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The Journal of Nutrition Oct 2007African Americans in the southern United States have a high prevalence of chronic disease. Tocopherol intake and status have been associated with protection against...
African Americans in the southern United States have a high prevalence of chronic disease. Tocopherol intake and status have been associated with protection against several chronic diseases. Our objectives were, therefore, to examine the association between tocopherol intakes as measured by 2 regional FFQ and their corresponding concentrations in serum and to report on dietary sources of tocopherols in 404 men and women participating in the cross-sectional Diet and Physical Activity Sub-Study of the Jackson Heart Study. A large proportion (49% of men and 66% of women) reported dietary supplement use. Only 5.8% of men and 4.5% of women met the estimated average requirement (EAR) for vitamin E from foods alone, whereas 44.2% men and 49.2% women met it from foods and supplements. Total (diet + supplement) intake of alpha-tocopherol was associated with its corresponding measure in serum. Vitamin E supplement use, sex, serum cholesterol, education, and BMI, but not gamma-tocopherol intakes, were associated with serum gamma-tocopherol. For delta-tocopherol, associated variables included sex and serum cholesterol. The top food sources of alpha- and gamma-tocopherol were snack chips and the top food source of delta-tocopherol was margarine. Despite prevalent vitamin E supplement use, more than one-half of this population did not meet the EAR for alpha-tocopherol intake and very few met it from food alone. Supplement use was associated with higher alpha- but lower gamma-tocopherol concentration in serum. The possible health implications of this difference in relative tocopherol subtypes require further study.
Topics: Adult; Black or African American; Aged; Aged, 80 and over; Diet; Diet Surveys; Female; Humans; Male; Middle Aged; alpha-Tocopherol
PubMed: 17885014
DOI: 10.1093/jn/137.10.2297 -
The Journal of Nutritional Biochemistry Jul 2004Nutritionists generally consider all-rac-alpha-tocopherol and RRR-alpha-tocopherol equivalent in vitamin E activity but disagree whether equivalency requires a dosage... (Review)
Review
Nutritionists generally consider all-rac-alpha-tocopherol and RRR-alpha-tocopherol equivalent in vitamin E activity but disagree whether equivalency requires a dosage ratio of 1.36:1 or 2:1. In contrast, we hypothesize that all-rac- and RRR-alpha-tocopherols are not equivalent in any dosage ratio. Previous observations that all-rac- and RRR-alpha-tocopherols are distributed and eliminated via saturable and stereospecific pathways imply that their relative bioavailability varies with the saturation of these pathways and therefore varies with dosage. Indeed, previous studies observed that the relative bioavailability of all-rac- and RRR-alpha-tocopherols varies between tissues as well as with dose, time after dosing, and duration of dosing. This non-constant relative bioavailability predicts non-constant relative activity (i.e., non-parallel dose-concentration curves predict non-parallel dose-effect curves). Non-constant relative bioavailability suggests that a fixed dosage ratio of all-rac- and RRR-alpha-tocopherols cannot produce a fixed ratio of effects on all processes in all tissues at all times after all dosages. However, previous studies suggest that all-rac- and RRR-alpha-tocopherols have equivalent effects (parallel dose-effect curves) in vitamin E-deficient animals and non-vitamin E-deficient humans. We re-evaluate the data from these animal studies and find non-parallel dose-effect and concentration-effect curves. We discuss pharmacokinetic and pharmacodynamic reasons why previous studies in non-vitamin E-deficient humans did not find non-parallel dose-effect curves for all-rac- and RRR-alpha-tocopherols. We note that saturable elimination predicts that all-rac- and RRR-alpha-tocopherols might inhibit and/or induce elimination of other compounds (including 30-40% of prescription drugs) eliminated via the same saturable pathways, and stereospecific elimination predicts that all-rac- and RRR-alpha-tocopherol have non-parallel dose-effect curves for these interactions.
Topics: Animals; Biological Availability; Dietary Supplements; Dose-Response Relationship, Drug; Humans; Kinetics; Stereoisomerism; Structure-Activity Relationship; Therapeutic Equivalency; Vitamin E Deficiency; alpha-Tocopherol
PubMed: 15219923
DOI: 10.1016/j.jnutbio.2003.12.011 -
The Journal of Nutritional Biochemistry Dec 2018In rats, plasma and tissue concentrations of α-tocopherol, a predominant form of vitamin E in mammals, are known to differ between the sexes. In order to examine sex...
In rats, plasma and tissue concentrations of α-tocopherol, a predominant form of vitamin E in mammals, are known to differ between the sexes. In order to examine sex differences in α-tocopherol metabolism, we investigated urinary excretion of the α-tocopherol metabolite α-carboxymethylhydroxychroman (α-CEHC) using Wistar rats. First, we measured α-CEHC in urine of 9-week-old male and female rats in basal and α-tocopherol-administered conditions. We observed that female rats excrete significantly more α-CEHC than male rats via urine. This sex difference was observed in matured 9-week-old rats but not in premature 3-week-old rats, suggesting that the difference may relate to sex hormones. In order to confirm this, we examined the effect of ovariectomy and orchiectomy on female and male rats, respectively. The results of castration clearly demonstrated that orchiectomy enhanced urinary excretion of α-CEHC, supporting the hypothesis that testosterone repressed α-tocopherol metabolism. We then administered testosterone propionate to orchiectomized rats and observed down-regulation of α-CEHC excretion. Taken together, these results indicate that testosterone represses the metabolism and urinary excretion of α-tocopherol in rats. This is the first report to show a sex-dependent difference in urinary excretion rate of an α-tocopherol metabolite and contributes to the understanding of vitamin E metabolism.
Topics: Animals; Chromans; Female; Male; Orchiectomy; Ovariectomy; Rats, Wistar; Sex Factors; Testosterone; alpha-Tocopherol
PubMed: 30253278
DOI: 10.1016/j.jnutbio.2018.08.006 -
Alcohol (Fayetteville, N.Y.) Nov 2022Alcoholism affects about 2 billion people worldwide. Withdrawal causes a neuroinflammatory response that increases anxiety. α-tocopherol is the most important...
Evaluation of the effect of alpha-tocopherol on anxiety and the neuroinflammatory process during alcohol withdrawal in a model of forced and chronic self-administration of liquid diet containing ethanol: Behavioral and neurochemical evidence.
Alcoholism affects about 2 billion people worldwide. Withdrawal causes a neuroinflammatory response that increases anxiety. α-tocopherol is the most important antioxidant that has its in vivo action currently known. Therefore, this study aimed to evaluate the effect of α-tocopherol on the neuroinflammatory process in brain regions involved in anxiety and its anxiolytic potential during alcohol withdrawal. For this, male Wistar rats were divided into four groups and submitted to a procedure of forced and chronic self-administration of liquid diet containing 6% and 8% ethanol for 15 days, followed by abrupt interruption of treatment. Animals in the control group received the liquid diet without ethanol. Twenty-four or 48 h after ethanol discontinuation, and 30 min after the last administration of α-tocopherol or saline, animals were evaluated in the elevated plus maze, light/dark box, and open field tests. At the end of the tests, each experimental group underwent brain tissue collection for analysis of cytokine levels. The results showed that: alcohol induces the neuroinflammatory process and anxiety; the stress generated by withdrawal can induce oxidative stress, which alters the production of inflammatory cytokines in the amygdaloid nuclei (AN) and medial hypothalamic nucleus (mHN); α-tocopherol exhibited anxiolytic and anti-inflammatory activity, attenuating the anxious behavior of abstinent animals and reducing neuroinflammation in AN and mHN; and the intensity of the anxiolytic and anti-inflammatory effect of α-tocopherol is dose-dependent. These results identify α-tocopherol as a potential therapeutic target supporting the fight against relapse during alcohol withdrawal.
Topics: Animals; Rats; Male; Substance Withdrawal Syndrome; Alcoholism; Ethanol; alpha-Tocopherol; Anti-Anxiety Agents; Rats, Wistar; Anxiety; Diet
PubMed: 35987315
DOI: 10.1016/j.alcohol.2022.08.002 -
Journal of Pediatric Gastroenterology... Feb 2016The aim of the study was to evaluate and compare the levels of alpha-tocopherol in colostrum milk and serum of mothers with premature birth, classified as severe...
OBJECTIVE
The aim of the study was to evaluate and compare the levels of alpha-tocopherol in colostrum milk and serum of mothers with premature birth, classified as severe prematurity and moderate prematurity.
METHODS
Cross-sectional study with 65 women, 18 births classified as severe prematurity (<32 weeks of gestation) and 47 as moderate prematurity (≥32 weeks of gestation). The study only included mothers without any conditions associated with pregnancy and who had a single conception without any malformation. Samples of serum and colostrum were collected during fasting in the immediate postpartum, and alpha-tocopherol was analyzed by high-performance liquid chromatography. To determine the biochemical nutritional status of vitamin E, a serum cutoff (11.6 μmol/L) was adopted. The Student t test for independent variables compared the average concentrations of alpha-tocopherol in serum and colostrum among prematurity groups. Differences were considered significant when P < 0.05.
RESULTS
The alpha-tocopherol concentrations in colostrum were similar in both groups, being 34.5 ± 20.2 μmol/L for women with severe prematurity and 35.1 ± 16.3 μmol/L for moderate prematurity. For the serum of puerperal women with severe prematurity, alpha-tocopherol concentration was, however, lower than in women with moderate prematurity, 22.2 ± 4.4 μmol/L versus 27.1 ± 8.6 μmol/L (P < 0.05). The serum levels of alpha-tocopherol indicated nutritional risk at 5.6% (n = 1) of women with severe prematurity and 4.3% (n = 2) for those with moderate prematurity.
CONCLUSIONS
Severe prematurity affected the levels of alpha-tocopherol in maternal serum; however, the level of prematurity did not change the concentration of vitamin E in colostrum.
Topics: Adolescent; Adult; Chromatography, High Pressure Liquid; Colostrum; Cross-Sectional Studies; Female; Humans; Infant, Premature; Middle Aged; Nutritional Status; Obstetric Labor, Premature; Postpartum Period; Pregnancy; Premature Birth; Young Adult; alpha-Tocopherol
PubMed: 26334256
DOI: 10.1097/MPG.0000000000000969 -
Journal of Endodontics Aug 2019It has been reported that bond strength can be reversed to prebleached levels with the application of 10% alpha-tocopherol in a 2-hour time frame or by delaying bonding...
It has been reported that bond strength can be reversed to prebleached levels with the application of 10% alpha-tocopherol in a 2-hour time frame or by delaying bonding for 2 weeks. This study evaluated the effectiveness of a 5-minute application of 20% alpha-tocopherol to reverse the deleterious effects of nonvital bleaching on consequent bond strength. Thirty third molars were assigned to the following 3 groups: unbleached, bleached, and bleached followed by treatment with alpha-tocopherol. The bleached groups were exposed to sodium perborate (2 g/mL) for 7 days. The postbleach treatment group was subsequently treated with 20% alpha-tocopherol for 5 minutes, and then all groups were restored with composite resin. After 24 hours of storage at 37°C and 100% humidity, restored tooth specimens were sectioned into 1-mm dentin-composite beams. Six beams from each tooth were subjected to microtensile bond strength testing. Representative beams were further evaluated with Raman microspectroscopy and scanning electron microscopy. The mean bond strength values (MPa) for each group were as follows: unbleached control group = 26.2, bleached control group = 20.3, and post-bleach treatment group = 18.5. A 1-factor analysis of variance and Tukey post hoc test (α = 0.05) indicated that bleaching had a detrimental effect on bond strength and that short-term alpha-tocopherol treatments did not improve postbleach bond strength. Raman microspectroscopy and scanning electron microscopy revealed no noted improvement for the post-bleach treatment group.The application of 20% alpha-tocopherol in a clinically relevant time frame was not effective in counteracting the deleterious effect of bleaching on bond strength. Bonding procedures should be delayed after tooth bleaching.
Topics: Antioxidants; Borates; Composite Resins; Dental Bonding; Dentin; Resin Cements; Tensile Strength; Tooth Bleaching; alpha-Tocopherol
PubMed: 31155299
DOI: 10.1016/j.joen.2019.04.013 -
Molecular Nutrition & Food Research May 2010Rodents fed alpha-tocopherol (alphaT)-depleted diets develop neuromuscular deficits. Unequivocal role of alphaT in the prevention of these deficits is confounded by... (Review)
Review
Rodents fed alpha-tocopherol (alphaT)-depleted diets develop neuromuscular deficits. Unequivocal role of alphaT in the prevention of these deficits is confounded by possible neurotoxic oxidant products generated, ex vivo in alphaT-depleted diets. The discovery that large doses of alphaT could ameliorate neuromuscular deficits, attributed to very low serum alphaT caused by mutations in either the microsomal triglyceride transfer protein or the alphaT-transfer protein (alphaTTP), underscores the necessity of alphaT for neuromuscular health in humans. The discovery of human alphaTTP provided physiological relevance to biochemical data from rodents documenting alphaT-binding transfer protein, expressed exclusively in liver. The cloning of alphaTTP gene and the creation of alphaTTP-knockout mice allowed to achieve severe systemic alphaT deficiency in brain and muscles, possibly at birth, eliminating the possible confounding effects of ex vivo-generated oxidant products in vitamin E-stripped diets. alphaTTP-knockout mice have proven useful models to discover alphaT-regulated phenotypes and molecular actions of alphaT in vivo. The results suggest that antioxidant and non-antioxidant actions of alphaT in vivo may not be mutually exclusive. These studies also suggest that low levels of dietary alphaT can achieve in excess of nanomolar alphaT levels in tissues and maintain normal neuromuscular functions. This is consistent with biochemical and crystallographic data of alpha-TTP and of other alphaT-binding proteins that have dissociation constants in nanomolar range. Molecular mechanisms that cause a long delay for the development of deficiency symptoms remain enigmatic. It is likely that alphaT is metabolically stable in post-mitotic neurons and myocytes and, if it undergoes redox-cycling in vivo, a large repertoire of alphaT-regenerating systems maintains its biological activity before it is totally depleted.
Topics: Adipose Tissue; Animals; Ataxia; Atrophy; Carrier Proteins; Diet; Disease Models, Animal; Exercise; Free Radicals; Humans; Mice; Mice, Knockout; Neuromuscular Diseases; Physical Endurance; Vitamin D Deficiency; alpha-Tocopherol
PubMed: 20187127
DOI: 10.1002/mnfr.200900575 -
Journal of Agricultural and Food... Jun 2023The antioxidant interactions between α-tocopherol and myricetin in stripped soybean oil-in-water emulsions at pH 4.0 and pH 7.0 were analyzed. At pH 7.0, α-tocopherol...
The antioxidant interactions between α-tocopherol and myricetin in stripped soybean oil-in-water emulsions at pH 4.0 and pH 7.0 were analyzed. At pH 7.0, α-tocopherol (α-TOC):myricetin (MYR) ratios of 2:1 and 1:1 yielded interaction indices of 3.00 and 3.63 for lipid hydroperoxides and 2.44 and 3.00 for hexanal formation, indicating synergism. Myricetin's ability to regenerate oxidized α-tocopherol and slow its degradation was identified as the synergism mechanism. Antagonism was observed at pH 4.0 due to high ferric-reducing activity of myricetin in acidic environment. The interaction between α-tocopherol and taxifolin (TAX) was also investigated due to structural similarities of myricetin and taxifolin. α-Tocopherol and taxifolin combinations exhibited antagonism at both pH 4.0 and pH 7.0. This was associated with taxifolin's inability to recycle α-tocopherol while still increasing the prooxidant activity of iron. The combination of α-tocopherol and myricetin was found to be an excellent antioxidant strategy for oil-in-water emulsions at pH values near neutrality.
Topics: alpha-Tocopherol; Antioxidants; Emulsions; Water; Oxidation-Reduction
PubMed: 37279160
DOI: 10.1021/acs.jafc.3c01226 -
The Journal of Nutrition Dec 2020Alpha-tocopherol (αT), the bioactive constituent of vitamin E, is essential for fertility and neurological development. Synthetic αT (8 stereoisomers; all rac-αT) is...
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.
Topics: Animals; Brain; Diet; Female; Gene Expression Regulation; Hippocampus; Male; Mice; Milk; alpha-Tocopherol
PubMed: 32937657
DOI: 10.1093/jn/nxaa249 -
Journal of Agricultural and Food... Jan 2020This study aimed to determine α-tocopherol (α-T) and its thermal oxidation products simultaneously. A novel method based on an ultra-performance liquid chromatography...
This study aimed to determine α-tocopherol (α-T) and its thermal oxidation products simultaneously. A novel method based on an ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was developed. This approach was achieved by means of a BEH C18 analytical column under gradient elution conditions with eluents of acetonitrile/isopropanol (1:9, v/v) and acetonitrile/water (4:6, v/v). Compounds were elucidated through exact molecular mass and fragmentation ions obtained from the Q-TOF-MS detector. Two oxidation products, α-tocopheryl quinone and 5-formyl-γ-tocopherol, were identified, and one new compound was determined. This approach offered a simple, precise, and reliable method to determine oxidation products of α-T, which may give a way to understand the mechanism of the thermal oxidative process of α-T.
Topics: Chromatography, High Pressure Liquid; Hot Temperature; Mass Spectrometry; Molecular Structure; Oxidation-Reduction; alpha-Tocopherol
PubMed: 31855428
DOI: 10.1021/acs.jafc.9b06544