Background. The increasing incidence of metabolic diseases such as obesity or diabetes have made them a major public health problem. Increasing oxidative stress induced by reactive oxygen species, which initiate the oxidative adverse changes in the cell, is mentioned, among other risk factors, to underlie these diseases. Vitamin A, C and E are listed among the non-enzymatic mechanisms counteracting this phenomenon. Vitamin D deficiency is also associated with cardiovascular diseases.
High doses of synthetic antioxidative vitamins: A, E, C and β-carotene are often used on long-term basis in numerous preventive and therapeutic medical applications. Instead of expected health effects, the use of those vitamins may however lead to cases of hypervitaminosis and even to intoxication. The article points out main principles of safety which are to be observed during supplementation with antioxidative vitamins. Toxic effects resulting from erroneous administration of high doses of those substances on organs and systems of the organism are also discussed. Attention is drawn to interactions of antioxidative vitamins with concomitantly used drugs, as well as intensification of adverse effects caused by various exogenous chemical factors. Moreover, the article presents the evaluation of supplementation with these vitamins, which was performed in large studies.
blood pressure or hypertension treatment, fasting hyperglycemia or diagnosed type 2 diabetes, abnormal lipid profile (hypertriglyceridemia and/or low HDL-cholesterol) A -research concept and design; B -collection and/or assembly of data; C -data analysis and interpretation; D -writing the article; E -critical revision of the article; F -final approval of article AbstractBackground. Metabolic syndrome (MS) is a coexistence of metabolic risk factors affecting the development of cardiovascular diseases. Reactive oxygen species, which are excessively produced in MS, participate in its pathogenesis. Vitamins A, C and E are an important part of the non-enzymatic antioxidative barrier in humans. Objectives. The aim of the study was to estimate plasma vitamin A, C and E levels and the intake of these vitamins from the diet in patients with MS. Material and Methods. The study included 182 patients with MS, 94 men and 88 women, aged 30-65 years (mean 57.31 ± 8.28 years). The control group was comprised of 91 subjects, 56 men and 35 women, aged 41-65 years (mean 57.75 ± 5.84 years). The MS diagnosis was based on IDF criteria. The determination of the serum level of vitamin A, C and E was performed using the spectrophotometric method. The food intake was assessed by 24-h dietary recall. Results. The mean plasma vitamin A, C and E levels were significantly lower in MS patients than in the controls (p = 0.05). No correlation was found between vitamin A, C and E intake from the diet and their plasma concentrations in MS patients. Plasma vitamin A, C and E deficiency was observed significantly more often in MS patients than in the control group (15.38% vs. 2.19%, 79.12% vs. 8.79% and 60.45% vs. 5.49%, p < 0.0001, respectively). BMI was the one factor significantly affecting the mean value of vitamin A, C and E levels in MS patients. Conclusions. MS patients demonstrated significantly lower plasma levels of vitamin A, C and E compared to the healthy subjects. Lower plasma levels of antioxidant vitamins with their high intake from the diet indicate antioxidant barrier impairment in MS patients (Adv Clin Exp Med 2016, 25, 4, 689-700).
The phosphotungstate reagent (PTR) was used for quantitative spectrophotometric determination of physiological forms of vitamin C in blood plasma. An immediate action of PTR on the first half of the tested samples allowed to determine reduced vitamin C concentrations (I) at 700 nm. 10 mм dithiothreitol added to the second half of the samples reduced oxidized vitamin C in it - hence the total amount of this vitamin was reduced with a concentration (II) determined as above (remains of dithiothreitol were removed with N-ethylmaleimide). The difference of results (II) and (I) gave the concentration of oxidized vitamin C. The method is characterised by fault-less analytical parameters: correlation coefficients of analytical curves > 0.99, recovery factor 100.5%, variation coefficients intra- and inter-serial < 3% and < 5%, respectively, detection limit 0.05 μm. The simplicity of the method enables an easy control of the ratio of oxidized and reduced vitamin C concentrations in blood plasma - the biomarker of the level of oxidative damage to cells.
Objectives: The increasing number of devices emitting electromagnetic radiation (EMR) in people's everyday life attracted the attention of researchers because of possible adverse effects of this factor on living organisms. One of the EMR effect may be peroxidation of lipid membranes formed as a result of free radical process. The article presents the results of in vitro studies aimed at identifying changes in malondialdehyde (MDA) concentration -a marker of lipid peroxidation and antioxidant role of vitamin A during the exposure of blood platelets to electromagnetic radiation generated by liquid-crystal-display (LCD) monitors. Material and Methods: Electromagnetic radiation emitted by LCD monitors is characterized by parameters: 1 kHz frequency and 220 V/m intensity (15 cm from display screen). The time of exposure was 30 and 60 min. The study was conducted on porcine blood platelets. The samples were divided into 6 groups: unexposed to radiation, unexposed + vitamin A, exposed for 30 min, exposed for 30 min + vitamin A, exposed for 60 min, exposed for 60 min + vitamin A. Results: The MDA concentration in blood platelets increases significantly as compared to control values after 60 min of exposure to EMR. A significant decrease in MDA concentration after the addition of vitamin A was noticed. In the blood samples exposed to EMR for 30 and 60 min the MDA concentration was significantly increased by addition of vitamin A. Conclusions: The results show the possibly negative effect of electromagnetic radiation on the cellular membrane structure manifested by changes in malondialdehyde concentration and indicate a possible protective role of vitamin A in this process. Int J Occup Med Environ Health 2017;30(5):695-703
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