Vitamin E and vitamin C plasma levels in premature infants following supplementation of vitamin C

Our preliminary data suggest that supplementation of premature neonates with vitamin C is required to maintain adequate ascorbate plasma levels and may have a sparing effect on vitamin E metabolism. Further studies are required to validate our findings and evaluate the possible antioxidant advantage of ascorbic acid administration.     

Effects of dietary vitamin E and high supplementation of vitamin C on plasma glucose and cholesterol levels

Weanling male Sprague Dawley rats were fed ad libitum a purified basal diet free of vitamins E and C. In Experiment I (4 weeks), 24 rats were divided into four groups with 2×2 factorial design. They were supplemented with 0 or 45 IU/kg diet of vitamin E, and O or 2.0 g/kg diet of vitamin C. In Experiment II (16 weeks), 36 rats were divided into six groups with 2×3 factorial design. Vitamin E was supplemented at the level of O or 45 IU/kg diet, and vitamin C was supplemented at the level of O, 1.5, or 3.0 g/kg diet, respectively. Plasma glucose level and cholesterol level were determined in both experiments. The plasma levels of glucose and cholesterol were significantly and negatively correlated. Plasma glucose level was significantly increased and plasma cholesterol level significantly decreased by the high supplementation of vitamin C with or without vitamin E in the diet. Vitamin E deficiency decreased plasma glucose level and increased plasma cholesterol level significantly with or without vitamin C supplementation. The groups with adequate level of vitamin E (45 IU/kg diet) and no vitamin C showed moderate plasma glucose and cholesterol levels.     

Differential response of plasma and immune cell's vitamin E levels to physical activity and antioxidant vitamin supplementation

OBJECTIVE: To assess the differential response of plasma, lymphocyte and neutrophil vitamin E levels to high-intensity physical activity and to vitamin C and E supplementation. SUBJECTS: In all, 14 male trained amateur runners (32-36 y old) were randomly divided in two groups (supplemented and placebo), and participated in a half marathon race. The subjects did not take any other supplements than the ones provided for this study. INTERVENTION: Vitamin C (152 mg/day) and E (50 mg/day) supplementation was administrated to athletes for a month, using a new almond-based isotonic and energetic beverage (supplemented group). The usual dietary habits of participants were assessed using a self-reported 7-day 24-h recall before the day of the study. To avoid the beverage influence, nonenriched vitamin C and E almond-based isotonic and energetic beverage was given to the placebo group. After 1 month, subjects participated in a half marathon race (21 km run). Vitamin E concentration was determined in plasma, neutrophils and lymphocytes before and immediately after the race, and 3 h after finishing the race. RESULTS: Daily energy intake and caloric profile of supplemented and placebo group were not different except for vitamin C and E supplementation. Vitamin supplementation and exercise had no effect on vitamins E levels in plasma. The exercise significantly (P<0.05) increased the lymphocyte vitamin E concentration both in the placebo (+119%) and supplemented groups (+128%), and neutrophil vitamin E content in the supplemented group (+88%). These levels remained significantly (P<0.05) high after the short recovery. After exercise, vitamin E levels in lymphocytes and neutrophils of supplemented subjects were practically twice the levels before exercise, whereas neutrophil vitamin E content of the placebo group was close to those in plasma. CONCLUSION: After endurance exercise, lymphocytes increased their vitamin E content in the supplemented and placebo subjects whereas this trend in neutrophils was just observed in the supplemented group. The determination of vitamin E content in lymphocytes and neutrophils after exercise is a useful tool to assess the functional status of vitamin E.     

Dietary vitamin C and E modulates antioxidant levels in blood, brain, liver, muscle, and testes in diabetic aged rats

While tissue dysfunction is a well-recognized consequence of diabetes mellitus in aged people, the underlying mechanisms are poorly understood. Daily (VCE) supplementation of vitamins C and E can be beneficial to diabetic aged animals in reducing free radical production. The aim of this study was to investigate whether dietary VCE supplementation modulates oxidative stress and antioxidant redox systems in streptozotocin (STZ)-induced aged diabetic rats. Thirty aged rats (18 - 20 months) were randomly divided into three groups. The first group acted as a control and the second group was diabetic. VCE-supplemented feed was given to aged, diabetic rats, constituting the third group. Diabetes was induced using a single dose of intraperitoneal STZ. On the 21(st) day after STZ dosage, blood and tissue samples were taken from all animals. Glutathione peroxidase activity in liver, erythrocytes, muscle, and testes; catalase activity in plasma and erythrocytes; reduced glutathione levels in plasma; vitamin E concentration in plasma, liver, and muscle; b-carotene concentration in brain; and high-density lipoprotein (HDL)-cholesterol levels in plasma were lower in the diabetic group than in the control group. Lipid peroxidation (LP) levels in plasma, liver, brain, and muscle, and alanine aminotransferase (ALT), aspartate aminotransferase (AST), triacyglycerols, and total and low-density lipoprotein (LDL)-cholesterol values in plasma were higher in the diabetic group than in the control group. The LP, enzyme, vitamin, and lipid profile values levels were mostly restored by VCE treatment. Liver and testis weights did not change by diabetic status and VCE supplementation, although body weight was lower in the diabetic group than in the control group. In conclusion, brain, liver, and testes tissues seem most sensitive in aged diabetic rats to oxidative stress. We observed that VCE supplementation relieves oxidative stress in the blood and tissues of diabetic aged rats by modulating the antioxidant system and lipid profile.     

维生素E对大鼠抗氧化能力及DNA损伤影响

目的观察补充维生素E（VE）对大鼠抗氧化能力及DNA氧化损伤的影响。方法将42只健康初断乳Wistar大鼠。随机分为对照组、S1、S2组。各组饲料VE含量分别为24．18，70．83，114．04mg／kg，实验期为8周。实验结束后采集血样，分别采用荧光法测定血浆vE水平，采用试剂盒检测血浆谷胱甘肽过氧化物酶（GSH—Px）及丙二醛（MDA）含量，并通过单细胞凝胶电泳法检测淋巴细胞DNA氧化损伤情况。结果S1、S2组血浆VE含量较对照组明显升高（P〈0．01）；S1、S2组血浆GSH．Px和MDA含量与对照组间差异无统计学意义；Ⅶ干预各组淋巴细胞DNA自发损伤无明显差别，在5，10，25μmol／L的H2O2作用下，各组损伤均明显加重，但组间差异无统计学意义（P〉0．05）。结论本实验补充剂量的VE对于健康幼年大鼠血浆GSH-Px及脂质过氧化产物MDA的含量无显著影响；对淋巴细胞DNA自发损伤及不同浓度H2O2诱导的DNA氧化损伤，单纯补充VE亦未表现出明显的保护作用。     

Effect of vitamin E supplementation on aminotransferase levels in patients with NAFLD,NASH, and CHC: Results from a meta-analysis

ObjectiveThe antioxidant vitamin E has been extensively employed to treat chronic liver diseases. The aim of this study was to assess the effect of vitamin E supplementation in lowering alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in patients with nonalcoholic fatty liver disease (NAFLD), nonalcoholic steatohepatitis (NASH), and chronic hepatitis C (CHC).MethodsWe searched all publications in PubMed, Web of Science, and Cochrane Library databases up to June 2013. In total, eight articles met the eligibility criteria, among which, two studies about NAFLD, four studies about NASH, and three studies about CHC, were identified and included in the meta-analysis.ResultsAccording to standardized mean difference and 95% confidence interval, 12.19 (−4.08 to 28.46) for ALT and 6.84 (−3.18 to 16.86) for AST in patients with NAFLD, 4.54 (1.62–7.46) for ALT and 3.55 (1.39–5.71) for AST in patients with NASH, and 0.61 (0.20–1.02) for ALT and 0.68 (0.07–1.29) for AST in patients with CHC, vitamin E supplementation could optimize ALT and AST levels in patients with NASH and CHC, although it was not statistically significantly associated with reduced ALT and AST levels in patients with NAFLD.ConclusionTo summarize, the evidence currently available supported the theory that vitamin E supplementation can optimize aminotransferase levels for patients with NAFLD, NASH, and CHC, and more well-designed, large-scale clinical trials are encouraged to examine the therapeutic effect of vitamin E for these disorders.     

Effect of vitamin E, vitamin C, and beta-carotene on stroke risk

In a recent prospective observational study, vitamins C and E and beta-carotene did not elicit protective effects on stroke risk. Lutein, however, may elicit such protection. Nevertheless, these nutrients may be important modulators of the outcome after the occurrence of a stroke. At present, optimal control of the classic stroke risk factors in combination with increased consumption of fruits, vegetables, and antioxidant nutrients may represent the safest and most efficient strategy to control stroke risk.     

The effect of vitamin E (alpha-tocopherol) supplementation on hepatic levels of vitamin A and E in ethanol and cod liver oil fed rats

Eight groups of 5 rats were fed 8 differing liquid diets with and without ethanol, cod liver oil and/or increased levels of vitamin E. Hepatic levels of vitamins A and E were determined following the 28-day feeding time. Ethanol consumption decreased the levels of hepatic vitamin E (p less than 0.05), vitamin A (p less than 0.05) and the ratio of vitamin A/E (p less than 0.05). Hepatic levels of vitamins A and E were unaffected in rats fed cod liver oil. Supplementation of the normal dietary level of 30 IU of vitamin E per kg diet, with an additional 142 IU alpha tocopherol/kg diet, restored hepatic concentrations of vitamin E to normal levels in alcohol-fed rats. The hepatic levels of vitamin A in rats fed ethanol diets supplemented with vitamin E were less than that of control rats but were 4.3 times greater than that of rats on ethanol diets unsupplemented with vitamin E. However, the vitamin A and E ratio was equal to normal in this group of rats. The vitamin A/E ratio was reduced in liver of rats fed non-alcoholic diets supplemented with vitamin E due to increased levels of hepatic vitamin E. Additionally, rats fed cod liver oil diets containing ethanol also indicated decreased hepatic vitamin A and E levels. However, these levels were greater than that of rats fed only alcoholic diets suggesting that these vitamins are replaced by the vitamin A and E content in the cod liver oil.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of vitamin E supplementation on vitamin K status in adults with normal coagulation status

BACKGROUND: Cases of enhanced anticoagulant effect in response to high-dose vitamin E supplementation have been reported among patients taking oral anticoagulants. Although a vitamin E-vitamin K interaction was proposed to underlie this effect, it has not been systematically investigated in adults with normal baseline coagulation status. OBJECTIVE: The objective was to study the effect of 12 wk of supplementation with 1000 IU RRR-alpha-tocopherol/d on biochemical measures of vitamin K status in men and women not taking oral anticoagulants. DESIGN: Vitamin K status, which was assessed with the use of plasma phylloquinone concentrations, the degree of under-gamma-carboxylation of prothrombin (proteins induced by vitamin K absence-factor II, PIVKA-II), and the percentage of undercarboxylated osteocalcin (ucOC), was determined in 38 men and women with rheumatoid arthritis (study A) and in 32 healthy men (study B) participating in 2 independent, 12-wk randomized clinical trials of vitamin E supplementation (1000 IU/d). RESULTS: Mean (+/- SD) PIVKA-II increased from 1.7 +/- 1.7 to 11.9 +/- 16.1 ng/mL (P < 0.001) in study A and from 1.8 +/- 0.6 to 5.3 +/- 3.9 ng/mL (P < 0.001) in study B in response to 12 wk of vitamin E supplementation. An increase in PIVKA-II is indicative of poor vitamin K status. In contrast, the other measures of vitamin K status (ie, plasma phylloquinone concentration and percentage of ucOC) did not change significantly in response to the supplementation. CONCLUSIONS: High-dose vitamin E supplementation increased PIVKA-II in adults not receiving oral anticoagulant therapy. The clinical significance of these changes warrants further investigation, but high doses of vitamin E may antagonize vitamin K. Whether such an interaction is potentially beneficial or harmful remains to be determined.     

Effect of dietary protein on vitamin E levels in erythrocytes and tissues of rats

The effect of dietary protein level on the transfer of alpha-tocopherol in blood to tissues including RBC was studied using rats. The first experiment comprised a 10% casein (low protein), 20% casein (normal) and 20% SPI (normal soybean protein) diet groups supplemented with 71.5 mg of alpha-Toc/kg diet. In Exp. 2 the relationship of the tissue alpha-Toc level and protein level in diets, as shown by recovery from vitamin E-deficient status after the administration of alpha-Toc for 3 days, was checked by adjusting the protein level in diets to 10%, 20% and 40% casein. In Exp. 1 alpha-Toc in RBC decreased significantly in the 10% casein and 20% SPI groups compared to the 20% casein group. Moreover, alpha-Toc in kidney, lung and muscle decreased significantly in the 10% casein and 20% SPI groups. alpha-Toc in liver in the 20% SPI group decreased significantly compared to the 20% casein group. In Exp. 2 similar results were observed (Table 4), but alpha-Toc in RBC showed only a tendency to decrease with the low protein diet. In Exp. 1 free cholesterol in RBC increased significantly in the 10% casein group compared with the other two groups.     

Effect of different vitamin E levels on lipid peroxidation in streptozotocin-diabetic rats.

Administration of streptozotocin is used to induce diabetes in experimental models, causing a selective destruction of pancreatic beta islet cells associated with generation of free radicals. Supplementation with antioxidant vitamins such as vitamin E is a protective factor against free radicals. The objective of this study was to determine the effect of administration of a diet supplemented with, or deficient in vitamin E to streptozotocin diabetic rats, controlled or not with insulin, on plasma glucose, hepatic vitamin E and hepatic thiobarbituric acid reactive substance (TBARS) levels before streptozotocin and 24 hours and one and two weeks after drug administration. Deficiency of vitamin E alone increased TBARS levels, and streptozotocin elevated TBARS two times in deficient groups, regardless of insulin control. In rats supplemented with vitamin E, a reduction of plasma glucose and liver vitamin E was observed two weeks after streptozotocin administration (p < 0.05). In conclusion, vitamin E supplementation probably protected against lipoperoxidation and contributed to the absence of elevation of plasma glucose levels, and vitamin E deficiency produced an increase in hepatic TBARS levels in streptozotocin diabetic rats.     

Effect of vitamin A supplementation on haemoglobin and vitamin A levels during pregnancy

About 450 pregnant women from a low-income group were recruited to study the effect of vitamin A supplementation on plasma vitamin A levels in the mother and cord and on the birth weights of the neonates. Results showed that supplementation with 1800 micrograms vitamin A/d for more than 12 weeks prevented the decline in plasma vitamin A that otherwise occurs during the last few weeks of pregnancy. This improvement in maternal values for vitamin A at a critical time of development favourably affected availability to the fetus, as reflected by the marked elevation in cord levels. Supplementation for a period of 12 weeks was found to be sufficient, since subsequent discontinuation did not alter the beneficial response. Apart from increasing maternal and cord vitamin A levels, vitamin A supplementation along with iron prevented, in this study, the significant decline in haemoglobin occurring at 26-28 weeks of gestation. The birth weights were not altered by vitamin A supplementation.     

Iron supplementation increases disease activity and vitamin E ameliorates the effect in rats with dextran sulfate sodium-induced colitis

Inflammatory bowel disease is often associated with iron deficiency anemia and oral iron supplementation may be required. However, iron may increase oxidative stress through the Fenton reaction and thus exacerbate the disease. This study was designed to determine in rats with dextran sulfate sodium (DSS)-induced colitis whether oral iron supplementation increases intestinal inflammation and oxidative stress and whether the addition of an antioxidant, vitamin E, would reduce this detrimental effect. Four groups of rats that consumed 50 g/L DSS in drinking water were studied for 7 d and were fed: a control, nonpurified diet (iron, 270 mg, and dl-alpha-tocopherol acetate, 49 mg/kg); diet + iron (iron, 3000 mg/kg); diet + vitamin E (dl-alpha-tocopherol acetate, 2000 mg/kg) and the diet + both iron and vitamin E, each at the same concentrations as above. Body weight change, rectal bleeding, histological scores, plasma and colonic lipid peroxides (LPO), plasma 8-isoprostane, colonic glutathione peroxidase (GPx) and plasma vitamin E were measured. Iron supplementation increased disease activity as demonstrated by higher histological scores and heavier rectal bleeding. This was associated with an increase in colonic and plasma LPO and plasma 8-isoprostane as well as a decrease in colonic GPx. Vitamin E supplementation decreased colonic inflammation and rectal bleeding but did not affect oxidative stress, suggesting another mechanism for reducing inflammation. In conclusion, oral iron supplementation resulted in an increase in disease activity in this model of colitis. This detrimental effect on disease activity was reduced by vitamin E. Therefore, the addition of vitamin E to oral iron supplementation may be beneficial.     

亚慢性染毒2,3,7,8-四氯二苯并二(噁)英(TCDD)对大鼠血清维生素A、E的影响

目的了解亚慢性暴露于2，3，7，8-四氯二苯并二噁英（TCDD）对Wistar大鼠血清维生素A、E水平的影响。方法将64只实验Wistar大鼠按雌、雄随机分为染毒高（250ng／kg）、中（25ng／ks）、低（2．5ng／kg）剂量和空白对照共4组，每组8只，经口染毒。90d后对实验大鼠股动脉取血，离心后取上层血清，用无水乙醇沉淀蛋白，加环己烷萃取后，使用荧光分光光度仪在不同波长下测定其荧光值，计算出维生素A、E浓度，进行统计分析。结果与对照组比较，TCDD染毒大鼠血清维生素A和维生素E的平均水平降低，差别具有统计学意义（P〈0．05）。结论在实验条件下，TCDD亚慢性暴露可以对Wistar大鼠血清维生素A与维生素E的质量浓度水平有一定影响。     

Vitamin E and vitamin C supplementation in patients with chronic obstructive pulmonary disease

The purpose of this study was to determine whether vitamin E or vitamin C supplementation alters the DNA damage of whole blood white blood cells (WBC) in patients with chronic obstructive pulmonary disease (COPD). Thirty-five patients with stable COPD were recruited in this randomized and placebo-controlled study. Patients were randomly assigned to placebo (n = 8), 400 mg/day vitamin E (E400, n = 9), 200 mg/day vitamin E (E200, n = 9), or 250 mg/day vitamin C (C250, n = 9) for 12 weeks. The results showed that vitamin E or C supplementation did not significantly change the mean level of endogenous DNA breakages. Whereas, after 12 weeks of vitamin supplementation, the H2O2-induced DNA breakages were significantly suppressed by 45%, 59%, and 52%, respectively, in E400, E250 and C250 groups (p < 0.05). In addition, neither the level of thiobarbituric acid-reactive substances (TBARS) nor spirometric parameters were significantly changed after 12 weeks of supplementation. In conclusion, vitamin E or C supplementation for 12 weeks may improve the resistance of DNA in whole blood WBC against oxidative challenge, although more research is needed to demonstrate the beneficial effect on slowing the decline of lung function in patients with COPD.     

Lipid peroxidation in relation to vitamin C and vitamin E levels

Oxidative stress plays an important contributory role in the pathogenesis of age-related chronic diseases. Increased lipid peroxidation process is caused by an enhanced free radical formation together with a higher supply of substrates and by an insufficient defense by antioxidants as well. Levels of malondialdehyde to content of lipid peroxidation substrates (polyunsaturated fatty acids), promoters (homocysteine--hydroxyl radical producer) and inhibitors (essential vitamins C and E) were estimated in a group (n=92) of subjective healthy adults randomly selected from general population. The relationship of malondialdehyde levels to values of peroxidisability index of fatty acids as well as to levels of homocysteine is significantly positive linear A significant inverse linear correlation between malondialdehyde levels and natural antioxidant levels (vitamin C, vitamin E) was recorded. Lipid peroxidation products (conjugated dienes of fatty acids--initial, malondialdehyde--secondary) are significantly increased in groups of subjects with deficient levels of vitamin C (below the limit from antioxidative point of view), vitamin E and both vitamins, if compared to group with normal vitamin levels (over limit in accordance with antioxidative criterion). The results document that the deficiency in two key antioxidants for lipid peroxidation inhibition means the insufficient defense against free radicals and the increased lipid peroxidation.     

Effect of ascorbic acid and vitamin E on biochemical changes associated with vitamin E deficiency in rats

Weanling male Sprague Dawley rats were fed a vitamin E and C-free basal diet with or without supplementation of 100 IU vitamin E per kg diet. After 20 weeks, the vitamin E-deficient rats were divided into four groups, six in each group, and received supplemental ascorbic acid and/or vitamin E by tube feeding daily for 7 days: Group I, 30 mg ascorbic acid/100 g body wt.; Group II, 0.03 mg RRR-alpha-tocopheryl acetate/100 g body wt.; Group III, 30 mg ascorbic acid and 0.03 mg RRR-alpha-tocopheryl acetate/100 g body wt.; and Group IV, placebo. The six control rats (Group V) received placebo. The rats were sacrificed, blood and liver samples were collected for biochemical determinations. Vitamin E deficiency significantly increased erythrocyte (RBC) spontaneous hemolysis, liver thiobarbituric acid (TBA) value, activities of glutamateoxaloacetate transaminase (GOT), pyruvate kinase (PK), and creatine phosphokinase (CPK) in plasma, and significantly lowered plasma vitamin E levels and glutathione peroxidase (GPX) activities. Tube-feeding ascorbic acid for 7 days produced partial reversal effect on liver TBA values, activities of plasma PK, GOT, CPK, and plasma vitamin E levels but not on RBC hemolysis and plasma GPX activity. Tube feeding both ascorbic acid and vitamin E showed similar partial reversal effect as feeding vitamin E alone on all the parameters stated above. The results suggest that ascorbic acid may spare the metabolism of vitamin E and partially reverse the changes in some of the biochemical parameters characteristic of vitamin E deficiency.     

Vitamin E supplementation in very-low-birth-weight infants: long-term follow-up at two different levels of vitamin E supplementation

This study evaluates the need of vitamin E supplementation in very-low-birth-weight infants by long-term follow-up of plasma vitamin E status during the first 15 mo of life, with two different levels of supplementation. The subjects were 51 newborn infants with birth weights less than or equal to 1520 g. During hospitalization the infants were fed human milk. On the third day of life oral vitamin E supplementation of less than or equal to 10 mg/d was started in all infants. In addition, 23 infants selected at random were given intramuscular vitamin E (20 mg/kg/d) during the first 3 d. The data indicate that the 10 mg/d supplement resulted in an adequate plasma concentration of vitamin E. After cessation of supplementation at age 3 mo, the risk of low plasma vitamin E levels increased. Although intramuscular administration resulted in long-lasting increments in mean plasma vitamin E values, some later levels in these infants were marginal.