Plasma Concentrations Of Antioxidant Vitamins Research Articles

Effect of Statin Therapy on the Plasma Concentrations of Retinol, Alpha-Tocopherol and Coenzyme Q10 in Children with Familial Hypercholesterolemia

PurposeFamilial hypercholesterolemia (FH) requires early treatment. However, statins, which are regarded the first-line therapy, have an influence on redox balance. Antioxidant vitamins are important for many metabolic processes in the developing body. There are few data available on the long-term safety of statin use in children. The aim of this study was to evaluate the influence of statin treatment in children with FH on plasma concentrations of antioxidant vitamins: retinol, alpha-tocopherol and coenzyme Q10.MethodsThe first study group consisted of 13 children aged 10–18 years treated with simvastatin for at least 6 months, and the second group comprised 13 age- and sex-matched children with hypercholesterolemia, in whom pharmacological treatment had not been applied yet. Analyses were performed using a high-performance liquid chromatograph coupled with a MS detector.ResultsThe analysis did not reveal significant differences in the concentration of retinol, alpha-tocopherol or coenzyme Q10 between the studied groups. The adjustment of the concentrations of the vitamins to the cholesterol level also indicated no significant differences. We found no deficits in antioxidant vitamins in patients treated with statins, or any risk of adverse effects associated with an increase in their concentration.ConclusionThere is no rationale for additional supplementation using antioxidant vitamins or modification of low-fat and low-cholesterol diet in pediatric patients treated with statins.

A Multi-Locus Genetic Risk Score for Primary Open-Angle Glaucoma (POAG) Variants Is Associated with POAG Risk in a Mediterranean Population: Inverse Correlations with Plasma Vitamin C and E Concentrations.

Primary open-angle glaucoma (POAG) is a leading cause of blindness worldwide. The genetics of POAG are complex, and population-specific effects have been reported. Although many polymorphisms associated with POAG risk have been reported, few studies have analyzed their additive effects. We investigated, in a southern European Mediterranean population, the association between relevant POAG polymorphisms, identified by initial genome-wide association studies (GWASs) and POAG risk, both separately and as an aggregated multi-locus genetic risk score (GRS). Also, bearing in mind that oxidative stress is a factor increasingly recognized in the pathogenesis of POAG, we analyzed the potential association of the GRS with plasma concentrations of antioxidant vitamins (C and E). We carried out a case–control study including 391 POAG cases and 383 healthy controls, and analyzed four genetic polymorphisms (rs4656461-TMCO1, rs4236601-CAV1/CAV2, rs2157719-CDKN2B-AS1 and rs3088440-CDKN2A). An unweighted GRS including the four non-linked polymorphisms was constructed. A strong association between the GRS and POAG risk was found. When three categories of the GRS were considered, subjects in the top category of the GRS were 2.92 (95% confidence interval (CI): 1.79–4.77) times more likely to have POAG compared with participants in the bottom category (p < 0.001). Moreover, the GRS was inversely correlated with plasma vitamin C (p = 0.002) and vitamin E (p = 0.001) concentrations, even after additional adjustment for POAG status. In conclusion, we have found a strong association between the GRS and POAG risk in this Mediterranean population. While the additional correlation found between GRS and low levels of vitamins C and E does not indicated a causal relationship, it does suggest the need for new and deeper research into the effects of oxidative stress as a potential mechanism for those associations.

The role of antioxidant vitamins in the etiology of rheumatoid arthritis

There is evidence that insufficient intake of antioxidants may increase the risk of autoimmune inflammatory diseases, including rheumatoid arthritis (RA). Also, lower plasma concentrations of antioxidant vitamins can be a sign of their heavy expenditure to suppress inflammatory processes in the preclinical stage of RA. This article provides an overview of modern studies that have assessed a relationship between the incidence of RA and serum levels or dietary intake of vitamins A, E, C and beta-carotene. Case-control studies have revealed that α-tocopherol and β-cryptoxanthin have a protective effect and their high plasma levels are associated with the decreased incidence of RA. An inverse relationship has been also found between the dietary intake of carotenoids and vitamin C and the risk of RA. At the same time, larger prospective cohort studies have failed to confirm the relationship between the levels of consumption of the major antioxidant vitamins and the risk of RA. The currently available data on the role of antioxidant vitamins in the development of RA remains controversial. Conceivably, sufficient intake of the vitamins has no self-protective activity against RA, but serves as a marker for a healthier lifestyle that lowers the risk of many diseases, including autoimmune disorders.

The effects of antioxidant vitamin supplementation on expiratory flow rates at rest and during exercise.

Previous studies suggest that pulmonary function is associated with fruit and vegetable consumption and plasma concentrations of antioxidant vitamins. Also, expiratory flow limitation (EFL) has been reported to limit ventilation during exercise in healthy individuals. We hypothesized antioxidant vitamin supplementation (AVS) would increase resting expiratory flow rates in healthy subjects and reduce EFL during exercise. Ten healthy, nonsmoking subjects (5 M/5 W), consuming <5 servings of fruit and vegetables per day, participated in a randomized, single-blinded crossover design study with subjects receiving a placebo (PLA) or AVS [vitamins C (500 mg), E (400 IU), beta-carotene (15,000 IU), zinc (7.5 mg), selenium (50 mg), copper (1 mg), and manganese (2.5 mg)] for 4 weeks. After a minimum 4-week washout period, subjects received the alternate supplementation. Pulmonary function tests and total antioxidant status (TAS) from plasma were measured pre- and post-supplement period. Subjects completed a pre- and post-supplement treadmill test for 20 min at 70% [Formula: see text] followed by increasing workload until exhaustion. AVS increased (p < 0.05) TAS by ~21% and resting expiratory flow rates (FEF25-75, FEF50) by ~9%. Following AVS, %EFL was significantly reduced by ~15% at minute 15, 20, and end-exercise with no change (p > 0.05) in end-expiratory lung volumes. Breathing frequency and ratings of perceived exertion and dyspnea were also lower (p < 0.05) at min 20 of exercise. No changes (p > 0.05) were evident at rest or during exercise with PLA. These results suggest that AVS can increase TAS, improve resting expiratory flow rates and reduce EFL during exercise in healthy subjects who are not meeting fruit and vegetable recommendations.

Oxidative Stress in Algerian Adults Obesity

Abstract Background: Obesity increases the incidence of diabetes, hypertension, dyslipidemia, atherosclerosis, and cancer. Oxidative stress has been considered one of the mechanisms linking obesity to these pathologies. Our aim was to evaluate the oxidative stress status in obese Adults Methods: Our study focused on a sample of 187 healthy volunteers in the city of Constantine, divided according to their BMI into three groups: group A (BMI <25, normal nutritional status), group B (25 ≤ BMI <30, overweight) and group C (BMI ≥ 30, obesity). The status of oxidative stress was evaluated by determining the activities of erythrocyte antioxidant enzymes glutathione peroxidas (GPx) and superoxide dismutase (SOD), plasma concentrations of antioxidant vitamins (E,A) and lipid peroxidation marker , the malondialdehyde (MDA). Results: Vitamin E / Lipids ratio and vitamin A plasma concentration were significantly lower in obese subjects compared with those having normal BMI: 3.40 ± 1.16 mg / g vs 3.87 ± 1.16 mg / g; p <0.05 and 0.63 (0.46-0.76) mg/l vs 0.69 (0.57-0.86) mg/l, p <0.05 respectively. MDA plasma concentrations were significantly higher in obese versus overweight subjects and those having normal BMI: 11.4 (7.1 to 14.6) mg/l vs 8.6 (5.9 to 11.6) g/l, p <0.01 and 11.4 (7.1 to 14.6) mg/l vs 8.4 (5.9 to 12.3) mg/l, p <0.05 respectively. There was no significant difference between the MDA plasma concentration of overweight subjects and those having normal BMI. Erythrocyte SOD and Gpx activities of different classes of BMI were comparable. MDA was positively and significantly correlated with BMI (r = 0.149, p <0.05). Conclusion: The decrease in antioxidant defenses and increased lipid peroxidation in obese subjects reflect a profound oxidative stress, which would be one of the mechanisms involved in the onset of diseases caused by the obesity.

Effects of supplementation of antioxidant vitamins and lipid peroxidation in critically ill patients.

Critical patients present systemic inflammatory process that can be followed by decrease in plasma concentrations of antioxidant vitamins. [corrected] The aim of this study was to evaluate the effect of the supplementation of antioxidant vitamins in critical patients and their relation with lipid peroxidation. 23 patients went on a standard diet (G1) and 11 went on a diet with daily supplementation of 10,000 IU of vitamin A, 400 mg of vitamin E and 600 mg of vitamin C (G2). The APACHE II score was made. Serum concentrations of retinol, β-carotene, vitamins C and E, malondialdehyde (MDA) and C-reactive protein was measured before (T0) and on the 8th day after the beginning of the nutritional therapy (T1). The groups had been monitored on T0, T1 and T2, (at discharges or death) on the following parameters: mechanical ventilation; hospitalization days; mortality; infection incidence. Serum concentrations of MDA and vitamin E were significantly lower in G2 after intervention and strong tendency to increase vitamin C. There were not significant differences between the groups regarding the clinical parameters. The doses of vitamin A, C and E that were indicated were effective for the current lipid peroxidation reduction.

Protective properties of complex of quercetin, selenium, catechins and curcumin against DNA damage

Nutrition plays an important role in prevention of degenerative age-related diseases. Sufficient intake of bioactive compounds such as polyphenols, vitamins, minerals, fiber, unsaturated fat with antisclerotic, antioxidative, antiinflammatory and anticarcinogenic properties in form of functional foods or separately is a correct way of this prevention. In a group of randomly selected 50 apparently healthy non-smoking men aged 30-50 years on traditional mixed diet (general population) plasma concentrations of antioxidant vitamins, catechins, selenium and lymphocyte DNA damage values were measured before consumption of cereal biscuit with selenized onion, green tea and curcuma as the sources of bioactive quercetin, selenium, catechins, curcumin, after 2-month consumption and after 2-month wash-out. The significantly increased plasma concentrations of biscuit antioxidants (selenium, catechins) after 2-month consumption and the non-changed antioxidant vitamins and carotenoids (vitamins C, E, β-carotene and lycopene) during the study mean that the biscuit antioxidants (selenium, catechins and non-measured quercetin, curcumin but present in biscuit) actually caused the significantly reduced values of DNA strand breaks, DNA breaks with oxidized purines and DNA breaks with oxidized pyrimidines. After two months wash-out period, a trend to return of these values derived from biscuit as well as DNA damage values to levels before consumption was expressed. The results of reduced values of DNA damage document a beneficial effect of biscuit as functional food containing polyphenols with antioxidant and anticarcinogenic properties in prevention of DNA instability and prevention of oxidative stress.

Role of dietary zinc in heat-stressed poultry: A review

High ambient temperatures compromise performance and productivity through reducing feed intake and decreasing nutrient utilization, growth rate, egg production, egg quality, and feed efficiency, which lead to economic losses in poultry. Environmental stress also leads to oxidative stress associated with a reduced antioxidant status in the bird in vivo, as reflected by increased oxidative damage and lowered plasma concentrations of antioxidant vitamins (e.g., vitamins E, A, and C) and minerals (e.g., Zn). Zinc has an important role in numerous biological processes in avian and mammalian species. For instance, Zn is an essential component of many enzymes, and it has both structural and catalytic functions in metalloenzymes. Furthermore, dietary Zn is required for normal immune function as well as proper skeletal development and maintenance. One of the most important functions of Zn is related to its antioxidant role and its participation in the antioxidant defense system. This work compiles past and present information about the role of Zn in heat-stressed poultry health.

Plasma Antioxidants and Asymptomatic Carotid Atherosclerotic Disease

Background: Atherosclerosis remains clinically mute for a long time and frequently manifests itself with an acute cardiovascular event. The possibility of detecting this disease in a subclinical phase and reducing or reversing its progression is an issue of relevance. Published studies on the association between antioxidant vitamins and carotenoids and carotid intima-media thickness (CIMT) have been inconclusive. Methods: We enrolled 220 consecutive, asymptomatic participants. After carotid ultrasound investigation, a medical history was taken, a physical examination was performed and venous blood samples were collected. Venous blood samples were analyzed for concentrations of antioxidant vitamins and carotenoids. Results: Low concentrations of vitamin A (p < 0.01), vitamin E (p < 0.001), lycopene (p < 0.01) and β-carotene (p < 0.001) were significantly associated with carotid atherosclerosis (CIMT ≧0.8 mm). In addition, marginally higher body mass index, plasma haemoglobin and high-density lipoprotein cholesterol were also associated with carotid atherosclerosis, while other laboratory parameters considered in this study (total cholesterol, low-density lipoprotein cholesterol, triglycerides and C-reactive protein) were not significantly associated with carotid atherosclerosis. Conclusions: Low plasma concentrations of antioxidant vitamins (A, E, β-carotene) and lycopene were associated with early carotid atherosclerotic lesions as measured by CIMT. Regular intake of foods rich in lycopene and antioxidant vitamins may slow the progression of atherosclerosis.

Oxidative Stress in Children on Peritoneal Dialysis

Enhanced oxidative stress has been observed in dialysis and predialysis adult patients with chronic kidney disease (CKD), which resulted in increased mortality and morbidity within this population. Not much attention in the literature has been paid to nonenzymatic antioxidant defense in children with CKD on peritoneal dialysis (PD). The aim of the present study was to describe the plasma, erythrocyte, and dialysate concentrations of oxidized (GSSG) and reduced glutathione (GSH) and vitamins A, E, and C in a pediatric PD population. 10 children on PD and 27 age-matched healthy subjects were enrolled in the study. Erythrocyte and plasma GSH concentrations were lower in PD patients, erythrocyte concentration of GSSG remained unchanged, and plasma GSSG was significantly higher in children on PD. Children on PD exhibited decreased plasma concentrations of antioxidant vitamins compared to healthy subjects. Moreover, we documented loss of vitamins A, E, and C into ultrafiltrate. Such low plasma levels of vitamins A, E, and C and simultaneously decreased activity of erythrocyte GSH may be responsible for the increased oxidative stress occurring in children with CKD on PD.

Selenium supplementation in heat-stressed poultry.

Abstract Stress evoked by high ambient temperature results in economic loss through reducing feed intake while decreasing nutrient utilization, growth rate, egg production, egg quality and feed efficiency. Moreover, environmental stress leads to oxidative stress and reduces the antioxidant status of the bird in vivo , resulting in increased oxidative damage and lowered plasma concentrations of antioxidant vitamins (vitamin C, vitamin E) and minerals (zinc and selenium). Selenium is an essential trace element for animals and humans because of its role in the antioxidant enzyme glutathione peroxidase which protects cell membranes from damage caused by lipid peroxidation. Selenium deficiency causes several disorders in animal species and severe health problems in humans. Selenium supplementation has been found to eliminate selenium deficiency problems. Selenium is also used in the diets of heat-stressed poultry because of its reported benefits. This review deals with the effects of dietary selenium supplementation in poultry maintained at a high ambient temperature.

Antioxidant capacities in adenoma polyp patients after dietary intervention with antioxidant‐rich foods

Intakes of high fiber, fruits and vegetables and low fat have been suggested to have protective effect on colorectal adenoma and cancer. This study was carried out by supplementing antioxidant-rich foods to enhance the antioxidant capacities of the colorectal adenoma patients. A total of 38 patients (aged 35 to 74) were provided with dietary supplement of 1 bowl of sprouted rice porridge (D.W. F&B) and 2 cans of mixed vegetable juice (N.S. Co., Ltd.,) daily for 12 weeks. The plasma concentrations of antioxidant vitamins; β-carotene (24.8±1.86 vs 28.4±1.77 μg/dL, p<0.02), lutein (8.72±0.97 vs 9.91±1.13 μg/dL, p<0.003), lycopene (7.56±0.54 vs 8.66±0.62 μg/dL, p<0.002) increased significantly after the intervention. The serum levels of antioxidant minerals; Se (7.28±0.56 vs 8.52±0.63 μg/dL, p<0.008) and Zn (89.3±3.64 vs 97.7±3.62 μg/dL, p<0.03) were increased, the Cu/Zn ratio (1.12±0.05 vs 1.05±0.04, p<0.03) showed a significant decrease. Serum folate level (8.1±0.65 vs 9.2±0.79 ng/mL, p<0.05) and the folate/homocysteine ratio (0.92±0.09 vs 1.11±0.12, p<0.02) were also significantly elevated. In addition, the serum TG level significantly dropped (153.9 ±11.5 vs 133.1±8.8 mg/dL, p<0.05) at the end of the study. This study supports the possibility of improving antioxidant capacities of adenoma polyp patients with antioxidant-rich supplement foods for a relatively short period of time. Supported by the Korea Science & Engineering Foundation, Nong Shim Co., Ltd., and Dong Won F&B.

Obesity and Plasma Concentrations of Alpha-Tocopherol and Beta-Carotene in Epileptic Girls Treated with Valproate

To investigate whether epileptic patients who become obese after valproic acid (VPA) therapy can have a high risk of atherosclerosis related to the oxidation of low-density lipoprotein, we prospectively studied the plasma concentrations of lipid-soluble antioxidant vitamins in a group of 20 epileptic girls and 20 controls. After 1 year of VPA treatment, epileptic patients who gained weight had decreased plasma concentrations of α-tocopherol and α- and β-carotene, the main lipid-soluble antioxidants. Moreover, 5 patients who gained weight were reevaluated 6 months after withdrawal from VPA therapy and showed normal body mass indices and normalized plasma levels of antioxidants. In conclusion, the data suggest that epileptic patients who gain weight after VPA therapy have reduced plasma concentrations of antioxidant vitamins and that these reductions are reversible after VPA withdrawal.

Dietary and circulating antioxidant vitamins in relation to carotid plaques in middle-aged women

The results of the few studies conducted on the relation between antioxidant vitamins and carotid atherosclerosis have been inconclusive. We evaluated the association between preclinical carotid atherosclerosis, as determined by high-resolution B-mode ultrasound, and both the intake amounts and plasma concentrations of antioxidant vitamins. Among 5062 participants in Progetto Atena, a population-based study on the etiology of cardiovascular disease and cancer in women, 310 women were examined by B-mode ultrasound to detect early signs of carotid atherosclerosis. The participants answered a food-frequency questionnaire, and their plasma concentrations of vitamin E, vitamin A, and carotenoids were measured. None of the women took vitamin supplements. The occurrence of atherosclerotic plaques at the carotid bifurcation was inversely associated with tertiles of vitamin E intake; the test for a linear trend across tertiles was significant (P < 0.05). Similarly, the ratio of plasma vitamin E to plasma cholesterol was inversely related to the presence of plaques at the carotid bifurcation; the test for a linear trend across tertiles was significant (P < 0.02). No association was found between the intake of other antioxidant vitamins (vitamins A and C and carotenoids) or their plasma concentrations and the presence of carotid plaques. An inverse association was found between both the intake amount and plasma concentration of vitamin E and preclinical carotid atherosclerosis in middle-aged women. This association was independent of other cardiovascular risk factors, was not related to vitamin supplements, and supports the hypothesis that low vitamin E intake is a risk factor for early atherosclerosis.

Effects of fruit and vegetable consumption on plasma antioxidant concentrations and blood pressure: a randomised controlled trial

High dietary intakes of fruit and vegetables are associated with reduced risks of cancer and cardiovascular disease. Short-term intensive dietary interventions in selected populations increase fruit and vegetable intake, raise plasma antioxidant concentrations, and lower blood pressure, but long-term effects of interventions in the general population are not certain. We assessed the effect of an intervention to increase fruit and vegetable consumption on plasma concentrations of antioxidant vitamins, daily fruit and vegetable intake, and blood pressure. We undertook a 6-month, randomised, controlled trial of a brief negotiation method to encourage an increase in consumption of fruit and vegetables to at least five daily portions. We included 690 healthy participants aged 25-64 years recruited from a primary-care health centre. Plasma concentrations of alpha-carotene, beta-carotene, lutein, beta-cryptoxanthin, and ascorbic acid increased by more in the intervention group than in controls (significance of between-group differences ranged from p=0.032 to 0.0002). Groups did not differ for changes in lycopene, retinol, alpha-tocopherol, gamma-tocopherol, or total cholesterol concentrations. Self-reported fruit and vegetable intake increased by a mean 1.4 (SD 1.7) portions in the intervention group and by 0.1 (1.3) portion in the control group (between-group difference=1.4, 95% CI 1.2-1.6; p<0.0001). Systolic blood pressure fell more in the intervention group than in controls (difference=4.0 mm Hg, 2.0-6.0; p<0.0001), as did diastolic blood pressure (1.5 mm Hg, 0.2-2.7; p=0.02). The effects of the intervention on fruit and vegetable consumption, plasma antioxidants, and blood pressure would be expected to reduce cardiovascular disease in the general population.

Plasma antioxidant vitamins and carotenoids and age-related cataract

Objective To investigate the relationships between plasma concentrations of antioxidant vitamins and carotenoids and nuclear, cortical, and posterior subcapsular cataracts in a group of elderly men and women. Design Cross-sectional survey. Participants Three hundred seventy-two men and women, aged 66 to 75 years, born and still living in Sheffield, England. Methods The Lens Opacities Classification System (LOCS) III was used to grade nuclear, cortical, and posterior subcapsular lens opacities. Fasting blood samples were taken to assess plasma concentrations of vitamin C, vitamin E, α-carotene, β-carotene, lycopene, lutein, zeaxanthin, and β-cryptoxanthin. Main outcome measures Logistic regression analyses of the associations between plasma vitamin concentrations and cataract subtype, adjusting for age, gender, and other risk factors. Results After adjustment for age, gender, and other risk factors, risk of nuclear cataract was lowest in people with the highest plasma concentrations of α-carotene (odds ratio [OR], 0.5; 95% confidence interval [CI], 0.3–0.9, P for trend 0.006) or β-carotene (OR, 0.7; 95% CI, 0.4–1.4, P for trend 0.033). Risk of cortical cataract was lowest in people with the highest plasma concentrations of lycopene (OR, 0.4; 95% CI, 0.2–0.8, P for trend 0.003), and risk of posterior subcapsular cataract was lowest in those with higher concentrations of lutein (OR, 0.5; 95% CI, 0.2–1.0, P for trend 0.012). High plasma concentrations of vitamin C, vitamin E, or the carotenoids zeaxanthin and β-cryptoxanthin were not associated with decreased risk. Conclusions These findings suggest that a diet rich in carotenoids may protect against cataract development, but because they are based on observational data, they need to be confirmed in randomized controlled trials.

Antioxidant vitamin status and carotid atherosclerosis in the elderly

The oxidative modification of LDL is thought to play a crucial role in the initiation of atherosclerosis. Antioxidant vitamins can protect LDL from oxidation, and high intakes or blood concentrations of these vitamins have been linked with a reduced risk of cardiovascular disease. Few data are available on the importance of antioxidant vitamins in earlier stages of atherogenesis. We investigated the cross-sectional relation between antioxidant vitamin status and carotid atherosclerosis in a group of elderly persons. The study sample comprised 468 men and women aged 66-75 y living in Sheffield, United Kingdom. Duplex ultrasonography was used to measure intima-media thickness and the degree of stenosis in the extracranial carotid arteries. Antioxidant vitamin status was assessed by measuring fasting plasma concentrations of vitamin C, vitamin E, and beta-carotene. In the men, after adjustment for age and cardiovascular disease risk factors, a 20% higher plasma vitamin C concentration was associated with a 0.004-mm smaller intima-media thickness; a 20% higher beta-carotene concentration was associated with a 0.005-mm smaller intima-media thickness. Compared with men with high blood concentrations of beta-carotene or cholesterol-adjusted vitamin E, those with low blood concentrations of these vitamins were 2.5 times as likely to have carotid stenosis of >30%. We found no significant trends between plasma concentrations of antioxidant vitamins and either measure of carotid atherosclerosis in the women. A high antioxidant vitamin status may help to prevent the initiation and progression of early atherosclerotic lesions in men.

Lipid peroxidation and plasma antioxidant micronutrients in Crohn disease

In Crohn disease (CD), the increased production of reactive oxygen species from activated neutrophils may reduce plasma concentrations of antioxidant vitamins and result in increased oxidative stress. We compared lipid peroxidation, a measure of reactive-oxygen-species production, and plasma antioxidant vitamin concentrations between CD patients and healthy control subjects. Thirty-seven nonsmoking CD patients (22 women and 15 men) were compared with an equal number of healthy control subjects who were matched by age, sex, and body mass index. In patients the mean CD activity index (CDAI) was 141.2 +/- 18.7 (range: 9.0-514), and 11 of 37 patients (30%) had a CDAI > or =150. Seventy-eight percent of patients were taking > or = 1 medication. Medication use by subjects included the following: 5-aminosalicylic acid (40% of subjects), antibiotics (22%), oral corticosteroids (30%), and immunosuppressants (19%). Lipid peroxidation as measured by breath pentane output (CD patients, 7.47 +/- 0.98 pmol x kg(-1) x min(-1); control subjects, 4.97 +/- 0.48 pmol x kg(-1) x min(-1); P < or = 0.025), breath ethane output (CD patients, 11.24 +/- 1.17 pmol x kg(-1) x min(-1); control subjects, 5.46 +/- 0.71 pmol x kg(-1) x min(-1); P < or = 0.0005) and F2-isoprostane (CD patients, 78.6 +/- 8.0 ng/L; control subjects, 60.6 +/- 3.7 ng/L; P < or = 0.047) were significantly higher in CD patients than in control subjects. Plasma antioxidant vitamins (ascorbic acid, alpha- and beta-carotene, lycopene, and beta-cryptoxanthin) were all significantly lower in CD patients than in control subjects. There were no significant differences in macro- and micronutrient intakes between groups. Patients with CD are oxidatively stressed, which was observed even though 70% of patients had a CDAI < or =150 and 78% of them were taking medications to treat CD.

Racial group differences in plasma concentrations of antioxidant vitamins and carotenoids in hemodialysis patients

Approximately 50% of the mortality in hemodialysis patients is due to cardiovascular disease. Antioxidant vitamins and carotenoids may be protective because oxidation of low-density lipoproteins appears to be a necessary prerequisite for the development of atherogenesis, and hemodialysis itself may stimulate the generation of oxygen reactive species. African Americans comprise a substantial proportion of dialysis patients because they have higher rates of hypertension, glomerulonephritis, and diabetic end-stage renal disease than do whites. The purpose of this cross-sectional study was to determine the plasma concentrations of antioxidant vitamins and carotenoids in hemodialysis patients and to investigate whether differences in these concentrations in the major racial or ethnic groups exist. Plasma concentrations of alpha- and gamma-tocopherol, carotenoids, and retinol were measured with HPLC and plasma vitamin C was measured with a spectrophotometric method in 109 white and African American hemodialysis patients. Dietary intakes of selected micronutrients were also compared by using data from a food-frequency questionnaire. Overall, plasma vitamin C and alpha-tocopherol concentrations were comparable but plasma carotenoid concentrations were lower than those reported for other populations. African American patients had significantly higher mean plasma concentrations of retinol (P < 0.04), lutein (P < 0.02), and total carotenoids minus lycopene (P < 0.04); whites had significantly higher mean plasma concentrations of alpha-tocopherol (P < 0.02), independent of age and plasma lipid concentrations. Diabetes comorbidity had an independent negative association with plasma beta-carotene concentration but was not associated with other measures.

Cretan Mediterranean diet for prevention of coronary heart disease

As a result of the Seven Countries Study, the Mediterranean diet has been popularized as a healthy diet. Nevertheless, it has not replaced the prudent diet commonly prescribed to coronary patients. Recently, we completed a secondary, randomized, prospective prevention trial in 605 patients recovering from myocardial infarction in which we compared an adaptation of the Cretan Mediterranean diet with the usual prescribed diet. After a mean follow-up period of 27 mo, recurrent myocardial infarction, all cardiovascular events, and cardiac and total death were significantly decreased by > 70% in the group consuming the Mediterranean diet. These protective effects were not related to serum concentrations of total, low-density-lipoprotein (LDL), or high-density-lipoprotein (HDL) cholesterol. In contrast, protective effects were related to changes observed in plasma fatty acids: an increase in n-3 fatty acids and oleic acid and a decrease in linoleic acid that resulted from higher intakes of linolenic and oleic acids, but lower intakes of saturated fatty acids and linoleic acid. In addition, higher plasma concentrations of antioxidant vitamins C and E were observed. We conclude that a Cretan Mediterranean diet adapted to a Western population protected against coronary heart disease much more efficiently than did the prudent diet. Thus, it appears that the favorable life expectancy of the Cretans could be largely due to their diet.