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Query: UMLS:C0042875 (vitamin E deficiency)
 916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vitamin E is important in maintaining normal neurological structure and function. In this study, 100 children with protein-energy malnutrition (PEM) were studied and compared to a suitably age-matched control group. Posterior column deficits, cerebellar deficits, and problems with fine motor coordination were present to a significant degree in the PEM subjects. The presence of neurological signs was correlated with various parameters of vitamin E deficiency, including low serum alpha-tocopherol levels and a low tocopherol/total lipid ratio which was present in 92 per cent of subjects. There was good concordance between vitamin E levels and vitamin E to serum lipid ratio in assessing vitamin E deficiency. We conclude that vitamin E deficiency is prevalent, to a hitherto unsuspected degree, in children with PEM and that these malnourished children have significant neurological deficits attributable to low vitamin E levels. This observation is of clinical significance as the neurological deficits are potentially reversible with vitamin E supplementation.
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PMID:Vitamin E deficiency and associated neurological deficits in children with protein-energy malnutrition. 981 93

To study how the expression of alpha-tocopherol transfer protein (alpha-TTP) and its mRNA are affected by protein and vitamin E status, Long-Evans male weanling rats were fed a vitamin E-deficient (DE), high vitamin E (HE, 5 g/kg diet of all-rac-alpha-tocopheryl acetate) or control (C) diet for 12 wk in Experiment 1; and fed a low-protein (LP) or control (C) diet for 6 wk in Experiment 2. The high and deficient vitamin E status of HE and DE groups in Experiment 1 were confirmed by changes in plasma pyruvate kinase activity as well as the concentrations of alpha-tocopherol in plasma and liver. As shown by the Northern and Western Blot Analysis, the expression of alpha-TTP in the liver of the DE group was significantly lower than, while that of the HE group was not different from, that of the controls. In contrast, the alpha-TTP mRNA levels did not differ among the C, DE and HE groups. alpha-Tocopherol in most peripheral tissues of rats fed the LP diet in Experiment 2 was significantly lower than that of the C. Both the alpha-TTP and its mRNA were significantly lower in the LP group than in the C. The results suggested that dietary vitamin E does not affect alpha-TTP gene expression except that the protein levels in the liver were lowered by vitamin E deficiency. On the other hand, protein inadequacy appeared to down-regulate the expression of the alpha-TTP gene.
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PMID:Liver alpha-tocopherol transfer protein and its mRNA are differentially altered by dietary vitamin E deficiency and protein insufficiency in rats. 986 80

Vitamin E is one of the most important lipid-soluble antioxidant nutrient. Severe vitamin E deficiency (VED) can have a profound effect on the central nervous system. VED causes ataxia and peripheral neuropathy that resembles Friedreich's ataxia. We report here a patient presenting this syndrome, but also a prolactin and FSH adenoma. Both the neurological syndromes and the adenoma regressed after treatment with alpha-tocopherol. Although, the presence of the prolactinoma in this patient may not be related to his vitamin E deficiency, alpha-tocopherol treatment seems to be beneficial and might usefully be tested in patients with hypophyseal secreting other forms of adenoma.
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PMID:Vitamin E deficiency ataxia associated with adenoma. 1006 78

Vitamin E (alpha-tocopherol) is an essential nutrient and an important antioxidant. Its plasma levels are dependent upon oral intake, absorption and transfer of the vitamin to a circulating lipoprotein. The latter step is controlled by alpha-tocopherol transfer protein (alpha-TTP), which is a 278 amino acid protein encoded on chromosome 8, known to be synthesized in the liver. Mutations in alpha-TTP are associated with a neurological syndrome of spinocerebellar ataxia, called ataxia with vitamin E deficiency (AVED). Earlier studies suggested that alpha-TTP is found only in the liver. In order to establish whether alpha-TTP is expressed in the human brain, and what relationship this has to AVED, we studied immunohistochemically the presence of alpha-TTP in the brains of a patient with AVED, normal subjects, and patients with Alzheimer's disease (AD), Down's syndrome (DS), cholestatic liver disease (CLD) and abetalipoproteinemia (ABL). The neuropathology of both AD and DS is thought to be related in part to oxidative stress. The diseases of AVED, of cholestatic liver disease, and of abetalipoproteinemia are thought to be due to lack of circulating tocopherol, leading to inadequate protection against oxidative damage. We demonstrate the presence of alpha-TTP in cerebellar Purkinje cells in patients having vitamin E deficiency states or diseases associated with oxidative stress.
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PMID:Localization of alpha-tocopherol transfer protein in the brains of patients with ataxia with vitamin E deficiency and other oxidative stress related neurodegenerative disorders. 1008 86

A critical analysis of the changes in fatty acid patterns and their metabolism elicited by vitamin E deficiency leads to the proposal that a major role of dietary RRR-alpha-tocopherol (alpha-TOC) is as an enzymatic precursor of alpha-tocopherolquinone (alpha-TQ) whose semiquinone radical functions as an essential enzyme cofactor for the fatty acid desaturases of the recently elucidated carnitine-dependent, channeled, mitochondrial desaturation-elongation pathway; a detailed mechanism for its function is proposed. Pathophysiological states produced by vitamin E deficiency and alpha-TOC transfer protein defects, such as ataxia, myopathy, retinopathy, and sterility are proposed to develop from the effects of impaired alpha-TQ-dependent desaturases and the resulting deficiency of their polyenoic fatty acid products.
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PMID:A function for the vitamin E metabolite alpha-tocopherol quinone as an essential enzyme cofactor for the mitochondrial fatty acid desaturases. 1010 Jun 2

If the function of vitamin E is that of an antioxidant and the various forms of vitamin E have similar antioxidant activities, then why does RRR-alpha-tocopherol have the highest biologic activity? This chapter describes how interactions by investigators from various scientific disciplines using stable isotopes, molecular biology tools, and sophisticated genetic studies of humans with vitamin E deficiency have led to an understanding of this problem. This chapter provides an overview of (a) studies using deuterated tocopherols that demonstrated that the plasma preference for alpha-tocopherol is dependent on metabolic processes in the liver; (b) the isolation, molecular biology, and function of the alpha-tocopherol transfer protein; and (c) studies that demonstrated that patients who were vitamin E deficient as a result of no known cause had defective alpha-tocopherol transfer protein genes. Finally, we focus on the future--what remains to be learned about the regulation of vitamin E in tissues.
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PMID:Molecular mechanisms of vitamin E transport. 1044 28

Vitamin E occurs in nature in eight different forms, but animal body is enriched in alpha-tocopherol compared with other forms. alpha-Tocopherol transfer protein (alpha-TTP) is a liver cytosolic protein, which specifically binds alpha-tocopherol, and plays an important role in the discrimination of various tocopherols in the body. Furthermore, alpha-TTP is a product of the causative gene for familial isolated vitamin E deficiency. Using cell culture system, it was shown that alpha-TTP functions to enhance secretion of alpha-tocopherol from liver cells and that the reaction utilizes a novel non-Golgi mediated pathway which may be linked to cellular cholesterol metabolism and/or transport.
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PMID:[Molecular mechanism of vitamin E transport in the body]. 1054 Aug 74

Preterm infants may be susceptible to chronic lung disease and retinopathy of prematurity because of deficient antioxidant mechanisms including deficiency of vitamin E. The aim of this study was to evaluate the status of the antioxidant vitamin E among preterm and term livebirths. Umbilical cord blood samples collected from 40 preterm and 180 term babies were analyzed for vitamin E levels using high performance liquid chromatography. Linear regression analysis was used to examine the relationship of vitamin E with gestational age, birth weight and appropriateness of weight for gestational age. The median vitamin E level of preterm babies (2.61 mg/L) was not significantly different from that of term babies (2.77 mg/L), p = 0.2. Linear regression analysis demonstrated a weak but statistically significant correlation between cord blood vitamin E levels and gestational age (r = 0.14, p = 0.046). Vitamin E levels did not correlate with birth weight or weight for gestational age. Preterm babies had a higher incidence of vitamin E deficiency compared to term babies (38% v 19%, p = 0.02). Our findings lead us to conclude that vitamin E accumulates in the fetus throughout the third trimester so that preterm infants are likely to have vitamin E deficiency.
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PMID:Vitamin E status of infants at birth. 1064 61

Vitamin E is a potent antioxidant and has an ability to modulate host immune functions. This chapter consists of five parts: (1) vitamin E deficiency and immunity, (2) vitamin E supplementation and immunity, (3) vitamin E and the decreased cellular immunity with aging, (4) vitamin E and T-cell differentiation in the thymus, and (5) vitamin E and acquired immune deficiency syndrome (AIDS). In vitamin E deficiency most of the immune parameters show a downward trend, which is associated with increased infectious diseases and the incidence of tumors. In contrast, vitamin E supplementation has various beneficial effects on the host immune system. The decreased cellular immunity with aging or during the development of AIDS is markedly improved by the intake of a high vitamin E diet. In addition, vitamin E plays an important role in the differentiation of immature T cells in thymus. Vitamin E deficiency induces the decreased differentiation of immature T cells, which results in the early decrease of cellular immunity with aging in spontaneously hypertensive rats. Conversely, vitamin E supplementation induces a higher differentiation of immature T cells via increased positive selection by thymic epithelial cells, which results in the improvement of decreased cellular immunity in the aged. Furthermore, vitamin E supplementation induces the early recovery of thymic atrophy following X-ray irradiation. Taken together, these results suggest that vitamin E is an important nutrient for maintaining the immune system, especially in the aged.
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PMID:Vitamin E and immunity. 1071 44

Vitamin E is the general term for all tocopherols and tocotrienols, of which alpha-tocopherol is the natural and biologically most active form. Although gamma-tocopherol makes a significant contribution to the vitamin E CONTENT in foods, it is less effective in animal and human tissues, where alpha-tocopherol is the most effective chain-breaking lipid-soluble antioxidant. The antioxidant function of vitamin E is critical for the prevention of oxidation of tissue PUFA. Animal experiments have shown that increasing the degree of dietary fatty acid unsaturation increases the peroxidizability of the lipids and reduces the time required to develop symptoms of vitamin E deficiency. From these experiments, relative amounts of vitamin E required to protect the various fatty acids from being peroxidized, could be estimated. Since systematic studies on the vitamin E requirement in relation to PUFA consumption have not been performed in man, recommendations for vitamin E intake are based on animal experiments and human food intake data. An intake of 0.6 mg alpha-tocopherol equivalents per gram linoleic acid is generally seen as adequate for human adults. The minimum vitamin E requirement at consumption of fatty acids with a higher degree of unsaturation can be calculated by a formula, which takes into account the peroxidizability of unsaturated fatty acids and is based on the results of animal experiments. There are, however, no clear data on the vitamin E requirement of humans consuming the more unsaturated fatty acids as for instance EPA (20:5, n-3) and DHA (22:6, n-3). Studies investigating the effects of EPA and DHA supplementation have shown an increase in lipid peroxidation, although amounts of vitamin E were present that are considered adequate in relation to the calculated oxidative potential of these fatty acids. Furthermore, a calculation of the vitamin E requirement, using recent nutritional intake data, shows that a reduction in total fat intake with a concomitant increase in PUFA consumption, including EPA and DHA, will result in an increased amount of vitamin E required. In addition, the methods used in previous studies investigating vitamin E requirement and PUFA consumption (for instance erythrocyte hemolysis), and the techniques used to assess lipid peroxidation (e.g. MDA analysis), may be unsuitable to establish a quantitative relation between vitamin E intake and consumption of highly unsaturated fatty acids. Therefore, further studies are required to establish the vitamin E requirement when the intake of longer-chain, more-unsaturated fatty acids is increased. For this purpose it is necessary to use functional techniques based on the measurement of lipid peroxidation in vivo. Until these data are available, the widely used ratio of at least 0.6 mg alpha-TE/g PUFA is suggested. Higher levels may be necessary, however, for fats that are rich in fatty acids containing more than two double bonds.
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PMID:Relationship between vitamin E requirement and polyunsaturated fatty acid intake in man: a review. 1080 54


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