Plasma Alpha-tocopherol Concentrations Research Articles

Alpha-tocopherol concentrations correlate with carotid artery intima-media thickness in type 2 diabetes

Background and Aims: A recent meta-analysis shows that higher circulating plasma alpha-tocopherol concentrations (Vit-E) is associated with lower cardiovascular mortality. We studied the association between Vit-E and carotid artery intima-media thickness (CIMT) (a surrogate marker of cardiovascular risk) in type 2 diabetes (T2D).

Influence of specific management practices on blood selenium, vitamin E, and beta‐carotene concentrations in horses and risk of nutritional deficiency

BackgroundSelenium or alpha‐tocopherol deficiency can cause neuromuscular disease. Beta‐carotene has limited documentation in horses.ObjectiveTo evaluate the effect of owner practices on plasma beta‐carotene concentration and risk of selenium and alpha‐tocopherol deficiencies.AnimalsThree‐hundred and forty‐nine adult (≥1 year), university and privately owned horses and mules.MethodsCross‐sectional study. Whole blood selenium, plasma alpha‐tocopherol, and plasma beta‐carotene concentrations were measured once. Estimates of daily selenium and vitamin E intake, pasture access, and exercise load were determined by owner questionnaire. Data were analyzed using t tests, Mann‐Whitney tests, parametric or nonparametric analysis of variance (ANOVA), Kruskal‐Wallis test, Spearman's correlation and contingency tables (P < .05).ResultsNearly 88% of the horses received supplemental selenium; 71.3% received ≥1 mg/d. Low blood selenium concentration (<80 ng/mL) was identified in 3.3% of horses, and 13.6% had marginal concentrations (80‐159 ng/mL). Non‐supplemented horses were much more likely to have low blood selenium (odds ratio [OR], 20.2; 95% confidence interval [CI], 9.26‐42.7; P < .001). Supplemental vitamin E was provided to 87.3% of horses; 57.7% received ≥500 IU/d. Deficient (<1.5 μg/mL) and marginal (1.5‐2.0 μg/mL) plasma (alpha‐tocopherol) occurred in 15.4% and 19.9% of horses, respectively. Pasture access (>6 h/d) and daily provision of ≥500 IU of vitamin E was associated (P < .001) with higher plasma alpha‐tocopherol concentrations. Plasma beta‐carotene concentration was higher in horses with pasture access (0.26 ± 0.43 versus 0.12 ± 0.13 μg/mL, P = .003).Conclusions and Clinical ImportanceSuboptimal blood selenium and plasma alpha‐tocopherol concentrations occurred in 16.7% and 35.5% of horses, respectively, despite most owners providing supplementation. Inadequate pasture access was associated with alpha‐tocopherol deficiency, and reliance on selenium‐containing salt blocks was associated with selenium deficiency.

Evaluation of hematological and plasma biochemical parameters in green sea turtle (Chelonia mydas Linnaeus, 1758) from nesting colonies of the northern coast the Sea of Oman

The green turtle (Chelonia mydas) has been a species of global concern for decades. As an attempt to study health status of nesting green turtles, Blood biochemistry and hematological values were obtained from 18 clinically normal, nesting female green sea turtles on the northern coast of the sea of Oman. Mean curved carapace length (CCL) was 111 ± 4 cm with a range of 103—122 cm. Barnacles were recorded on three turtles. No fibropapillomas were observed on any of the 18 turtle.The mean PCV was 0.41 (proportion of 1) with a range of 0.30–0.58. No basophils or hemoparasites were detected in any of the 18 turtles tested. All biochemistry and hematological values of green sea turtles were within published reference ranges of healthy sea turtle population. No statistically significant differences were noted between the two anticoagulants for Plasma biochemistry values. Plasma alpha–tocopherol concentrations in the 18 turtles tested was 7.8 ± 2.8 g/ml with a range of 0.5—11.8 g/ml. Plasma retinol was evaluated in 18 turtles and the concentration was 0.4 ±0.1 g/ml with a range of 0.2—0.6 g/ml. The present study provides baseline data of the green sea turtle characterized by biological and nonbiological factors, which may provide the basis for future studies.

Delineation of the Individual Effects of Vitamin E Isoforms on Early Life Incident Wheezing

To test the hypothesis that maternal plasma alpha-tocopherol levels are associated with protection from childhood wheeze and that this protection is modified by gamma-tocopherol. We conducted a prospective nested study in the Infant Susceptibility to Pulmonary Infections and Asthma Following Respiratory Syncytial Virus Exposure birth cohort of 652 children with postpartum maternal plasma vitamin E isoforms used as a surrogate for pregnancy concentrations. Our outcomes were wheezing and recurrent wheezing over a 2-year period, ascertained using validated questionnaires. We assessed the association of alpha- and gamma-tocopherol with wheezing outcomes using multivariable adjusted logistic regression, and tested for interaction between the isoforms with respect to the risk for wheezing outcomes. Children with wheezing (n = 547, n = 167; 31%) and recurrent wheezing (n = 545, n = 55; 10.1%) over a 2-year period were born to mothers with significantly lower postpartum maternal plasma concentrations of alpha-tocopherol, P = .016 and P = .007, respectively. In analyses of IQR increases, alpha-tocopherol was associated with decreased risk of wheezing (aOR 0.70 [95% CI 0.53,0.92]) and recurrent wheezing (aOR 0.63 [95% CI 0.42,0.95]). For gamma-tocopherol, the aOR for wheezing was 0.79 (95% CI 0.56-1.10) and the aOR for recurrent wheezing was 0.56 (95% CI 0.33-0.94, with nonmonotonic association). The association of alpha-tocopherol with wheezing was modified by gamma-tocopherol (P interaction = .05). Increases in postpartum maternal plasma alpha-tocopherol isoform concentrations were associated with decreased likelihood of wheezing over a 2-year period. Gamma-tocopherol modified this association.

A study on gender related differences in oxidative stress status

Female lives longer than male and incidence of cardiovascular disease is lower in young female. However the role of oxidative stress has been repeatedly described in various diseases but rarely healthy people. The objective of the study was to observe the gender related differences in oxidative stress status and to show significance in alteration. This cross sectional and comparative study was carried out in the Department of Physiology, Rajshahi Medical College during the period from January 2013 to June 2014. Total 45 healthy adult subjects (25 males and 20 females) were enrolled in the study. Systematic sampling technique was used to select each study subject from students, doctors and staffs of Rajshahi Medical College. Malondialdehyde (MDA), a lipid peroxide and alpha-tocopherol, an antioxidant in plasma was measured. MDA:alpha-tocopherol ratio was used as a reliable marker of oxidative stress status. The mean plasma alpha-tocopherol concentration was significantly higher (p &lt; 0.05) and plasma MDA: alpha-tocopherol ratio was significantly lower (p &lt; 0.05) in female group than male group. The mean plasma alpha-tocopherol concentration was significantly higher (p &lt; 0.05) in female group aged 18-21 years than the corresponding male group. From the results of this study, it can be concluded that oxidative stress is less in female than in male indicating presence of potent compensatory response against oxidative stress in female which may be attributed to influence of female sex hormones.&#x0D; Mediscope Vol. 6, No. 1: Jan 2019, Page 13-18

Red palm olein supplementation on cytokines, endothelial function and lipid profile in centrally overweight individuals: a randomised controlled trial.

The consumption of antioxidant-rich cooking oil such as red palm olein may be cardioprotective from the perspective of subclinical inflammation and endothelial function. Using a crossover design, we conducted a randomised controlled trial in 53 free-living high-risk abdominally overweight subjects, comparing the effects of incorporating red palm olein (with palm olein as control) in a supervised isocaloric 2100 kcal diet of 30% en fat, two-thirds (45 g/day) of which were derived from the test oil for a period of 6 weeks each. We did not observe a significant change in interleukin-6 (IL-6), in parallel with other pro-inflammatory (tumour necrosis factor-β, interleukin-1β, IL-1β, high sensitivity C-reactive protein, hsCRP) and endothelial function (soluble intercellular adhesion molecules, sICAM, soluble intravascular adhesion molecules, sVCAM) parameters. Interestingly, we observed a significant reduction in oxidised LDL levels (P < 0.0386) while on the red palm olein diet, together with the increase in plasma alpha tocopherol (P < 0.0002), alpha carotene (P < 0.0001) and beta carotene (P < 0.0001) concentrations compared with palm olein diet. Red palm olein did not improve subclinical inflammation and endothelial function despite profound increase in antioxidant levels. The positive improvement in oxidised LDL merits further attention in this group of subjects at risk of developing cardiovascular disease.

Systemowa równowaga antyoksyacyjna u pacjentów bez klinicznej manifestacji miażdżycy

Introduction. Oxidative stress plays an important role in atherosclerosis, but numerous clinical trials have not confirmed a favourable effect of antioxidant supplementation. We aimed to determine the oxidative stress parameters in patients without clinical manifestation of vascular disease. Material and methods. Forty-eight patients were divided into two groups in relation to the presence or absence of clinically silent signs of atherosclerosis (ankle-brachial index < 0.9, intima-media thickness ≥ 0.9 mm, the presence of carotid atherosclerotic plaques, silent ischaemia in a treadmill stress test or focal myocardial contractility found in echocardiography). Plasma concentrations of: retinol, ascorbic acid, alpha-tocopherol and uric acid, as well as the products of oxidative DNA damage repair: 8-oxo-7,8-dihydro-2’-deoxyguanosine (8-oxodG) in blood leucocytes and urine, and 8-oxo-7,8-dihydroguanine (8-oxo-Gua) in urine. Results. Patients with signs of subclinical atherosclerosis had lower blood concentration of alpha- tocopherol, and a non-significantly greater urine concentration of 8-oxoGua. Women had significantly greater blood concentration of ascorbic acid and alpha-tocopherol, as well as lower level of retinol and uric acid. They also had greater leucocyte concentration of 8-oxodG. Plasma concentration of alpha-tocopherol 30.34 μM distinguished patients with and without signs of subclinical atherosclerosis. Conclusions. Oxidative stress has clinical importance in the early stages of atherosclerosis and may be helpful in predicting its subclinical stage. Women had higher level of antioxidant defence, which explains their natural protection against early atherosclerosis development. Further studies are needed to determine the usefulness of tocopherol determination as a biomarker for atherosclerosis risk evaluation.

Plasma alpha-tochopherol determined by HPLC in dogs at different stages of chronic kidney disease: a retrospective study.

The aim of the present study was to investigate retrospectively the plasma concentration of alpha-tocopherol in dogs with naturally acquired chronic kidney disease (CKD), at different stages of severity. Forty dogs (CKD group) with different stages of CKD (IRIS 1 n=12, IRIS 2 n=8, IRIS 3 n=11, IRIS 4 n=9) and 20 clinically healthy dogs were considered. Plasma alpha-tocopherol was assessed in both groups through high performance liquid chromatography (HPLC). Dogs of CKD group showed significantly lower (p=0.0002) levels of plasma alpha-tocopherol compared with clinically healthy dogs. A significant difference (p<0.04) in the number of patients with plasma alpha-tocopherol > or ≤ 21.5 ppm was found in CKD patients at different stages of severity. No significant correlation between plasma levels of alpha-tocopherol and plasma creatinine was found. In the present study, dogs affected by spontaneous CKD showed significantly lower plasma concentrations of alpha-tocopherol compared with clinically healthy dogs. Plasma alpha-tocopherol deficiency seems to be more severe in IRIS stage 1 and 4, compared with IRIS stage 2 and 3. The finding of marked alpha-tocopherol deficiency in patients in IRIS stage 1 should encourage further studies on the early use of prescription renal diet and antioxidant in this group of patients.

A comparison of via of administration of the injection of vitamin E in newly received feedlot calves

Fifty Holstein steers calves (121 ± 4 kg) were used in order to determine the effects of route of administration of vitamin E at the time of arrival of feedlot cattle on levels of plasma alpha-tocopherol concentrations during the initial 16 days following their arrival into the feedlot. Ten steers served as controls, the remaining 40 steers (20 steers/treatment) were injected either intramuscular (IM) or subcutaneous (SQ) with 1500 IU of vitamin E (d-alpha tocopherol). Vitamin E treatments were administered on days 1 and 8 of the arrival, while blood samples were obtained on days 1, 4, 8, 12 and 16. Injection sites were examined visually on day 16 to determine if route of administration affected incidence of injection-site inflammation. Steers were fed a steam-flaked corn based receiving diet with a 72:28 concentrate-to-forage ratio. Plasma alpha-tocopherol concentrations of control steers remained low (range from 0.06 to 0.10 mg/dL) throughout the 16-d period. Vitamin E injection increased (P&lt;0.01) 4-fold the plasma alpha-tocopherol concentration. Route of vitamin E administration did not influence (P &gt; 0.10) the incidence of injection site inflammation, averaging 17.5% (χ2, P&gt;0.05). Plasma alpha-tocopherol concentrations were not affected (P &gt; 0.30) by the presence of injection site inflammation. Since the risk of lesions in meat are considerably higher with intramuscular application and plasma alpha-tocopherol concentrations were not different between routes of application, it is concluded that subcutaneous administration is a practical alternative to the traditional intramuscular of administration of injectable vitamin E for feedlot cattle.

Effect of anti-hyperlipidemia drugs on the alpha-tocopherol concentration and their potential for murine malaria infection.

The current preventions of malaria are protection against mosquito bites and taking chemoprophylactic anti-malarial drugs. However, drug therapies are usually associated with adverse events and emergency of drug-resistant malaria parasites. Previous study showed that host plasma alpha-tocopherol deficiency enhanced resistance against malaria infection in mice. Here, we report a new prevention strategy against malaria by using anti-hyperlipidemia drugs, ezetimibe, berberine, cholestyramine, and probucol to modify the host plasma alpha-tocopherol concentration. The drugs were mixed with diet and fed to C57BL/6J mice for 2 weeks. Although all drugs reduced plasma alpha-tocopherol concentration after 2 weeks of feeding, probucol-treated mice showed 90 % reduction and it was the lowest alpha-tocopherol concentration among the four drugs. Ezetimibe, berberine, and combination of ezetimibe and berberine pretreatment for 2 weeks were not effective against infection of Plasmodium yoelii XL17, a lethal strain, for survival and parasitemia in mice. Two-week pretreatment and 1-week treatment after infection of cholestyramine had also no effect on malaria infection. Survival rates of cholestyramine, ezetimibe, and/or berberine treated mice were 0-22 %. However, probucol caused significant decrease in parasitemia and increased in mice survival following 2-week pretreatment and 1-week treatment after infection. All control mice died while all probucol treated mice survived during the course of infection. Thus, probucol which reduced plasma alpha-tocopherol concentration was effective in enhancing the host to resist malaria infection in mice. Our finding indicates that plasma alpha-tocopherol reducing drugs like probucol might be a candidate for beneficial prevention strategy for travelers from malaria-free area.

The Oral Intake of Organic Germanium, Ge-132, Elevates α-Tocopherol Levels in the Plas-ma and Modulates Hepatic Gene Expression Profiles to Promote Immune Activation in Mice.

The common water-soluble organic germanium compound poly-trans-[(2-carboxyethyl) germasesquioxane] (Ge-132) exhibits activities related to immune responses and antioxidant induction. In this study, we evaluated the antioxidative effect of dietary Ge-132 in the plasma of mice. Male ICR mice (seven mice per group) received an AIN-76 diet with 0.05% Ge-132; three groups received the Ge-132-containing diet for 0, 1 or 4 days. The plasma alpha-tocopherol (α-tocopherol) concentration increased from 6.85 to 9.60 μg/ml after 4 days of Ge-132 intake (p<0.05). We evaluated the changes in hepatic gene expression related to antioxidative activity as well as in the entire expression profile after one day of Ge-132 intake, using DNA microarray technology. We identified 1,220 genes with altered expression levels greater than 1.5-fold (increased or decreased) as a result of Ge-132 intake, and α-tocopherol transfer protein (Ttpa) gene expression was increased 1.62-fold. Immune activation was identified as the category with the most changes (containing 60 Gene Ontology (GO) term biological processes (BPs), 41 genes) via functional clustering analysis of altered gene expression. Ge-132 affected genes in clusters related to ATP production (22 GO term BPs, 21 genes), lipid metabolism (4 GO term BPs, 38 genes) and apoptosis (5 GO term BPs). Many GO term BPs containing these categories were significantly affected by the Ge-132 intake. Oral Ge-132 intake may therefore have increased plasma α-tocopherol levels by up-regulating α-tocopherol transfer protein (Ttpa) gene expression.

Effect of the type of dietary triacylglycerol fatty acids on alpha-tocopherol concentration in plasma and tissues of growing pigs

Effect of the type of dietary triacylglycerol fatty acids on alpha-tocopherol concentration in plasma and tissues of growing pigs

Dietary Alpha-Tocopherol Affects Tissue Vitamin E and Malondialdehyde Levels but Does not Change Antioxidant Enzymes and Fatty Acid Composition in Farmed Atlantic Salmon (Salmo salar L.)

In this study the effect of increasing dietary alpha tocopherol on vitamin E tissue concentrations, lipid peroxidation (malondialdehyde), antioxidant enzymes, and fatty acid composition has been investigated in farmed Atlantic salmon. To this end fish (initial body weight ~ 193 g, n = 70 per group) were fed diets based on fish oil (27.5 %), fish meal (15.0 %), wheat gluten (20.6 %), and soy protein concentrate (24.0 %) for 14 weeks. Diets were supplemented with 0 (negative control), 150, and 400 mg/kg vitamin E as all-rac alpha-tocopheryl acetate. Dietary vitamin E did not affect feed conversion efficiency ratio but significantly (p < 0.05) increased alpha-tocopherol concentrations in salmon plasma, liver, and fillet (n = 8 per group each). The increase in fillet alpha-tocopherol was accompanied by a considerable decrease (p < 0.01) in malondialdehyde concentrations at the higher supplementation level. Furthermore, we observed an antagonistic interaction between alpha- and gamma-tocopherol in plasma at the highest supplementation level, since high dietary alpha-tocopherol reduced plasma gamma-tocopherol concentrations. Liver antioxidant enzymes, including glutathione peroxidase and superoxide dismutase, remained largely unchanged in response to dietary alpha-tocopherol. Dietary alpha-tocopherol did not affect eicosapentaenoic acid and docosahexaenoic acid concentrations in salmon fillet. Present data suggest that alpha-tocopherol supplementations beyond dietary recommendations may further improve flesh quality and nutritional value of Atlantic salmon fillet as far as malondialdehyde and vitamin E concentrations are concerned.

Antioxidants Supplementation in Elderly Cardiovascular Patients

Supplementation with antioxidants and its benefit-risk relationship have been largely discussed in the elderly population. We evaluated whether antioxidants supplementation improved the biochemical profile associated with oxidative metabolism in elderly cardiovascular patients. Patients (n = 112) received daily supplementation with α-TP 400 mg, beta-carotene 40 mg, and vitamin C 1000 mg for 2 months (treatment). Plasma concentrations of alpha-tocopherol (α-TP), β-carotene (βC), ubiquinol-10 (QH-10), glutathione, and thiobarbituric acid reactive substances (TBARS) were determined before and after treatment. Response to treatment was dependent on pretreatment α-TP and βC levels. Increase in α-TP and βC levels was observed only in patients with basal levels <18 μM for α-TP (P < 0.01) and <0.30 μM for βC (P < 0.02). Ubiquinol-10, glutathione, and TBARS were unaffected by treatment: QH-10 (+57%, F 1,110 = 3.611, P < 0.06, and N.S.), glutathione (+21%, F 1,110 = 2.92, P < 0.09, and N.S.), and TBARS (−29%, F 1,110 = 2.26, P < 0.14, and N.S.). Treatment reduced oxidative metabolism: 5.3% versus 14.6% basal value (F 1,110 = 9.21, P < 0.0003). Basal TBARS/α-TP ratio was higher in smokers compared to nonsmokers: 0.11 ± 0.02 versus 0.06 ± 0.01 (F 32,80 = 1.63, P < 0.04). Response to antioxidant supplementation was dependent on basal plasma levels of α-TP and βC. Smoking status was strongly associated with atherosclerotic cardiovascular disease and high TBARS/α-TP ratio (lipid peroxidation).

Association between the plasma proteome and plasma alphatocopherol concentrations in humans

Vitamin E has been inversely associated with chronic disease; however, the biological processes regulated by this vitamin have not been fully elucidated. The objective of the present study was to examine the association between α‐tocopherol and the plasma proteome. Subjects are from the Toronto Nutrigenomics and Health Study and include men and women (n=1,022) who completed a general health and lifestyle questionnaire and 196‐ item food frequency questionnaire and provided a fasting blood sample. Levels of α‐tocopherol were analyzed using a reversed‐phase isocratic HPLC method with fluorescent detection. Fifty‐four plasma proteins were assayed by a mass spectrometry‐based multiple reaction monitoring method. Analysis of covariance was used to compare mean concentrations of plasma proteins across tertiles of α‐tocopherol. Levels of apolipoprotein C‐III, fibrinogen alpha, beta, and gamma chains, fibronectin and fibrinopeptide A were significantly and positively associated to plasma α‐tocopherol, while intermediate levels of α‐tocopherol were significantly associated with higher levels of alpha‐1B‐glycoprotein (all P&lt;0.0009). In conclusion, circulating levels of α‐tocopherol were significantly associated with plasma proteins from several physiological pathways. This research was funded by the Advanced Foods and Materials Network.

Determination of alpha-tocopherol in plasma by high performance liquid chromatography with fluorescence detection and stability of alpha-tocopherol under different conditions.

In order to study the clinical effects of the antioxidant alpha-tocopherol (tocofersolan, CAS 30999-06-5) a simple, robust, sensitive and reliable high performance liquid chromatography (HPLC) method using fluorescence detection for the daily measurement of alpha-tocopherol concentration in plasma is described. Several methods of HPLC analysis using fluorescence techniques are published, however, investigations of the stability of alpha-tocopherol during sample preparation under different conditions are relevant in the routine measurements and have to date not been reported. Therefore a modified method, both sensitive and robust, qualified for the day-by-day measurement of alpha-tocopherol in plasma was established and the stability of alpha-tocopherol during sample preparation was analysed under different conditions. This method enables the complete separation of alpha-tocopherol from other compounds within 14 min. In addition, investigations on the stability of alpha-tocopherol during sample preparation showed the necessity of rapid sample preparation without delay. Prepared samples can be stored in liquid nitrogen for at least 56 days.

The Relationship between Plasma alpha-Tocopherol Concentration and Vitamin E Intake in Patients with Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (DM2) predisposes to an increased production of free radicals and a probable reduction in plasma antioxidants, including vitamin E. This cross-sectional study investigated the relationship between plasma alpha-Tocopherol concentration and vitamin E intake in 58 Brazilians with DM2. Plasma alpha-Tocopherol was determined by high-performance liquid chromatography. The intake of vitamin E-rich foods was assessed by a food frequency questionnaire. Total cholesterol and fractions were measured by colorimetric enzymatic methods. Data on demographic and socioeconomic factors, life habits, and anthropometry were obtained by a questionnaire and physical examination. The association between plasma alpha-Tocopherol and vitamin E intake was assessed by multiple linear regression analysis. The following variables were included in the regression model: alpha-Tocopherol, vitamin E intake, total cholesterol and fractions, body mass index, waist circumference, gender, age, education, occupation, income, smoking, alcohol intake, and blood pressure. There was no association between alpha-Tocopherol and vitamin E intake, but there were significant associations between alpha-Tocopherol and total cholesterol (p < 0.001) and waist circumference (p = 0.003). There were 36.2 % diabetics with low alpha-Tocopherol concentrations (< 12 µmol/L) and 32.7 % with a low alpha-Tocopherol/total cholesterol ratio (< 2.2). Further large, epidemiological, longitudinal studies, including measurements of gamma-tocopherol in blood, should be conducted to confirm our results.

Impact of Lipophilic Antioxidants and Level of Antibodies Against Oxidized Low-Density Lipoprotein in Polish Children with Phenylketonuria

The treatment of phenylketonuria (PKU) patients constitutes a phenylalanine (Phe) intake restriction in their diet, which is achieved by adding a special Phe-free amino acid mixture to the diet. It has been reported that this diet could have some micronutrient deficiency. Several authors have also reported an increased oxidative stress or impaired antioxidant status in human and experimental PKU. Our project assessed the concentrations of retinol, alpha-tocopherol, coenzyme Q10, and anti-oxidized low-density lipoprotein (ox-LDL) antibodies in PKU children's plasma. It was found that retinol concentration in PKU children remains within the norm despite a low intake. The lower plasma alpha-tocopherol concentration in PKU children compared with normal children was associated with the lower level of antibodies against ox-LDL. This raises the question whether higher than observed circulatory alpha-tocopherol is indeed beneficial to lower plasma ox-LDL levels. Further studies are needed to explain the genetic factor in PKU patients (e.g., CD36/FAT polymorphism gene). The open clinical question is whether daily supplementation of alpha-tocopherol changes the PKU patients' level of antibodies against ox-LDL.

Physical Activity, Antioxidant Status, and Protein Modification in Adolescent Athletes

Exercise may increase reactive oxygen species production, which might impair cell integrity and contractile function of muscle cells. However, little is known about the effect of regular exercise on the antioxidant status of adolescents. This study aimed to evaluate the impact of exercise on the antioxidant status and protein modifications in adolescent athletes. In 90 athletes and 18 controls (16 +/- 2 yr), exercise-related energy expenditure was calculated on the basis of a 7-d activity protocol. Antioxidant intake and plasma concentrations of alpha-tocopherol, carotenoids, and uric acid were analyzed. Plasma antioxidant activity was determined by Trolox equivalent (TE) antioxidant capacity and electron spin resonance spectrometry. Protein modifications were assessed with structural changes of transthyretin using a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Data were analyzed by two-way ANOVA and post hoc by the Tukey-Kramer test (alpha = 0.05). Antioxidant intake correlated with energy intake and was within the recommended daily allowance for vitamins C and E and beta-carotene. Plasma levels of neither nutritional antioxidants nor uric acid differed between the groups. TE antioxidant capacity was higher in athletes (men = 1.47 +/- 0.2 mmol TE per liter, women = 1.45 +/- 0.2 mmol TE per liter) compared with controls (men = 1.17 +/- 0.04 mmol TE per liter, women = 1.14 +/- 0.04 mmol TE per liter) and increased with exercise-related energy expenditure (P = 0.007). Transthyretin cysteinylation rate differed between the groups, with the highest rate of protein modifications in moderately active subjects (P = 0.007). Results suggest that if the nutritional choice of athletes is well balanced, enough antioxidants are provided to meet recommended amounts. Moreover, regular exercise increases blood antioxidant capacity in young athletes, whereas chronic exercise was not shown to promote protein modifications. Thus, in young athletes who are sufficiently supplied with antioxidants, beneficial effects of exercise on antioxidant status rather than on oxidative stress may be anticipated.

Dietary flavonoids do not affect vitamin E status in growing rats

This study aimed at investigating potential effects of the flavonoids genistein, quercetin and catechin and the role of co-ingested dietary fat on vitamin E concentrations in rats. In experiment 1, genistein, quercetin and catechin were fed to rats, incorporated into semisynthetic diets at concentrations of 2 g/kg, either as individual compounds or in combination to investigate their individual and possible synergistic actions towards alpha-tocopherol in plasma and selected tissues. For experiments 2 and 3, quercetin was selected as a representative model flavonoid to study the effects of the quantity (5% vs. 10%) and type of dietary fat (coconut fat plus corn oil vs. rapeseed oil; experiment 2) and the role of cholesterol (experiment 3) on potential flavonoid-vitamin E interactions. The concentrations of alpha-tocopherol and gamma-tocopherol in the plasma, liver, lung and cortex of flavonoid-fed rats were not significantly different from the concentrations measured in control rats in all three experiments. However, increasing the amount of coconut fat plus corn oil from 5 to 10% resulted in lower alpha-tocopherol concentrations in plasma and tissue. The alpha-tocopherol concentrations in the rats fed rapeseed oil were significantly higher than in rats fed coconut fat plus corn oil. The addition of 0.2% cholesterol to the diet did not influence the tocopherol concentrations in plasma and tissue in both quercetin-supplemented and control rats. Additionally, the mRNA levels of alpha-TTP, CYP3A4, CYP4F and Mdr2, which are integral proteins involved in vitamin E homeostasis were measured. Only genistein reduced the Mdr2 mRNA level, but none of the other transcripts. All other flavonoids were without effect. In conclusion, co-ingested dietary fat appears to influence vitamin E concentrations in rats, but does not seem to be an important determinant of flavonoid-vitamin E interactions.