Dietary antioxidants: Do they have a role to play in the ongoing fight against abnormal glucose metabolism?

Putative mechanism of a multivitamin treatment against insulin resistance

Insulin resistance is caused by the abnormal secretion of proinflammatory cytokines in adipose tissue, which is induced by an increase in lipid accumulation in adipocytes, hepatocytes, and myocytes. The inflammatory pathway involves multiple targets such as nuclear factor kappa B, inhibitor of nuclear factor κ-B kinase, and mitogen-activated protein kinase. Vitamins are micronutrients with anti-inflammatory activities that have unclear mechanisms. The present study aimed to describe the putative mechanisms of vitamins involved in the inflammatory pathway of insulin resistance. The strategy to achieve this goal was to integrate data mining and analysis, target prediction, and molecular docking simulation calculations to support our hypotheses. Our results suggest that the multitarget activity of vitamins A, B1, B2, B3, B5, B6, B7, B12, C, D3, and E inhibits nuclear factor kappa B and mitogen-activated protein kinase, in addition to vitamins A and B12 against inhibitor of nuclear factor κ-B kinase. The findings of this study highlight the pharmacological potential of using an anti-inflammatory and multitarget treatment based on vitamins and open new perspectives to evaluate the inhibitory activity of vitamins against nuclear factor kappa B, mitogen-activated protein kinase, and inhibitor of nuclear factor κ-B kinase in an insulin-resistant context.

Investigation of Advanced Glycation End Products in Liver, Adipose, and Renal Tissue of Mice on a High-Fat Diet

Obesity is a complex condition associated with disruptions in carbohydrate, protein, and fat metabolism, linked to increased insulin resistance and glucose intolerance. High levels of Advanced Glycation End-products (AGEs) are associated with a range of chronic diseases, including kidney diseases, diabetic complications, cardiovascular diseases, and neurodegenerative diseases. Our study aims to investigate the accumulation of AGEs in the liver, renal and adipose tissues of mice fed a high-fat diet, contributing to a deeper understanding of obesity and its related metabolic disorders. Our study consists of three different groups fed with diets containing 60% and 10% fat. The Experiment 1 group was maintained on their diet for 12 weeks, while the obese 2 and control groups continued their diets for 24 weeks. AGEs in the liver and kidney tissues obtained were measured using the High-performance liquid chromatography grade (HPLC) method. Higher accumulation of AGEs has been observed in kidney tissue compared to adipose and liver tissues (p < 0.05). Moreover, the GO levels were notably higher in liver tissue than in adipose tissue of the D1 and D2 groups (p < 0.0001). Our results suggest that particularly in kidney tissue, increased filtration burden, functional impairment, and receptor interaction due to obesity may be effective. The lower levels of AGEs detected, especially in the obese groups compared to the control, can be attributed to the inability to metabolize AGEs due to tissue damage caused by obesity.

The differential effects of palmitic acid and oleic acid on the metabolic response of hypothalamic astrocytes from male and female mice

Diets rich in saturated fats are more detrimental to health than those containing mono- or unsaturated fats. Fatty acids are an important source of energy, but they also relay information regarding nutritional status to hypothalamic metabolic circuits and when in excess can be detrimental to these circuits. Astrocytes are the main site of central fatty acid β-oxidation, and hypothalamic astrocytes participate in energy homeostasis, in part by modulating hormonal and nutritional signals reaching metabolic neurons, as well as in the inflammatory response to high-fat diets. Thus, we hypothesized that how hypothalamic astrocytes process-specific fatty acids participates in determining the differential metabolic response and that this is sex dependent as males and females respond differently to high-fat diets. Male and female primary hypothalamic astrocyte cultures were treated with oleic acid (OA) or palmitic acid (PA) for 24 h, and an untargeted metabolomics study was performed. A clear predictive model for PA exposure was obtained, while the metabolome after OA exposure was not different from controls. The observed modifications in metabolites, as well as the expression levels of key metabolic enzymes, indicate a reduction in the activity of the Krebs and glutamate/glutamine cycles in response to PA. In addition, there were specific differences between the response of astrocytes from male and female mice, as well as between hypothalamic and cerebral cortical astrocytes. Thus, the response of hypothalamic astrocytes to specific fatty acids could result in differential impacts on surrounding metabolic neurons and resulting in varied systemic metabolic outcomes.

The effect of the dietary approaches to stop hypertension diet on total antioxidant capacity, superoxide dismutase, catalase, and body composition in patients with non-alcoholic fatty liver disease: a randomized controlled trial

Aim

Non-alcoholic fatty liver disease (NAFLD) is a condition characterized by the accumulation of fat in the liver without excessive alcohol consumption. Lifestyle modifications, such as adopting a healthy diet, represent the standard treatment for NAFLD. However, the impact of the Dietary Approaches to Stop Hypertension (DASH) diet on oxidative stress biomarkers in patients with NAFLD remains unclear. Therefore, this study aimed to determine the effect of the DASH diet on total antioxidant capacity (TAC), catalase (CAT), superoxide dismutase (SOD) levels, and body composition in overweight and obese patients with NAFLD.

Methods

A total of 70 overweight and obese patients aged 1870 years were randomly assigned to either the intervention (DASH diet, n = 35) or the control group (control diet, n = 35) for 12 weeks, with both groups following a calorie-restricted diet.

Results

The mean age of participants was 43.1 ± 8.1 years in the DASH group and 45.1 ± 8.6 years in the control group. At the end of the study, a significant difference was observed in the mean TAC and SOD levels between the two groups (p = 0.02). After adjusting for potential confounding factors, such as age, sex, diabetes, smoking, physical activity, and baseline values, the DASH diet maintained its significant effects on TAC and SOD compared to the control diet (p = 0.03). However, there were no significant differences in CAT levels between the two groups. Moreover, a significant reduction in visceral fat (p = 0.01) and a marginally significant decrease in BMI (p = 0.06) were observed in the DASH group compared to the control group after adjusting for potential confounders.

Conclusion

In conclusion, our study showed that following the DASH diet for 12 weeks in overweight and obese patients with NAFLD has beneficial effects on TAC, SOD, and visceral fat. These findings support the use of the DASH diet as a potential therapeutic intervention for the improvement of oxidative biomarkers in patients with NAFLD.

Clinical trial registration

www.irct.ir/, identifier IRCT20170117032026N3.

Redox Balance in Type 2 Diabetes: Therapeutic Potential and the Challenge of Antioxidant-Based Therapy

Oxidative stress is an important factor in the development of type 2 diabetes (T2D) and associated complications. Unfortunately, most clinical studies have failed to provide sufficient evidence regarding the benefits of antioxidants (AOXs) in treating this disease. Based on the known complexity of reactive oxygen species (ROS) functions in both the physiology and pathophysiology of glucose homeostasis, it is suggested that inappropriate dosing leads to the failure of AOXs in T2D treatment. To support this hypothesis, the role of oxidative stress in the pathophysiology of T2D is described, together with a summary of the evidence for the failure of AOXs in the management of diabetes. A comparison of preclinical and clinical studies indicates that suboptimal dosing of AOXs might explain the lack of benefits of AOXs. Conversely, the possibility that glycemic control might be adversely affected by excess AOXs is also considered, based on the role of ROS in insulin signaling. We suggest that AOX therapy should be given in a personalized manner according to the need, which is the presence and severity of oxidative stress. With the development of gold-standard biomarkers for oxidative stress, optimization of AOX therapy may be achieved to maximize the therapeutic potential of these agents.

Dietary total antioxidant capacity in relation to metabolic health status in overweight and obese adolescents

Background

Although several studies evaluated the relationship between individual dietary antioxidants and metabolic health conditions, data on the association between dietary total antioxidant capacity and metabolic health among children and adolescents is limited. This study investigated the relationship between dietary total antioxidant capacity and metabolic health status in Iranian overweight/obese adolescents.

Methods

This cross-sectional study was conducted on 203 overweight/obese adolescents. Dietary intakes were evaluated by a validated food frequency questionnaire. Ferric Reducing-Antioxidant Power (FRAP) was considered to indicate dietary total antioxidant capacity. Anthropometric parameters and blood pressure status were measured. Fasting blood samples were obtained to determine circulating insulin, glucose, and lipid profile. Two different methods (modified International Diabetes Federation (IDF) criteria and IDF criteria along with insulin resistance) were applied to classify participants as metabolically healthy obese (MHO) or metabolically unhealthy obese (MUO).

Results

According to IDF and IDF/HOMA definitions, a total of 79 (38.9%) and 67 (33.0%) adolescents were respectively defined as MUO. Considering IDF criteria, the highest tertile of FRAP was related to lower odds of being MUO in the maximally-adjusted model (OR: 0.40; 95%CI: 0.16–0.96), compared to the lowest tertile. However, based on the IDF/HOMA-IR criteria, no significant relation was found between FRAP and odds of MUO (OR: 0.49; 95%CI: 0.19–1.23) after considering all possible confounders.

Conclusions

Adolescents with higher intakes of dietary antioxidants have a lower possibility of being MUO based on IDF criteria. However, no substantial relation was found considering HOMA-IR/IDF definition. Further prospective cohort studies need to be done to confirm these findings.

Age-Specific Modulation of Prefrontal Cortex LTP by Glucocorticoid Receptors Following Brief Exposure to HFD

The corticolimbic circuits in general and the medial prefrontal cortex in particular, undergo maturation during juvenility. It is thus expected that environmental challenges in forms of obesogenic diet can exert different effects in juvenile animals compared to adults. Further, the relationship between glucocorticoids and obesity has also been demonstrated in several studies. As a result, glucocorticoid receptor (GR) antagonists are currently being tested as potential anti-obesity agents. In the present study, we examined the effects of short-term exposure to high-fat diet (HFD) on prefrontal long-term potentiation (LTP) in both juvenile and adult rats, and the role of glucocorticoid receptors (GRs) in modulating these effects. We found HFD impaired prefrontal LTP in both juveniles and adults, but the effects of GR modulation were age- and diet-dependent. Specifically, GR antagonist RU-486 reversed the impairment of LTP in juvenile animals following HFD, and had no effect on control-diet animals. In adult animals, RU-486 has no effect on HFD-impaired LTP, but abolished LTP in control-diet animals. Furthermore, impairments in the prefrontal LTP following HFD are involved with an increase in the mPFC GR levels only in the juveniles. Further, we found that in vivo application of GR agonists into adult mPFC rescued HFD-induced impairment in LTP, suggesting that these receptors might represent strategic therapeutic targets to potentially combat obesity and metabolic related disorder.

Impact of the Dietary Approaches to Stop Hypertension (DASH) diet on glycaemic control and consumption of processed and ultraprocessed foods in pregnant women with pre-gestational diabetes mellitus: a randomised clinical trial

The aim of this study was to evaluate the impact of the Dietary Approaches to Stop Hypertension (DASH) diet on glycaemic control and consumption of processed (PF) and ultraprocessed (UPF) foods in pregnant women with pre-gestational diabetes mellitus (PGDM). This is a randomised, controlled, single-blind clinical trial with forty-nine adult women with PGDM, followed at a public maternity hospital in Rio de Janeiro, Brazil. The control group (CG) received a standard diet consisting of 45-55 % of the total energy intake of carbohydrates, 15-20 % of proteins and 25-30 % of lipids. The DASH group (DG) received an adapted DASH diet, which did not differ from the standard diet in the percentage of macronutrients, but had higher contents of fibre, unsaturated fats and minerals such as Ca, Mg and K; and lower contents of Na and saturated fats than the standard diet. In the analysis by protocol, the DG presented a higher incidence of glycaemic control after 12 weeks of intervention (57·1 v. 8·3 %, P = 0·01, moderate effect size) and a lower mean consumption of UPF (-9·9 %, P = 0·01) compared with the CG. There was no statistically significant difference in fasting and postprandial blood glucose concentrations, or in the consumption of PF between the groups (P > 0·05). The DASH diet may be a strategy for glycaemic control in pregnant women with PGDM, favouring the adoption of a nutritionally adequate diet with lower consumption of UPF. Further studies are needed to investigate the effect of the DASH diet on glycaemic profile, and maternal and perinatal outcomes in women with PGDM.

Effects of heavy metal, vitamin, and curry consumption on metabolic syndrome during menopause: a Korean community-based cross-sectional study

OBJECTIVE

To determine the associations between metabolic syndrome (MetS) during menopause and serum heavy metal levels and vitamin and curry consumption.

METHODS

A data set of 7,131 pre- and postmenopausal women aged ≥ 20 years collected between 2009 and 2017 was used to obtain information on sociodemographic, lifestyles, family histories, food intakes, and serum heavy metal levels and MetS. Logistic regression was used to identify associations between the presence of MetS and risk factors and to predict risks of MetS based on marginal effects.

RESULTS

Our results show that postmenopausal women had a higher risk of MetS than premenopausal women. During postmenopause elevations in the levels of serum cadmium by one unit increased the risk of MetS by 33% (OR 1.33; 95% CI, 1.03-1.72, P = 0.028). Risks of MetS in pre- and postmenopausal women, when serum Hb levels increased by 1 unit increased 21% (OR 1.21; 95% CI, 1.09-1.33, P < 0.001) and 26% (OR 1.26; 95% CI, 1.16-1.38, P < 0.001), respectively. Furthermore, the risk of MetS risk in pre- and postmenopausal women was increased 2.49-fold and 2.79-fold by a 1% increase in HbA1c level (OR 2.49; 95% CI, 1.97-3.16, P < 0.001) and (OR 2.79; 95% CI, 2.30-3.38, P < 0.001), respectively. High curry consumption reduced the risk of MetS significantly more than low curry consumption (OR 0.60; 95% CI, 0.39-0.91, P = 0.017) in premenopausal women. Furthermore, an increase in daily vitamin B2 intake by 1 mg reduced the risk of MetS by 45% (OR 0.55; 95% CI, 0.32-0.94, P = 0.028) in postmenopausal women.

CONCLUSION

Vitamin B2 and curry supplementation may protect against MetS. Further work is needed to reduce risk factors associated with heavy metals and determine the effects of vitamins and curry consumption on MetS during menopause.

Effects of Antioxidant Vitamins, Curry Consumption, and Heavy Metal Levels on Metabolic Syndrome with Comorbidities: A Korean Community-Based Cross-Sectional Study

The burden of metabolic syndrome (MetS) has increased worldwide, especially during the COVID-19 pandemic, and this phenomenon is related to environmental, dietary, and lifestyle risk factors. We aimed to determine the association between the levels of serum heavy metals, hs-CRP, vitamins, and curry intake and to predict risks of MetS based on marginal effects. A data set of 60,256 Koreans aged ≥ 15 years between 2009 and 2017 was used to obtain information on sociodemographic, lifestyle, family history characteristics, MetS, food intake survey, and serum heavy metals. Daily intake of vitamins was measured by a one-day 24 h recall, and curry consumption was calculated using a food frequency questionnaire. Serum heavy metal levels were quantified by graphite furnace atomic absorption spectrometry and using a mercury analyzer. We found that vitamin B1, B2, B3, C, and A intakes were significantly lower in subjects with than without MetS. In contrast, serum levels of Pb, Hg, Cd, vitamin A, E, and hs-CRP were significantly higher in subjects with MetS. The risk of MetS was significantly lower for high curry consumers than low curry consumers (adjusted odds ratio 0.85, 95%CI 0.74-0.98). The risks of MetS were reduced by 12% and 1%, when vitamin B1 and C intakes increased by one mg, respectively, but were increased by 14%, 3%, and 9%, when serum levels of Pb, Hg, and hs-CRP increased by one unit. These results show that the potential health benefits resulting from vitamin and curry intakes could protect the public against the dual burden of communicable and non-communicable diseases. Further studies are required to reduce risk factors associated with serum heavy metal levels and to determine whether interactions between vitamin and curry consumption influence the presence of MetS.

Association of fourteen years diet quality trajectories and type 2 diabetes mellitus with related biomarkers

Diet quality fluctuates throughout one’s adulthood, yet it remains unclear how long-term diet quality changes are related to type 2 diabetes mellitus (T2DM) and its biomarkers. We aimed to examine the association of long-term diet quality with T2DM and its biomarkers. Diet quality was assessed by the revised DBI-07, in which diet quality distance levels (DQD) represented the overall diet quality. Participants were clustered into classes sharing similar DQD levels using latent class mixed model. We used Cox regression and random effect linear regression to assess DQD trajectories’ association with T2DM and its biomarkers. Three DQD trajectories were derived: moderate to gradual decrease, high to moderate, high stable DQD level representing 2.14%, 6.18% and, 91.68% of the population. Compared to class 1, class 2 and 3 were associated with an increased risk of T2DM [HR=4.40; 95%CI: 2.02-9.59]; [HR=3.68; 95% CI: 2.11-6.43]. When class 3 was used as a reference, class 1 was also associated with an increased risk of TDM [HR=2.71; 95%CI: 1.55-4.73]. Our findings suggest that a long-term unhealthy diet is associated with an increased risk of T2DM. Gradually reducing DQD level may not make a difference, which establishes the importance of promoting healthy eating habits at early adulthood.

A Health-Conscious Food Pattern Is Associated with Prediabetes and Gut Microbiota in the Malmö Offspring Study

BACKGROUND

Diet is a determinant of gut microbiota. Both diet and gut microbiota have been linked to metabolic diseases.

OBJECTIVE

We aimed to examine data-driven food patterns in relation to the prevalence of prediabetes and gut microbiota composition and food pattern-associated bacteria in relation to prediabetes.

METHODS

Food patterns were extracted using principal component analysis in 1726 individuals (aged 18-71 y, 55% women, mean BMI = 25.5 kg/m2) without diabetes from the population-based Malmö Offspring Study. The gut (fecal) microbiota was analyzed by sequencing the 16S ribosomal RNA gene (V1-V3 region). Prediabetes classification was based on fasting glucose ≥6.0 mmol/L and/or glycated hemoglobin ≥42 mmol/L at baseline and/or type 2 diabetes diagnosis during follow-up (0-3.8 y). Logistic regression was used to investigate cross-sectional associations with prediabetes, and the general linear model to examine associations between food patterns and bacterial genera.

RESULTS

Two food patterns, the Health-conscious and the Sugar and High-Fat Dairy patterns, were identified. Adherence to the Health-conscious pattern was associated with a lower prevalence of prediabetes (OR comparing highest quintile with lowest: 0.54; 95% CI: 0.32, 0.92; P-trend = 0.03) and with the abundance of several gut bacterial genera, of which the most robust findings were with a higher abundance of Roseburia and Lachnospira and with a lower abundance of Eubacterium. Roseburia was also associated with a lower prevalence of prediabetes (OR comparing highest quintile with lowest: 0.56; 95% CI: 0.35, 0.92; P-trend = 0.01) and the association between the Health-conscious pattern and prediabetes was attenuated after adjustment for abundance of Roseburia and BMI. Adherence to the Sugar and High-Fat Dairy pattern was associated with a higher prevalence of prediabetes in women (P-trend across food pattern quintiles = 0.03).

CONCLUSIONS

In this Swedish population-based study, a Health-conscious food pattern showed an inverse association with the prevalence of prediabetes. Potential underlying explanations may involve links between healthy diet and BMI, as well as gut microbiota, especially a higher abundance of Roseburia.

Association of Dietary Patterns with Type 2 Diabetes Mellitus among Middle-Aged Adults in Uygur Population of Xinjiang Region

Observational and interventional studies have showed associations between dietary patterns and the risk of type 2 diabetes (T2DM). The aim of the present study was to identify dietary patterns and examine their association with incident of T2DM and physiopathologic mechanism in the Uygur population of Xinjiang, China. A community-based case control study in Urumqi, Xinjiang Uygur Autonomous Region, China. We enrolled 836 Uygur adults (345 newly diagnosed T2DM and 491 healthy controls) receiving physical examination in community health service centers. Dietary patterns were evaluated using a validated 121 items semi-quantitative food frequency questionnaire (SQFFQ). Dietary patterns were identified by exploratory factor analysis. Data on demographic, anthropometric, socioeconomic characteristics were collected. Homeostasis model assessment index for insulin resistance (HOMA-IR) and for β cell function (HOMA-β) were calculated. Multivariate logistic regression were used to estimate the associations between dietary patterns and the risk of T2DM and multiple linear regression were used to evaluate the association between dietary patterns and fasting plasm glucose (FPG), fasting insulin (FINS), HOMA-IR and HOMA-β, adjusting for confounding factors. Five major dietary patterns were identified: (1) the "vegetable and tubes" pattern; (2) the "fruit and nut" pattern; (3) the "refined grains and meat" pattern; (4) the "dairy, legume and egg" pattern; and (5) the "oil and salt" pattern. Logistic regression results demonstrated that the "vegetable and tubes" dietary pattern and the "fruit and nut" dietary pattern were related to T2DM, OR values were 0.223 (95% CI: 0.135-0.371), 0.160 (95% CI: 0.093-0.275), respectively. The "refined grains and meat" dietary pattern and the "oil and salt" dietary pattern were related to T2DM, OR values were 6.146 (95% CI: 3.217-11.739), 9.554 (95% CI: 5.668-16.104), respectively. Multiple linear regression analysis showed that the above five dietary patterns were related to log (FPG), β values were -0.040, -0.039, 0.028, -0.010 and 0.036, respectively, all p<0.05. The "vegetable and tubes" pattern, the "fruit and nut" pattern, the "refined grains and meat" pattern and the "oil and salt" pattern were related to log (HOMA-IR), β values were -0.061, -0.060, 0.045, and 0.042, and were related to log (HOMA-β), β values were 0.071, 0.063, -0.035 and -0.070, respectively, all p<0.05. The "refined grains and meat" dietary pattern and the "oil and salt" dietary pattern may be the important reason for the rapid increase of T2DM incidence among Chinese Uygur residents. Our findings suggest that modifying dietary patterns could reduce T2DM incidence in the adult Uygur population.

Silencing of CD133 inhibits GLUT1-mediated glucose transport through downregulation of the HER3/Akt/mTOR pathway in colon cancer

Cluster of differentiation 133 (CD133) is a transmembrane glycoprotein that has been reported as a marker of cancer stem cells or cancer-initiating cells in various cancers. However, its contribution to tumorigenesis and differentiation remains to be elucidated. To determine the role of CD133 in colon cancer, we silenced CD133 in human colon cancer cells. Silencing of CD133 results in decreased cell proliferation, survival, migration, invasion, and glucose transport. These effects are mediated by downregulation of the human epidermal growth factor receptor 3 (HER3)/Akt/mTOR signaling pathway, culminating in reduced expression of the glucose transporter GLUT1. We also confirm that the cellular phenotypes of CD133-silenced cells are mediated by GLUT1 downregulation. We conclude that CD133 is a potential tumor initiator that positively regulates GLUT1 expression through modulation of HER3/Akt/mTOR signaling.

Pathobiological mechanisms underlying metabolic syndrome (MetS) in chronic obstructive pulmonary disease (COPD): clinical significance and therapeutic strategies

Chronic obstructive pulmonary disease (COPD) is a major incurable global health burden and is currently the 4th largest cause of death in the world. Importantly, much of the disease burden and health care utilisation in COPD is associated with the management of its comorbidities (e.g. skeletal muscle wasting, ischemic heart disease, cognitive dysfunction) and infective viral and bacterial acute exacerbations (AECOPD). Current pharmacological treatments for COPD are relatively ineffective and the development of effective therapies has been severely hampered by the lack of understanding of the mechanisms and mediators underlying COPD. Since comorbidities have a tremendous impact on the prognosis and severity of COPD, the 2015 American Thoracic Society/European Respiratory Society (ATS/ERS) Research Statement on COPD urgently called for studies to elucidate the pathobiological mechanisms linking COPD to its comorbidities. It is now emerging that up to 50% of COPD patients have metabolic syndrome (MetS) as a comorbidity. It is currently not clear whether metabolic syndrome is an independent co-existing condition or a direct consequence of the progressive lung pathology in COPD patients. As MetS has important clinical implications on COPD outcomes, identification of disease mechanisms linking COPD to MetS is the key to effective therapy. In this comprehensive review, we discuss the potential mechanisms linking MetS to COPD and hence plausible therapeutic strategies to treat this debilitating comorbidity of COPD.

The Dietary Approaches to Stop Hypertension (DASH)-Style Diet and an Alternative Mediterranean Diet are Differently Associated with Serum Inflammatory Markers in Female Adults

Background:

Studies on the association between a priori dietary patterns and serum highly sensitive C-reactive protein (hs-CRP) have led to inconsistent results, and we are not aware of any study on interleukin 17A (IL-17A) as an inflammatory marker associated with autoimmune diseases.

Objective:

The present study aimed to investigate the association between Dietary Approaches to Stop Hypertension (DASH) and the Mediterranean dietary patterns with circulating hs-CRP and IL-17A levels.

Methods:

In this cross-sectional study, female teachers (aged 20-50 years) who lived in Yazd, Iran, were randomly selected from elementary, guidance, and high schools from September 2015 to February 2016. Anthropometric data, as well as general information and dietary food intakes, were gathered, and each participant gave 1 blood sample. Participants were categorized into tertiles based on the DASH and the Mediterranean diet calculated scores. The associations between the dietary patterns and serum hs-CRP and IL-17A levels were assessed in the crude and multivariable models. In total, 320 female teachers aged 40.38 (8.08) years were included.

Results:

The DASH diet was associated with lower serum hs-CRP levels in the crude ( P = .05) and the fully adjusted models ( P = .02), while it was not significantly associated with IL-17A levels. The participants with the highest adherence to the Mediterranean diet had significantly lower circulating IL-17A levels ( P = .04) even controlling for all confounders ( P = .02); however, there was not a significant relationship between this diet and hs-CRP levels.

Conclusions:

The DASH and the Mediterranean dietary patterns might be differently associated with inflammatory markers. Further prospective studies are recommended to confirm our results.

FOOD INTAKE EVALUATION DURING THE FIRST YEAR OF POSTOPERATIVE OF PATIENTS WITH TYPE 2 DIABETES MELLITUS OR GLYCEMIC ALTERATION SUBMITTED TO ROUX-EN-Y GASTRIC BYPASS

BACKGROUND

: Obesity is one of the main causes of glycemic change. Failure of clinical obesity treatment may lead to an increase in bariatric surgery. Dietary guidance, in conjunction with disabsorptive and hormonal factors resulting from the anatomical and physiological changes provoked by the surgery, is associated with changes in food intake.

AIM

To analyze food intake evolution during the first postoperative year of Roux-en-y gastric bypass in patients with type 2 diabetes mellitus or glycemic alteration.

METHODS

: This was a longitudinal and retrospective observational study. For food intake evolution analysis, linear regression models with normal errors were adjusted for each of the nutrients.

RESULTS

At 12 months, all patients presented improvement in glycemic levels (p<0.05). During the first postoperative year, there was a reduction in energy intake, macronutrients, consumption of alcoholic beverages and soft drinks. Conversely, there was an increase in fiber intake and diet fractionation. It was observed that, despite gastric restrictions, the micronutrient intake specifically recommended for glycemic control was greater up to six months postoperatively.

CONCLUSION

There was change in the quantity and quality of food intake. It was the most prevalent glycemic control contributor up to six months postoperatively. At the end of one year, the diet underwent a change, showing a similar tendency to the preoperative food intake pattern.

No Additive Effects of Polyphenol Supplementation and Exercise Training on White Adiposity Determinants of High-Fat Diet-Induced Obese Insulin-Resistant Rats

One of the major insulin resistance instigators is excessive adiposity and visceral fat depots. Individually, exercise training and polyphenol intake are known to exert health benefits as improving insulin sensitivity. However, their combined curative effects on established obesity and insulin resistance need further investigation particularly on white adipose tissue alterations. Therefore, we compared the effects on different white adipose tissue depot alterations of a combination of exercise and grape polyphenol supplementation in obese insulin-resistant rats fed a high-fat diet to the effects of a high-fat diet alone or a nutritional supplementation of grape polyphenols (50 mg/kg/day) or exercise training (1 hr/day to 5 days/wk consisting of treadmill running at 32 m/min for a 10% slope), for a total duration of 8 weeks. Separately, polyphenol supplementation and exercise decreased the quantity of all adipose tissue depots and mesenteric inflammation. Exercise reduced adipocytes' size in all fat stores. Interestingly, combining exercise to polyphenol intake presents no more cumulative benefit on adipose tissue alterations than exercise alone. Insulin sensitivity was improved at systemic, epididymal, and inguinal adipose tissues levels in trained rats thus indicating that despite their effects on adipocyte morphological/metabolic changes, polyphenols at nutritional doses remain less effective than exercise in fighting insulin resistance.

Higher dietary total antioxidant capacity is inversely related to prediabetes: A case-control study

OBJECTIVES

Dietary total antioxidant capacity (DTAC) has been proposed as a tool for assessing the intake of antioxidants. The relationship between DTAC and blood glucose levels has been investigated mostly in healthy people. The aim of this study was to evaluate the association between DTAC and prediabetes morbidity in a case-control study.

METHODS

We examined 300 individuals with and without prediabetes (n = 150/group) who attended a Diabetes Screening Center in Shahreza, Iran. The anthropometric measures, physical activity, and blood glucose levels of all participants were measured. Food intake over the previous year was determined using a semiquantitative food frequency questionnaire, and sex-specific, energy-adjusted DTAC was calculated using the U.S. Department of Agriculture's database. Logistic reg/ression was used to model the relationship between DTAC and prediabetes morbidity.

RESULTS

The mean DTAC was significantly lower in individuals with prediabetes than in the control group (P < 0.001). Across increasing DTAC quartiles, the participants had lower fasting blood glucose and 2-h postchallenge plasma glucose (P_trend < 0.02). After adjustment for body mass index; physical activity; education; dietary intake of fiber, fat, energy, and coffee; participants in the fourth quartile of DTAC were less likely to experience prediabetes compared with those in the first quartile (odds ratio, 0.18; 95% confidence interval, 0.07-0.49).

CONCLUSION

The DTAC score appears useful when assessing the antioxidant capacity of diet and to better understand the relationship between diet and prediabetes morbidity. Future studies are needed to confirm the findings from the present study in other populations.

Relationship between dietary factors and the number of altered metabolic syndrome components in Chinese adults: a cross-sectional study using data from the China Health and Nutrition Survey

OBJECTIVES

To study the correlation between dietary factors and the number of altered metabolic syndrome components (MetS) in Chinese adults systematically.

SETTING

A cross-sectional study using demographic and dietary data of adults aged 18-75 years from the China Health and Nutrition Survey (2009) was conducted in nine provinces in China.

PARTICIPANTS

There were 6034 eligible subjects (2800 men and 3234 women) in this study.

OUTCOMES

The primary outcome of this study were diet assessments and the number of altered MetS components. Dietary intake was measured using a combination of a 3-day period with 24-hour and household food inventory; average daily intakes of nutrients were estimated according to the Chinese Food Composition Table. Blood samples were analysed in a national central laboratory and the number of clustering MetS components was calculated by adding the presence of each MetS component.

RESULTS

After adjusting for covariates, and taking zero MetS as comparison, the high risk factors correlating with increased numbers of altered MetS components in men were higher intake of protein (70.4-73.4 g; Ptrend=0.0004), cholesterol (238.7-266.6 mg; Ptrend=0.004), meat (90.6-105.7 g; Ptrend=0.016), fish/seafood (30.4-42.3 g; Ptrend=0.001), and lower intake of coarse cereals (16.5-12.7 g; Ptrend=0.051), tubers (37.3-32.7 g; Ptrend=0.030), and dietary fibre (11.7-11.5 g; ANCOVA p=0.058). Meanwhile, the high risk factors correlating with the increased number of altered MetS components in women were higher intake of wheat (101.9-112.6 g; Ptrend=0.066) and sodium (3862.3-4005.7 mg, Ptrend=0.032), and lower intake of β-carotene (1578.6-1382.7 µg; Ptrend=0.007), milk, and dairy products (17.8-11.5 g; Ptrend=0.002).

CONCLUSIONS

Some foods and nutritional factors correlate with an increased number of altered MetS components in Chinese adults. More prospective, multicentre and clinical research work to further examine these associations is underway.

The Impact of Environmental Factors in Influencing Epigenetics Related to Oxidative States in the Cardiovascular System

Oxidative states exert a significant influence on a wide range of biological and molecular processes and functions. When their balance is shifted towards enhanced amounts of free radicals, pathological phenomena can occur, as the generation of reactive oxygen species (ROS) in tissue microenvironment or in the systemic circulation can be detrimental. Epidemic chronic diseases of western societies, such as cardiovascular disease, obesity, and diabetes correlate with the imbalance of redox homeostasis. Current advances in our understanding of epigenetics have revealed a parallel scenario showing the influence of oxidative stress as a major regulator of epigenetic gene regulation via modification of DNA methylation, histones, and microRNAs. This has provided both the biological link and a potential molecular explanation between oxidative stress and cardiovascular/metabolic phenomena. Accordingly, in this review, we will provide current insights on the physiological and pathological impact of changes in oxidative states on cardiovascular disorders, by specifically focusing on the influence of epigenetic regulation. A special emphasis will highlight the effect on epigenetic regulation of human's current life habits, external and environmental factors, including food intake, tobacco, air pollution, and antioxidant-based approaches. Additionally, the strategy to quantify oxidative states in humans in order to determine which biological marker could best match a subject's profile will be discussed.

Sea Buckthorn (Hippophae Rhamnoides) Lipids and their Functionality on Health Aspects

Hippophae rhamnoides, also named as Sea Buckthorn(SB) is a spiny bush with long and narrow leaves, and orange yellow berries. It is native to Europe and mainly to Asia. The leaves, fruits and the seeds of sea bucHippophae rhamnoides, also named as Sea Buckthorn(SB) is a spiny bush with long and narrow leaves, and orange yellow berries. It is native to Europe and mainly to Asia. The leaves, fruits and the seeds of sea buckthorn contain many bioactive compounds. These compounds are various natural antioxidants such as ascorbic acid, tocopherols, carotenoids, flavonoids, whereas besides them all we can find macronutrients such as proteins, lipids (mainly unsaturated fatty acids and phytosterols), vitamins (especially vitamin C), minerals, small amounts of sugars and organic acids . The present review focuses on the functionality of SB lipids and refers to those studies that suggest the sea buckthorn could have various beneficial effects on cardiovascular health, insulin and glucose response, renal health, hepatic health, Gastric health, epidermis health, cancer, ophthalmologic health and oxidative stress and toxicity.kthorn contain many bioactive compounds. These compounds are various natural antioxidants such as ascorbic acid, tocopherols, carotenoids, flavonoids, whereas besides them all we can find macronutrients such as proteins, lipids (mainly unsaturated fatty acids and phytosterols), vitamins (especially vitamin C), minerals, small amounts of sugars and organic acids . The present review focuses on the functionality of SB lipids and refers to those studies that suggest the sea buckthorn could have various beneficial effects on cardiovascular health, insulin and glucose response, renal health, hepatic health, Gastric health, epidermis health, cancer, ophthalmologic health and oxidative stress and toxicity.

Strain differences in antioxidants in rat models of cardiovascular disease exposed to ozone

We examined the hypothesis that antioxidant substances and enzymes in lung, heart and in bronchoalveolar lavage fluid (BALF) are altered in response to O3 in cardiovascular disease and/or metabolic syndrome (CVD)-prone rat models. CVD strains [spontaneously hypertensive (SH), SH stroke-prone (SHSP), SHHF/Mcc heart failure obese (SHHF), insulin-resistant JCR:LA-cp obese (JCR) and Fawn-Hooded hypertensive (FHH)] were compared with normal strains [Wistar, Sprague-Dawley (SD) and Wistar Kyoto (WKY)]. Total glutathione (GSH + GSSG or GSx), reduced ascorbate (AH2), uric acid (UA) and antioxidant enzymes were determined in lung, heart and BALF immediately (0 h) or 20-h post 4-h nose-only exposure to 0.0, 0.25, 0.5 and 1.0 ppm O3. Basal- and O3-induced antioxidant substances in tissues varied widely among strains. Wistar rats had a robust O3-induced increase in GSx and AH2 in the lung. Two CVD strains (JCR and SHHF) had high basal levels of AH2 and GSx in BALF as well as high basal lung UA. Across all strains, high BALF GSx was only observed when high BALF AH2 was present. CVD rats tended to respond less to O3 than normal. High-basal BALF AH2 levels were associated with decreased O3 toxicity. In summary, large differences were observed between both normal and CVD rat strains in low-molecular weight antioxidant concentrations in lung, BALF and heart tissue. Wistar (normal) and JCR and SHHF (CVD) rats appeared to stand out as peculiar in terms of basal- or O3-induced changes. Results elucidate interactions among antioxidants and air pollutants that could enhance understanding of cardiopulmonary disease.

Mitochondrial Hormesis links nutrient restriction to improved metabolism in fat cell

Fasting promotes longevity by reprogramming metabolic and stress resistance pathways. However, although the impact on adipose tissue physiology through hormonal inputs is well established, the direct role of fasting on adipose cells is poorly understood. Herein we show that white and beige adipocytes, as well as mouse epididymal and subcutaneous adipose depots, respond to nutrient scarcity by acquiring a brown-like phenotype. Indeed, they improve oxidative metabolism through modulating the expression of mitochondrial-and nuclear-encoded oxidative phosphorylation genes as well as mitochondrial stress defensive proteins (UCP1, SOD2). Such adaptation is placed in a canonical mitohormetic response that proceeds via mitochondrial reactive oxygen species (^mtROS) production and redistribution of FoxO1 transcription factor into nucleus. Nuclear FoxO1 (ⁿFoxO1) mediates retrograde communication by inducing the expression of mitochondrial oxidative and stress defensive genes. Collectively, our findings describe an unusual white/beige fat cell response to nutrient availability highlighting another health-promoting mechanism of fasting.

The effects of DASH diet on weight loss and metabolic status in adults with non-alcoholic fatty liver disease: a randomized clinical trial

BACKGROUND & AIMS

This study was designed to determine the effects of the Dietary Approaches to Stop Hypertension (DASH) diet on weight loss and metabolic status in overweight patients with non-alcoholic fatty liver disease (NAFLD).

METHODS

This randomized controlled clinical trial was done among 60 overweight and obese patients with NAFLD. Patients were randomly allocated to consume either the control (n = 30) or the DASH eating pattern (n = 30) for 8 weeks. Both diets were designed to be calorie-restricted. Both diets were consisted of 52-55% carbohydrates, 16-18% proteins and 30% total fats; however, the DASH diet was designed to be rich in fruits, vegetables, whole grains, and low-fat dairy products and low in saturated fats, cholesterol and refined grains.

RESULTS

Adherence to the DASH eating pattern, compared to the control diet, weight (P = 0.006), BMI (P = 0.01), alanine aminotransferase (ALT) (P = 0.02), alkalin phosphatase (ALP) (P = 0.001), insulin levels (P = 0.01), homoeostasis model of assessment-estimated insulin resistance (HOMA-IR) (P = 0.01) significantly decreased and quantitative insulin sensitivity check index (QUICKI) (P = 0.004) significantly increased. Compared with the control diet, the DASH diet has resulted in significant reductions in serum triglycerides (P = 0.04) and total-/HDL-cholesterol ratio (P = 0.01). Finally, decreased concentrations of serum high-sensitivity C-reactive protein (hs-CRP) (P = 0.03), malondialdehyde (MDA) (P = 0.04), increased levels of nitric oxide (NO) (P = 0.01) and glutathione (GSH) (P = 0.009) were found in the DASH group compared with the control group.

CONCLUSIONS

Consumption of DASH diet for 8 weeks among patients with NAFLD had beneficial effects on weight, BMI, ALT, ALP, triglycerides, markers of insulin metabolism, inflammatory markers, GSH and MDA.

Cytoprotective mechanism of ferulic acid against high glucose-induced oxidative stress in cardiomyocytes and hepatocytes

Background

Ferulic acid (FA), a phenolic acid, is a potential therapy for diabetes mellitus. FA has been shown to protect against hepatic and myocardial injury and oxidative stress in obese rats with late-stage diabetes, but the mechanism of the antioxidative activity of FA is still unclear.

Objective

The aim of this study was to elucidate whether FA can prevent damage to cardiomyocytes and hepatocytes caused by high glucose (HG)-induced oxidative stress and whether the protection effects of FA on these cells are related to the Keap1-Nrf2-ARE signaling pathways.

Design

Cells were divided into four groups: a control group (cultured with normal medium), an HG group (medium containing 80 mmol/L glucose), an FA+HG group (medium containing 80 mmol/L glucose and 1, 5, or 10 µg/mL FA), and a dimethylbiguanide (DMBG)+HG group (medium containing 80 mmol/L glucose and 50 µg/mL DMBG).

Results

FA treatment significantly increased cell viability and significantly decreased cell apoptosis compared with the HG-treated group. Moreover, FA down-regulated the expression of Keap1 protein and up-regulated the expression of Nrf2 protein and gene transcription of HO-1 and glutathione S-transferase (GST) in a dose-dependent manner.

Conclusion

FA alleviated the HG-induced oxidative stress and decreased cell apoptosis in hepatocytes and cardiomyocytes. These effects were associated with the Keap1-Nrf2-ARE signaling pathway.

Grape polyphenols supplementation reduces muscle atrophy in a mouse model of chronic inflammation

OBJECTIVES

Polyphenols (PP) have demonstrated beneficial effects on low-grade inflammation and oxidative stress; however, little is known about their effect on highly inflamed muscle. The purposes of this study were (i) to evaluate muscle alteration induced by high-grade inflammation, and (ii) to test the effects of red grape PP supplementation on these alterations.

METHODS

We used a transgenic mice model (transforming growth factor [TGF] mice) to develop a high T cell-dependent inflammation and C57 BL/6 control (CTL) mice model. Skeletal muscles of TGF and CTL mice were investigated for inflammation, atrophy and oxidative stress markers. Isolated mitochondria from hindlimb muscles were used for respiration with pyruvate as substrate and oxidative damages were measured by Western blot. TGF mice were supplemented with a mixture of red grape polyphenols (50 mg/kg/d) for 4 wk. Data were analyzed by one-way analysis of variance (ANOVA) and post hoc Bonferroni's multiple comparison tests.

RESULTS

TGF mice presented skeletal muscle inflammation, oxidative stress, mitochondrial alteration and muscle atrophy. Atrophy was associated with two distinct pathways: (i) one linked to inflammation, NF-κB activation and increased ubiquitin ligase expression, and (ii) one dependent on reactive oxygen species (ROS) production leading to damaged mitochondria accumulation and activation of caspase-9 and 3. Supplementation of TGF mice with a mixture of red grape polyphenols (50 mg/kg/d) for 4 wk improved mitochondrial function and highly decreased caspases activation, which allowed muscle atrophy mitigation.

CONCLUSIONS

These observations suggest that nutritional dosages of red grape polyphenols might be beneficial for reducing skeletal muscle atrophy, even in a high-grade inflammation environment.

Dietary pattern trajectories during 15 years of follow-up and HbA1c, insulin resistance and diabetes prevalence among Chinese adults

BACKGROUND

Most research on dietary patterns and health outcomes does not include longitudinal exposure data. We used an innovative technique to capture dietary pattern trajectories and their association with haemoglobin A1c (HbA1c), homeostasis model of insulin resistance (HOMA-IR) and prevalence of newly diagnosed diabetes.

METHODS

We included 4096 adults with 3-6 waves of diet data (1991-2006) and biomarkers measured in 2009 from the China Health and Nutrition Survey. Diet was assessed with three 24-h recalls and a household food inventory. We used a dietary pattern previously identified with reduced rank regression that positively predicted diabetes in 2006 (high in wheat products and soy milk and low in rice, legumes, poultry, eggs and fish). We estimated a score for this dietary pattern for each subject at each wave. Using latent class trajectory analysis, we grouped subjects with similar dietary pattern score trajectories over time into five classes.

RESULTS

Three trajectory classes were stable over time, and in two classes the diet became unhealthier over time (upward trend in dietary pattern score). Among two classes with similar scores in 2006, the one with the lower (healthier) initial score had an HbA1c 1.64% lower (-1.64 (95% CI -3.17 to -0.11)) and non-significantly a HOMA-IR 6.47% lower (-6.47 (-17.37 to 4.42)) and lower odds of diabetes (0.86 (0.44 to 1.67)).

CONCLUSIONS

Our findings suggest that dietary pattern trajectories with healthier scores longitudinally had a lower HbA1c compared with those with unhealthier scores, even when the trajectories had similar scores in the end point.

Antioxidants and human diseases

Oxidative stress plays a pivotal role in the development of human diseases. Reactive oxygen species (ROS) that includes hydrogen peroxide, hyphochlorus acid, superoxide anion, singlet oxygen, lipid peroxides, hypochlorite and hydroxyl radical are involved in growth, differentiation, progression and death of the cell. They can react with membrane lipids, nucleic acids, proteins, enzymes and other small molecules. Low concentrations of ROS has an indispensable role in intracellular signalling and defence against pathogens, while, higher amounts of ROS play a role in number of human diseases, including arthritis, cancer, diabetes, atherosclerosis, ischemia, failures in immunity and endocrine functions. Antioxidants presumably act as safeguard against the accumulation of ROS and their elimination from the system. The aim of this review is to highlight advances in understanding of the ROS and also to summarize the detailed impact and involvement of antioxidants in selected human diseases.

Sestrin2 inhibits uncoupling protein 1 expression through suppressing reactive oxygen species

Uncoupling protein 1 (Ucp1), which is localized in the mitochondrial inner membrane of mammalian brown adipose tissue (BAT), generates heat by uncoupling oxidative phosphorylation. Upon cold exposure or nutritional abundance, sympathetic neurons stimulate BAT to express Ucp1 to induce energy dissipation and thermogenesis. Accordingly, increased Ucp1 expression reduces obesity in mice and is correlated with leanness in humans. Despite this significance, there is currently a limited understanding of how Ucp1 expression is physiologically regulated at the molecular level. Here, we describe the involvement of Sestrin2 and reactive oxygen species (ROS) in regulation of Ucp1 expression. Transgenic overexpression of Sestrin2 in adipose tissues inhibited both basal and cold-induced Ucp1 expression in interscapular BAT, culminating in decreased thermogenesis and increased fat accumulation. Endogenous Sestrin2 is also important for suppressing Ucp1 expression because BAT from Sestrin2(-/-) mice exhibited a highly elevated level of Ucp1 expression. The redox-inactive mutant of Sestrin2 was incapable of regulating Ucp1 expression, suggesting that Sestrin2 inhibits Ucp1 expression primarily through reducing ROS accumulation. Consistently, ROS-suppressing antioxidant chemicals, such as butylated hydroxyanisole and N-acetylcysteine, inhibited cold- or cAMP-induced Ucp1 expression as well. p38 MAPK, a signaling mediator required for cAMP-induced Ucp1 expression, was inhibited by either Sestrin2 overexpression or antioxidant treatments. Taken together, these results suggest that Sestrin2 and antioxidants inhibit Ucp1 expression through suppressing ROS-mediated p38 MAPK activation, implying a critical role of ROS in proper BAT metabolism.

Effects of thiol antioxidant β-mercaptoethanol on diet-induced obese mice

AIMS

Obesity and insulin resistance are associated with increased oxidant stress. However, treatments of obese subjects with different types of antioxidants often give mixed outcomes. In this work, we sought to determine if long-term supplementation of a thiol antioxidant, β-mercaptoethanol, to diet-induced obese mice may improve their health conditions.

MAIN METHODS

Middle-age mice with pre-existing diet-induced obesity were provided with low concentration β-mercaptoethanol (BME) in drinking water for six months. Animals were assessed for body composition, gripping strength, spontaneous physical and metabolic activities, as well as insulin and pyruvate tolerance tests. Markers of inflammation were assessed in plasma, fat tissue, and liver.

KEY FINDINGS

BME-treated mice gained less fat mass and more lean mass than the control animals. They also showed increased nocturnal locomotion and respiration, as well as greater gripping strength. BME reduced plasma lipid peroxidation, decreased abdominal fat tissue inflammation, reduced fat infiltration into muscle and liver, and reduced liver and plasma C-reactive protein. However, BME was found to desensitize insulin signaling in vivo, an effect also confirmed by in vitro experiments.

SIGNIFICANCE

Long-term supplementation of low dose thiol antioxidant BME improved functional outcomes in animals with pre-existing obesity. Additional studies are needed to address the treatment impact on insulin sensitivity if a therapeutic value is to be explored.

Biological relevance of inflammation and oxidative stress in the pathogenesis of arterial diseases

Over the past three decades, age-adjusted rates of cardiovascular morbidity and mortality have fallen in the United States, but the prevalence of obesity and associated metabolic disorders has risen dramatically. Recent studies have begun to unravel the complex linkages between adipose and vascular tissues that may accelerate the development of atherosclerosis in the context of obesity. Experimental models indicate that inflammation and oxidative stress, which mutually amplify each other within the vasculature and in visceral fat, are key processes that drive the initiation, progression, and subsequent rupture of the atherosclerotic lesion. Emerging research is further elucidating the contributions made by chemokines and their receptors, adipokines, and miRNAs to arterial disease. Translation of these basic science findings to clinical applications represents a tantalizing possibility for reducing the global burden of obesity-associated atherosclerosis and other cardiovascular diseases.

Dietary total antioxidant capacity is related to glucose tolerance in older people: the Hertfordshire Cohort Study

BACKGROUND AND AIMS

Dietary antioxidants may play a protective role in the aetiology of type 2 diabetes. However, observational studies that examine the relationship between the antioxidant capacity of the diet and glucose metabolism are limited, particularly in older people. We aimed to examine the relationships between dietary total antioxidant capacity (TAC) and markers of glucose metabolism among 1441 men and 1253 women aged 59-73 years who participated in the Hertfordshire Cohort Study, UK.

METHODS AND RESULTS

Diet was assessed by food frequency questionnaire. Dietary TAC was estimated using published databases of TAC measured by four different assays: oxygen radical absorbance capacity (ORAC), ferric-reducing ability of plasma (FRAP), total radical-trapping antioxidant parameter (TRAP) and trolox equivalent antioxidant capacity (TEAC). Fasting and 120-min plasma glucose and insulin concentrations were measured during a standard 75-g oral glucose tolerance test. In men, dietary TAC estimated by all four assays was inversely associated with fasting insulin concentration and homoeostasis model assessment of insulin resistance (HOMA-IR); with the exception of ORAC, dietary TAC was also inversely related to 120-min glucose concentration. There were no associations with fasting glucose or 120-min insulin concentrations. In women, with the exception of the association between ORAC and 120-min insulin concentration, dietary TAC estimated by all assays showed consistent inverse associations with fasting and 120-min glucose and insulin concentrations and HOMA-IR. These associations were more marked among women with BMI ≥ 30 kg/m(2).

CONCLUSION

These findings suggest dietary TAC may have important protective effects on glucose tolerance, especially in older obese women.

Antioxidants and diabetic retinopathy

The biochemical perturbations in diabetes mellitus (DM) create the conditions for the production of free radicals, the consequence of which is increased oxidative stress. Evidence has accrued over the past 2 decades that suggests that oxidative stress is an important pathogenetic factor in the development of diabetic retinopathy (DR). Experimental data show that the use of strategies that ameliorate oxidative stress can prevent and retard the development of DR in the animal model. Clinical observations also suggest that reducing oxidative stress may help to reverse pathological manifestations of DR. The present article constitutes an examination of the role of antioxidants in the management of DR and the current state of clinically relevant knowledge.