***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background This study was design ed to determine the optimal timing of vitamins E and C to prevent oxidative stress induced by a high‐fat evening meal in type 2 diabetes . Methods and Results Eleven subjects were admitted on 4 occasions . Euglycemia was maintained for 24 hours by insulin infusion . Participants were fed a high‐fat test supper equivalent to a McDonald 's Big Mac Meal . Blood was drawn for measurement of C‐reactive protein ( CRP ) , interleukin 6 ( IL‐6 ) , plasminogen activator inhibitor‐1 ( PAI‐1 ) , malonyldialdehyde ( MDA ) , and total radical antioxidant parameter ( TRAP ) before and during the 4 hours after the test meal . Studies were performed in r and om sequence with vitamin E 800 IU and vitamin C 1 g given either before breakfast or before supper in a double‐blind manner on the day of the test meal . Control studies were performed with no vitamins and no test meal administered . There was a significant rise in CRP and PAI‐1 after the test supper ( P<0.05 compared with “ no meal ” ) . Either presupper or prebreakfast vitamins E and C prevented the meal‐induced rise in CRP ( P=0.03 ) , although presupper vitamins were more effective ( P=0.03 compared with prebreakfast vitamins ) . Only prebreakfast vitamins prevented the meal‐induced rise in PAI‐1 ( P=0.006 ) . There were no significant meal‐related changes in the concentrations of IL‐6 , MDA , or TRAP . Conclusions The timing of administration of antioxidant vitamins has variable effects on markers of meal‐induced inflammation and fibrinolysis . This observation may be one reason why cardiovascular disease prevention trials using these vitamins have reported conflicting results . ( Circulation . 2003;108:24‐31 . Objective This study evaluated the possibility of inhibiting protein glycosylation in vivo with vitamin E. Research Design and Methods Two groups of 10 insulin-requiring diabetic patients , matched for duration of disease and metabolic control , received daily vitamin E supplementation of 1200 and 600 mg , respectively , for 2 mo . A third group of 10 diabetic patients , matched for duration of disease and metabolic control , served as the control group and received placebo .  Fasting plasma glucose , mean daily plasma glucose , fasting labile HbA1 , and glycosylated proteins were measured in the basal state and after 1 and 2 mo of treatment . In addition , hyperglycemic clamp studies were performed in basal state and after 1 mo of vitamin E administration in all patients . Results Glycemic indices did not show any significant changes during the study , whereas fasting labile HbA , and glycosylated proteins decreased significantly after 1 and 2 mo in patients on vitamin E administration . Stable HbA1 decreased after 2 mo . Mean glycemic incremental area in the hyperglycemic clamp procedure was similar before and after treatment , whereas a significant reduction in mean labile HbA1 incremental area was found after vitamin E supplementation . A significant difference was also found in both fasting and incremental labile HbA1 levels , stable HbA1 , and glycosylated proteins between the two groups of diabetic patients on the two doses of vitamin E ; the diabetic patients who received the higher dose of vitamin E showed the greater reduction . No significant changes in these parameters were observed in diabetic patients on placebo administration . Conclusions These results demonstrate that vitamin E administration may reduce protein glycosylation in diabetic subjects independently of changes in plasma glucose , an effect that may be due to the inhibition of labile glycosylation , the first step of the Maillard reaction . Long-term studies will help establish the usefulness of vitamin E administration for the prevention of diabetic complications BACKGROUND Type 2 diabetes is associated with elevated oxidative stress and declines in antioxidant defense . The disease is also characterized by an imbalance in the ratio of cardiac sympathetic to parasympathetic tone . Antioxidants , vitamin E in particular , may have beneficial effects on the cardiac autonomic nervous system through a decline in oxidative stress . OBJECTIVE We investigated the possible effects of vitamin E on the cardiac autonomic nervous system , as assessed by analysis of heart rate variability , in patients with type 2 diabetes and cardiac autonomic neuropathy . DESIGN In a double-blind r and omized controlled trial , 50 patients with type 2 diabetes were assigned to treatment with vitamin E ( 600 mg/d ) or placebo for 4 mo . RESULTS The anthropometric characteristics of the patients remained unchanged throughout the study . Chronic vitamin E administration was associated with decreases in concentrations of glycated hemoglobin ( P < 0.05 ) , plasma insulin ( P < 0.05 ) , norepinephrine ( P < 0.03 ) , and epinephrine ( P < 0.02 ) ; a lower homeostasis model assessment index ( P < 0.05 ) ; and improved indexes of oxidative stress . Furthermore , vitamin E administration was associated with increases in the R-R interval ( P < 0.05 ) , total power ( P < 0.05 ) , and the high-frequency component of heart rate variability ( HF ; P < 0.05 ) and decreases in the low-frequency component ( LF ; P < 0.05 ) and the ratio of LF to HF ( P < 0.05 ) . Finally , change in the plasma vitamin E concentration was correlated with change in the LF-HF ratio ( r = -0.43 , P < 0.04 ) independently of changes in the homeostasis model assessment index and plasma catecholamines concentrations . CONCLUSIONS Chronic vitamin E administration improves the ratio of cardiac sympathetic to parasympathetic tone in patients with type 2 diabetes . Such an effect might be mediated by a decline in oxidative stress BACKGROUND Most Koreans with type 2 diabetes are insulin deficient and insulin resistant . Continuous subcutaneous insulin infusion ( CSII ) provides a suitable amount of insulin to overcome insulin deficiency and achieve near-normal blood glucose concentrations . Our previous study showed , however , that CSII does not reduce oxidative stress even though it normalizes blood glucose concentrations . OBJECTIVE The purpose of this study was to determine whether CSII plus alpha-tocopherol supplementation for 2 mo would alter oxidative stress in Korean patients with type 2 diabetes . DESIGN Ninety-eight subjects received CSII plus either 200 mg alpha-tocopherol/d ( n = 48 ) or a placebo ( n = 50 ) for 2 mo . The general characteristics ( age , duration of diabetes , body mass index , and blood glucose concentrations ) of the 2 groups were not significantly different . RESULTS Fasting and postpr and ial blood glucose concentrations of all subjects were normalized after CSII . Fasting plasma insulin concentrations did not differ significantly between the 2 groups after CSII . Lipid peroxide concentrations in plasma and red blood cells decreased and alpha-tocopherol concentrations in plasma and red blood cells increased after alpha-tocopherol supplementation . However , these changes were not affected significantly by CSII . Plasma vitamin C concentrations increased significantly after CSII plus alpha-tocopherol supplementation . However , the activities of antioxidant enzymes in red blood cells did not change significantly after CSII plus alpha-tocopherol supplementation . CONCLUSION alpha-Tocopherol supplementation was beneficial in decreasing blood lipid peroxide concentrations without altering antioxidant enzyme activities in Korean patients with type 2 diabetes treated with CSII BACKGROUND Some studies have shown potential benefit of vitamin E on platelet function , but several clinical trials failed to show improved cardiovascular outcome with alpha-tocopherol supplementation . Gamma-tocopherol , a major dietary form of vitamin E , may have protective properties different from those of alpha-tocopherol . OBJECTIVE We compared the effects of supplementation with alpha-tocopherol ( 500 mg ) and a gamma-tocopherol-rich compound ( 500 mg , containing 60 % gamma-tocopherol ) on serum and cellular tocopherol concentrations , urinary tocopherol metabolite excretion , and in vivo platelet activation in subjects with type 2 diabetes . DESIGN Fifty-eight subjects were r and omly assigned to receive either 500 mg alpha-tocopherol/d , 500 mg mixed tocopherols/d , or matching placebo .  Serum , erythrocyte , and platelet tocopherol and urinary metabolite concentrations were measured at baseline and after the 6-wk intervention . Soluble CD40 lig and , urinary 11-dehydro-thromboxane B2 , serum thromboxane B2 , soluble P-selectin , and von Willebr and factor were measured as biomarkers of in vivo platelet activation . RESULTS Serum alpha-tocopherol increased with both tocopherol treatments . Serum and cellular gamma-tocopherol increased 4-fold ( P < 0.001 ) in the mixed tocopherol group , whereas red blood cell gamma-tocopherol decreased significantly after alpha-tocopherol supplementation . Excretion of alpha-carboxyethyl-hydroxychroman increased significantly after supplementation with alpha-tocopherol and mixed tocopherols . Excretion of gamma-carboxyethyl-hydroxychroman increased significantly after supplementation with mixed tocopherols and after that with alpha-tocopherol , which may reflect the displacement of gamma-tocopherol by alpha-tocopherol due to incorporation of the latter into lipoproteins in the liver . Neither treatment had any significant effect on markers of platelet activation . CONCLUSIONS Supplementation with alpha-tocopherol decreased red blood cell gamma-tocopherol , whereas mixed tocopherols increased both serum alpha-tocopherol and serum and cellular gamma-tocopherol . Changes in serum tocopherol closely reflect changes in cellular concentrations of tocopherols after supplementation Objective : The present study design ed to assess the effect of Mg+Zn , vitamin C+E , and combination of these micronutrients on blood pressure in type 2 diabetic patients . Material s and Methods : In a r and omized , double-blind , placebo controlled clinical trial , 69 type 2 diabetic patients were r and omly divided into four groups , each group receiving one of the following daily supplement for three months ; group M : 200 mg Mg and 30 mg Zn ( n = 16 ) , group V : 200 mg vitamin C and 150 mg vitamin E ( n = 18 ) , group MV : minerals plus vitamins ( n = 17 ) , group P : placebo ( n = 18 ) . Blood pressure was measured at the beginning and at the end of the trial . Treatment effects were analyzed by general linear modeling . Results : Results indicate that after three months of supplementation  levels of systolic , diastolic and mean blood pressure decreased significantly in the MV group by 8 mmHg ( 122 ± 16 vs. 130 ± 19 mmHg ) , 6 mmHg ( 77 ± 9 vs. 83 ± 11 mmHg ) , and 7 mmHg ( 92 ± 9 vs. 99 ± 13 mmHg ) , respectively ( p < 0.05 ) . Also combination of vitamin and mineral supplementation had significantly effects in increasing serum potassium ( p < 0.05 ) and in decreasing serum malondialdehyde ( p < 0.05 ) . There was no significant change in the levels of these parameters in the other three groups . Conclusion : The results of the present study indicated that in type 2 diabetic patients  a combination of vitamins and minerals , rather than vitamin C and E or Mg and Zn , might decrease blood pressure Objective — Clinical trials of vitamin E have failed to demonstrate a decrease in cardiovascular events . However , these studies did not address possible benefit to subgroups with increased oxidative stress . Haptoglobin ( Hp ) , a major antioxidant protein , is a determinant of cardiovascular events in patients with Type 2 diabetes mellitus ( DM ) . The Hp gene is polymorphic with 2 common alleles , 1 and 2 . The Hp 2 allelic protein product provides inferior antioxidant protection compared with the Hp 1 allelic product . We sought to test the hypothesis that vitamin E could reduce cardiovascular events in DM individuals with the Hp 2 - 2 genotype , a subgroup that comprises 2 % to 3 % of the general population . Methods and Results —1434 DM individuals ≥55 years of age with the Hp 2 - 2 genotype were r and omized to vitamin E ( 400 U/d ) or placebo . The primary composite outcome was myocardial infa rct ion , stroke , and cardiovascular death . At the first evaluation of events , 18 months after initiating the study , the primary outcome was significantly reduced in individuals receiving vitamin E ( 2.2 % ) compared with placebo ( 4.7 % ; P=0.01 ) and led to early termination of the study . Conclusions —Vitamin E supplementation appears to reduce cardiovascular events in individuals with DM and the Hp 2 - 2 genotype ( Clinical Trials.gov NCT00220831 ) OBJECTIVE The present study was design ed to assess the effect of magnesium plus zinc 
    Output:
    
Vitamin E supplementation did not improve glycaemic control in the full set of type 2 diabetes patients .
WHAT IS NEW AND CONCLUSIONS The evidence suggests no beneficial effect of vitamin E supplementation in improving glycaemic control in unselected patients with type 2 diabetes .
However , HbA(₁c ) may decrease with vitamin E supplementation in patients with inadequate glycaemic control or low serum levels of vitamin E. This shows the importance of targeting therapy .