Dietary antioxidants and cardiovascular disease

Evaluation of serum antioxidants in age-related hearing loss

BACKGROUND

Age-related hearing loss (ARHL) has been linked to the shift in the pro-oxidant/antioxidant ratio. Our objectives were to assess serum levels of retinol and zinc among the elderly individuals and to correlate the levels with hearing threshold.

METHODS

Prospective study of apparently healthy individuals aged ≥60 years of age. Participants had complete clinical history, physical examination and pure tone average conducted. Blood samples were collected for determination of serum levels of retinol and zinc. Mann-Whitney U test was used to compare retinol and zinc values. Pearson's correlation test was used to determine the relationship between hearing threshold and serum levels of retinol and zinc.

RESULTS

Among 126 elderly participants with mean age 67 ± 2.7 years; the mean pure tone average for air conduction was 29.3 ± 1.6 dBHL while the mean bone conduction was 36.5 ± 1.8 dBHL. The median values of serum retinol and zinc levels in the elderly participants who had hearing loss in the speech frequencies were 52 and 83.3 μg/L, respectively, while among participants with normal hearing threshold, values were 50 and 89.9 μg/L, respectively (p = 0.59 and 0.99, respectively). For the high frequencies, the median value of serum retinol and zinc levels among the elderly participants with normal hearing threshold was 70.3 and 99.9 μg/L, while among those with hearing loss, it was 46.9 and 83.2 μg/L, respectively (p = 0.000 and 0.005, respectively).

CONCLUSION

Serum retinol and zinc levels were significantly lower among elderly with hearing loss involving the high frequencies. This is added evidence to extant literature on the possible role of antioxidants in the development of ARHL and suggests further study on the effect of antioxidants supplementation in the control of ARHL which is presently controversial and inconclusive.

Meta-analysis of the association between whole grain intake and coronary heart disease risk

Epidemiologic studies evaluating the association of whole-grain intake with risk for coronary heart disease (CHD) have produced inconsistent results. The aim of this meta-analysis was to summarize the evidence from observed studies regarding the association between whole-grain intake and risk for CHD. Pertinent studies were identified by searching the Web of Knowledge and PubMed up to July 2014. A random-effects model was used to combine the results. Publication bias was estimated using Begg's funnel plot and Egger's regression asymmetry test. Ultimately, fourteen reports of 18 studies (15 cohort studies and 3 case-control studies) involving 14,427 patients with CHD and 400,492 participants were used in this meta-analysis. Pooled results suggested that highest whole-grain intake amount compared with the lowest amount was significantly associated with reduced risk for CHD (summary relative risk 0.787, 95% confidence interval 0.743 to 0.833), with no between-study heterogeneity observed (I(2) = 0%, p = 0.537). The association was significant in cohort studies but not in case-control studies. Inverse associations were also found in the United States and Europe. No publication bias was found. In conclusion, this meta-analysis indicates that higher whole-grain intake has a protective effect against CHD.

Habitual high intake of fatty fish is related to lower levels of F₂-isoprostane in healthy women

OBJECTIVE

The aim of this study was to determine whether habitual dietary intake of fatty fish, whole grains, fruits and vegetables, or a combination of them all, is associated with oxidative stress levels, measured as urine concentration of 8-iso-prostaglandin F2α (8-iso-PGF2α) in healthy women.

METHODS

Eighty-one participants were included in this cross-sectional study. Mean age of the women was 26.1 ± 6.2 (mean ± SD) years and mean body mass index (BMI) was 22.4 ± 3.0 kg/m(2). The concentration of 8-iso-PGF2α was determined in urine, and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels were determined in blood. Participants' habitual fish, whole grain, fruit, and vegetable intake was estimated from a food frequency questionnaire.

RESULTS

In the multivariate analysis, there was a significant inverse association between 8-iso-PGF2α and high fatty fish intake (P < 0.001). Fatty fish intake was positively correlated to serum phospholipid concentrations of EPA (P = 0.001) and DHA (P = 0.002). A borderline effect of DHA was seen on 8-iso-PGF2α, but higher serum phospholipid concentrations of fatty acids were generally not related to lower F2-isoprostane levels. No overall effect from whole grains or fruits and vegetables was seen.

CONCLUSIONS

The results indicate that high intake of fatty fish is related to lower levels of oxidative stress, but high levels of ω-3 fatty acids in intake may not alone explain the effect. High habitual intake of whole grains or fruits and vegetables did not seem to affect the F2-isoprostane level.

Association between paraoxonases gene expression and oxidative stress in hepatotoxicity induced by CCl4

Objectives. The purpose of the study is to evaluate the hepatoprotective effect of rutin in carbon tetrachloride- (CCl₄-) induced liver injuries in rat model. Methods. Forty male Wistar albino rats were divided into four groups. Group I was the control group and received dimethyl sulphoxide (DMSO) and olive oil. Group II received rutin. Groups III was treated with CCl₄. Group IV was administered rutin after 48 h of CCl₄ treatment. Liver enzymes level, lipid profile, lipid peroxidation, and hydrogen peroxide were measured. The genes expression levels were monitored by real time RT-PCR and western blot techniques. Results. CCl₄ group showed significant increase in alanine aminotransferase (ALT), aspartate aminotransferase (AST), thiobarbituric acid reactive substances (TBAR), hydrogen peroxide (H₂O₂), and lipid profile and a significant decrease in glutathione peroxidase (GPx), glutathione S transferase (GST), catalase (CAT), paraoxonase-1 (PON-1), paraoxonase-3 (PON-3), peroxisome proliferator activated receptor delta (PPAR-δ), and ATP-binding cassette transporter 1 (ABAC1) genes expression levels. Interestingly, rutin supplementation completely reversed the biochemical and gene expression levels induced by CCl₄ to control values. Conclusion. CCl₄ administration causes aberration of genes expression levels in oxidative stress pathway resulting in DNA damage and hepatotoxicity. Rutin causes hepatoprotective effect through enhancing the antioxidant genes.

Immunomodulatory effect of a wild blueberry anthocyanin-rich extract in human Caco-2 intestinal cells

Intestinal inflammation is a natural process crucial for the maintenance of gut functioning. However, abnormal or prolonged inflammatory responses may lead to the onset of chronic degenerative diseases, typically treated by means of pharmacological interventions. Dietary strategies for the prevention of inflammation are a safer alternative to pharmacotherapy. Anthocyanins and other polyphenols have been documented to display anti-inflammatory activity. In the present study, three bioactive fractions (anthocyanin, phenolic, and water-soluble fractions) were extracted from a wild blueberry powder. The Caco-2 intestinal model was used to test the immunomodulatory effect of the above fractions. Only the anthocyanin-rich fraction reduced the activation of NF-κB, induced by IL-1β in intestinal epithelial Caco-2 cells. Specifically, concentrations of 50 and 100 μg mL(-1) decreased NF-κB activation by 68.9 and 85.2%, respectively (p ≤ 0.05). These preliminary results provide further support for the role of food bioactives as potential dietary anti-inflammatory agents.

The effects of omega-3 plus vitamin E and zinc plus vitamin C supplementation on cardiovascular risk markers in postmenopausal women with type 2 diabetes

BACKGROUND

We investigate the effects of omega-3 plus vitamin E and vitamin C plus zinc supplementations on cardiovascular risk markers in postmenopausal women with type 2 diabetes.

METHODS

In this double-blind placebo-controlled clinical trial, 75 postmenopausal women with type 2 diabetes were randomly assigned to one of three groups to take, daily, for 12 weeks: (1) 1.8 g omega-3 fatty acids plus 400 mg vitamin E; (2) 5 mg zinc plus 300 mg vitamin C; or (3) a placebo.

RESULTS

Although the cardiovascular risk markers variations decreased at the end of intervention, we did not find any significant differences in cardiovascular risk markers between therapeutic groups and the control group. Results of repeated measures analysis of variance (ANOVA) of markers showed that total cholesterol, low-density lipoprotein (LDL) cholesterol, Apo A1 and Apo B100 in two time periods were significant (p = 0.001). The level of total and LDL cholesterol decreased significantly (p = 0.05) in patients diagnosed with diabetes equal or less than 7 years in the group receiving omega-3 plus vitamin E. However, decreased LDL cholesterol (p = 0.003) and increased high-density lipoprotein (HDL) cholesterol (p = 0.03) were predominant in patients who had been diagnosed with diabetes equal or less than 7 years in the group receiving zinc plus vitamin C.

CONCLUSION

The effectiveness of nutraceutical supplementation was varied on biochemical biomarkers based on the kind of supplement or supplement pharmacogenomics, duration of diabetes affected and other pathophysiologic status in studied groups.

Consumption of nuts and legumes and risk of incident ischemic heart disease, stroke, and diabetes: a systematic review and meta-analysis

BACKGROUND

Relations between the consumption of nuts and legumes and risk of ischemic heart disease (IHD), stroke, and diabetes have not been well established.

OBJECTIVE

We systematically investigated and quantified associations of nut and legume consumption with incident IHD, stroke, and diabetes.

DESIGN

We systematically searched multiple databases to identify randomized controlled trials or observational studies that examined the relations. Studies were excluded if they reported only intermediate physiologic measures, soft cardiovascular outcomes, or crude risk estimates. Data were extracted independently and in duplicate. We assessed pooled dose-response relations by using a generalized least-squares trend estimation, and prespecified sources of heterogeneity were assessed by using metaregression. The potential for publication bias was explored by using funnel plots, Begg's and Egger's tests, and Duval and Tweedie trim-and-fill methods.

RESULTS

Of 3851 abstracts, 25 observational studies (23 prospective and 2 retrospective studies) and 2 trial reports met inclusion criteria and comprised 501,791 unique individuals and 11,869 IHD, 8244 stroke, and 14,449 diabetes events. The consumption of nuts was inversely associated with fatal IHD (6 studies; 6749 events; RR per 4 weekly 28.4-g servings: 0.76; 95% CI: 0.69, 0.84; I(2) = 28%), nonfatal IHD (4 studies; 2101 events; RR: 0.78; 0.67, 0.92; I(2) = 0%), and diabetes (6 studies; 13,308 events; RR: 0.87; 0.81,0.94; I(2) = 22%) but not stroke (4 studies; 5544 events). Legume consumption was inversely associated with total IHD (5 studies; 6514 events; RR per 4 weekly 100-g servings: 0.86; 0.78, 0.94; I(2) = 0%) but not significantly associated with stroke (6 studies; 6690 events) or diabetes (2 studies; 2746 events). A meta-regression did not identify the effect modification by age, duration of follow-up, study location, or study quality. Mixed evidence was seen for publication bias, but analyses by using the Duval and Tweedie trim-and-fill method did not appreciably alter results.

CONCLUSION

This systematic review supports inverse associations between eating nuts and incident IHD and diabetes and eating legumes and incident IHD.

Total antioxidant intake in relation to prostate cancer incidence in the Health Professionals Follow-Up Study

Epidemiologic evidence on the association of antioxidant intake and prostate cancer incidence is inconsistent. Total antioxidant intake and prostate cancer incidence have not previously been examined. Using the ferric-reducing antioxidant potential (FRAP) assay, the total antioxidant content (TAC) of diet and supplements was assessed in relation to prostate cancer incidence. A prospective cohort of 47,896 men aged 40-75 years was followed from 1986 to 2008 for prostate cancer incidence (N = 5,656), and they completed food frequency questionnaires (FFQs) every 4 years. A FRAP value was assigned to each item in the FFQ, and for each individual, TAC scores for diet, supplements and both (total) were calculated. Major contributors of TAC intake at baseline were coffee (28%), fruit and vegetables (23%) and dietary supplements (23%). In multivariate analyses for dietary TAC a weak inverse association was observed [highest versus lowest quintiles: 0.91 (0.83-1.00, p-trend = 0.03) for total prostate cancer and 0.81 (0.64-1.01, p-trend = 0.04) for advanced prostate cancer]; this association was mainly due to coffee. No association of total TAC on prostate cancer incidence was observed. A positive association with lethal and advanced prostate cancers was observed in the highest quintile of supplemental TAC intake: 1.28 (0.98-1.65, p-trend < 0.01) and 1.15 (0.92-1.43, p-trend = 0.04). The weak association between dietary antioxidant intake and reduced prostate cancer incidence may be related to specific antioxidants in coffee, to nonantioxidant coffee compounds or other effects of drinking coffee. The indication of increased risk for lethal and advanced prostate cancers with high TAC intake from supplements warrants further investigation.

Vegetarianism as a protective factor for reflux esophagitis: a retrospective, cross-sectional study between Buddhist priests and general population

BACKGROUND/AIMS

Several risk factors for reflux esophagitis, such as smoking, alcohol consumption, obesity, and metabolic syndrome, are recognized. But vegetarianism as a protective factor for reflux esophagitis has not been reported. The aim of this study is to elucidate the protective effect of vegetarianism for reflux esophagitis.

METHODS

This is a cross-sectional study that compared the prevalence of reflux esophagitis of 148 Buddhist priests, who are obligatory vegetarians with that of age- and sex-matched controls who underwent health checkups in a health promotion center.

RESULTS

The prevalence of reflux esophagitis was higher in the control group than in the Buddhist priest group (21.6 vs 12.2 %). Weight, body mass index, waist circumference, waist-to-hip ratio, and abdominal adipose tissue area were higher and high density lipoprotein (HDL) cholesterol and total cholesterol were lower in the Buddhist priest group. The prevalence of metabolic syndrome was higher in the Buddhist priest group than the control group (30.4 vs 17.6 %). In univariate analysis, male sex (odds ratio [OR] = 3.325; 95 % confidence interval [CI], 1.659-6.666), current smoking (OR = 3.37; 95 % CI, 1.439-7.881), alcohol consumption (OR = 2.75; 95 % CI, 1.375-5.481), waist circumference (OR = 1.99; 95 % CI, 1.062-3.739), negative for Helicobacter pylori IgG antibody (OR = 1.89; 95 % CI, 1.018-3.491) and non-vegetarianism (OR = 1.99; 95 % CI, 1.062-3.739) were associated with reflux esophagitis. According to multivariate analysis, male sex (OR = 3.44; 95 % CI, 1.698-6.970), non-vegetarianism (OR = 2.08; 95 % CI, 1.086-3.974) and negative H. pylori IgG antibody (OR = 1.96; 95 % CI, 1.039-3.712) were significantly associated with reflux esophagitis.

CONCLUSIONS

A non-vegetarian diet is associated with reflux esophagitis.

Total antioxidant capacity of the diet and major neurologic outcomes in older adults

OBJECTIVE

To evaluate total antioxidant capacity of the diet, measured by the ferric-reducing antioxidant power (FRAP) assay, in relation to risks of dementia and stroke, as well as key structural brain volumes, in the elderly.

METHODS

We prospectively studied 5,395 participants in the Rotterdam Study, aged 55 years and older, who were dementia free and provided dietary information at study baseline; 5,285 individuals were also stroke free at baseline, and 462 were dementia and stroke free at the time of an MRI brain scan 5 years after baseline. Dietary data were ascertained using a semiquantitative food-frequency questionnaire, and combined with food-specific FRAP measurements from published tables; this information was aggregated across the diet to obtain "dietary FRAP scores." Multivariable-adjusted Cox proportional hazard models were used to estimate relative risks of dementia and stroke, and multivariable-adjusted linear regression was used to estimate mean differences in structural brain volumes, across tertiles of dietary FRAP scores.

RESULTS

During a median 13.8 years of follow-up, we identified approximately 600 cases each of dementia and stroke. In multivariable-adjusted models, we observed no associations between dietary FRAP scores and risk of dementia (p trend = 0.3; relative risk = 1.12, 95% confidence interval = 0.91-1.38, comparing the highest vs lowest FRAP tertiles) or risk of stroke (p trend = 0.3; relative risk = 0.91, 95% confidence interval = 0.75-1.11, comparing extreme FRAP tertiles); results were similar across subtypes of these outcomes. Dietary FRAP scores were unrelated to brain tissue volumes as well.

CONCLUSIONS

Total antioxidant capacity of the diet, measured by dietary FRAP scores, does not seem to predict risks of major neurologic diseases.

Vitamin C enhances vitamin E status and reduces oxidative stress indicators in sea bass larvae fed high DHA microdiets

Docosahexaenoic acid (DHA) is an essential fatty acid necessary for many biochemical, cellular and physiological functions in fish. However, high dietary levels of DHA increase free radical injury in sea bass (Dicentrarchus labrax) larvae muscle, even when vitamin E (α-tocopherol, α-TOH) is increased. Therefore, the inclusion of other nutrients with complementary antioxidant functions, such as vitamin C (ascorbic acid, vitC), could further contribute to prevent these lesions. The objective of the present study was to determine the effect of vitC inclusion (3,600 mg/kg) in high DHA (5% DW) and α-TOH (3,000 mg/kg) microdiets (diets 5/3,000 and 5/3,000 + vitC) in comparison to a control diet (1% DHA DW and 1,500 mg/kg of α-TOH; diet 1/1,500) on sea bass larvae growth, survival, whole body biochemical composition and thiobarbituric acid reactive substances (TBARS) content, muscle morphology, skeletal deformities and antioxidant enzymes, insulin-like growth factors (IGFs) and myosin expression (MyHC). Larvae fed diet 1/1,500 showed the best performance in terms of total length, incidence of muscular lesions and ossification degree. IGFs gene expression was elevated in 5/3,000 diet larvae, suggesting an increased muscle mitogenesis that was confirmed by the increase in the mRNA copies of MyHC. vitC effectively controlled oxidative damages in muscle, increased α-TOH larval contents and reduced TBARS content and the occurrence of skull deformities. The results of the present study showed the antioxidant synergism between vitamins E and C when high contents of DHA are included in sea bass larvae diets.

Differing Relations to Early Atherosclerosis between Vitamin C from Supplements vs. Food in the Los Angeles Atherosclerosis Study: A Prospective Cohort Study

OBJECTIVE

To determine the relationship of vitamin c intake from supplements vs food on early atherosclerosis detected by carotid intima media thickness (IMT).

BACKGROUND

Oxidative stress and endothelial dysfunction play a critical role in the pathogenesis of atherosclerosis. Dietary vitamin C appears to have anti-oxidant properties and beneficial relations to endothelial function, yet vitamin C taken as a vitamin supplement does not appear to protect from cardiovascular events. The impact of vitamin c intake from supplements vs food on progression of atherosclerosis is unknown.

METHODS

We examined 3-year progression of carotid IMT in a randomly sampled cohort of 573 healthy women and men aged 40-60 years. Progression of carotid IMT was determined bilaterally with B-mode ultrasound at 3 examinations (1.5-year intervals). Intake of dietary vitamin C was measured by six, 24-hour recall interviews. Intake of vitamin C from vitamin supplements was measured by questionnaire in quartiles of supplement intake and no supplement. Vitamin C wasmeasured in plasma as ascorbic acid.

RESULTS

Carotid IMT progressed 10.0±16.5 μm/year (mean±SD) among all those with follow-up (n=500; 87%). For those who took vitamin C supplements, carotid IMT progression increased with dose (p-trend=0.0009). Among persons in the highest quartile (857-5000 mg/day) of vitamin C supplement intake compared to those not consuming any vitamin C supplements, carotid IMT progression increased three-fold (20.3±2.6 versus 7.6±1.8 μm/year (mean±SD); p<0.001). The adverse association of vitamin C supplement intake with carotid IMT was two-fold greater in the upper tertile of serum cholesterol compared to the lower two tertiles (p=0.01). In contrast to the adverse association of vitamin C supplements, vitamin C intake from food had a weak protective relationship on carotid IMT progression (reduced progression -5.0±1.9 μm/year; p=0.008).

CONCLUSIONS

Vitamin C supplementation is associated with accelerated early atherosclerosis measured by carotid IMT compared to a protective association with vitamin C from food. Theadverse association of vitamin C supplementation may be greater in patients with higher serum cholesterol levels. The current results provide a potential mechanistic understanding for the observed differences between Vitamin C in supplements vs food in prior studies. Given these observations,vitamin C supplementation does not appear to be currently advisable for prevention or treatment of atherosclerosis.

Comparison of the simple cyclic voltammetry (CV) and DPPH assays for the determination of antioxidant capacity of active principles

Antioxidant activity of a number of small (low molecular weight) natural compounds found in spices, condiments or drugs (gallic acid, sesamol, eugenol, thymol, carvacrol, vanillin, salicylaldehyde, limonene, geraniol, 4-hexylresorcinol, etc.) has been evaluated using electrochemical and DPPH• radical scavenging measurements. Structural analysis of the tested compound suggest a remarkable activity for phenol derivatives and the importance of the -R groups located on the phenolic ring in the molecule's ability to act as free radical scavenging as well as their influence in the electrochemical behavior. The voltammetric method can be used for the determination of the antioxidant capability in the same manner as the DPPH• radical scavenging because of the correlation found between oxidation potentials and anti-radical power (ARP = 1/EC₅₀). Such electrochemical determination is fast and cheap and allows making measurements under a variety of experimental conditions. The accuracy of the electrochemical measurements is the same for all the compounds, irrespective of their scavenging activity, the opposite of what occurs in the DPPH• test.

Protection of lung fibroblast MRC-5 cells against hydrogen peroxide-induced oxidative damage by 0.1-2.8 kDa antioxidative peptides isolated from whey protein hydrolysate

Antioxidative peptides (0.1-2.8 kDa) obtained from gel filtration of Alcalase-hydrolysed whey protein were subjected to individual peptide isolation by RP-HPLC. The sub-fraction P4 and a prominent pentapeptide identified by mass spectrometry (Val-His-Leu-Lys-Pro) (P4c) were found to be highly antioxidative, therefore, used to assess the efficacy against hydrogen peroxide (H(2)O(2))-induced human lung fibroblast MRC-5 cell oxidative injury. MRC-5 cells were damaged by incubation with H(2)O(2), but cell death was significantly reduced when exposed to P4 and P4c (P<0.05). Compared to the H(2)O(2)-damaged model control, P4 and P4c enhanced the activity of cell superoxide dismutase, glutathione peroxidase, and catalase, and decreased the levels of malonaldehyde (P<0.05). These results, with a more pronounced action of P4c than P4, demonstrated that antioxidative peptides had a significant protection of MRC-5 cells against the toxicity caused by H(2)O(2).

Deltamethrin-induced oxidative stress and biochemical changes in tissues and blood of catfish (Clarias gariepinus): antioxidant defense and role of alpha-tocopherol

Background

The pyrethroid class of insecticides, including deltamethrin, is being used as substitutes for organochlorines and organophosphates in pest-control programs because of their low environmental persistence and toxicity. This study was aimed to investigate the impact of commonly used pesticides (deltamethrin) on the blood and tissue oxidative stress level in catfish (Clarias gariepinus); in addition to the protective effect of α-tocopherol on deltamethrin induced oxidative stress.

Catfish were divided into three groups, 1^st control group include 20 fish divided into two tanks each one contain 10 fish, 2^nd deltamethrin group, where Fish exposed to deltamethrin in a concentration (0.75 μg/l) and 3^rd Vitamin E group, Fish exposed to deltamethrin and vitamin E at a dose of 12 μg/l for successive 4 days.

Serum, liver, kidney and Gills were collected for biochemical assays. Tissue oxidative stress biomarkers malondialdhyde (MDA) and catalase activity in liver, kidney and gills tissues, serum liver enzymes (ALT and AST), serum albumin, total protein, urea and creatinine were analysed.

Results

Our results showed that 48 h. exposure to 0.75 μg/l deltamethrin significantly (p < 0.05) increased lipid peroxidation (MDA) in the liver, kidney and gills while catalase activity was significantly decreased in the same tissues. This accompanied by significant increase in serum ALT, AST activity, urea and creatinine and a marked decrease in serum albumin and total proteins.

Conclusions

It could be concluded that deltamethrin is highly toxic to catfish even in very low concentration (0.75 μg/l). Moreover the effect of deltamethrin was pronounced in the liver of catfish in comparison with kidneys and gills. Moreover fish antioxidants and oxidative stress could be used as biomarkers for aquatic pollution, thus helping in the diagnosis of pollution. Adminstration of 12 μg/l α-tocopherol restored the quantified tissue and serum parameters, so supplementation of α-tocopherol consider an effective way to counter the toxicity of deltamethrin in the catfish.

Dried blood spot (DBS) sample collection for determination of the oxidative stress biomarker 8-epi-PGF(2α) in humans using liquid chromatography/tandem mass spectrometry

RATIONALE

F2-isoprostanes are a series of prostaglandin F2-like compounds that are formed by free-radical-catalyzed peroxidation of arachidonic acid (ARA). Several F2-isoprostanes, but in particular 8-epi-PGF(2α), are widely used as oxidative stress biomarkers. In this study we have developed an analytical tool for finger-tip blood sampling and analysis of 8-epi-PGF(2α) from dried blood spots (DBS).

METHODS

We have applied solid-phase extraction (SPE) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) for the extraction, separation and detection of 8-epi-PGF(2α) in DBS and have studied the stability of this marker using the DBS collection platform.

RESULTS

The mass limit of detection (mLOD) for 8-epi-PGF(2α) extracted from DBS samples was 1.5 pg while the concentration limit of detection (cLOD) and concentration limit of quantitation (cLOQ) were 6 pg/mL and 18 pg/mL, respectively. All values based on triplicate analysis. Sufficient stability of 8-epi-PGF(2α) in DBS was achieved by preconditioning DBS paper with vitamin E and BHT.

CONCLUSIONS

The developed method is sensitive, specific, robust, efficient, and can accurately measure endogenous concentrations of 8-epi-PGF(2α) in DBS. Thus, it offers an analytical approach to measure 8-epi-PGF(2α) by a novel sample collection technique that is less invasive and costly than conventional techniques.

Genetic determinants of dietary antioxidant status

Oxidative stress refers to a physiological state in which an imbalance between pro-oxidants and antioxidants results in oxidative damage. Oxidative stress has been associated with the development of numerous chronic diseases such as type 2 diabetes, cardiovascular disease (CVD), osteoporosis, and cancer. Endogenous production of free radicals occurs during normal physiological processes, such as aerobic metabolism, oxidation of biological molecules, and enzymatic activity. Environmental factors such as ultraviolet radiation, air pollution, and cigarette smoking can also contribute to the accumulation of free radicals in the body. Excess free radicals can damage tissues and promote the upregulation of disease-related pathways such as inflammation. Modulating oxidative stress by dietary supplementation with antioxidant micronutrients such as vitamins C and E or phytochemicals such as different carotenoids may help prevent or delay the development of certain diseases. However, research on antioxidant supplementation and disease has yielded inconsistent findings, which may be due, in part, to interindividual genetic variation. Polymorphisms in genes coding for endogenous antioxidant enzymes or proteins responsible for the absorption, transport, distribution, or metabolism of dietary antioxidants have been shown to affect antioxidant status and response to supplementation. These genetic variants may also interact with environmental factors, such as diet, to determine an individual's overall antioxidant status. This chapter examines current knowledge of the relationship between genetic variation and dietary antioxidant status.

Oxidised fish oil does not influence established markers of oxidative stress in healthy human subjects: a randomised controlled trial

Intake of fish oil reduces the risk of CHD and CHD deaths. Marine n-3 fatty acids (FA) are susceptible to oxidation, but to our knowledge, the health effects of intake of oxidised fish oil have not previously been investigated in human subjects. The aim of the present study was to investigate markers of oxidative stress, lipid peroxidation and inflammation, and the level of plasma n-3 FA after intake of oxidised fish oil. In a double-blinded randomised controlled study, healthy subjects (aged 18–50 years, n 54) were assigned into one of three groups receiving capsules containing either 8 g/d of fish oil (1·6 g/d EPA+DHA; n 17), 8 g/d of oxidised fish oil (1·6 g/d EPA+DHA; n 18) or 8 g/d of high-oleic sunflower oil (n 19). Fasting blood and morning spot urine samples were collected at weeks 0, 3 and 7. No significant changes between the different groups were observed with regard to urinary 8-iso-PGF2α; plasma levels of 4-hydroxy-2-hexenal, 4-hydroxy-2-nonenal and α-tocopherol; serum high sensitive C-reactive protein; or activity of antioxidant enzymes in erythrocytes. A significant increase in plasma level of EPA+DHA was observed in both fish oil groups, but no significant difference was observed between the fish oil groups. No changes in a variety of in vivo markers of oxidative stress, lipid peroxidation or inflammation were observed after daily intake of oxidised fish oil for 3 or 7 weeks, indicating that intake of oxidised fish oil may not have unfavourable short-term effects in healthy human subjects.

Antioxidant capacity in cultivated and wild Solanum species: the effect of wound stress

Wild potatoes are of increasing interest as a gene pool in breeding. In this study, 23 genotypes of two cultivated (S. tuberosum subsp. andigena, S. phureja) and two wild Solanum species (S. chacoense, S. pinnatisectum) were evaluated for contents of soluble phenols and soluble proteins as well as their antioxidant capacity measured as ascorbic acid and trolox equivalent. Amounts of phenols present in tuber tissue ranged from 0.25 to 2.84 mg kg(-1) fw. On average, S. pinnatisectum (pnt) exhibited 3.9-fold greater quantities of phenols in its tuber tissue than the other Solanum species. In pnt tissue, high phenol content coincided with high levels of soluble proteins and antioxidants. It is concluded that an involvement of individual accessions of pnt in breeding could be profitable for the antioxidant potential and thus for the nutritional value of new potato cultivars. The results also revealed that soluble phenols as well as proteins present in tuber tissue substantially contributed to the total antioxidant capacity of potatoes. Moreover, it was found that quantities of soluble phenols, proteins and antioxidants increased notably upon wounding the tubers, a fact which underlines the role of all these components in wound stress responses of potatoes.

Micronutrient-enriched rapeseed oils improve the brain oxidant/antioxidant system in rats fed a high-fat diet

The main proposal of this study was to evaluate in vivo whether micronutrient-enriched rapeseed oils obtained using different crushing and refining procedures and characterized by different quantities and qualities of micronutrients (optimized oils) could have any beneficial effect on the antioxidant status of the brain. Sprague-Dawley rats were fed a high-fat diet for 4 weeks. The lipid source consisted of 20% optimized rapeseed oils with different quantities and qualities of micronutrients. The control group received traditional refined rapeseed oil. The experimental optimized oils decreased lipid peroxidation and increased endogenous antioxidant status in parallel with the enhancement of micronutrients. No alteration in acetylcholinesterase activity was induced by the high-fat diet in any experimental group. These results indicate that a regular intake of optimized rapeseed oils can prevent oxidative stress, providing evidence that optimized rapeseed oils could be a functional food with potentially important neuroprotective properties.

Vegetarian diet improves insulin resistance and oxidative stress markers more than conventional diet in subjects with Type 2 diabetes

AIMS

The aim of this study was to compare the effects of calorie-restricted vegetarian and conventional diabetic diets alone and in combination with exercise on insulin resistance, visceral fat and oxidative stress markers in subjects with Type 2 diabetes.

METHODS

A 24-week, randomized, open, parallel design was used. Seventy-four patients with Type 2 diabetes were randomly assigned to either the experimental group (n = 37), which received a vegetarian diet, or the control group (n = 37), which received a conventional diabetic diet. Both diets were isocaloric, calorie restricted (-500 kcal/day). All meals during the study were provided. The second 12 weeks of the diet were combined with aerobic exercise. Participants were examined at baseline, 12 weeks and 24 weeks. Primary outcomes were: insulin sensitivity measured by hyperinsulinaemic isoglycaemic clamp; volume of visceral and subcutaneous fat measured by magnetic resonance imaging; and oxidative stress measured by thiobarbituric acid reactive substances. Analyses were by intention to treat.

RESULTS

Forty-three per cent of participants in the experimental group and 5% of participants in the control group reduced diabetes medication (P < 0.001). Body weight decreased more in the experimental group than in the control group [-6.2 kg (95% CI -6.6 to -5.3) vs. -3.2 kg (95% CI -3.7 to -2.5); interaction group × time P = 0.001]. An increase in insulin sensitivity was significantly greater in the experimental group than in the control group [30% (95% CI 24.5-39) vs. 20% (95% CI 14-25), P = 0.04]. A reduction in both visceral and subcutaneous fat was greater in the experimental group than in the control group (P = 0.007 and P = 0.02, respectively). Plasma adiponectin increased (P = 0.02) and leptin decreased (P = 0.02) in the experimental group, with no change in the control group. Vitamin C, superoxide dismutase and reduced glutathione increased in the experimental group (P = 0.002, P < 0.001 and P = 0.02, respectively). Differences between groups were greater after the addition of exercise training. Changes in insulin sensitivity and enzymatic oxidative stress markers correlated with changes in visceral fat.

CONCLUSIONS

A calorie-restricted vegetarian diet had greater capacity to improve insulin sensitivity compared with a conventional diabetic diet over 24 weeks. The greater loss of visceral fat and improvements in plasma concentrations of adipokines and oxidative stress markers with this diet may be responsible for the reduction of insulin resistance. The addition of exercise training further augmented the improved outcomes with the vegetarian diet.

Nuts: anti-atherogenic food?

The prevalence of cardiovascular disease as the leading cause of morbidity and mortality is increasing worldwide. This fact is mainly attributed to the modern lifestyle with predominant characteristics the change of dietary habits and the reduced physical activity which lead to metabolic disorders such as obesity and diabetes. Therefore, drastic dietary interventions are considered necessary in order to reduce cardiovascular risk. Nuts, as a nutritional component have drawn particular attention, due to their beneficial cardiovascular properties derived from their nutrient composition. This is a comprehensive review concerning the potential general effects of nuts. It includes data from older large epidemiologic studies as well as recent significant information from clinical trials regarding this topic. All studies conclude that nuts can play an important role as part of a healthy diet in order to minimize cardiovascular risk and obtain multiple health benefits.

Hepatoprotective and antioxidant effects of porcine plasma protein hydrolysates on carbon tetrachloride-induced liver damage in rats

Porcine plasma protein hydrolysate (PPH) prepared by alcalase for 5 h was fractioned by ultrafiltration. Four fractions, H(1) (MW>10k), H(2) (MW 6-10k), H(3) (MW 3-6k) and H(4) (MW<3k), were obtained. H(4) possessed the highest antioxidant activity as indicated by thiobarbituric acid-reactive substance values and hydroxyl radical scavenging activity (P<0.01). Male rats were pretreated with H(4) at dose of 50, 100, and 200 mg/kg of body weight orally once daily for 12 days, then they were treated intraperitoneally with a single dose of CCl(4) (2 mL/kg of body weight). The results showed that oral feeding of H(4) could significantly lower (P<0.01) the serum levels of hepatic enzyme markers (aspartate transaminase and alanine transaminase). Compared with the CCl(4)-only treatment group, levels of hepatic superoxide dismutase, glutathione peroxidase, catalase and total antioxidant capacity were significantly increased, and the malondialdehyde levels were sharply decreased (P<0.01) in rats treated by all doses of PPH fraction H(4). A histological examination of the liver showed that lesions, including necrosis, lymphocyte infiltration and fatty degeneration, were partially healed by treatment with H(4) fractions. These data suggest that in rats, PPH can protect the liver against CCl(4)-induced oxidative damage.

Antioxidant vitamins in barley green biomass

Two malting hulled varieties (Sebastian, Malz) and one nonmalting hull-less variety (AF Lucius) were used to assess vitamins C and E in the green biomass of young plants of spring barley ( Hordeum vulgare L.) in three stages of growth and development (BBCH 29, 31, 32-33). The samples from sampling I (BBCH 29) had statistically significantly higher vitamin C content and vitamin E activity compared to sampling I (BBCH 31). The highest average vitamin content was determined in the malting variety Sebastian (vitamin C, 520 mg 100 g(-1) DM; vitamin E, 73.06 mg kg(-1) DM) compared to the varieties Malz (501 mg 100 g(-1) DM; 61.84 mg kg(-1) DM) and AF Lucius (508 mg 100 g(-1) DM; 67.81 mg 100 g(-1) DM). The locality Kroměříž (Czech Republic, CR), with vitamin C and E contents of 524 mg 100 g(-1) DM and 68.74 mg kg(-1) DM, respectively, proved to be more suitable for growing green biomass compared to the locality Žabčice (CR) (content of vitamins C and E, 477 mg 100 g(-1) DM and 66.39 mg kg(-1) DM, respectively). During the research period (2005-2007), it was determined that the green mass of young plants of spring barley was a significant source of vitamins C and E in the growth stage BBCH 29; in later samplings (BBCH 32-33) the vitamin levels dropped (by as much as 48%). These vitamins are important antioxidants for human health. Therefore, "green barley" can be recommended for the preparation of natural dietary supplements and is preferred to synthetic vitamin preparations.

Total antioxidant capacity intake and colorectal cancer risk in the Health Professionals Follow-up Study

OBJECTIVE

To examine the association between total antioxidant capacity (TAC) intake and colorectal cancer incidence.

METHODS

TAC intake was assessed in 1986 and every 4 years thereafter in the Health Professionals Follow-up Study, a prospective cohort study of 47,339 men. Between 1986 and 2004, 952 colorectal cancer cases were diagnosed. Cox proportional hazards regression models were used to estimate relative risks (RR) and 95% confidence intervals (CI).

RESULTS

Comparing the highest versus lowest quintile, TAC intake from foods only (dietary TAC) was not associated with colorectal (multivariate-RR: 0.98; 95% CI: 0.78, 1.23) or colon (multivariate-RR: 1.20; 95% CI: 0.90, 1.61) cancer risk, but was inversely associated with rectal cancer risk (multivariate-RR: 0.58; 95% CI: 0.35, 0.96). For the same comparison, TAC intake from foods and supplements (total TAC) was not associated with colorectal (multivariate-RR: 0.91; 95% CI: 0.73, 1.14), colon (multivariate-RR: 1.01; 95% CI: 0.77, 1.33), or rectal (multivariate-RR: 0.85; 95% CI: 0.52, 1.38) cancer risk.

CONCLUSIONS

Dietary and total TAC intakes were not associated with colorectal and colon cancer risk. Dietary, but not total, TAC intake was inversely associated with rectal cancer risk, suggesting antioxidants per se may not be associated with rectal cancer risk.

Physical Activity and Adherence to Mediterranean Diet Increase Total Antioxidant Capacity: The ATTICA Study

We studied the association of physical activity and adherence to the Mediterranean diet, in total antioxidant capacity (TAC). A random sample of 1514 men and 1528 women was selected from Attica region. Physical activity was assessed with a translated version of the validated "International Physical Activity Questionnaire" (iPAQ), and dietary intake through a validated Food Frequency Questionnaire (FFQ). Adherence to the Mediterranean diet was assessed by the MedDietScore that incorporated the inherent characteristics of this diet. TAC was positively correlated with the degree of physical activity (P < .05). TAC was also positively correlated with MedDietScore (r = 0.24, P < .001). Stratified analysis by diet status revealed that the most beneficial results were observed to highly active people as compared to inactive, who also followed the Mediterranean diet (288 ± 70 μmol/L, 230 ± 50 μmol/L, resp.), after adjusting for various confounders. Increased physical activity and greater adherence to the Mediterranean diet were associated with increased total antioxidant capacity.

A "zero sample concentration approach": standardization of methods for the estimation of total antioxidant activity by the use of extrapolation to zero sample concentration. A novel standard. 1. ABTS cation radical scavenging

The study presents the general method of standardization of estimations of total antioxidant activity (TAA) by extrapolating parameters to zero sample concentration based on a pseudo-first-order kinetics model. To test its suitability, the method was applied to the ABTS cation radical scavenging assay, as the first choice. Two alternative methods of extrapolation were presented, via linear regression and numerical fitting to the dose-response profile. An extrapolation method gives the highest value of estimates, independent of sample concentration, and creates a new standard approach to the methods of TAA estimation. It is proposed to designate the modified index as "standard equivalent antioxidant capacity at zero" (SEAC0) or TEAC0 (for Trolox as standard). The examples of estimates for some foods and rat plasma are presented and compared with the literature method. The applicability of the extrapolation approach to the other TAA measurement methods is under evaluation.

Antioxidant intake and risks of rheumatoid arthritis and systemic lupus erythematosus in women

Antioxidants may protect against development of rheumatoid arthritis or systemic lupus erythematosus by combating oxidative stress. The authors identified and confirmed incident cases of rheumatoid arthritis and systemic lupus erythematosus among 184,643 US women followed in the Nurses' Health Study and Nurses' Health Study II cohorts in 1980-2004. Semiquantitative food frequency questionnaires assessed intakes of vitamins A, C, and E and alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, lutein, and zeaxanthin from foods and supplements. The authors examined total antioxidant intake by calculating a "ferric-reducing ability of plasma" score, a new method for quantifying the total antioxidant effect of a food based on the reduction of ferric to ferrous iron by antioxidants. Cumulative updated total energy-adjusted dietary intakes were used. Associations between intake of each nutrient and incident rheumatoid arthritis and systemic lupus erythematosus were examined in age-adjusted and Cox proportional hazards models, adjusted for confounders. Results from the cohorts were pooled meta-analytically by using random-effects models. The authors identified 787 incident rheumatoid arthritis cases and 192 systemic lupus erythematosus cases for whom prospective dietary information was available. In these large, prospective cohorts of women, antioxidant intake was not associated with the risk of developing either rheumatoid arthritis or systemic lupus erythematosus.

Micronutrient-enriched rapeseed oils reduce cardiovascular disease risk factors in rats fed a high-fat diet

Many epidemiological studies have demonstrated that vegetable food consumption is associated with a reduced risk of cardiovascular diseases. The beneficial effects have been attributed to the content of bioactive molecules present in large quantities in plant food. The main proposal of this study was to evaluate in vivo whether micronutrient-enriched rapeseed oils (optimised oils) obtained using different crushing and refining procedures and characterised by different quantities and qualities of micronutrients, could have any beneficial effect on lipid profile and antioxidant status of plasma and liver. Sprague-Dawley rats were fed a high-fat diet for 4 weeks. The lipid source consisted of 20% optimised rapeseed oils with different quantities and qualities of micronutrients. The control group received traditional refined rapeseed oil. The experimental optimised oils all had a hypolipidaemic effect. In the group fed the highest levels of micronutrients, the reduction in plasma and hepatic triglycerides reached 25% and 17%, respectively, that of cholesterol 20% and 14%, respectively. In plasma, the ferric antioxidant capacity, superoxide dismutase, glutathione peroxidase and reduced glutathione significantly increased and lipid peroxidation decreased in parallel with the enhancement of micronutrients. The same trend was observed in the liver, except for glutathione peroxidase which was not affected by optimised oils. These results indicate that a regular intake of optimised rapeseed oils can help to improve lipid status and prevent oxidative stress, providing evidence that optimised oils could be a functional food with potentially important cardioprotective properties.

Reconvene and reconnect the antioxidant hypothesis in human health and disease

The antioxidants are essential molecules in human system but are not miracle molecules. They are neither performance enhancers nor can prevent or cure diseases when taken in excess. Their supplemental value is debateable. In fact, many high quality clinical trials on antioxidant supplement have shown no effect or adverse outcomes ranging from morbidity to all cause mortality. Several Chochrane Meta-analysis and Markov Model techniques, which are presently best available statistical models to derive conclusive answers for comparing large number of trials, support these claims. Nevertheless none of these statistical techniques are flawless. Hence, more efforts are needed to develop perfect statistical model to analyze the pooled data and further double blind, placebo controlled interventional clinical trials, which are gold standard, should be implicitly conducted to get explicit answers. Superoxide dismutase (SOD), glutathione peroxidase and catalase are termed as primary antioxidants as these scavenge superoxide anion and hydrogen peroxide. All these three enzymes are inducible enzymes, thereby inherently meaning that body increases or decreases their activity as per requirement. Hence there is no need to attempt to manipulate their activity nor have such efforts been clinically useful. SOD administration has been tried in some conditions especially in cancer and myocardial infarction but has largely failed, probably because SOD is a large molecule and can not cross cell membrane. The dietary antioxidants, including nutrient antioxidants are chain breaking antioxidants and in tandem with enzyme antioxidants temper the reactive oxygen species (ROS) and reactive nitrogen species (RNS) within physiological limits. Since body is able to regulate its own requirements of enzyme antioxidants, the diet must provide adequate quantity of non-enzymic antioxidants to meet the normal requirements and provide protection in exigent condition. So far, there is no evidence that human tissues ever experience the torrent of reactive species and that in chronic conditions with mildly enhanced generation of reactive species, the body can meet them squarely if antioxidants defense system in tissues is biochemically optimized. We are not yet certain about optimal levels of antioxidants in tissues. Two ways have been used to assess them: first by dietary intake and second by measuring plasma levels. Lately determination of plasma/serum level of antioxidants is considered better index for diagnostic and prognostic purposes. The recommended levels for vitamin A, E and C and beta carotene are 2.2-2.8 μmol/l; 27.5-30 μmol/l; 40-50 μmol/l and 0.4-0.5 μmol/l, respectively. The requirement and recommended blood levels of other dietary antioxidants are not established. The resolved issues are (1) essential to scavenge excess of radical species (2) participants in redox homeostasis (3) selective antioxidants activity against radical species (4) there is no universal antioxidant and 5) therapeutic value in case of deficiency. The overarching issues are (1) therapeutic value as adjuvant therapy in management of diseases (2) supplemental value in developing population (3) selective interactivity of antioxidant in different tissues and on different substrates (4) quantitative contribution in redox balance (5) mechanisms of adverse action on excess supplementation (6) advantages and disadvantages of prooxidant behavior of antioxidants (7) behavior in cohorts with polymorphic differences (8) interaction and intervention in radiotherapy, diabetes and diabetic complications and cardiovascular diseases (9) preventive behavior in neurological disorders (10) benefits of non-nutrient dietary antioxidants (11) markers to assess optimized antioxidants status (12) assessment of benefits of supplementation in alcoholics and heavy smokers. The unresolved and intriguing issues are (1) many compounds such as vitamin A and many others possessing both antioxidant and non-antioxidant properties contribute to both the activities in vivo or exclusively only to non-antioxidant activity and (2) since human tissues do not experience the surge of FR, whether there is any need to develop stronger synthetic antioxidants. Theoretically such antioxidants may do more harm than good.

Antioxidants and glucose metabolism disorders

PURPOSE OF REVIEW

Recent evidence suggests that oxidative stress is a cornerstone of the metabolic mechanisms by which overfeeding leads to insulin resistance. This review is an update of the most recent arguments in favor of this theory and of the possible role of antioxidants.

RECENT FINDINGS

Reactive oxidative species (ROS) are produced by multiple pathways within the cell and are essential for many cellular functions. ROS production is balanced by enzymatic and nonenzymatic antioxidant systems. The perturbation of the pro-oxidant/antioxidant balance can lead to increased oxidative damage of macromolecules, a phenomenon known as 'oxidative stress'. ROS are involved both in insulin signal transduction and in insulin resistance when produced in excess. Overfeeding, saturated fatty acids, and obesity play a key role in the excessive production of ROS. However, a diet rich in fruits and vegetables, and therefore antioxidants, has demonstrated beneficial effects against oxidative damages and insulin resistance.

SUMMARY

Experimental data are in favor of a beneficial role of antioxidants in glucose metabolism, but clinical data in humans are more controversial. Even if a diet rich in fruits and vegetables could provide an optimal mix of antioxidants, it remains unclear whether supplementation with antioxidants alone can reproduce the same effect.

Effect of micronutrient-enriched sunflower oils on plasma lipid profile and antioxidant status in high-fat-fed rats

The main objective of this study was to evaluate in vivo whether micronutrient-enriched high-oleic sunflower oils (optimized oils) obtained using different crushing and refining procedures could have any beneficial effect on plasma lipid profile and antioxidant status. Sprague-Dawley rats were fed a high-fat diet for 4 weeks. The lipid source consisted of 20% optimized sunflower oils with different quantities and qualities of micronutrients. The control group received traditional refined high-oleic sunflower oil. The experimental optimized oils in the diets had a hypolipidemic effect. The reduction in plasma triglyceride and total cholesterol levels was 43% and 20%, respectively, in the group fed the diet with the highest levels of micronutrients. The serum ferric antioxidant capacity, superoxide dismutase, glutathione peroxidase and reduced glutathione significantly increased and lipid peroxidation decreased in parallel with the enhancement of micronutrients. These results suggest that a regular intake of optimized sunflower oils can help to improve lipid status and reduce lipid peroxidation in plasma.

Effects of peanut processing on body weight and fasting plasma lipids

Peanuts and peanut butter are commonly consumed as a snack, meal component and ingredient in various commercial products. Their consumption is associated with reduced CVD risk and they pose little threat to positive energy balance. However, questions have arisen as to whether product form (e.g. whole nut v. butter) and processing properties (e.g. roasting and adding flavours) may compromise their positive health effects. The present study investigated the effects of peanut form and processing on two CVD risk factors: fasting plasma lipids and body weight. One hundred and eighteen adults (forty-seven males and seventy-one females; age 29.2 (sd 8.4) years; BMI 30.0 (sd 4.5) kg/m2) from Brazil, Ghana and the United States were randomised to consume 56 g of raw unsalted (n 23), roasted unsalted (n 24), roasted salted (n 23) or honey roasted (n 24) peanuts, or peanut butter (n 24) daily for 4 weeks. Peanut form and processing did not differentially affect body weight or fasting plasma lipid responses in the total sample. However, HDL-cholesterol increased significantly at the group level, and total cholesterol, LDL-cholesterol and TAG concentrations decreased significantly in individuals classified as having elevated fasting plasma lipids compared with those with normal fasting plasma lipids. These observations suggest that the processing attributes assessed in this trial do not compromise the lipid-lowering effects of peanuts, and do not negatively impact body weight. Further studies are warranted to determine the effects of form and processing on other health risk factors.

Suppression of inflammatory mediators by cruciferous vegetable-derived indole-3-carbinol and phenylethyl isothiocyanate in lipopolysaccharide-activated macrophages

This study was aimed to examine the effects of indole-3-carbinol (I3C) and beta-phenylethyl isothiocyanate (PEITC), bioactive components present in cruciferous vegetable, on the production of inflammatory mediators, including nitric oxide (NO), tumor necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10), in lipopolysaccharide- (LPS-) stimulated RAW 264.7 macrophages. Possible mechanisms of the NO-inhibitory effects were also explored. The results indicated that I3C and PEITC inhibited NO production, and this suppression was associated with decreased production of TNF-alpha and IL-10 by activated macrophages. In addition, I3C suppressed NO production even after the inducible nitric oxide synthase (iNOS) protein had been produced, but such an inhibitory effect was not observed in cells treated with PEITC. Furthermore, both compounds reduced the NO contents generated from an NO donor in a cell-free condition, suggesting that the increased NO clearance may have contributed to the NO-inhibitory effects. In summary, both I3C and PEITC possessed antiinflammatory effects by inhibiting the productions of NO, TNF-alpha, and IL-10, although the NO-inhibitory effects may have involved in different mechanisms.

The total antioxidant content of more than 3100 foods, beverages, spices, herbs and supplements used worldwide

BACKGROUND

A plant-based diet protects against chronic oxidative stress-related diseases. Dietary plants contain variable chemical families and amounts of antioxidants. It has been hypothesized that plant antioxidants may contribute to the beneficial health effects of dietary plants. Our objective was to develop a comprehensive food database consisting of the total antioxidant content of typical foods as well as other dietary items such as traditional medicine plants, herbs and spices and dietary supplements. This database is intended for use in a wide range of nutritional research, from in vitro and cell and animal studies, to clinical trials and nutritional epidemiological studies.

METHODS

We procured samples from countries worldwide and assayed the samples for their total antioxidant content using a modified version of the FRAP assay. Results and sample information (such as country of origin, product and/or brand name) were registered for each individual food sample and constitute the Antioxidant Food Table.

RESULTS

The results demonstrate that there are several thousand-fold differences in antioxidant content of foods. Spices, herbs and supplements include the most antioxidant rich products in our study, some exceptionally high. Berries, fruits, nuts, chocolate, vegetables and products thereof constitute common foods and beverages with high antioxidant values.

CONCLUSIONS

This database is to our best knowledge the most comprehensive Antioxidant Food Database published and it shows that plant-based foods introduce significantly more antioxidants into human diet than non-plant foods. Because of the large variations observed between otherwise comparable food samples the study emphasizes the importance of using a comprehensive database combined with a detailed system for food registration in clinical and epidemiological studies. The present antioxidant database is therefore an essential research tool to further elucidate the potential health effects of phytochemical antioxidants in diet.

Pre-radiotherapy plasma carotenoids and markers of oxidative stress are associated with survival in head and neck squamous cell carcinoma patients: a prospective study

Background

The purpose of this study was to compare plasma levels of antioxidants and oxidative stress biomarkers in head and neck squamous cell carcinoma (HNSCC) patients with healthy controls. Furthermore, the effect of radiotherapy on these biomarkers and their association with survival in HNSCC patients were investigated.

Methods

Seventy-eight HNSCC patients and 100 healthy controls were included in this study. Follow-up samples at the end of radiotherapy were obtained in 60 patients. Fifteen antioxidant biomarkers (6 carotenoids, 4 tocopherols, ascorbic acid, total antioxidant capacity, glutathione redox potential, total glutathione and total cysteine) and four oxidative stress biomarkers (total hydroperoxides, γ-glutamyl transpeptidase, 8-isoprostagladin F_2α and ratio of oxidized/total ascorbic acid) were measured in plasma samples. Analysis of Covariance was used to compare biomarkers between patients and healthy controls. Kaplan-Meier plots and Cox' proportional hazards models were used to study survival among patients.

Results

Dietary antioxidants (carotenoids, tocopherols and ascorbic acid), ferric reducing antioxidant power (FRAP) and modified FRAP were lower in HNSCC patients compared to controls and dietary antioxidants decreased during radiotherapy. Total hydroperoxides (d-ROMs), a marker for oxidative stress, were higher in HNSCC patients compared to controls and increased during radiotherapy. Among the biomarkers analyzed, high levels of plasma carotenoids before radiotherapy are associated with a prolonged progression-free survival (hazard rate ratio: 0.42, 95% CI: 0.20-0.91, p = 0.03). Additionally, high relative increase in plasma levels of d-ROMs (hazard rate ratio: 0.31, 95% CI: 0.13-0.76, p = 0.01) and high relative decrease in FRAP (hazard rate ratio: 0.42, 95% CI: 0.17-0.998, p = 0.05) during radiotherapy are also positively associated with survival.

Conclusions

Biomarkers of antioxidants and oxidative stress are unfavourable in HNSCC patients compared to healthy controls, and radiotherapy affects many of these biomarkers. Increasing levels of antioxidant biomarkers before radiotherapy and increasing oxidative stress during radiotherapy may improve survival indicating that different factors/mechanisms may be important for survival before and during radiotherapy in HNSCC patients. Thus, the therapeutic potential of optimizing antioxidant status and oxidative stress should be explored further in these patients.

Reactive oxygen species, reactive nitrogen species and antioxidants in etiopathogenesis of diabetes mellitus type-2

Diabetes mellitus type-2 (DMT-2) is a hyperglycemic syndrome with several characteristic features. It continues to rise unabatedly in all pockets of the world, parallels with affluence and can be controlled but not cured. It has a definite involvement of genetic component but environmental factors play overwhelmingly dominant role in etiopathogenesis. Insulin resistance (IR) and obesity are singular instigators of DMT-2. The various events cause critical defects in insulin signaling cascade followed by beta-cell dysfunction. Over a period of time, numerous other metabolic aberrations develop, resulting in diabetic complications which could be both vascular (cardiovascular complications, nephropathy, neuropathy, retinopathy and embryopathy) or a-vascular (cataract and glaucoma etc). It has been proposed that all these abnormal events are initiated or activated by a common mechanism of superoxide anion, which is accompanied with generation of a variety of reactive oxygen species (ROS), reactive nitrogen specie (RNS) and resultant heightened oxidative stress (OS). Provoked OS causes IR and altered gene expressions. Hyperglycemia induces OS through multiple routes: a)stimulated polyol pathway where in ≤ 30% glucose can be diverted to sorbitol and fructose, b)increased transcription of genes for proinflammatory cytokines and plasminogen activator inhibitor-1 (PAI-1) c) activation of protein kinase-C (PKC) leading to several molecular changes d)increased synthesis of Advanced Glycation End Products (AGEs) e)changes in a receptor far AGEs and f) autooxidation of glucose with formation of ketoimines and AGEs. All these processes are accompanied with alteration in redox status, ROS, RNS and OS which trigger DMT-2 and its complications. Initial hurriedly planned and executed experimental and clinical studies showed promising results of antioxidant therapies, but recent studies indicate that excess intake/supplement may have adverse outcomes including increased mortality. It is advocated that antioxidants should be given only if preexisting deficiency is present. Selection of antioxidant is another important aspect. Lastly but most importantly the impact of OS is not obligatory but facultative. As such only those diabetic patients will be benefited by antioxidant therapies that have impelling punch of prooxidants.