Effect of High-Dose Vitamin E on Insulin Resistance and Associated Parameters in Overweight Subjects (original) (raw)
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Galen Medical Journal, 2015
Background: Atherosclerosis is one of the prevalent complications in diabetic patients. Increased free radical levels in diabetes activate stress-sensitive signaling pathway, resulting in this outcome. This study examines the effect of short-term supplementation of vitamin E on different biochemical markers in type 2 diabetic patients to prevent from atherosclerosis. Materials and Methods: In this single-blind placebo controlled trial, 30 type 2 diabetic patients were randomly divided into two groups of study to receive vitamin E (400IU) or identical placebo capsules daily for 6 weeks. Serum level of lipoproteins, glucose, insulin, malondialdehyde (MDA), interleukin-6 (IL-6), high-sensitivity C-reactive protein (hs CRP), pulse rate and blood pressure were measured in fasting and postprandial (after a fatty meal) states before and after six weeks of supplementation. Results: There was not any significant difference in fasting and postprandial lipid profile (Triglyceride, HDL-, LDL- a...
Proceedings of the 1st Jenderal Soedirman International Medical Conference in conjunction with the 5th Annual Scientific Meeting (Temilnas) Consortium of Biomedical Science Indonesia, 2020
Obesity is a risk factor for diabetes mellitus (DM) and coronary heart disease. In obesity, oxidative stress and adipokine hormone increase, leading to insulin resistance (IR) which can develop into DM. Vitamin E is an antioxidant that is expected to lower IR. This study aims to determine the effects of 8-week supplementation of vitamin E on reducing IR in non-diabetic obese subjects. The design was PROBE (Prospective Randomized Open Blinded End-point). The subjects were ≥18 years old with ≥25 kg/m 2 body mass index and HOMA-IR value >2.7 The exclusion criteria were DM patients and those taking metformin or antioxidants. Twenty subjects in group A received 800 IU Vitamin E supplementation while 20 subjects in group B received placebo, both for 8 weeks. Reduced IR was measured from the decreasing HOMA-IR value after 8 weeks. The difference in decreasing HOMA-IR value between both groups was analyzed using independent t-test. The mean in group A was 0.199 ± 0.336, while group B had-0.078 ± 0.271. The between both groups was statistically significant, with p = 0.004, 95% CI (0.096-0.457. Supplementation of 800 UI Vitamin E for 8 weeks could decrease IR in obese non-diabetic subjects.
Insulin decreases circulating vitamin E levels in humans
Metabolism-clinical and Experimental, 1996
Both hyperinsulinemia and free oxygen radicals have been implicated in the pathogenesis of atherosclerosis, but the relationshi p between insulin levels or insulin action and the oxidant/antioxidant balance has not been explored. We measured the effect of physiologic hyperinsulinemia on plasma concentrations of vitamin E, a major free radical scavenger molecule. Isoglycemic clamps (at an insulin infusion rate of 6 pmol • min -1 • kg -1) were performed in fou r groups of subjects: (1) 12 nOn-insulin-dependent diabetic (NIDDM) patients, (2) eight patients with essential hypertension, (3) 11 nondiabetic obese individuals, and (4) 12 healthy subjects. In 10 healthy volunteers, a time-control experiment was performed by replacing the insulin infusion with normal saline. Vitamin E and plasma lipid levels were determined at baseline and after 2 hours of insulin/saline infusion. Insulin sensitivity was reduced in diabetic, obese, and hypertensive groups in comparison to healthy controls, but fasting plasma vitamin E concentrations were similar in all groups. A consistent decrement in plasma vitamin E concentrations (averaging 12% of baseline, p < .000!' ) was observed in all subjects receiving insulin regardless of the level of insulin sensitivity, whereas no significan t changes in plasma vitamin E were Seen in subjects receiving saline infusion (P < .001 v insulin infusion groups). The insulin-induced decrement persisted in all study groups when plasma vitamin E concentrations were corrected for total serum cholesterol levels (-8.9% _+ 1.2% v -0.4 +_ 2.3% of saline controls, P = ,0004) or serum low-density lipoProtein (LDL (-10.0% -+ 1,2% v -0,4% -+ 2.2%, P = .0002}. We conclude that insulin infusion acutely depletes vitamin E in circulating iipids regardless of insulin resistance. This effect may represent a physiologic means of transferring vitamin E into cell membranes, alternatively, it might reflect a pro-oxidant action of insulin in vivo.
Indian Journal of Clinical Biochemistry, 2011
Increased oxidative stress is a widely accepted participant in the development and progression of diabetes and its complications. The present study has been undertaken to evaluate oxidative stress in type 2 diabetes mellitus and effect of vitamin E supplementation on oxidative stress. In all 120 subjects were enrolled in the present study, 40 subjects are age and sex matched controls. Test group comprised of clinically diagnosed (n = 80) type 2 diabetic patients. Biochemical parameters like serum MDA, nitric oxide, superoxide dismutase, erythrocyte reduced glutathione and platelet aggregation were analyzed in control and diabetic group. Test group is further categorized as Group I (n = 40) diabetics were treated by only hypoglycemic drugs and Group II (n = 40) diabetics were treated by hypoglycemic drugs with vitamin E supplementation. All above biochemical parameters were again reassessed after 3 months follow-up in both group and its values were compared with its respective baseline levels. The study shows, reduction of oxidative stress, improvement in antioxidant enzymes and endothelial dysfunction in group II, those were on treatment of hypoglycemic drugs along with vitamin E supplementation. Hence the present study may conclude that vitamin E supplementation along with hypoglycemic drugs may be beneficial to type 2 DM patients to minimize vascular complications.
Vitamin E levels in patients with controlled and uncontrolled type 2 diabetes mellitus
International Journal Of Community Medicine And Public Health
Background: Diabetes type 2 associates with increased oxidative stress and reduced antioxidant. Vitamin E supplementation reduces oxidative stress in diabetic patients. We intended to measure the level of this vitamin in these patients to assess its relationship in control of patients' diabetes by designing present study.Methods: This is a descriptive and cross-sectional study and carried out on 186 patients with diabetes type 2 diagnosis. The levels of HbA1C (measured by HPLC method), TG, cholesterol, HDL, LDL and Cr were measured, and given to that the level of HbA1C lower than 7 (controlled group) and or more than 7 (uncontrolled group), patients were divided in two groups. Were designed a check list involved questions such as age and information of each patient associated with measured vitamin E level were entered into the check list and after that were analyzed data.Results: In the existing study 186 diabetic patients were examined. From within examined patients, 129 (69.3%...
Journal of High Institute of Public Health, 2007
Background: There is growing evidence that excess generation of highly reactive free radicals, largely due to hyperglycemia, causes oxidative stress which further exacerbates the development and progression of diabetes and its complications. There are multiple sources of oxidative stress in diabetes including non-enzymatic, enzymatic, and mitochondrial pathways. Vitamin E is a fat-soluble vitamin that prevents lipid peroxidation. Objective: the present study was carried out to test the effect of vitamin E on blood glucose, insulin, and lipid peroxides in blood and liver tissue of rats in relation to oxidative damage associated with diabetes induced by streptozotocin (STZ). Methods: 24 male albino rats were randomly assigned to control (group I), streptozotocin (STZ)-induced diabetic rats (group II), the third group (vitamin E group) were STZ-induced diabetic rats fed 400 mg of vitamin E/kg diet. After 4 weeks of the induction of diabetes, rats were sacrificed and the following determinations were done on the blood, serum or plasma. Blood glucose, serum insulin, lipid peroxide concentration in plasma as malonyldialdehyde (MDA) level in nmol/g protein, the amount of thiobarbituricp acid reactive materials in plasma (TBARM), serum antioxidant capacity (assayed by measuring the total peroxy radical trapping capacity (TRAP) of serum, and serum superoxide dismutase, enzyme activity (SOD). In the liver, the following parameters were determined: liver MDA, SOD and Glutathione peroxidase (GSH-Px) enzyme activaties, and Glutathione (GSH) concentration. Results: Hyperglycemia, hypoinsulinemia were regarded in group II which were ameliorated by vitamin E administration. Oxidant stress was found in diabetic rats group II manifested by increase concentration of MDA-plasma and liver, increase TBARM concentration, and TRAP-plasma and serum respectively. Also increased serum SOD, liver SOD, and GSH-Px enzyme activities in these diabetic rats. Administration of vitamin E in the diet decreased the oxidant stress parameters (MDA, TBARM, and TRAP), increased the antioxidant defense parameter (increased GSH concentration in liver), and decreased the oxidant stress as manifested by the decrease in serum SOD enzyme activity; liver SOD; and GSH-Px enzyme activities. Conclusion: Vitamin E was found to be excellent for strengthening the antioxidant defense system in STZdiabetic rats and it may therefore have a therapeutic role in combating the damaging effect of ROS in diabetes and preventing its complications.
Vitamin E, diabetes and related diseases: an update
Mediterranean Journal of Nutrition and Metabolism, 2010
Natural vitamin E is a mixture of tocopherols and tocotrienols synthesized only by plants. It is very difficult to determine the optimal dietary intake of vitamin E, but there is a general agreement indicating a level of 8 mg/ day (12-15 IU). This value seems to be sufficient only to prevent deficiency syndromes of vitamin E. In humans, vitamin E is absorbed together with nutritional lipids in the proximal part of the intestine and released in the lymph within chylomicrons. Vitamin E supplementation, as other minerals and vitamins, is able to participate in the decrease of oxidative stress in diabetic patients by improving glycemic control and/or by other mechanisms related to its antioxidant activity, therefore cooperating to the control of diabetic complications. Many interventional trials evaluating the effect of antioxidant supplementation on insulin resistance, plasma glucose levels and risk of T2D give inconsistent results. At present, a controversial hypothesis about the role played by vitamin E supplementation still exists. In fact, while laboratory data report great cellular and biochemical beneficial actions, clinical trials have failed to support these claims. Concerning clinical trials, the discrepancies have been attributed to differences in selection of individuals, dosage, chemical forms of vitamin E, duration of treatment, stage of the disease and geographical area. Because of these variables, further studies aimed to clarify the relationship between diabetes, cardiovascular risk factors and vitamin E are necessary.
Plasma and Dietary Vitamin E in Relation to Incidence of Type 2 Diabetes
Diabetes Care, 2002
OBJECTIVE—To evaluate the association of vitamin E with incidence of type 2 diabetes and to do so separately among individuals who did and those who did not report regular use of vitamin supplementation. RESEARCH DESIGN AND METHODS—The Insulin Resistance Atherosclerosis Study (IRAS) included 895 nondiabetic adults at baseline (including 303 with impaired glucose tolerance [IGT]), 148 of whom developed type 2 diabetes according to World Health Organization (WHO) criteria during the 5-year follow-up. At baseline, dietary vitamin E was estimated by a validated food frequency interview, usual supplement use was confirmed by supplement label, and plasma α-tocopherol was measured. Analyses were conducted separately for individuals who did (n = 318) and did not (n = 577) use vitamin E supplements. RESULTS—Among supplement nonusers, reported mean intake of vitamin E (mg α-tocopherol equivalents [α-TE]) did not differ between those who remained nondiabetic (n = 490) and those who developed d...