Scientific evidence to support a vitamin E and heart disease health claim: research needs

[Association of nutritional patterns and arterial hypertension in Russia: does it exist?]

AIM

To evaluate nutritional patterns in patient with arterial hypertension (AH) compared to the control group without elevated blood pressure.

MATERIALS AND METHODS

Retrospective search for unique records of the patients aged 1875 y.o. with complete data on usual nutrition with food frequency methods who had no mentions of diabetes mellitus, food intolerance or allergies, and history of major abdominal surgery, as well as signs of secondary reasons of AH. Nutritional patterns were assessed with the use of healthy eating pyramid principles. Ststistical analysis was performed with the use of SPSS 13.0 for Windows software (SPSS Inc., USA).

RESULTS

The data of 711 patients were available for the final analysis (595 of them in AH group). Both groups consumed lower compared to the recommended amounts of fruits, dairy and higher amounts of meat. Those with AH consumed larger amounts of vegetables (1.130.74 compared to the values of healthy eating pyramid vs 0.940.63 in the control group; p=0.004), fruits (0.800.66 vs 0.520.57; p=0.001), meat (1.851.05 vs 1.620.91; p=0.002) and fats (0.770.60 vs 0.490.55; p=0.001). On the other hand, there were lower rates of consumption of sugars, and confectionaries in the structure of nutritional patterns in patients with AH compared to the control group: (0.350.44 of the healthy eating pyramid in AH vs 1.930.98, in the control group; p=0.0001).

CONCLUSION

Nutritional patterns of patients with arterial hypertension significantly differ compared to the control group. The obtained data may be used for diet modification in patients with arterial hypertension.

Total Antioxidant Capacity from Dietary Supplement Decreases the Likelihood of Having Metabolic Syndrome in Korean Adults

This study was conducted to estimate antioxidant vitamin intake and total antioxidant capacity (TAC) from diet and dietary supplements and to examine their association with metabolic syndrome (MetS) in Korean adults. Out of 6308 adults 19~64 years old from the 2010~2011 Korea National Health and Nutrition Examination Survey, 1847 adults were classified as dietary supplement users and the other 4461 adults were classified as non-users. Antioxidant intake and TAC from diet and dietary supplements were estimated using dietary intake data and linked with the antioxidant and TAC database for common Korean foods. The prevalence of MetS was lower in dietary supplement users (odds ratio (OR) = 0.82; 95% confidence interval (CI), 0.68–0.98) than that in non-users. Among dietary supplement users, a lower prevalence of MetS was observed in the highest tertile for vitamin A (OR = 0.72; 95% CI, 0.53–0.99) and vitamin E (OR = 0.74; 95% CI, 0.55–0.99) intake than that in the lowest tertile among non-users. Subjects in the highest tertile of TAC among dietary supplement users showed a lower prevalence of MetS (OR = 0.72; 95% CI, 0.52–0.99) than non-users. The results imply that intake of vitamin A, vitamin E, and TAC from dietary supplements might have a protective effect on MetS among Korean adults.

Phytochemical composition and β-glucan content of barley genotypes from two different geographic origins for human health food production

In the present study, 27 barley genotypes (Hordeum vulgare L.) grown in two geographic origins (Czech Republic and Spain) were analysed for their contents of β-glucan, tocols and phenolic compounds (free and bound). The samples included hulled, hull-less and coloured genotypes. The results showed that concentrations of β-glucan range from 2.40 to 7.42g/100g. Total tocol content of the barley samples ranged between 39.9 and 81.6μg/g. A total of 64 compounds were identified in the barley samples. These included 19 phenolic acids and aldehydes, 9 flavan 3-ols, 9 flavone glycosides, and 27 anthocyanins. The results showed a wide range of phenolic concentrations in the barley samples, highlighting the presence of considerable amounts of anthocyanins in purple barley genotypes. In synthesis, barley should be considered a good source of bioactive components, especially because of the broad spectrum of phytochemicals with potential health benefits besides the soluble fibre (β-glucan).

Antioxidant defense system in familial hypercholesterolemia and the effects of lipoprotein apheresis

Oxidative stress is thought to play an important role in the pathogenesis of disorders associated with atherosclerosis. Alpha-tocopherol is considered to be an effective lipophilic antioxidant, which protects lipid membranes against peroxidation and thus prevents cell damage by reaction with free radicals. However, measurement of alpha-tocopherol concentration in serum does not reflect the content of α-tocopherol in membranes whereas erythrocyte alpha-tocopherol may be good indicator of antioxidative status. Therefore a simple isocratic reversed phase HPLC method has been developed and validated for the determination of alpha-tocopherol in human erythrocytes in a clinical setting. The content of alpha-tocopherol in human erythrocyte membrane and lipoperoxidation were studied in patients with severe hypercholesterolemia treated by lipoprotein apheresis. The group of hypercholesterolemic patients (n = 14) treated by lipoprotein apheresis was compared to healthy adult normolipidemic controls. After lipoprotein apheresis, the content of in membrane alpha-tocopherol did not change significantly despite decreased tocopherol in serum and lipoprotein fractions. We observed significantly decreased lipoperoxidation as revealed by serum TBARS, representing end products of lipid peroxidation, which increased from third day afterwards and remained significantly higher in comparison to controls until the next LDL-apheresis. We conclude that aggressive lipid lowering procedure with lipoprotein apheresis was associated with favorable transient decrease of lipoperoxidation. Simultaneously the cell membrane bound antioxidative defense mechanisms as reflected by the content of alpha-tocopherol in human erythrocyte membrane where not depressed in spite of its decreased plasma lipid carrier. Another variables involved remain to be investigated.

Various Effects of Omega 3 and Omega 3 Plus Vitamin E Supplementations on Serum Glucose Level and Insulin Resistance in Patients with Coronary Artery Disease

BACKGROUND

Omega 3 and vitamin E are two critical nutrients which include beneficial effects in coronary artery disease (CAD). The aim of this study was to assess the effects of omega 3 alone supplementation or in combination with vitamin E on serum glucose and lipid levels and insulin resistance in CAD patients.

METHODS

Participants of this clinical trial included 60 male patients with CAD who selected from Tehran Heart Center in Tehran, Iran in 2014. They received 4 g/day omega 3 plus 400 IU/day vitamin E (OE), 4 g/day omega 3 with vitamin E placebo (OP), or omega 3 and vitamin E placebo (PP) for two months. Serum glucose, lipids and insulin were assessed and HOMA-IR was calculated before and after the trial and effects of these nutrients on the highlighted parameters were compared within the study groups.

RESULTS

Serum glucose level increased significantly in OP group (P=0.004), but not in OE group. OE and OP groups showed a significant decrease in fasting serum TG (P=0.020 and P=0.001, respectively). Serum insulin and HOMA-IR decreased significantly in OE group (P=0.044 and P=0.039, respectively) but did not change significantly in OP group.

CONCLUSION

Although, omega 3 supplementation may include adverse effects on serum glucose level, co-administration of omega 3 and vitamin E can beneficially decrease serum insulin and insulin resistance in CAD patients.

Biomarkers of Metabolic Syndrome: Biochemical Background and Clinical Significance

Biomarkers of the metabolic syndrome are divided into four subgroups. Although dividing them in groups has some limitations, it can be used to draw some conclusions. In a first part, the dyslipidemias and markers of oxidative stress are discussed, while inflammatory markers and cardiometabolic biomarkers are reviewed in a second part. For most of them, the biochemical background and clinical significance are discussed, although here also a well-cut separation cannot always be made. Altered levels cannot always be claimed as the cause, risk, or consequence of the syndrome. Several factors are interrelated to each other and act in a concerted, antagonistic, synergistic, or modulating way. Most important conclusions are summarized at the end of every reviewed subgroup. Genetic biomarkers or influences of various food components on concentration levels are not included in this review article.

Improvement of genetic stability in lymphocytes from Fanconi anemia patients through the combined effect of α-lipoic acid and N-acetylcysteine

Fanconi Anemia (FA) is a rare genetic disorder, characterized by progressive bone marrow failure and increased predisposition to cancer. Despite being highly heterogeneous, all FA patients are hypersensitive to alkylating agents, in particular to 1,2:3,4-diepoxybutane (DEB), and to oxidative damage. Recent studies point to defective mitochondria in FA cells, which is closely related with increased production of reactive oxygen species (ROS) and concomitant depletion of antioxidant defenses, of which glutathione is a well-known biomarker.The objective of the present work is to evaluate the putative protective effect of α-lipoic acid (α-LA), a mitochondrial protective agent, and N-acetylcysteine (NAC), a direct antioxidant and a known precursor for glutathione synthesis, in spontaneous and DEB-induced chromosome instability (CI) in lymphocyte cultures from FA patients.For that purpose, lymphocyte cultures from 15 FA patients and 24 healthy controls were pre-treated with 20 μM α-LA, 500 μM NAC and α-LA plus NAC at the same concentrations, and some of them were exposed to DEB (0.05 μg/ml). A hundred metaphases per treatment were scored to estimate the relative frequency of spontaneous and DEB-induced chromosome breakage.The obtained results revealed that a cocktail of α-LA and NAC can drastically improve the genetic stability in FA lymphocytes in vitro, decreasing CI by 60% and 80% in cultures from FA patients and FA mosaic/chimera patients, respectively. These results suggest that the studied cocktail can be used as a prophylactic approach to delay progressive clinical symptoms in FA patients caused by CI, which can culminate in the delay of the progressive bone marrow failure and early cancer development.

Association between diet and polymorphisms in individuals with statin-controlled dyslipidaemia grouped according to oxidative stress biomarkers

The objective of this study was to investigate whether differences in diet and in single-nucleotide polymorphisms (SNPs) found in paraoxonase-1 (PON-1), 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR), cholesterol ester transfer protein (CETP) and apolipoprotein E (APOE) genes, are associated with oxidative stress biomarkers and consequently with susceptibility of low-density cholesterol (LDL) to oxidation. A multivariate approach was applied to a group of 55 patients according to three biomarkers: plasma antioxidant activity, malondialdehyde and oxidized LDL (oxLDL) concentrations. Individuals classified in Cluster III showed the worst prognoses in terms of antioxidant activity and oxidative status. Individuals classified in Cluster I presented the lowest oxidative status, while individuals grouped in Cluster II presented the highest levels of antioxidant activity. No difference in nutrient intake was observed among the clusters. Significantly higher γ- and δ-tocopherol concentrations were observed in those individuals with the highest levels of antioxidant activity. No single linear regression was statistically significant, suggesting that mutant alleles of the SNPs selected did not contribute to the differences observed in oxidative stress response. Although not statistically significant, the p value of the APO E coefficient for oxLDL response was 0.096, indicating that patients who carry the TT allele of the APO E gene tend to present lower plasma oxLDL concentrations. Therefore, the differences in oxidative stress levels observed in this study could not be attributed to diet or to the variant alleles of PON-1, CETP, HMGCR or APO E. This data supports the influence of γ-tocopherol and δ-tocopherol on antioxidant activity, and highlights the need for further studies investigating APO E alleles and LDL oxidation.

Gamma-tocopherol supplementation alone and in combination with alpha-tocopherol alters biomarkers of oxidative stress and inflammation in subjects with metabolic syndrome

Metabolic syndrome (MetS) is associated with increased incidence of diabetes and cardiovascular disease (CVD). Prospective clinical trials with alpha-tocopherol (AT) have not yielded positive results. Because AT supplementation decreases circulating gamma-tocopherol (GT), we evaluated supplementation with GT (800 mg/day), AT (800 mg/day), the combination or placebo for 6 weeks alone AT and GT concentrations, biomarkers of oxidative stress, and inflammation in subjects with MetS (n=20/group). Plasma AT and GT levels increased following supplementation with AT alone or GT alone or in combination. AT supplementation significantly decreased GT levels. Urinary alpha- and gamma-CEHC, metabolites of the respective Ts, also increased correspondingly, i.e., alpha-CEHC with AT and gamma-CEHC with GT supplementation, compared to placebo. HsCRP levels significantly decreased in the combined AT+GT group. LPS-activated whole blood release of IL-1 and IL-6 did not change. There was a significant decrease in TNF with AT alone or in combination with GT. Plasma MDA/HNE and lipid peroxides were significantly decreased with AT, GT, or in combination. Nitrotyrosine levels were significantly decreased only with GT or GT+AT but not with AT compared to placebo. Thus, the combination of AT and GT supplementation appears to be superior to either supplementation alone on biomarkers of oxidative stress and inflammation and needs to be tested in prospective clinical trials to elucidate its utility in CVD prevention.

One is okay, more is better? Pharmacological aspects and safe limits of nutritional supplements

The use of vitamins, minerals and other supplements has increased considerably during recent years. In the National Diet and Nutrition Survey of British adults aged 19-64 years 40% of those surveyed were taking supplements. In 2005 sales of dietary supplements in the UK were approximately pound sterling 325.7 x 106 in 'bricks and mortar' shops (excluding health food shops). The physiological effects of vitamins and minerals in amounts approximating to the UK reference nutrient intake or the EU RDA are well understood in terms of reducing the risk of micronutrient deficiency. However, the effects of vitamins, minerals and other supplements in larger amounts have attracted much attention in recent decades, and these effects, some of which may be pharmacological, are not as well categorised. Some of these effects are beneficial, some are not. Although vitamins and minerals and other supplements are generally safe at higher doses, there are some safety issues that are relevant in the context of the wide availability of supplements without a doctor's prescription. Thus, several authorities throughout the world have established upper limits (UL) for the intake of vitamins and minerals, and the EU is in the process of setting maximum permitted levels (MPL) for vitamins and minerals in food supplements. The present paper discusses the potential benefits and safety issues relating to the use of supplements at doses higher than the RDA. The rationale for the establishment of UL is also discussed, explaining the differences between the values set by different authorities and the expected guidance and legislation from the European Commission on MPL for vitamins and minerals in food supplements.

Effect of high-dose alpha-tocopherol supplementation on biomarkers of oxidative stress and inflammation and carotid atherosclerosis in patients with coronary artery disease

BACKGROUND

Oxidative stress and inflammation are crucial in atherogenesis. alpha-Tocopherol is both an antioxidant and an antiinflammatory agent.

OBJECTIVE

We evaluated the effect of RRR-alpha-tocopherol supplementation on carotid atherosclerosis in patients with stable coronary artery disease (CAD) on drug therapy.

DESIGN

Randomized, controlled, double-blind trial compared RRR-alpha-tocopherol (1200 IU/d for 2 y) with placebo in 90 patients with CAD. Intimal medial thickness (IMT) of both carotid arteries was measured by high-resolution B-mode ultrasonography at 0, 1, 1.5, and 2 y. At 6-mo intervals, plasma alpha-tocopherol concentrations, C-reactive protein (CRP), LDL oxidation, monocyte function (superoxide anion release, cytokine release, and adhesion to endothelium), and urinary F(2)-isoprostanes were measured.

RESULTS

alpha-Tocopherol concentrations were significantly higher in the alpha-tocopherol group but not in the placebo group. High-sensitivity CRP concentrations were significantly lowered with alpha-tocopherol supplementation than with placebo (32%; P < 0.001). alpha-Tocopherol supplementation significantly reduced urinary F(2)-isoprostanes (P < 0.001) and monocyte superoxide anion and tumor necrosis factor release compared with baseline and placebo (P < 0.001). No significant difference was observed in the mean change in total carotid IMT in the placebo and alpha-tocopherol groups. In addition, no significant difference in cardiovascular events was observed (P = 0.21).

CONCLUSIONS

High-dose RRR-alpha-tocopherol supplementation in patients with CAD was safe and significantly reduced plasma biomarkers of oxidative stress and inflammation but had no significant effect on carotid IMT during 2 y.

The 'vitamin E regeneration system' (VERS) and an algorithm to justify antioxidant supplementation in diabetes--a hypothesis

In studies of vitamin E effectiveness in diabetes, there are still controversies surrounding negative observational and positive experimental results. However, there is no controversy that antioxidant vitamin E is regenerated from its pro-oxidant tocopheroxyl radical by a network of interacting co-antioxidants. The network of interacting co-antioxidants has only been studied individually. The hypothesis we propose is that a vitamin E regeneration system (VERS) model based on the complex interactions of the co-antioxidants provides a rationale for vitamin E supplementation as a therapeutic adjunct in diabetes. Furthermore, the factors considered prior to the use of Vitamin E as a supplement in diabetes research and therapy, the effectiveness of vitamin E supplementation and the limitations have been identified in the literature. There is no single study of vitamin E supplementation or efficacy that has determined vitamin E levels in combination with all of the co-antioxidants that interact to regenerate oxidised vitamin E. Therefore, there is a lack of good evidence for or against vitamin E being unilaterally depleted in the antioxidant network. There is also lack of rationale for choice of co-antioxidant supplementation. In essence, the normal conditions for effective antioxidant activity of vitamin E supplementation have yet to be fully explored. We propose a coherent model of VERS, and recommend that VERS status needs to be assessed, as part of evidence-based clinical practice to determine whether vitamin E should be recommended for the diabetic patient. We also propose an algorithm, based on the antioxidant activity and confounding factors, to guide the formulation of a credible hypothesis for clinical trials in assessing the function of vitamin E and treatment outcomes. The proposed model hinges on pertinent questions that have to be addressed to avoid organising a clinical trial that has been identified as biased.

Total alpha-tocopherol intakes are associated with serum alpha-tocopherol concentrations in African American adults

African Americans in the southern United States have a high prevalence of chronic disease. Tocopherol intake and status have been associated with protection against several chronic diseases. Our objectives were, therefore, to examine the association between tocopherol intakes as measured by 2 regional FFQ and their corresponding concentrations in serum and to report on dietary sources of tocopherols in 404 men and women participating in the cross-sectional Diet and Physical Activity Sub-Study of the Jackson Heart Study. A large proportion (49% of men and 66% of women) reported dietary supplement use. Only 5.8% of men and 4.5% of women met the estimated average requirement (EAR) for vitamin E from foods alone, whereas 44.2% men and 49.2% women met it from foods and supplements. Total (diet + supplement) intake of alpha-tocopherol was associated with its corresponding measure in serum. Vitamin E supplement use, sex, serum cholesterol, education, and BMI, but not gamma-tocopherol intakes, were associated with serum gamma-tocopherol. For delta-tocopherol, associated variables included sex and serum cholesterol. The top food sources of alpha- and gamma-tocopherol were snack chips and the top food source of delta-tocopherol was margarine. Despite prevalent vitamin E supplement use, more than one-half of this population did not meet the EAR for alpha-tocopherol intake and very few met it from food alone. Supplement use was associated with higher alpha- but lower gamma-tocopherol concentration in serum. The possible health implications of this difference in relative tocopherol subtypes require further study.

Genome-wide screening of alpha-tocopherol sensitive genes in heart tissue from alpha-tocopherol transfer protein null mice (ATTP(-/-))

Alpha-tocopherol transfer protein (ATTP) null mice (ATTP(-/-)) have a systemic deficiency of alpha-tocopherol (AT). The heart AT levels of ATTP(-/-) are <10% of those in ATTP(+/+) mice. The genomic responses of heart to AT deficiency were determined in 3 months old male ATTP(-/-) mice and compared with their ATTP(+/+) littermate controls using Affymetrix 430A 2.0 high density oligonucleotide arrays. Differential analysis of approximately 13000 genes identified repression of genes related to immune system and activation of genes related to lipid metabolism and inflammation with no significant change in the expression of classical antioxidant genes (catalase, superoxide dismutase, glutathione peroxidase) in ATTP(-/-) as compared to ATTP(+/+) mice. The present data identifies novel classes of AT sensitive genes in heart tissue.

Heart disease and single-vitamin supplementation

Heart disease is the number one cause of death in the United States and has long been recognized to be multifactorial. A growing body of evidence suggests that not only free radical-mediated reactions but also inflammatory responses play major roles in atherogenesis. Vitamin E has both antioxidant and antiinflammatory properties and is the most widely studied vitamin in clinical trials and thus will be the primary example used in this review. Clinical trials of vitamin E efficacy, in hindsight, have been overly optimistic in their expectation that a vitamin could reverse poor dietary habits and a sedentary lifestyle as well as provide benefit beyond that of pharmaceutical agents in treating heart disease. However, it is also apparent that most Americans do not consume dietary amounts adequate to meet established vitamin E requirements. In response to oxidative stressors, vitamin E can decrease biomarkers of lipid peroxidation, is itself killed, and requires optimal vitamin C status to function most effectively. Thus, adequate vitamin E intakes are clearly needed, but what is adequate for what function has yet to be defined. It is noteworthy that in most trials, biomarkers were not used nor were oxidative stress and lipid peroxidation markers used or plasma vitamin E concentrations measured.

Alpha-Tocopherol Distribution in Lipoproteins and Anti-Inflammatory Effects Differ between CHD-Patients and Healthy Subjects

OBJECTIVE

The purpose of this study was to investigate the dose-dependent effects of RRR-alpha-tocopherol supplementation in coronary heart disease (CHD) patients and healthy subjects on plasma alpha-tocopherol levels, plasma lipoprotein distribution, LDL oxidation, and inflammatory plasma markers.

METHODS

12 patients with coronary heart disease and 12 healthy subjects were supplemented with increasing dosages of RRR-alpha-tocopherol at 100, 200 and 400 mg/day for a period of 3 weeks per dose. Lipoproteins were separated by FPLC and ultracentrifugation. Alpha-tocopherol was measured by HPLC. Resistance of LDL to oxidation was determined by reading the absorption at 234 nm after CuCl2-induced oxidation. Clinical chemistry and inflammatory markers were measured on automated analysis systems.

RESULTS

Plasma alpha-tocopherol concentrations at baseline were comparable between CHD-patients and healthy subjects (21.7 +/- 4.7 micromol/L and 25.8 +/- 7.6 micromol/L, respectively). CHD-patients showed a significant increase (59%) of plasma alpha-tocopherol concentrations to 34.6 +/- 9.8 micromol/L at a dosage of 100 mg/day RRR-alpha-tocopherol, whereas healthy subjects showed a significant (54%) increase to 39.7 +/- 6.1 micromol/L only with 400 mg/day RRR-alpha-tocopherol. In addition, CHD-patients showed a significantly increased enrichment of alpha-tocopherol in VLDL. Supplementation (200 mg/day) caused a significant decrease of the acute phase plasma proteins C-reactive protein (CRP) (-65%) and fibrinogen (-24%).

CONCLUSION

Our data demonstrate that CHD-patients require lower dosages of alpha-tocopherol supplementation than healthy subjects to exert biological effects on plasma lipoproteins and acute phase response.

Dietary intake and risk of coronary heart disease differ among ethnic subgroups of black Americans

Coronary heart disease (CHD) morbidity and mortality are more prevalent in Blacks than Whites in the United States. Most studies evaluate the dietary intake and health of Black Americans as one group and do not consider possible differences among ethnic subgroups within the U.S. Black population. We used data from NHANES III to assess whether dietary intake, CHD risk factors, and predicted 10-y risk of CHD differed between non-Hispanic Black adults born in the United States (NHB-US), and non-Hispanic and Hispanic Black adults born outside of the United States (NHB-non US, HB-non US). Data were provided from single 24-h dietary recalls, biochemical measures, the medical examination, and self-reported responses to survey questions. NHB-US had higher intakes of energy, fat, protein, meat, added sugars, and sodium, and lower intakes of fruits, fiber, and most micronutrients. NHB-US also had higher predicted 10-y risk of developing CHD (5.8%) than NHB-non US (3.7%, P<0.001) or HB-non US (4.7%, P=0.017). Both immigrant groups had better CHD risk profiles and lower proportions of persons with metabolic syndrome and other CHD-related conditions. Our findings show differences in dietary intake and risk of CHD and related health conditions among ethnic subgroups of Blacks living in the United States. Future studies of diet and health should consider cultural differences within the Black population to better understand and reduce overall health disparities in the United States.

Vitamin E inhibits CD36 scavenger receptor expression in hypercholesterolemic rabbits

A numerous studies suggest that Vitamin E has a preventive role in atherosclerosis, although the mechanism of action still remains unclear. CD36, a member of the scavenger receptor family is centrally involved in the uptake of oxidized low density proteins (oxLDLs) from bloodstream. During the atherosclerotic process, the lipid cargo of oxLDL accumulates in macrophages and smooth muscle cells, inducing their pathological conversion to foam cells. In the present study, we investigate the role of Vitamin E on CD36 expression in an in vivo model. Atherosclerosis was induced by a 2% cholesterol containing Vitamin E poor diet. Three groups of six rabbits each were studied. The first group (control) was fed on Vitamin E poor diet. The second group was fed with Vitamin E poor diet containing 2% cholesterol and the rabbits in the third group were fed with Vitamin E poor diet containing 2% cholesterol and received injections of 50 mg/kg of Vitamin E i.m. After 4 weeks, aortas were removed and analysed by light microscopy for atherosclerotic lesions. Aortic samples were analysed for CD36 mRNA expression. The aortas of cholesterol-fed rabbits showed typical atherosclerotic lesions, detected by macroscopic and microscopic examination, and exhibited an increase in CD36 mRNA expression. Vitamin E fully prevented cholesterol induced atherosclerotic lesions and the induction of CD36 mRNA expression. The effects observed at the level of CD36 scavenger receptor expression in vivo suggest an involvement of reduced foam cell formation in the protective effect of Vitamin E against atherosclerosis.

Failure of vitamin E in clinical trials: is gamma-tocopherol the answer?

Oxidative stress and inflammation play a crucial role in atherosclerosis. However, prospective clinical trials of dietary antioxidants with anti-inflammatory properties, such as alpha-tocopherol (AT), have not yielded positive results. AT supplementation decreases gamma-tocopherol (GT) levels. GT is an antioxidant with potent anti-inflammatory activity, and plasma GT levels are inversely associated with cardiovascular diseases. Thus, studies using pure GT, alone or in conjunction with AT, will elucidate its utility in cardiovascular disease prevention.