Plasma Tocopherol Concentrations Research Articles

Effects of multiple vitamin E levels and two fat sources in diets for swine fed to heavy slaughter weight of 150 kg: II. Tissue fatty acid profile, vitamin E concentrations, immune capacity, and antioxidant capacity of plasma and tissue.

The study objective was to evaluate the effect of two fat sources and graded levels of vitamin E (VE) supplementation on tissue fatty acid profile, VE concentrations, immune capacity, and antioxidant capacity of plasma and tissues of pigs at heavy slaughter weight (150 kg). A total of 48 individually-fed pigs (24 barrows, 24 gilts; 28.44 ± 2.69 kg) were randomly assigned to eight dietary treatments in a 2 × 4 factorial arrangement. The two fat treatments were either 5% tallow (TW) or 5% distiller's corn-oil (DCO). The VE treatments included four levels of α-tocopheryl-acetate (11, 40, 100, and 200 ppm). Compared to pigs fed the DCO diet, pigs fed the TW diet had greater SFA (C14, C16, and C18; P < 0.05) and MUFAs (C14:1, C16:1, C18:1, and C20:1; P < 0.05), lower PUFA (C18:2n-6, C18:3n-3, C20:2, C20:3, and C20:4; P < 0.05) and iodine value in the backfat and belly fat. Increasing dietary VE supplementation level increased α- and total tocopherol concentrations in plasma (linear and quadratic, P < 0.05), liver, and loin muscle (linear, P < 0.06), superoxide dismutase activity (quadratic, P < 0.05), but decreased γ-tocopherol concentrations in liver (linear, P = 0.06), plasma, and loin muscle (quadratic, P < 0.07), and decreased liver glutathione disulfide (GSSG; linear, P = 0.07) and malondialdehyde (MDA) content (quadratic, P < 0.05). There was an interaction between fat sources and dietary VE supplementation level on the concentration of α-tocopherol in the loin muscle (P < 0.05) wherein a greater increase was observed in the TW treatment than the DCO treatment with the increasing dietary VE supplementation level. In conclusion, dietary FA composition in TW and DCO affected the composition of most FA in backfat, belly fat, and liver while increasing VE supplementation level did not significantly alter the FA profile in these tissues. Increasing dietary VE supplementation level increased tocopherol concentrations in plasma, liver and loin muscle, and improved antioxidant capacity while tocopherol concentrations in plasma, liver and loin muscle in the TW treatment increased more than they did in the DCO treatment.

The Vitamin A and E Forms Influence Differently the Plasma Vitamin Concentrations in Newly Received Calves

Ten Holstein steer calves (105±3 kg) were used to evaluate bioavailability of two Vitamin A or E forms, “natural” (EA1) or “synthetic” (EA2), based on plasma vitamin concentrations during a 3-d period post injection(subcutaneous). Plasma retinyl palmitate and plasma Vitamin A concentration (retinol equivalent of all forms) was greater 24 and 48 h (P<0.01) post injection of retinyl palmitate vs retinyl propionate. Likewise, plasma retinol was greater (P = 0.04) 72 h post injection of retinyl palmitate. Plasma retinyl propionate was undetected for either treatment, indicative that it is not absorbed as a parent compound. Plasma retinyl palmitate, retinol and total Vitamin A concentrations peaked 24 h (P<0.01) post injection, decreasing toward baseline levels by 72 h post injection. Plasma tocopherol concentration was greater 24 h post injection (P<0.01) for calves injected with D-α-tocopherol vs DL-α-tocopherol. Levels were not different among treatments 48 h post injection (P>0.10). Plasma tocopherol concentrations were maximal (P<0.01) 24 h post injection of D-α-tocopherol, promptly decreasing by 72 h post injection (a level comparable to that observed with DL-α-tocopherol injection). We concluded that based on plasma concentrations, bioavailability of parenterally supplemented retinyl palmitate and D-α-tocopherol are greater than that of retinyl propionate and DL-α-tocopherol under acute Vitamin A or E supplementation.

Tissue and plasma antioxidant status in response to dietary methionine concentration and source in broilers.

This study hypothesized that plasma and tissue antioxidant status of broilers is positively influenced when dietary Met concentrations exceed, and negatively when they go below NRC recommendations. In addition, different Met sources are hypothesized to affect the antioxidant defence system differently. Day-old male Cobb-500 broilers (n=336) were allotted to seven groups and phase-fed three wheat-soya bean meal-based basal diets during days 1-10, 11-21 and 22-35. The basal diets (Met- group, Met+Cys concentration 15% below NRC recommendations) were supplemented with 0.10%, 0.25% or 0.40% Met either as DL-Met (DLM) or DL-2-hydroxy-4-(methylthio) butanoic acid (DL-HMTBA) (equimolar comparison). Growth performance and carcass weights were lower in the Met- group compared to the groups whose diets met or exceeded Met requirements. The antioxidant defence system was not influenced by the Met source. However, in the liver, concentrations of glutathione increased with increasing dietary Met concentrations. Tocopherol concentrations in the liver at days 10 and 21 were lower in the Met- group than in the groups supplemented with Met. However, liver concentrations of thiobarbituric acid reactive substances (TBA-RS) and protein carbonyls (PC) were largely not influenced by dietary Met concentration. Plasma tocopherol concentrations at day 35 were lower, and those of TBA-RS and PC at day 35 were higher in Met- group than in the groups fed the Met-supplemented diets. In jejunum, but not in liver, relative mRNA abundances and activities of superoxide dismutase, catalase and glutathione peroxidase were higher in the Met- group than in the groups fed Met-supplemented diets. These data indicate that suboptimum supply of Met results in decreased antioxidant concentrations in plasma and body tissues, and increases oxidative stress in the jejunum mucosa. However, supplementation of Met in excess of the requirements (based on NRC) compared to diets adequate in Met+Cys did not influence the antioxidant defence system.

Influence of supplemental tocopherol level (0, 250 and 500 IU RRR-α-tocopherol/d/steer) and injectable retinol form (retinyl propionate vs retinyl palmitate) on growth performance, carcass characteristics and plasma concentration in calf-fed Holstein steers

ABSTRACTThe influence of supplemental tocopherol level (0, 250 and 500 IU RRR-α-tocopherol/d/steer) and injectable retinol form (retinyl propionate vs retinyl palmitate) on growth performance, carcass characteristics and plasma tocopherol and retinol concentrations were evaluated in 108 Holstein steers fed a steam flaked corn-based finishing diet during 314-d feeding period. There were no treatment interactions (P > 0.10). During the initial 112-d period, dietary supplemental tocopherol tended to increase ADG (linear, P = 0.07) and DMI (linear, P = 0.06). Overall 314-d ADG, DMI, gain efficiency and carcass characteristics were not affected (P > 0.10) by dietary supplemental tocopherol. Overall DMI tended to be greater (3%, P ≤ 0.10) for steers injected with retinyl palmitate vs retinyl propionate. It is concluded that vitamin E supplementation above basal requirements may enhance growth performance during the initial 112-d phase. However, the overall effect on growth performance and carcass characteristics was not appreciable. Injectable retinol ester form did not affect overall ADG, gain efficiency, or dietary NE. Based on plasma retinol concentrations, the bioavailability of retinyl palmitate is greater than that of retinyl propionate.

Plasma Retinol Concentration Is Mainly Driven by Transthyretin in Hemodialysis Patients

Micronutrients deficiencies in hemodialysis patients are due to low dietary intakes and intradialytic losses for hydrophilic micronutrients. Conversely, lipophilic nondialyzable compounds might accumulate because of a lack of elimination through renal metabolism or dialysis. Other compounds have complex metabolism: their concentration is not explained by these phenomenons. The aim of this study was to report plasma concentrations of lipophilic micronutrients in hemodialysis patients and to analyze if these concentrations were predictive of mortality. The design was monocentric observational longitudinal study. A total of 123 hemodialysis patients included in this observational study. Plasma concentration of lipophilic micronutrients retinol and its two co-transporters transthyretin and retinol-binding protein 4, tocopherol, and carotenoids (α-carotene and β-carotene, β-cryptoxanthin, lycopene, lutein, and zeaxanthin), and all factors associated with 1-year mortality. Within the 123 patients of the study, median age (interquartile range) was 77.5 (69.5-84.5) years and 58.5% were male. Median retinol plasma concentration was 4.07 (2.65-5.51)μmol/L, and 91.9% of patient had high plasma retinol concentrations. In monovariate analysis, retinol levels were inversely correlated with mortality (hazard ratio=0.57 [0.45-0.72]; P<.001). This effect remained significant after adjustment with several parameters. Nevertheless, the correlation between retinol and mortality disappeared as soon as transthyretin was added in the statistical model, suggesting an effect of transthyretin as confusing bias. Median tocopherol plasma concentration was 34.8 (28.3-42.9)μmol/L and 72.4% of patients had high plasma tocopherol concentration. Neither tocopherol plasma levels nor carotenoids concentrations were correlated with death in multivariate analysis. In hemodialysis patients, the correlation between retinol plasma concentration and mortality represents the nutritional status but not a direct biological effect of retinol. Retinol is only a surrogate predictor of mortality. It might not represent vitamin A levels, but likely the transthyretin level. Plasma retinol levels should be interpreted cautiously in hemodialysis patients.

Evaluation of supplemental vitamin E on 56-day feedlot growth performance and plasma tocopherol concentrations in calf-fed Holstein steers

ABSTRACTFifty-four Holstein steer calves, divided in two weight groupings (141.2 ± 4.9 kg and 454.2 ± 7.0 kg respectively), were used in a 56-day study to evaluate the influence of supplemental vitamin E on growth performance and plasma vitamin concentrations. Steers were assigned within body weight groupings to 18 pens, 3 steers/pen. Dietary treatments consisted of a steam-flaked corn-based growing-finishing diet supplemented to provide 0, 250, or 500 IU/d of vitamin E as all racemic α-tocopherol. No morbidity was apparent during the course of the study. Calves in the heavier weight grouping had greater average daily gain (24.4%, P < .01), dry matter intake (54.3%, P < .01), and lower gain efficiency (40.7%, P < .01). Vitamin E supplementation did not affect (P > .10) feedlot growth performance. Initial and 56-day plasma tocopherol were not influenced (P > .10) by weight grouping. Final 56-day plasma tocopherol increased linearly (P < .01) with level of vitamin E supplementation. Plasma tocopherol of non-supplemented steers decreased (P = .01) from an average initial concentration of 1.66–1.16 ug/mL at day 56. It is concluded that vitamin E supplementation of calf-fed Holstein steers receiving a conventional steam-flaked corn-based growing-finishing diet is not expected to enhance growth performance.

Vitamin E status of 20- to 59-year-old adults living in the Seoul metropolitan area of South Korea.

BACKGROUND/OBJECTIVESVitamin E is a fat-soluble vitamin and functions primarily as a lipid antioxidant. Inadequate vitamin E status may increase risk of several chronic diseases. Thus, the objectives of this study were to estimate intake and plasma concentration of each tocopherol and to evaluate vitamin E status of Korean adults.SUBJECTS/METHODSThree consecutive 24-h food recalls and fasting blood samples were collected from healthy 20- to 59-y-old adults (33 males and 73 females) living in the Seoul metropolitan area, South Korea. α-, β-, δ-, and γ-tocopherol intakes and plasma concentrations of tocopherols (α-, δ-, and γ-tocopherol) were analyzed by gender.RESULTSDietary vitamin E and total vitamin E intake (dietary plus supplemental vitamin E) was 17.68 ± 14.34 and 19.55 ± 15.78 mg α-tocopherol equivalents, respectively. The mean daily α-tocopherol, and γ-tocopherol intakes were 3.07 ± 2.27 mg and 5.98 ± 3.74 mg, respectively. Intakes of total vitamin E and each tocopherol of males were significantly higher than those of females (P < 0.05). Plasma α-tocopherol concentration was 15.45 ± 10.16 of males and 15.00 ± 4.54 µmol/L of females, respectively. There were no significant differences in plasma tocopherol concentrations by gender (P ≥ 0.05). Plasma α-tocopherol was negatively correlated with γ-tocopherol intake (P < 0.05). Twenty-three percent of the subjects had plasma α-tocopherol concentrations < 12 µmol/L indicating a biochemical deficiency of vitamin E. Approximately 8% and 9% of these participants had plasma α-tocopherol:total lipid ratio less than 1.59 µmol/mmol and plasma α-tocopherol:total cholesterol ratio less than 2.22 µmol/mmol, respectively, which are also indicative of vitamin E deficiency.CONCLUSIONSVitamin E intakes of Korean adults were generally adequate with the Korean Dietary Reference Intakes for vitamin E. However, α-tocopherol intake was lower than that reported in other countries, and 23% of the subjects in the current study were vitamin E deficient based on plasma α-tocopherol concentrations.

Dietary lipids reduce the expression of carotenoid-based coloration in Lacerta vivipara

1. The importance of dietary lipids for carotenoid-based ornaments has rarely been investigated, although theory predicts that dietary lipids may control the development of these widespread animal signals. Dietary lipids have been suggested to enhance the expression of male carotenoid-based ornaments because they provide carotenoids with a hydrophobic domain that facilitates their absorption and transport. Dietary lipids may also enhance the uptake of tocopherols (vitamin E), which share common absorption and transport routes with carotenoids. Here, we test whether dietary lipids enhance carotenoid availability and male carotenoid-based colorations. We also explore the effects of dietary lipids on plasma tocopherol concentration, which allow disentangling between different pathways that may explain how dietary lipids affect ornamental expression. 2. Following a two-factorial design, we manipulated dietary access of naturally occurring fatty acids (oleic acid) and carotenoids (lutein and zeaxanthin) and measured its effects on the circulating concentrations of carotenoids (lutein and zeaxanthin) and vitamin E (α- and γ-(β-) tocopherols) and on the ventral, carotenoid-based coloration of male common lizards (Lacerta vivipara). 3. Lutein but not zeaxanthin plasma concentrations increased with carotenoid supplementation, which, however, did not affect coloration. Lipid intake negatively affected circulating concentrations of lutein and γ-(β-) tocopherol and led to significantly less orange colorations. The path analysis suggests that a relationship between the observed colour change and the change in plasma concentrations of γ-(β-) tocopherol may exist. 4. Our study shows for the first time that dietary lipids do not enhance but reduce the intensity of male carotenoid-based ornaments. Although dietary lipids affected plasma carotenoid concentration, its negative effect on coloration appeared to be linked to lower vitamin E plasma concentrations. These findings suggest that a conflict between dietary lipids and carotenoid and tocopherol uptake may arise if these nutrients are independently obtained from natural diets and that such conflict may reinforce signal honesty in carotenoid-based ornaments. They also suggest that, at least in the common lizard, sexual selection with respect to carotenoid-based coloration may select for males with low antioxidant capacity and thus for males of superior health.

Dietary intakes and plasma concentrations of tocopherols of 20–59 y old adults in South Korea

To determine dietary intakes and plasma concentrations of tocopherols and to evaluate vitamin E status of Korean adults, three consecutive 24‐h food recalls and fasting blood samples were collected from healthy 20–59 y old adults (33 males and 73 females) living in Seoul and Gyeonggi areas, South Korea. The daily vitamin E, alpha‐tocopherol, and gamma‐tocopherol intakes (mean/SD) were 3.84/2.84 mg alpha‐tocopherol equivalents, 3.07/2.27 mg, and 5.98/3.74 mg, respectively. Only 3.7% of the subjects consumed vitamin E &gt; the Korean Adequate Intakes for vitamin E. The plasma alpha‐tocopherol concentration was 15.14/6.84 umol/L. There were no significant differences in tocopherol intakes and plasma tocopherol concentrations among the age groups (P&gt;=0.05). Twenty‐three percent of the subjects had plasma alpha‐tocopherol concentrations &lt;12 umol/L, which is indicative of vitamin E inadequacy status. Approximately 8% and 9% had plasma alpha‐tocopherol to total cholesterol + triglyceride &lt;1.59 umol/mmol and alpha‐tocopherol to total cholesterol &lt;2.22 umol/mmol, respectively, which are also indicative of vitamin E deficiency. In conclusion, most of these Korean adults had inadequate vitamin E intakes, and one‐quarters were in vitamin E deficient status. Supported by 2010 research fund of National Research Foundation of Korea (20100017207).

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.

Changes in Plasma Composition of Japanese Black Steers During Grazing and Fattening Periods

Nakamura, Y.-N., Orito, H., Tsuneishi, E., Hirano, K., Kato, N., Shoji, A., Kamiya, M. and Nakanishi, Y. 2008. Changes in plasma composition of Japanese black steers during grazing and fattening periods. J. Appl. Anim. Res., 34: 157–161. The plasma compositions of five Japanese black steers during about 23 months of grazing and fattening period of about 6 months were investigated. Plasma A/G, LDH, Glu, tCho and Ins concentrations increased (P<0.05), whereas TG, UNandNEFA concentrations decreased (P<0.05) during the fattening period. Plasma Na concentration increased (P<0.05) during the fattening period. Plasma Bβ-carotene and tocopherol concentrations decreased (P<0.05) during the fattening period. Changes in plasma chemical composition during grazing and fattening were related to the chemical composition of the feed consumed and lack of exercise during housing.

Vitamin E Inadequacy Observed in a Group of 2- to 6-Year-Old Children Living in Kwangju, Republic of Korea

Studies on the vitamin E status of Korean children are lacking. Dietary intakes and plasma concentrations of tocopherols of healthy 2- to 6-year-olds living in Kwangju, Republic of Korea, were determined and their vitamin E status evaluated. Subjects included 66 girls and 65 boys, with 21-32 subjects per age group. Subjects' intakes were recorded by a trained interviewer for foods eaten at preschool/kindergarten; otherwise, three consecutive 24-hour food recalls were obtained from parents. Plasma tocopherol concentrations were determined using high-performance liquid chromatography. Intakes of energy and total monounsaturated and polyunsaturated fats were significantly different (p < 0.05) among age groups, not gender, with 2- and 3-year-olds having lower intakes. Alpha- and gamma-tocopherol intakes were similar by age and gender. Sixty-seven percent consumed less than the Korean Adequate Intakes for vitamin E, and 77% had Alpha-tocopherol intakes less than USA/Canadian Estimated Average Requirements. Plasma alpha-tocopherol concentrations, but not gamma-tocopherol, were significantly higher (p < 0.05) for 2-year-olds. Two-thirds of subjects had plasma alpha-tocopherol concentrations less than 12 micromol/L, which is indicative of vitamin E inadequacy in adults; guidelines for children do not exist. Many of the Korean children had inadequate intakes and likely inadequate plasma concentrations of vitamin E.

Effects of mixed tocopherol versus alpha-tocopherol supplementation on tocopherol concentrations in plasma and buccal mucosal cells

Effects of mixed tocopherol versus alpha-tocopherol supplementation on tocopherol concentrations in plasma and buccal mucosal cells

Dietary intakes and plasma concentrations of tocopherols of 2‐6 y old children in Republic of Korea

To determine dietary intakes and plasma concentrations of tocopherols and to evaluate vitamin E status of Korean children, three consecutive 24-h food recalls and fasting blood samples were obtained from healthy children (n=131, 66 girls and 65 boys), aged 2–6 y, living in Kwangju, Republic of Korea. Twenty-one subjects were aged 2 y; 25, 3 y; 31, 4 y; 32, 5 y; and 22, 6 y. Dietary kcal, total fat, monounsaturated and polyunsaturated fat, but not saturated fat, were significantly different (P<0.05) among the age groups, but not by gender. Alpha-tocopherol intakes, but not gamma- and delta-tocopherol, for the 3 y age group were significantly different (P<0.05) from those of other groups. Sixty-seven percent consumed less than the Adequate Intakes for vitamin E of the Republic of Korea. Seventy-six percent of the subjects had alpha-tocopherol intakes less than the US/Canadian Estimated Average Requirements for vitamin E. Plasma alpha-tocopherol concentrations, but not gamma- or delta- tocopherol, were significantly higher (P<0.05) for the 2 y group as compared to other age groups; plasma tocopherol concentrations were similar by gender. Two-thirds of the subjects had plasma alpha-tocopherol concentrations less than 12 μmol/L, which is indicative of vitamin E inadequacy. Many of these Korean children had inadequate vitamin E status. Supported by the University of Nebraska Agricultural Research Division.

Vitamin E: maternal concentrations are associated with fetal growth

Few data exist on the effects of the 2 most abundant isomers of vitamin E (alpha- and gamma-tocopherols) on fetal growth. We measured maternal plasma concentrations of alpha- and gamma-tocopherols and examined their relation with measures of fetal growth. We also examined the relation, controlled for associated maternal factors, of diet and supplement use to tocopherol concentrations at week 28 of gestation. A cohort of 1231 gravid women from Camden, NJ, was studied from entry to care (16.0 +/- 0.15 wk gestation); plasma tocopherol concentrations were measured at entry and at week 28. Plasma concentrations of alpha-tocopherol at entry and at week 28 were positively related to increased fetal growth (birth weight for gestation), a decreased risk of small-for-gestational-age births, and an increased risk of large-for-gestational-age births. Concentration of alpha-tocopherol at week 28 was positively related to use of prenatal multivitamins and dietary intake of vitamin E; concentration of gamma-tocopherol was related positively to dietary fat intake and negatively to multivitamin use. Early and late circulating concentrations of alpha-tocopherol are positively associated with fetal growth.

A pecan-enriched diet increases γ-tocopherol/cholesterol and decreases thiobarbituric acid reactive substances in plasma of adults

Consumption of nuts is associated with a reduced risk of coronary heart disease, and dietary intervention studies incorporating pecans show improved lipid profiles. The unsaturated fats in pecans are protected against oxidation by the high concentrations of γ-tocopherol and polymeric flavanols. The aim of this study was to determine whether plasma concentrations of tocopherols and measures of antioxidant capacity and of oxidative stress are affected by incorporation of pecans in the diet. In a randomized, controlled, crossover feeding study, 24 subjects were assigned to 2 diets, each for 4 weeks: a control diet and a pecan-enriched (20% of energy) diet. Cholesterol-adjusted plasma γ-tocopherol increased by 10.1% ( P < .001), α-tocopherol decreased by 4.6% ( P < .001), and malondialdehyde concentrations measured as thiobarbituric acid reactive substances decreased by 7.4% ( P < .05) on the pecan diet. No changes were observed for ferric-reducing ability of plasma or Trolox equivalent antioxidant capacity values. These data provide some evidence for potential protective effects of pecan consumption in healthy individuals.

Vitamins C and E in adolescents and young adults with HIV infection

Oxidative stress during HIV infection may impair immune function, cause more rapid disease progression, and increase requirements for dietary antioxidants such as vitamins C and E. The study had 2 principal objectives. The first was to ascertain whether HIV infection and immune activation were associated with lower plasma concentrations of ascorbate, urate, and alpha- and gamma-tocopherols and with total antioxidant status (TAS). The second objective was to ascertain whether these antioxidants were associated with protection against oxidative damage. This was a cross-sectional study involving 241 HIV-positive and 115 HIV-negative subjects aged 14-23 y. Subjects were primarily female (76%) and African American (70%), and 21% were Hispanic. Plasma ascorbate was significantly lower, but gamma-tocopherol and TAS were significantly higher in subjects with HIV infection when the analysis was adjusted for dietary intake and sex. Plasma alpha-tocopherol did not differ significantly by HIV status. Plasma gamma-tocopherol also was higher in subjects with oxidative damage than in those without such damage. More than 90% of subjects had adequate plasma concentrations for both ascorbate and alpha-tocopherol, although alpha-tocopherol concentrations were lower than expected on the basis of third National Health and Nutrition Examination Survey data. Low plasma ascorbate concentrations in HIV-positive subjects suggest that vitamin C requirements are significantly higher in those with HIV infection. Plasma tocopherol concentrations were not depressed by HIV infection and may be maintained by compensatory mechanisms such as the activity of alpha-tocopherol transfer protein.

Effects of LDL‐immunoapheresis on plasma concentrations of vitamin E and carotenoids in patients with familial hypercholesterolemia

Recently very potent extracorporeal cholesterol-lowering treatment options have become available for patients with hypercholesterolemia. LDL immunoapheresis treatment selectively removes LDL and lipoprotein(a) from the circulation. Since LDL is the major carrier of lipophilic antioxidants in plasma, the purpose of the present study was to assess the effects of a single LDL apheresis treatment on plasma concentrations of tocopherols (alpha- and gamma-tocopherol) and carotenoids (alpha- and beta-carotene, zeaxanthin, cryptoxanthin, canthaxanthin, lycopene, and retinol). Plasma antioxidant concentrations were determined by HPLC in 7 patients with familial hypercholesterolemia before and after LDL immunoapheresis treatment. Plasma concentrations of both alpha- and gamma-tocopherol and the different carotenoids were significantly reduced by LDL apheresis. However, when standardized for cholesterol to adjust for cholesterol removal, alpha- and gamma-tocopherol, retinol, and the more polar carotenoids lutein and zeaxanthin increased in response to apheresis treatment, while the more unpolar carotenoids such as beta-carotene and lycopene did not change. These data demonstrate that a single LDL immunoapheresis treatment affects tocopherols and individual carotenoids differently. This may be explained by differences in chemical structure and preferential association with different lipoproteins. These results further imply that tocopherols, lutein, zeaxanthin, and retinol, are associated in part with lipoproteins and other carriers such as retinol-binding protein that are not removed during apheresis treatment.

Bakery Products Enriched with Phytosterol Esters, α-Tocopherol and β-Carotene Decrease Plasma LDL-Cholesterol and Maintain Plasma β-Carotene Concentrations in Normocholesterolemic Men and Women

The hypocholesterolemic effects of phytosterols have not been evaluated in bakery products, and the addition of liposoluble antioxidants to the carrier has never been tested. We investigated the effects of consuming croissants and magdalenas (Spanish muffins) enriched with sterol esters, alpha-tocopherol and beta-carotene on plasma lipid and fat-soluble antioxidant concentrations in normocholesterolemic, habitual consumers of bakery products following their usual diet and lifestyle. Using a randomized, double-blind, placebo-controlled design, the control (C) group (n = 29) received two pieces daily (standard croissant and muffin) and the sterol ester (SE) group (n = 28), the same products with sterol esters added (3.2 g/d) for 8 wk. Total and LDL cholesterol (LDL-C) decreased in the SE group by 0.24 mmol/L (P < 0.01) and 0.26 mmol/L (P < 0.005), respectively, whereas these variables did not change in the control group. The total difference in total and LDL-C changes between groups was 0.38 mmol/L (8.9%) and 0.36 mmol/L (14.7%), respectively (P < 0.001). Within-group changes in HDL cholesterol, triacylglycerol or lipoprotein(a) concentrations did not differ. Similarly, within-group changes over time in plasma tocopherol and carotenoid concentrations did not differ between groups. Our findings suggest that bakery products are excellent carriers for phytosterols, and their consumption is associated with a decrease in total and LDL-C concentrations, with no changes in alpha-tocopherol and beta-carotene. The ability of bakery products to include sufficient quantities of beta-carotene to compensate for a potential deficiency, and the fact that their efficacy was not associated with the time of day at which they were consumed, are interesting findings.

Does a 100-km walking affect indicators of vitamin status?

The status of thiamin (B1), riboflavin (B2), ascorbic acid (AA), and tocopherol was determined in 60 leisure athletes (age 46 +/- 10 y, BMI 23.7 +/- 2.0 kg.m-2, VO2max 39.4 +/- 6.5 ml.min-1.kg-1), who completed a 100-km walking race. Vitamin plasma levels and activities of erythrocyte transketolase (ETK) and glutathione reductase (EGR) were measured before start, immediately after finishing and 6 hours later. The participators finished the entire distance in 14.25 h (average speed 7 km.h-1). Before start, all participators showed an excellent vitamin status (prevalences of low vitamin status ranged between 1.7 and 1.8%). Plasma tocopherol concentrations correlated significantly with increased age (r = 0.35, p = 0.008). Compared to the values before start, plasma concentrations of B1 and B2 as well as ETK and/or EGR were increased significantly after finishing. The raised levels persisted 6 hours after finishing, whereas AA remained unaltered. The univariate analysis of variance revealed that the change in vitamin status after finish and 6 hours later was in part highly dependent on age, BMI and the level of physical fitness. Despite the long distance, the extensive character of the 100-km walking with its low intensity did not deteriorate the measured indicators of vitamin status.