Search results for "vitamin e"
showing 10 items of 147 documents
α-Tocopherol Modulates Phosphatidylserine Externalization in Erythrocytes
2006
Objective— The aim of the present study was to assess the effect of α-tocopherol, the main vitamin E isomer on phosphatidylserine (PS) exposure at the surface of circulating erythrocytes, and to determine consequences on erythrocyte properties. Methods and Results— In vitro α-tocopherol enrichment of isolated erythrocytes significantly decreased PS externalization as assessed by lower Annexin V-fluorescein isothiocyanate labeling. Plasma phospholipid transfer protein (PLTP) transfers vitamin E, and both α-and γ-tocopherol accumulated in circulating erythrocytes from PLTP-deficient homozygous (PLTP −/− ) mice as compared with wild-type mice. In agreement with in vitro studies, vitamin E–enr…
The Role of Vitamin Deficiency in Liver Disease: To Supplement or Not Supplement?
2021
Over the past few years, growing interest has been shown for the impact of dietary requirements and nutritional factors on chronic diseases. As a result, nutritional programs have been reinforced by public health policies. The precise role of micronutrients in chronic liver disease is currently receiving particular attention since abnormalities in vitamin levels are often detected. At present, treatment programs are focused on correcting vitamin deficiencies, which are frequently correlated to higher rates of comorbidities with poor outcomes. The literature reviewed here indicates that liver diseases are often related to vitamin disorders, due to both liver impairment and abnormal intake. M…
Is At Least One Vitamin Helping Our Vasculature?
2014
See related article, pp 1290–1298 Cardiovascular risk factors such as diabetes mellitus, arterial hypertension, chronic smoking, and hypercholesterolemia are cardiovascular risk factors known to be associated with endothelial dysfunction, a condition that may predict long-term progression of atherosclerosis as well as cardiovascular event rates (for review, see Munzel et al1) Although the mechanisms underlying this phenomenon are complex and multifactorial, there is growing body of evidence that oxidative stress attributable to increased production of reactive oxygen–derived free radicals may play a pivotal role in this process.2 Increased superoxide production by enzyme systems such as the…
Do Antioxidant Vitamins Prevent Exercise-Induced Muscle Damage? A Systematic Review
2020
Free radicals produced during exercise play a role in modulating cell signaling pathways. High doses of antioxidants may hamper adaptations to exercise training. However, their benefits are unclear. This review aims to examine whether vitamin C (VitC) and/or vitamin E (VitE) supplementation (SUP) prevents exercise-induced muscle damage. The PubMed, Web of Science, Medline, CINAHL, and SPORTDiscus databases were searched, and 21 articles were included. Four studies examined the effects of acute VitC SUP given pre-exercise: in one study, lower CK levels post-exercise was observed; in three, no difference was recorded. In one study, acute VitE SUP reduced CK activity 1 h post-exercise in condi…
Alpha-(13′-hydroxy)-6-hydroxychroman, the main product of alpha-tocopherol metabolism in human hepatocytes, regulates CYP4F2 and PPAR-γ expression
2017
The enzymatic metabolism of vitamin E in liver cells generates long chain metabolites (LCMs) with proposed regulatory activity on inflammatory and atherogenic genes. In this study the LCM formation kinetics was characterized in HepG2 and HepaRG human hepatic cells, supplemented with RRR-α-tocopherol (α-TOH). α-13’OH was the main product of α-TOH metabolism, while α-13’COOH metabolite and the short chain metabolite α-CEHC, were detected only in traces, thus demonstrating the poor efficiency of vitamin E catabolism in these cells. However, this metabolism was significantly simulated when the hepatic cells were challenged with (lipo)toxic agents, such as ethanol or palmitate. Under such condit…
Stability of ascorbic acid in adapted milk-based infant formulae during storage
2004
A study was made of the effects of storage (for up to 17 months at 22 or 37 °C) on the ascorbic acid contents of four adapted milk-based infant formulae with the same composition except for the iron salt added (lactate or sulphate) and/or the vitamin E source involved (α-tocopherol (α-T) or α-tocopherol acetate (α-TAc)). Ascorbic acid was measured by a voltammetric method. The ascorbic acid contents of the formulae ranged from 0.77–0.84 g kg−1 immediately after manufacture to 0.41–0.48 g kg−1 after 17 months of storage. Samples stored at 22 °C had higher ascorbic acid contents than those stored at 37 °C. A multiple regression analysis performed to evaluate ascorbic acid evolution throughout…
Effects of gamma-irradiation on the alpha-tocopherol and fatty acids content of raw unpeeled almond kernels (Prunus dulcis)
2014
Abstract The present study evaluated fatty acid composition and α-tocopherol content of almond as a function of irradiation dose in order to determine dose levels causing minimal undesirable changes to almonds. Raw unpeeled almonds variety Tuono ( Prunus dulcis (Mill.) D. A. Webb) were irradiated using 60 Co source at dose of 0.5, 1.5, 3, 6, 8 and 10 kGy. Both control and irradiated samples were kept frozen and immediately analyzed. The data obtained showed no change in fatty acid compositions up to a dose of 10 kGy; on the contrary, a general trend observed is that increasing the dose of irradiation resulted in the decrease of α-tocopherol content. The study has shown that irradiation is a…
On the problematic nature of vitamin E requirements: net vitamin E
1991
The requirement for vitamin E is closely related to the dietary intake of polyunsaturated fatty acids (PUFA). By the protective mechanism to prevent PUFA from being peroxidized, vitamin E is metabolically consumed. In addition, PUFA impair the intestinal absorption of vitamin E. Therefore PUFA generate an additional vitamin E requirement on the order of 0.6, 0.9, 1.2, 1.5, and 1.8 mg vitamin E (RRR-alpha-tocopherol-equivalents), respectively, for 1 g of dienoic, trienoic, tetraenoic, pentaenoic, and hexaenoic acid. For this reason, the gross vitamin E content of food containing PUFA does not allow an evaluation of this food as a source of vitamin E. A suitable measure is the net vitamin E c…
Mitochondrial Oxidative Stress in Diabetes
2014
Abstract Diabetes is a multifactorial disease associated with serious comorbidities. This condition has been related to oxidative stress and, as a consequence, to overproduction of reactive oxygen species (ROS), which are known to be produced by different sources in diabetes. Excessive production of ROS can be harmful, making antioxidant defenses of vital importance. Dietary antioxidants, such as vitamin E or vitamin C, polyphenols and flavonoids have been used to modulate the oxidative stress created in diabetes, producing contradictory results in clinical trials, perhaps as a consequence of the targets selected and/or the design of the studies in question. This chapter considers the proce…
Cytoprotective effects of the antioxidant phytochemical indicaxanthin in beta-thalassemia red blood cells
2006
Antioxidant phytochemicals are investigated as novel treatments for supportive therapy in beta-thalassemia. The dietary indicaxanthin was assessed for its protective effects on human beta-thalassemic RBCs submitted in vitro to oxidative haemolysis by cumene hydroperoxide. Indicaxanthin at 1.0-10 microM enhanced the resistance to haemolysis dose-dependently. In addition, it prevented lipid and haemoglobin (Hb) oxidation, and retarded vitamin E and GSH depletion. After ex vivo spiking of blood from thalassemia patients with indicaxanthin, the phytochemical was recovered in the soluble cell compartment of the RBCs. A spectrophotometric study showed that indicaxanthin can reduce perferryl-Hb ge…