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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The oxidative stress-sensitive c-Jun-N-terminal kinase (JNK) pathway is known to be activated in diabetic condition and is involved in the progression of insulin resistance. However, the effect of antioxidants on JNK pathway and insulin resistance has not been investigated. The present study was aimed to investigate the effect of antioxidants on redox balance, insulin sensitivity, and JNK pathway in high-fat-fed rats. Male Wistar rats were divided into four groups: the control group - received a rodent chow; control+antioxidant group - fed with rodent chow supplemented with 0.2% (w/w) vitamin E, 0.3% (w/w) vitamin C, and 0.5% (w/w) alpha-lipoic acid; high-fat group - received high-fat diet; and high fat+antioxidant group - fed with high-fat diet supplemented with above antioxidants. Fat feeding to rats for 9 weeks significantly increased IRS-1 serine phoshorylation, reduced insulin-stimulated IRS-1 tyrosine phosphorylation and insulin sensitivity. High-fat diet also impaired redox balance and activated the redox-sensitive serine kinase - JNK pathway. Antioxidant supplementation along with high-fat diet preserved the free radical defense system, inhibited the activation of JNK pathway, and improved insulin signaling and insulin sensitivity. The present study shows for the first time that antioxidants inhibit JNK pathway and IRS-1 serine phosphorylation while improving insulin sensitivity in fat-fed rats. These findings implicate the beneficial effect of antioxidants in obesity-/dyslipidemia-induced insulin resistance in humans.
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PMID:Antioxidants preserve redox balance and inhibit c-Jun-N-terminal kinase pathway while improving insulin signaling in fat-fed rats: evidence for the role of oxidative stress on IRS-1 serine phosphorylation and insulin resistance. 1843 58

The incidence of esophageal adenocarcinoma (EA) and its precursor condition, Barrett's esophagus, has risen rapidly in the United States for reasons that are not fully understood. Therefore, we evaluated the association between use of supplemental vitamins and minerals and risk of neoplastic progression of Barrett's esophagus and EA. The Seattle Barrett's Esophagus Program is a prospective study based on 339 men and women with histologically confirmed Barrett's esophagus. Participants underwent baseline and periodic follow-up exams, which included endoscopy and self-administered questionnaires on diet, supplement use, and lifestyle characteristics. Use of multivitamins and 4 individual supplements was calculated using time-weighted averages of reported use over the observational period. Cox proportional-hazards models were used to calculate hazard ratios (HR) for each endpoint: EA, tetraploidy, and aneuploidy. During a mean follow-up of 5 yr, there were 37 cases of EA, 42 cases of tetraploidy, and 34 cases of aneuploidy. After controlling for multiple covariates including diet, nonsteroidal anti-inflammatory drug use, obesity, and smoking, participants who took 1 or more multivitamin pills/day had a significantly decreased risk of tetraploidy [HR = 0.19; 95% confidence interval (CI) = 0.08-0.47) and EA (HR = 0.38; 95% CI = 0.15-0.99] compared to those not taking multivitamins. Significant inverse associations were also observed between risk of EA and supplemental vitamin C (> or = 250 mg vs. none: HR = 0.25; 95% CI = 0.11-0.58) and vitamin E (> or = 180 mg vs. none: HR = 0.25; 95% CI = 0.10-0.60). In this cohort study, use of multivitamins and single antioxidant supplements was associated with a significantly reduced risk of EA and markers of neoplastic progression among individuals with Barrett's esophagus.
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PMID:Dietary supplement use and risk of neoplastic progression in esophageal adenocarcinoma: a prospective study. 1844 34

The objective of this study was to test the hypothesis that the inflammatory response to a high-fat, low-carbohydrate weight loss diet (HF) we previously observed was due to oxidative stress. Nineteen overweight subjects (BMI>27 kg/m(2)) were randomly assigned to either an antioxidant supplement (AS) (1 g vitamin C/800 IU vitamin E) or a placebo (P) group and provided with a HF for 7 days. Fasted pre- and post serum samples were measured for markers of inflammation (C-reactive protein (CRP), interleukin-6 (IL-6), and monocyte chemoattractant protein-1 (MCP-1)), oxygen radical absorbance capacity (ORAC), and glucose, whereas urine was measured for oxidative stress (8-epi-prostaglandin-F(2alpha) (8-epi)). HF resulted in significant reductions in weight (-3.2%), glucose (-18.7%), and MCP-1 (-15%) (all P<0.01), with no difference between groups. There was a trend for a differential effect between groups for CRP as it decreased 32% in the AS group but increased 50% for P (P=0.076). Inverse correlations were noted between initial values and changes in several inflammatory and oxidative stress markers, including CRP (r= -0.501), 8-epi (r= -0.863), and ORAC (r= -0.546) (all P<0.05). It was concluded that weight loss on a short-term HF caused reduction of some but not all markers of inflammation. A role for oxidative stress in causing inflammation was not confirmed; however, longer term diet-controlled studies are necessary to further explore the trend for a differential response in CRP with antioxidant supplementation.
Obesity (Silver Spring) 2008 Jul
PMID:Inflammatory response to a high-fat, low-carbohydrate weight loss diet: effect of antioxidants. 1845 74

Data from epidemiologic, experimental, and animal studies indicate that diet plays an important role in the etiology of gastric cancer. High intake of fresh fruits and vegetables, lycopene and lycopene-containing food products, and potentially vitamin C and selenium may reduce the risk for gastric cancer. Data also suggest that high intake of nitrosamines, processed meat products, salt and salted foods, and overweight and obesity are associated with increased risk for gastric cancer. However, current data provide little support for an association of beta-carotene, vitamin E, and alcohol consumption with risk for gastric cancer.
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PMID:Nutrition and gastric cancer risk: an update. 1845 10

Oxidative stress is elevated in obesity, and may be a major mechanism for obesity-related diseases. Nonsmokers (n=396) were randomized to 1000 mg/day vitamin C, 800 IU/day vitamin E, or placebo, for 2 months. Treatment effect was examined in multiple regression analyses using an intention-to-treat approach. Vitamin C (P=0.001) and vitamin E (P=0.043) reduced plasma F2-isoprostanes. In the overall sample, changes from baseline were +6.8, -10.6, and -3.9% for placebo, vitamin C, and vitamin E groups, respectively. However, a significant interaction with baseline F2-isoprostane was found. When baseline F2-isoprostane was >50 microg/mL, vitamin C reduced F2-isoprostane by 22% (P=0.01). Vitamin E reduced it by 9.8% (P=0.46). Below that cut point, neither treatment produced further reductions. F2-isoprostane>50 microg/mL was strongly associated with obesity, and was present in 42% of the sample. Change in malondialdehyde concentration was minimal. These findings suggest a role for vitamin C in reducing lipid peroxidation. Future research on effects of vitamins C or E on plasma F2-isoprostane should limit participants to those with baseline levels >50 mug/mL. Further studies are needed to establish whether treatment with vitamins C or E in persons with concentrations above that cut point could slow the development of cardiovascular disease.
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PMID:The effect of vitamins C and E on biomarkers of oxidative stress depends on baseline level. 1845 17

Levels of antioxidants, activities of free radical scavenging enzymes and extent of lipid peroxidation were determined in the blood of 37 elderly diabetic men and 30 control elderly men, 16 without cardiovascular disease (CVD) and 14 with CVD. The mean +/-S.D. of the ages of the diabetic men was 66+/-5 and those of the control men was 69+/-5, while serum glucose levels of diabetic men were 213+/-81 mg/dl and that of control subjects were 95+/-14 mg/dl. Among the diabetic men, 13 men were obese with body mass index>30, 26 men had poor control of diabetes (glycohemoglobin>7%) and 25 men had retinopathy. The diets of the control and diabetic men were evaluated. Blood samples were collected and analyzed for major endogenous antioxidant defense parameters and lipid peroxidation. The results show that diabetic men had significantly lower blood reduced glutathione levels (p<0.001) and erythrocyte (RBC) CuZn-superoxide dismutase activity (p<0.001) when compared to control groups with or without CVD. There was no significant differences in plasma vitamin E levels and the activities of catalase and glutathione peroxidase in RBC among the three groups. The extent of lipid peroxidation was highest in diabetic patients, intermediate in controls with CVD, and lowest in controls without CVD. The results suggest that a decline of endogenous antioxidant defense capability contributes to oxidative stress in the diabetic elderly patients. Dietary survey showed that there were no differences in the nutrient intakes of diabetic and control groups. It appears that individual dietary advice is needed for a large portion of diabetic patients in view of their poor glycemic control, hypertriglyceridemia and obesity.
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PMID:Blood antioxidant defense system and dietary survey of elderly diabetic men. 1865 5

Plasma C-reactive protein (CRP) is an inflammatory biomarker that predicts cardiovascular disease. Lowering elevated CRP with statins has reduced the incidence of cardiovascular disease. We investigated whether vitamin C or E could reduce CRP. Healthy nonsmokers (N=396) were randomized to three groups, 1000 mg/day vitamin C, 800 IU/day vitamin E, or placebo, for 2 months. Median baseline CRP was low, 0.85 mg/L. No treatment effect was seen when all participants were included. However, a significant interaction was found, indicating that treatment effect depends on baseline CRP concentration. Among participants with CRP indicative of elevated cardiovascular risk (> or =1.0 mg/L), vitamin C reduced the median CRP by 25.3% vs placebo (p=0.02) (median reduction in the vitamin C group, 0.25 mg/L, 16.7%). These effects are similar to those of statins. The vitamin E effect was not significant. In summary, treatment with vitamin C but not vitamin E significantly reduced CRP among individuals with CRP > or =1.0 mg/L. Among the obese, 75% had CRP > or =1.0 mg/L. Research is needed to determine whether reducing this inflammatory biomarker with vitamin C could reduce diseases associated with obesity. But research on clinical benefits of antioxidants should limit participants to persons with elevations in the target biomarkers.
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PMID:Vitamin C treatment reduces elevated C-reactive protein. 1895 64

This review attempts to delineate the underlying mechanisms leading to the development of hypertension as well as the function of vitamins and minerals in the regulation of blood pressure. Physiological processes that regulate cardiac output and systemic vascular resistance impact on the control of blood pressure. Metabolic abnormalities associated with the tetrad of hypertension, dyslipidaemia, glucose intolerance and obesity share insulin resistance, which might be organ or cell specific, as an underlying feature representing different tissue manifestation of a common cellular ionic defect. As Ca is at the centre of ionic regulation of cellular functions, vitamins involved in Ca regulation have a significant role in the control of blood pressure. The endothelium-dependent vasodilator, NO, is susceptible to oxidative damage. Hence, antioxidant vitamins and related factors regulate blood pressure through protection of NO. Robust evidence for the involvement of vitamin B6 (pyridoxine), vitamin C, vitamin D and vitamin E in the regulation of blood pressure have been reported. The well-known roles of Na, K, Ca, Mg and Cl have been explored further. The action of various vitamins on blood pressure regulation cannot always be explained on the basis of their conventionally recognised "vitamin function". The non-traditional functions of vitamins and their derivatives can be exploited as an adjunct to available pharmacological modalities in the treatment of hypertension.
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PMID:Blood pressure regulation and micronutrients. 1908 15

The study objective was to evaluate the realization of the reducing diet recommended in the treatment of overweight or obesity (1500 kcal) with regard to the caloric value and the content of basic nutrients, vitamins and bioelements. The study was conducted on a group of 48 women. Daily food rations were evaluated based on a week's dietary register. Results were averaged in each patient and compared to the norms worked out by the Institute of Food and Feeding in Warsaw for subjects with low physical activity. The mean energetic value of the diets was found to meet the requirements. Approximately 50% of the obese women consumed high-protein, low-fat and low-carbohydrate food rations. The analysis of vitamin content in daily food rations showed insufficient intake of vitamin E (in 89.6% of women), thiamin (83.3%), riboflavin (93.7%), niacin (60.4%), vitamin B6 (87.5%), folic acid (89.6%) and vitamin C (72.9%). Vitamin A intake was higher than the recommended norm in 47.9% of women. The lowest realization was noted in the case of potassium (64.6% of rations below the norm), calcium (100% below the norm), magnesium (64.6% below the norm). However, dietary sodium and phosphate content in most obese women exceeded the norms. The intake was too low in the case of iron (in 91.7%), zinc (in 97.9%) and copper (in 100%). It seems that long-term compliance with such a diet requires additional individual supplementation.
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PMID:[Assessment of realization of a reducing diet by obese women during treatment of excessive body mass]. 1914 32

The mechanism, by which a high-fat (HF) diet could impair glucose metabolism, is not completely understood but could be related to inflammation, lipotoxicity and oxidative stress. Lipid peroxides have been proposed as key mediators of intracellular metabolic response. The purpose of the present study was to analyse, in mice fed with a HF diet, the possible association between obesity and glucose tolerance on the one hand, and between oxidative stress and lipid peroxidation on the other hand. The present results show that a HF diet (70 % energy as fat), v. a high-carbohydrate chow diet (control), increases body weight and fat mass development, and impairs glycaemia and insulinaemia within 4 weeks. It also promotes the expression of NADPH oxidase in the liver--signing both oxidative and inflammatory stress--but decreases thiobarbituric acid-reactive substances content in the liver as well as in epididymal, subcutaneous and visceral adipose tissues. HF diet, with elevated vitamin E content, induces high concentration of alpha-tocopherol in liver and adipose tissues, which contributes to the protection against lipid peroxidation. Thus, lipid peroxidation in key organs is not necessarily related to the development of metabolic disorders associated with diabetes and obesity.
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PMID:Lipid peroxidation is not a prerequisite for the development of obesity and diabetes in high-fat-fed mice. 1916 40


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