Dietary soya intake alters plasma antioxidant status and lipid peroxidation in postmenopausal women with the metabolic syndrome

Postmenopausal women with the metabolic syndrome are at high risk of oxidative stress. Several studies have suggested possible antioxidant properties of soya, but little evidence is available regarding the effect of soya on oxidative stress in postmenopausal women with the metabolic syndrome. The objective of the present study was to determine the effects of soya consumption on plasma total antioxidant capacity (TAC) and malondialdehyde (MDA) level in postmenopausal women with the metabolic syndrome. A randomised cross-over trial was undertaken on forty-two postmenopausal women with the metabolic syndrome. Participants were randomly assigned to consume a control (Dietary Approaches to Stop Hypertension; DASH) diet, a soya protein diet, or a soya nut diet, each for 8 weeks. Red meat in the DASH diet (one serving per d) was replaced by soya protein in the soya protein period and by soya nuts in the soya nut period. Significant differences between the end values of the control diet, soya protein diet and soya nut diet were seen for MDA (0.70, 0.64 and 0.63 mumol/l; global P < 0.01). The results also showed a significant difference between the end values for TAC (1950, 2030 and 2110 mumol/l, respectively; P < 0.01). The difference from control for TAC was +4.5 % (P < 0.01) in the soya nut period and +5.8 % (P < 0.01) in the soya protein regimen. Both soya nuts and soya protein decreased MDA significantly compared with the control diet (difference from control was - 7.9 % (P < 0.01) in the soya nut period and - 9.4 % (P < 0.01) in the soya protein diet). We conclude that soya consumption reduces plasma MDA and increases plasma TAC levels in postmenopausal women with the metabolic syndrome.     

Effects of alpha-tocopherol on oxidative status and metabolic profile in overweight women

Despite extensive research, the effects of alpha-tocopherol supplementation remain controversial. Few studies have been focused on obese and overweight people. We examined the effects of alpha-tocopherol (AT) on the oxidative status and metabolic profile in overweight women. Sixteen overweight women between the ages of 40-60 years old, received AT, 800 IU/day during 12 weeks, followed by a 6-week washout period. Blood samples were taken at the beginning and then every 6 weeks until the end of the study. AT, retinol, malondialdehyde (MDA), total antioxidant status (TAS), selenium-dependent glutathione peroxidase (GPx) and CuZn-superoxide dismutase (SOD) were quantified to evaluate the oxidative stress. The metabolic profile was estimated by measuring glycated hemoglobin (HbA1c) in erythrocytes and glucose, phosphate, magnesium, lipid and lipoprotein concentrations in serum. Under AT administration HbA1c, serum- MDA levels and erythrocyte GPx activity were markedly reduced. TAS, AT and Mg2+ concentrations in serum and SOD activity in erythrocytes were higher after AT treatment. Body weight; glucose, lipid and retinol concentrations, or blood cells count were unchanged. Lipid peroxidation was considerably reduced in AT treated women and also improved serum antioxidant status was observed, but the imbalanced response between erythrocyte SOD and GPx activities could affect normal response to oxidative stress.     

Effect of long-term fish oil supplementation on vitamin E status and lipid peroxidation in women.

Fifteen young (22-35 y) and 10 older (51-71 y) women received six capsules of fish oil (Pro-Mega)/d, providing a total of 1,680 mg eicosapentaenoic (EPA), 720 mg docosahexaenoic (DHA), 600 mg other fatty acids, and 6 IU vitamin E. Blood was collected before and after 1, 2 and 3 mo of supplementation. Compliance was confirmed by the significant increase in plasma EPA and DHA in all women. Older women had a significantly higher increase in EPA and DHA than did young women (10-fold increases in EPA and 2.5-fold increases in DHA vs. 8-fold in EPA and 2-fold in DHA for older and young women, respectively). The decrease in the arachidonic acid:EPA ratio was more dramatic in the older women. Plasma total triglycerides (TG) decreased significantly, and the ratio of polyunsaturated fatty acids to saturated fatty acids was significantly (P less than 0.01) increased. Plasma vitamin E levels did not change significantly after supplementation; however, after 3 mo of supplementation by young women, plasma vitamin E was significantly lower than after 1 mo. The vitamin E: TG ratio was significantly increased and vitamin E:(EPA + DHA) significantly decreased. All women showed a significant increase in plasma lipid peroxide through mo 2 of supplementation. After 2 mo, older women had significantly higher lipid peroxide levels than young women. The lipid peroxide:TG ratio, which declined by mo 3, was still significantly higher than baseline. These data indicate that although long-term fish oil supplementation may be beneficial in reducing plasma total TG, susceptibility of plasma lipids to free radical attack is potentiated.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of metabolic control on vitamin E nutritional status in children with type 1 diabetes mellitus

OBJECTIVE: To evaluate the effects of the metabolic control of the insulin-dependent diabetes mellitus (IDDM) on the nutritional status of vitamin E. METHODS: A total of 47 children with IDDM and a mean age of 11.91+/-1.60 (mean+/-SD) years were studied, matched for age and sex with 16 healthy children (11.75+/-1.83 years). Following the American and British Associations for IDDM, we used a classification of "good", "moderate" or "poor" control of the illness: (a) good control [glycosilated haemoglobin (HbAlc) < or =7%]; (b) moderate control (7%< HbAlc < or =8%); and (c) poor control (HbAlc>8%). Serum concentrations of total cholesterol (CHOL), triglycerides (TG), high-density lipoproteins-cholesterol (HDLc), very low- and low-density lipoproteins cholesterol (VLDLc and LDLc), plasma and erythrocyte vitamin E (Vit Ep and Vit Ee) and plasma vitamin A (Vit Ap) were measured in all children. RESULTS: The children with "poor" metabolic control of the illness presented significantly higher plasma concentrations of CHOL, LDLc, VLDLc, LDLc/HDLc, (VLDL+LDL)c/HDLc, TG and Vit Ep; higher indices Vit Ep/Vit Ee and Vit Ep/Vit Ap relative to those with a "good" control of the illness. Direct-linear correlations were found between Vit Ep and the percentage of HbAlc and with the markers of atherogenic risk in the IDDM children. CONCLUSION: There is a significant rise in Vit Ep concentrations as metabolic control of the illness worsens, whereas Vit Ee remained unchanged. These results suggest that vitamin E maintains its nutritional status despite a poor control of the IDDM during childhood.     

阿司匹林对代谢综合征患者氧化应激指标和P选择素及C反应蛋白的影响

目的观察阿司匹林对代谢综合征(MS)患者氧化应激指标、可溶性P-选择素(sPE)及C反应蛋白(CRP)的影响。方法收集年龄、性别匹配的MS患者(MS组)27例,健康组29例。MS组口服阿司匹林100mg,1/d。比较MS组和健康组超氧化物歧化酶(SOD)、丙二醛(MDA)、谷胱甘肽过氧化物酶(GSH)、氧化低密度脂蛋白(ox-LDL)、sPE以及CRP水平,以及MS组应用阿司匹林1个月后上述指标的变化。结果 MS组血清SOD、GSH水平较健康组显著降低,血清MDA、ox-LDL、CRP和sPE显著升高(P<0.05、P<0.01);应用阿司匹林1个月后,血清GSH水平显著升高,MDA、ox-LDL、CRP和sPE水平显著降低(P<0.05)。结论该剂量阿司匹林可能改善MS患者氧化应激、炎性反应和sPE的改变。     

阿司匹林对代谢综合征患者氧化应激指标和P选择素及C反应蛋白的影响

目的 观察阿司匹林对代谢综合征(MS)患者氧化应激指标、可溶性P-选择素(sPE)及C反应蛋白(CRP)的影响.方法 收集年龄、性别匹配的MS患者(MS组)27例,健康组29例.MS组口服阿司匹林100 mg,l/d.比较MS组和健康组超氧化物歧化酶(SOD)、丙二醛(MDA)、谷胱甘肽过氧化物酶(CSH)、氧化低密度脂蛋白(ox-LDL)、sPE以及CRP水平,以及MS组应用阿司匹林1个月后上述指标的变化.结果 MS组血清SOD、GSH水平较健康组显著降低,血清MDA、ox-LDL、CRP和sPE显著升高(P<0.01);应用阿司匹林1个月后,血清CSH水平显著升高,MDA、ox-LDL、CRP和sPE水平显著降低(P<0.05).结论 该剂量阿司匹林可能改善MS患者氧化应激、炎性反应和sPE的改变.     

Effects of selenium and vitamin E status on plasma creatine kinase activity in calves

In four experiments, attempts were made to induce nutritional myopathy in calves given a selenium- and vitamin E-deficient diet (less than 0.01 mg Se/kg, less than 2 mg total vitamin E/kg). In housed calves, combined selenium and vitamin E deficiency was insufficient to provoke the large increase in plasma creatine kinase activity typical of muscle damage. Such increases were only obtained when selenium- and vitamin E-deficient calves were turned out from indoor housing in small pens to open pasture. The rises in plasma creatine kinase activity on turnout were prevented when the calves had consumed diets supplemented with 0.1 mg Se/kg (as Na2SeO3). The percentage of the polyunsaturated fatty acid, linolenic acid (18:3 omega 3), in plasma total fatty acids was up to 10-fold higher in calves consuming fresh grass at pasture or indoors than in those housed indoors and fed purified diet. However, in the housed calves there were no rises in plasma creatine kinase activity, whereas large increases occurred in those turned out to pasture. Thus, because increased dietary polyunsaturated fatty acid at turnout is not the sole trigger for the development of myopathy in selenium- and vitamin E-deficient calves, additional unidentified dietary or environmental factors must also be involved.     

Low-energy cranberry juice decreases lipid oxidation and increases plasma antioxidant capacity in women with metabolic syndrome

Cranberries, high in polyphenols, have been associated with several cardiovascular health benefits, although limited clinical trials have been reported to validate these findings. We tested the hypothesis that commercially available low-energy cranberry juice (Ocean Spray Cranberries, Inc, Lakeville-Middleboro, Mass) will decrease surrogate risk factors of cardiovascular disease, such as lipid oxidation, inflammation, and dyslipidemia, in subjects with metabolic syndrome. In a randomized, double-blind, placebo-controlled trial, participants identified with metabolic syndrome (n = 15-16/group) were assigned to 1 of 2 groups: cranberry juice (480 mL/day) or placebo (480 mL/day) for 8 weeks. Anthropometrics, blood pressure measurements, dietary analyses, and fasting blood draws were conducted at screen and 8 weeks of the study. Cranberry juice significantly increased plasma antioxidant capacity (1.5 ± 0.6 to 2.2 ± 0.4 μmol/L [means ± SD], P < .05) and decreased oxidized low-density lipoprotein and malondialdehyde (120.4 ± 31.0 to 80.4 ± 34.6 U/L and 3.4 ± 1.1 to 1.7 ± 0.7 μmol/L, respectively [means ± SD], P < .05) at 8 weeks vs placebo. However, cranberry juice consumption caused no significant improvements in blood pressure, glucose and lipid profiles, C-reactive protein, and interleukin-6. No changes in these parameters were noted in the placebo group. In conclusion, low-energy cranberry juice (2 cups/day) significantly reduces lipid oxidation and increases plasma antioxidant capacity in women with metabolic syndrome.     

Role of vitamin E and oxidative stress in exercise.

Reactive oxygen species (ROS) play an important role as mediators of skeletal muscle damage and inflammation after strenuous exercise. These ROS arise largely from increases in mitochondrial oxygen consumption and electron transport flux. Bouts of intense exercise are associated with increases in lipid peroxidation, generating malondialdehyde and F(2alpha)-isoprostanes, and the release of muscle enzymes like lactate dehydrogenase and creatine kinase. Dietary and enzymatic antioxidant defenses appear to play a protective role in muscle cells by reducing associated oxidative damage to lipids, nucleic acids, and protein. However, studies of the use of dietary antioxidants like vitamin E to reduce exercise-induced muscle injury have met with mixed success. The equivocal nature of these results appear to reflect a diversity of factors including the antioxidant(s) tested, the nature and timing of the exercise, the age and fitness of the subjects, and the methodology for assessing oxidative stress.     

Effects of oral vitamin E and beta-carotene supplementation on ultraviolet radiation-induced oxidative stress in human skin

BACKGROUND: Ultraviolet radiation (UVR) generates reactive oxygen species in skin that can play a role in skin damage, but reports about the photoprotective properties of oral antioxidant supplements are conflicting. OBJECTIVE: We examined the ability of 2 lipid-soluble antioxidants, vitamin E and beta-carotene, to reduce markers of oxidative stress and erythema in human skin exposed to UVR. DESIGN: Sixteen healthy subjects took either alpha-tocopherol (n = 8; 400 IU/d) or beta-carotene (n = 8; 15 mg/d) for 8 wk. Biopsy samples before and after supplementation were taken from unexposed skin and skin 6 h after 120 mJ/cm(2) UVR. The effects of supplements on markers of oxidative stress in skin and the minimal erythema dose to UVR were assessed. RESULTS: Supplementary vitamin E was bioavailable, the plasma concentration increased from 14.0 +/- 0.66 (x +/- SEM) to 18.2 +/- 0.64 mug/mL (P < 0.01), and the skin concentration increased from 0.55 +/- 0.09 to 1.6 +/- 0.19 ng/mg protein (P < 0.01). Supplementary beta-carotene increased plasma concentrations from 1 +/- 0.3 to 2.25 +/- 0.3 mug/mL (P < 0.05), but skin concentrations were undetectable. Before vitamin E supplementation, UVR increased the skin malondialdehyde concentration from 0.42 +/- 0.07 to 1.24 +/- 0.16 nmol/mg protein (P < 0.01), whereas oxidized or total glutathione increased from 9.98 +/- 0.4% to 12.0 +/- 1.0% (P < 0.05). Vitamin E supplementation significantly decreased the skin malondialdehyde concentration, but neither vitamin E nor beta-carotene significantly influenced other measures of oxidation in basal or UVR-exposed skin. CONCLUSIONS: Vitamin E or beta-carotene supplementation had no effect on skin sensitivity to UVR. Although vitamin E supplements significantly reduced the skin malondialdehyde concentration, neither supplement affected other measures of UVR-induced oxidative stress in human skin, which suggested no photoprotection of supplementation.     

Effects of alcohol-free beer on lipid profile and parameters of oxidative stress and inflammation in elderly women

ObjectiveWe assessed the influence of alcohol-free beer on factors implicated in atherosclerosis, such as lipid profile, oxidative stress parameters, and proinflammatory cytokines, in postmenopausal women, a population particularly at risk for atherosclerotic disease.MethodsThe study was carried out in 29 nuns, 58 to 73 y old, who live in a convent with a disciplined, regular, and homogeneous lifestyle. The nuns maintained their habits and diet routine, but their meals were supplemented with 500 mL/d of alcohol-free beer (0.0%) divided into two doses over a 45-d period. Lipid profile, inflammatory markers such as C-reactive protein, interleukins 1 and 6, and tumor necrosis factor-α, and parameters of oxidative metabolism were determined before and after the study period.ResultsThere were no differences in the levels of C-reactive protein and proinflammatory cytokines after diet supplementation. The antibody titers to oxidized low-density lipoprotein were significant lower (P < 0.05), and thiobarbituric acid–reactive substances (?18%, P < 0.001) and plasma carbonyl group content (?21%, P < 0.001) were decreased when compared with initial values. Increases in α-tocopherol levels (+9%, P < 0.05) and erythrocytic glutathione levels (+29%, P < 0.001) were also noted. With respect to lipid profile, only subjects with cholesterol levels higher than 240 mg/dL showed lower levels after supplementation.ConclusionConsumption of non-alcoholic beer produces a decrease in oxidative stress that can have a beneficial impact on cardiovascular risk; however, the circulating concentrations of inflammatory mediators involved in its pathophysiology remained unchanged.     

Effects of DASH diet on lipid profiles and biomarkers of oxidative stress in overweight and obese women with polycystic ovary syndrome: A randomized clinical trial

ObjectiveThe aim of this study was to assess the effects of the Dietary Approaches to Stop Hypertension (DASH) diet on lipid profiles and biomarkers of oxidative stress in overweight and obese women with polycystic ovary syndrome (PCOS).MethodsThis randomized controlled clinical trial was conducted with 48 women diagnosed with PCOS. The women were randomly assigned to consume either the control (n = 24) or DASH diet (n = 24) for 8 wk. Both diets were designed to be calorie-restricted. Both diets consisted of 52% carbohydrates, 18% proteins, and 30% total fats. The DASH diet was designed to be rich in fruits, vegetables, whole grains, and low-fat dairy products and to be low in saturated fats, cholesterol, and refined grains. Fasting blood samples were taken at baseline and after 8-wk intervention to measure lipid profiles and biomarkers of oxidative stress including plasma total antioxidant capacity (TAC) and total glutathione (GSH).ResultsAdherence to the DASH diet, compared with the control diet, resulted in a significant decrease in weight (−4.4 versus −1.5 kg; P < 0.001) and body mass index (−1.7 versus −0.6 kg/m²; P < 0.001), decreased serum triglycerides (−10.0 versus +19.2 mg/dL; P interaction = 0.005) and very-low-density lipoprotein cholesterol levels (−2.0 versus +3.9 mg/dL; P interaction = 0.005). Increased concentrations of TAC (+98.6 versus −174.8 mmol/L; P interaction <0.001) and GSH (+66.4 versus −155.6 μmol/L; P interaction = 0.005) also were found in the DASH group compared with the control group.ConclusionConsumption of DASH diet for 8 wk led to a significant reduction in serum insulin, triglycerides and very-low-density lipoprotein cholesterol and a significant increase in TAC and GSH levels.     

Effect of vitamin B6 deficiency on antioxidative status in rats with exercise-induced oxidative stress

This study investigated the effect of vitamin B₆ deficiency on antioxidant enzyme activities and lipid profile in rats with exercise-induced oxidative stress. Forty eight rats were fed either a vitamin B₆ deficient diet (B6-) or a control diet (control) for 4 weeks and then subdivided into 3 groups: pre-exercise (PreE); post-exercise (PostE); recess after exercise (recessE). Compared to those of control group, plasma catalase and hepatic cytosol superoxide dismutase (SOD, EC 1.15.1.1) activities of B6- group were lower regardless of exercise. The ratio of reduced glutathione/oxidized glutathione (GSH/GSSG) of B6- group was lower in PreE and there was no difference between PostE and recessE. The level of malondialdehyde (MDA) of B6- was significantly higher in PreE and PostE. High-density lipoprotein-cholesterol (HDL-C) level of B6- group was lower regardless of exercise. Atherosclerotic index of B6- group was higher in PreE and there was no difference between PostE and recessE. It is suggested that a reduction in antioxidative status caused by vitamin B₆ deficiency may be aggravated under exercise-induced oxidative stress.     

维生素C、E对血管内皮细胞氧化损伤保护作用

目的 观察维生素C(VC)、维生素E(VE)对体外培养H₂O₂氧化损伤血管内皮细胞(VEC)超微结构的影响.方法 采用体外细胞培养方法,将血管内皮细胞分为正常对照组,H₂O₂氧化损伤对照组、VC+H₂O₂组(VC100μmol/L),VE+H₂O₂组(VE100μmol/L).分别将VC、VE加入到培养液中,预孵24h,再加入除菌后的H₂O₂进行损伤,终止培养后收集细胞,进行电镜观察.结果 透射电镜观察VEC,可见H₂O₂损伤对照组细胞超微结构明显异常,细胞表面呈光滑状,丢失特征性的细胞突起及微绒毛;胞质内线粒体损伤严重,形态模糊;粗面内质网明显扩张呈大囊泡状;溶酶体增多;少数细胞严重水肿,核形不规则,核内染色质部分溶解.VC+H₂O₂和VE+H₂O₂组血管内皮细胞超微结构仅有轻度损伤,多数细胞与正常对照组细胞相似;大部分细胞表面微绒毛和胞质突起均趋于正常,胞质内细胞器均在正常范围内;细胞核未见异常,核膜完好,核内染色质分布正常;仅有少数细胞粗面内质网有轻度扩张,线粒体结构模糊不清.结论 VC、VE可一定程度保护氧化损伤的血管内皮细胞的超微结构.     

Nut consumption has favorable effects on lipid profiles of Korean women with metabolic syndrome

Nut consumption has been studied for its cardioprotective effects. However, the findings of clinical intervention studies are inconsistent; and no intervention studies have been conducted in the Korean population. We hypothesized that nut supplementation may have favorable influence on metabolic markers. Therefore, this study aimed to investigate the effects of nut consumption on metabolic parameters and biomarkers related to inflammation, oxidative stress, and endothelial function in Korean adults with metabolic syndrome. To this end, we designed a randomized, parallel, controlled dietary intervention study (ClinicalTrials.gov NCT02023749). Subjects with metabolic syndrome and a body mass index of at least 23 kg/m² were randomized to the Control group and the Nut group, which received supplementation with 30 g/d of mixed nuts (walnuts, peanuts, and pine nuts) for 6 weeks. Sixty volunteers were included in the final analysis. Metabolic markers were evaluated at baseline and at the end of the study. Total cholesterol and non–high-density lipoprotein cholesterol levels significantly improved in the Nut group compared to those in the Control group (P = .023 and P = .016, respectively) in women. Biomarkers related to inflammation, oxidative stress, and endothelial function did not significantly change from baseline in either group. Thus, supplementing a usual diet with mixed nuts for 6 weeks had favorable effects on several lipid parameters in Korean women with metabolic syndrome. These findings present a possible mechanism for the cardioprotective effects of nut consumption.     

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

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

Antioxidant vitamin status in high exposure to oxidative stress in competitive athletes

We conducted a cross-sectional study in 118 well-trained athletes to investigate 'high exposure' to sub-deficient antioxidant status, and consequently to oxidative damage, in relation to estimated daily energy expenditure (EE) and dietary antioxidant intake. Subjects completed 7 d food and activity records. Blood samples were obtained on day 8. Of the athletes 81, 60 and 43% had intakes of vitamins E, C and beta-carotene below two-thirds of the French RDA respectively, which is adjusted for EE (FRDAa). The deficit in vitamin E intake was positively correlated with EE (r 0.51, P<0.0001). All the athletes had normal plasma vitamins E and C and 14% had marginal plasma beta-carotene. Plasma thiobarbituric acid-reactive substances (TBARS) did not increase with increased EE. As evidenced by ANOVA, EE-induced vitamin C intakes increased and consequently led to increased plasma ascorbic acid concentrations. In male athletes, plasma total carotenoids were negatively correlated with plasma TBARS concentrations (r -0.31, P<0.006). The relationship between vitamin C intakes and plasma concentrations was logarithmic (r 0.59, P< 0.0001). To summarize, it is not clear whether vitamin E requirements are overestimated with reference to EE in the FRDAa. Daily requirements for vitamin C do not exceed 200 mg. Our present results could be interpreted as meaning that carotenoids play a protective role as exogenous antioxidants. Carotenoid intakes in athletes must be considered carefully.