol (Free and Bound as Phosphatidylinositol) in Infant and Pediatric Formulas and Adult Nutritionals, was collaboratively studied. With this method free myo-inositol and phosphatidylinositol bound myo-inositol are extracted using two different sample preparation procedures, separated by ion chromatography using a combination of Dionex Carbo Pac PA1 and MA1 columns with column switching, and detected with pulsed amperometry using a gold electrode. Free myo-inositol is extracted from samples with dilute hydrochloric acid and water. Phosphatidylinositol is extracted from samples with chloroform and separated from other fats with silica SPE cartridges. Myo-inositol is then released from the glycerol backbone with concentrated acetic and hydrochloric acids at 120°C. During this collaborative study, nine laboratories from five different countries analyzed blind duplicates of nine infant and pediatric nutritional formulas for both free and phosphatidylinositol bound myo-inositol, and one additional laboratory only completed the free myo-inositol analyses. The method demonstrated acceptable repeatability and reproducibility and met the AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) Standard Method Performance Requirements (SMPRs®) for free myo-inositol plus phosphatidylinositol bound myo-inositol for all the matrixes analyzed. SMPRs for repeatability were ≤5% RSD at myo-inositol concentrations of 2-68 mg/100 g ready-to-feed (RTF) liquid. SMPRs for reproducibility were ≤8% RSD in products with myo-inositol concentrations ranging from 2 to 68 mg/100 g RTF liquid. During this collaborative study, repeatability RSDs ranged from 0.51 to 3.22%, and RSDs ranged from 2.66 to 7.55% for free myo-inositol plus phosphatidylinositol bound myo-inositol.

This normal-phase HPLC method with postcolumn reduction and fluorescence detection allows for the quantitative determination of trans vitamin K1 in infant, pediatric, and adult nutritionals. Vitamin K1 is extracted from products with iso-octane after precipitation of proteins and release of lipids with methanol. Prepared samples are injected onto a silica HPLC column where cis and trans vitamin K1 are separated with an iso-octane-isopropanol mobile phase. The column eluent is mixed with a dilute ethanolic solution of zinc chloride, sodium acetate, and acetic acid, and vitamin K1 is reduced to a fluorescent derivative in a zinc reactor column. The resulting hydroquinone is then detected by fluorescence at an excitation wavelength of 245 nm and an emission wavelength of 440 nm. During a single-laboratory validation of this method, repeatability and intermediate precision ranged from 0.6 to 3.5% RSD and 1.1 to 6.0% RSD, respectively. Mean overspike recoveries ranged from 91.9 to 106%. The method demonstrated good linearity over a standard range of approximately 2-90 μg/L trans vitamin K1 with r2 averaging 0.99995 and average calibration errors of <1%. LOQ and LOD in ready-to-feed nutritionals were estimated to be 0.03 and 0.09 μg/100 g, respectively. The method met AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals Standard Method Performance Requirements® and was approved as a first action method at the 2015 AOAC Mid-Year Meeting.

The applicability of AOAC Official Method 992.06, vitamin A (retinol) in milk-based infant formula can be extended to specialty infant formulas, and medical and adult nutritional products with a few minor modifications to the sample preparation procedure. Currently, AOAC Official Method 992.06 is only applicable to milk-based infant formulas containing >500 IU vitamin A per reconstituted quart. When this method is used as written to test specialty infant formulas, vitamin A recoveries are low compared to results generated with alternate validated vitamin A methods. AOAC Method 992.06 vitamin A recoveries can be improved significantly in specialty infant formulas if the amount of potassium hydroxide used during the saponification step is doubled. With this one minor modification to the sample preparation procedure, AOAC Method 992.06 demonstrates acceptable precision and accuracy for the quantitation of vitamin A (retinol) in specialty infant formulas, milk- and soy-based infant formulas, and adult and medical nutritionals. Because increasing the amount of potassium hydroxide can cause emulsions to form, 2-4 mL aliquots of reagent alcohol may need to be added to some samples to separate the organic and aqueous layers during the extraction step. A single-laboratory validation of these modifications was completed. During validation, 15 different product matrixes were analyzed. The intermediate precision averaged 2.70% RSD, and spike recovery data averaged 96.3%.

Modifications were made to AOAC Official Method 999.15 to extend its applicability to specialty infant formulas containing hydrolyzed proteins and free amino acids, and to medical and adult nutritional products. Minor changes to the sample preparation procedure and chromatographic separation improved vitamin K1 recoveries and reduced chromatographic interferences in these types of matrixes. Currently AOAC Method 999.15 is applicable only to the determination of total vitamin K1 (phylloquione) in infant formula and milk (fluid, ready-to-feed, and powdered) containing > 1 microg vitamin K1/100 g solids. AOAC Method 999.15 recoveries of vitamin K1 were improved by altering sample sizes, extraction solvents and amounts, and the reagent addition order and amount of water or aqueous solutions added. The chromatographic separation of vitamin K1 in medical nutritional products containing canola and marine oils was improved, and trans vitamin K1 was separated from the biologically inactive cis isomer in all products with a C30 3 microm column and a 100% methanol mobile phase. With these modifications to the extraction procedure and chromatographic separation, AOAC Method 999.15 demonstrated acceptable precision and accuracy for the quantitation of trans vitamin K1 in specialty infant formulas containing hydrolyzed proteins and free amino acids, and medical and adult nutritional products. A single-laboratory validation of these minor modifications was completed. Fourteen different product matrixes were analyzed during validation. The intermediate precision averaged 4.15% RSD (range 2.52-5.81% RSD), and recovery data averaged 100.1% (range 92.2-109%).