201
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Effects of ascorbic acid and β-carotene on HepG2 human hepatocellular carcinoma cell line. Mol Biol Rep 2010; 38:4265-72. [PMID: 21116852 DOI: 10.1007/s11033-010-0549-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Accepted: 11/17/2010] [Indexed: 12/31/2022]
Abstract
Recent studies have demonstrated that vegetable rich diets have protective effects on the occurrence and prognosis of various cancers. In addition to dietary intakes, ascorbic acid and β-carotene are also taken as supplements. The aim of this study was to assess effects of ascorbic acid, β-carotene and their combinations on human hepatocellular carcinoma cell line HepG2. Ascorbic acid and β-carotene were applied to cells as plasma peak concentrations (70 and 8 μM, respectively) and their half concentrations (35 and 4 μM, respectively) for 24 and 48 h. Genotoxic and cytotoxic effects of ascorbic acid and β-carotene were evaluated by alkali single cell gel electrophoresis (SCGE), acridine orange/ethidium bromide staining patterns of cells (apoptosis and necrosis) and lipid peroxidation (thiobarbituric acid reactive substances, TBARS). Results of the SCGE demonstrated that both ascorbic acid and β-carotene caused DNA damage on HepG2 which were also concordant to increased apoptosis and necrosis of cells. Increased TBARS values also demonstrated increased lipid peroxidation in these cells. Results of the present study demonstrates that when dietary intakes of ascorbic acid and β-carotene and their relevant achievable plasma level concentrations were considered, both ascorbic acid and β-carotene induce genotoxic and cytotoxic damage on HepG2 together with increased oxidative damage in contrast to their protective effect on healthy cells. This may be correlated to oxidative status and balance of ROS in hepatocellular carcinoma cells.
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202
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Jiang L, Yang KH, Tian JH, Guan QL, Yao N, Cao N, Mi DH, Wu J, Ma B, Yang SH. Efficacy of antioxidant vitamins and selenium supplement in prostate cancer prevention: a meta-analysis of randomized controlled trials. Nutr Cancer 2010; 62:719-27. [PMID: 20661819 DOI: 10.1080/01635581.2010.494335] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Several studies have evaluated the possible association between antioxidants vitamins or selenium supplement and the risk of prostate cancer, but the evidence is still inconsistent. We systematically searched PubMed, EMBASE, the Cochrane Library, Science Citation Index Expanded, Chinese biomedicine literature database, and bibliographies of retrieved articles up to January 2009. We included 9 randomized controlled trials with 165,056 participants; methodological quality of included trials was generally high. Meta-analysis showed that no significant effects of supplementation with beta-carotene (RR 0.97, 95% CI 0.90-1.05) (3 trials), vitamin C (RR 0.98, 95% CI 0.91-1.06) (2 trials), vitamin E (RR 0.96, 95% CI 0.85-1.08) (5 trials), and selenium (RR 0.78, 95% CI 0.41-1.48) (2 trials)versus placebo on prostate cancer incidence. The mortality of prostate cancer did not differ significantly by supplement of beta-carotene (RR 1.19, 95% CI 0.87 -1.65) (1 trial), vitamin C (RR 1.45, 95%CI 0.92-2.29) (1 trial), vitamin E (RR 0.85, 95%CI 0.58-1.24) (2 trials), and selenium (RR 2.98, 95% CI 0.12-73.16) (1 trial). Our findings indicate that antioxidant vitamins and selenium supplement did not reduce the incidence and mortality of prostate cancer, these data provide no support for the use of these supplements for the prevention of prostate cancer.
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Affiliation(s)
- Lei Jiang
- The First Hospital of Lanzhou University, 199 Donggang West Road, Chengguan District, Lanzhou, Gansu, China
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203
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Ginsburg I, Kohen R, Koren E. Microbial and host cells acquire enhanced oxidant-scavenging abilities by binding polyphenols. Arch Biochem Biophys 2010; 506:12-23. [PMID: 21081104 DOI: 10.1016/j.abb.2010.11.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Revised: 11/09/2010] [Accepted: 11/09/2010] [Indexed: 12/14/2022]
Abstract
The dilemma whether supplementations of dietary antioxidants might prevent the adverse consequences of oxidative stress, the inadequacy of the analytical methods employed to quantify oxidant scavenging ability (OSA) levels in whole blood and the distribution and fate of polyphenols and their metabolites in various body compartments following oral consumption are discussed. While none-metabolized polyphenols might exert their antioxidant effects mainly in the oral cavity, metabolized polyphenols might be beneficial in the gastrointestinal tract to counteract the toxicity of oxidants and also of the sequelae of inflammatory processes. Although only micromolar amounts of polyphenols and their metabolites eventually reach the blood circulation, these may nevertheless still be highly effective as scavengers of reactive oxygen and nitrogen species because of their ability to synergize with plasma low molecular-weight antioxidants and with albumin. Polyphenols can avidly bind to surfaces of microorganisms and of blood cells to markedly enhance their OSA, therefore the routine quantifications of antioxidant levels conducted in clinical settings should always use catalase-rich whole blood but not as customary, plasma alone. In addition to their antioxidant and metal chelating properties, polyphenols may also act as signaling agents capable of affecting metabolic, inflammatory, autoimmune, carcinogenic and aging processes.
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Affiliation(s)
- Isaac Ginsburg
- The Faculty of Dental Medicine, Institute for Dental Sciences, Hebrew University, Hadassah Medical Center, P.O. Box 12065, Jerusalem 91120, Israel.
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204
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Mekary RA, Wu K, Giovannucci E, Sampson L, Fuchs C, Spiegelman D, Willett WC, Smith-Warner SA. Total antioxidant capacity intake and colorectal cancer risk in the Health Professionals Follow-up Study. Cancer Causes Control 2010; 21:1315-21. [PMID: 20390446 DOI: 10.1007/s10552-010-9559-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2009] [Accepted: 03/26/2010] [Indexed: 12/31/2022]
Abstract
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.
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Affiliation(s)
- Rania A Mekary
- Department of Nutrition, Harvard School of Public Health, 665 Huntington Avenue, Bldg 2, Rm 355A, Boston, MA 02115, USA.
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205
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Giorgi C, Agnoletto C, Baldini C, Bononi A, Bonora M, Marchi S, Missiroli S, Patergnani S, Poletti F, Rimessi A, Zavan B, Pinton P. Redox control of protein kinase C: cell- and disease-specific aspects. Antioxid Redox Signal 2010; 13:1051-85. [PMID: 20136499 DOI: 10.1089/ars.2009.2825] [Citation(s) in RCA: 286] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Hormones, growth factors, electrical stimulation, and cell-cell interactions regulate numerous cellular processes by altering the levels of second messengers, thus influencing biochemical reactions inside the cells. The Protein Kinase C family (PKCs) is a group of serine/threonine kinases that are dependent on calcium (Ca(2+)), diacylglycerol, and phospholipids. Signaling pathways that induce variations on the levels of PKC activators have been implicated in the regulation of diverse cellular functions and, in turn, PKCs are key regulators of a plethora of cellular processes, including proliferation, differentiation, and tumorigenesis. Importantly, PKCs contain regions, both in the N-terminal regulatory domain and in the C-terminal catalytic domain, that are susceptible to redox modifications. In several pathophysiological conditions when the balance between oxidants, antioxidants, and alkylants is compromised, cells undergo redox stress. PKCs are cell-signaling proteins that are particularly sensitive to redox stress because modification of their redox-sensitive regions interferes with their activity and, thus, with their biological effects. In this review, we summarize the involvement of PKCs in health and disease and the importance of redox signaling in the regulation of this family of kinases.
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Affiliation(s)
- Carlotta Giorgi
- Department of Experimental and Diagnostic Medicine, Section of General Pathology, Interdisciplinary Center for the Study of Inflammation (ICSI), BioPharmaNet, University of Ferrara, Ferrara, Italy
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206
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Fuccio L, Eusebi LH, Bazzoli F. Gastric cancer, Helicobacter pylori infection and other risk factors. World J Gastrointest Oncol 2010; 2:342-7. [PMID: 21160805 PMCID: PMC2999139 DOI: 10.4251/wjgo.v2.i9.342] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2010] [Revised: 08/17/2010] [Accepted: 08/24/2010] [Indexed: 02/05/2023] Open
Abstract
Gastric cancer incidence is declining. However, it is too early to consider this neoplastic disease as rare and the worldwide mortality rate still remains high. Several risk factors have been identified for non-cardia gastric cancer and primary prevention is feasible since most of the risk factors can be removed. Helicobacter pylori eradication treatment reduces but does not abolish gastric cancer risk. Indeed, gastric cancer is a multifactorial disease and removing one factor does not therefore prevent all cases. Endoscopic surveillance is still needed, especially in subjects at higher risk. The definition of high-risk patients will be the future challenge as well as identifying the best surveillance strategy for such patients.
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Affiliation(s)
- Lorenzo Fuccio
- Lorenzo Fuccio, Leonardo Henry Eusebi, Franco Bazzoli, Department of Internal Medicine and Gastroenterology, University of Bologna, 40138 Bologna, Italy
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207
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Park Y, Spiegelman D, Hunter DJ, Albanes D, Bergkvist L, Buring JE, Freudenheim JL, Giovannucci E, Goldbohm RA, Harnack L, Kato I, Krogh V, Leitzmann MF, Limburg PJ, Marshall JR, McCullough ML, Miller AB, Rohan TE, Schatzkin A, Shore R, Sieri S, Stampfer MJ, Virtamo J, Weijenberg M, Willett WC, Wolk A, Zhang SM, Smith-Warner SA. Intakes of vitamins A, C, and E and use of multiple vitamin supplements and risk of colon cancer: a pooled analysis of prospective cohort studies. Cancer Causes Control 2010; 21:1745-57. [PMID: 20820901 DOI: 10.1007/s10552-010-9549-y] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Accepted: 03/18/2010] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To evaluate the associations between intakes of vitamins A, C, and E and risk of colon cancer. METHODS Using the primary data from 13 cohort studies, we estimated study- and sex-specific relative risks (RR) with Cox proportional hazards models and subsequently pooled RRs using a random effects model. RESULTS Among 676,141 men and women, 5,454 colon cancer cases were identified (7-20 years of follow-up across studies). Vitamin A, C, and E intakes from food only were not associated with colon cancer risk. For intakes from food and supplements (total), the pooled multivariate RRs (95% CI) were 0.88 (0.76-1.02, >4,000 vs. ≤ 1,000 μg/day) for vitamin A, 0.81 (0.71-0.92, >600 vs. ≤ 100 mg/day) for vitamin C, and 0.78 (0.66-0.92, > 200 vs. ≤ 6 mg/day) for vitamin E. Adjustment for total folate intake attenuated these associations, but the inverse associations with vitamins C and E remained significant. Multivitamin use was significantly inversely associated with colon cancer risk (RR = 0.88, 95% CI: 0.81-0.96). CONCLUSIONS Modest inverse associations with vitamin C and E intakes may be due to high correlations with folate intake, which had a similar inverse association with colon cancer. An inverse association with multivitamin use, a major source of folate and other vitamins, deserves further study.
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Affiliation(s)
- Yikyung Park
- Department of Nutrition, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA
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208
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Familial pancreatic cancer in Italy. Risk assessment, screening programs and clinical approach: a position paper from the Italian Registry. Dig Liver Dis 2010; 42:597-605. [PMID: 20627831 DOI: 10.1016/j.dld.2010.04.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Accepted: 04/22/2010] [Indexed: 12/11/2022]
Abstract
In Italy, pancreatic cancer is the fifth leading cause of tumor related death with about 7000 new cases per year and a mortality rate of 95%. In a recent prospective epidemiological study on the Italian population, a family history was found in about 10% of patients suffering from a ductal adenocarcinoma of the pancreas (PDAC). A position paper from the Italian Registry for Familial Pancreatic Cancer was made to manage these high-risk individuals. Even though in the majority of high-risk individuals a genetic test to identify familial predisposition is not available, a screening protocol seems to be reasonable for subjects who have a >10-fold greater risk for the development of PDAC. However this kind of screening should be included in clinical trials, performed in centers with high expertise in pancreatic disease, using the least aggressive diagnostic modalities.
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209
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Biesalski HK, Grune T, Tinz J, Zöllner I, Blumberg JB. Reexamination of a meta-analysis of the effect of antioxidant supplementation on mortality and health in randomized trials. Nutrients 2010; 2:929-49. [PMID: 22254063 PMCID: PMC3257709 DOI: 10.3390/nu2090929] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 08/17/2010] [Accepted: 08/26/2010] [Indexed: 12/14/2022] Open
Abstract
A recent meta-analysis of selected randomized clinical trials (RCTs), in which population groups of differing ages and health status were supplemented with various doses of β-carotene, vitamin A, and/or vitamin E, found that these interventions increased all-cause mortality. However, this meta-analysis did not consider the rationale of the constituent RCTs for antioxidant supplementation, none of which included mortality as a primary outcome. As the rationale for these trials was to test the hypothesis of a potential benefit of antioxidant supplementation, an alternative approach to a systematic evaluation of these RCTs would be to evaluate this outcome relative to the putative risk of greater total mortality. Thus, we examined these data based on the primary outcome of the 66 RCTs included in the meta-analysis via a decision analysis to identify whether the results provided a positive (i.e., benefit), null or negative (i.e., harm) outcome. Our evaluation indicated that of these RCTs, 24 had a positive outcome, 39 had a null outcome, and 3 had a negative outcome. We further categorized these interventions as primary (risk reduction in healthy populations) or secondary (slowing pathogenesis or preventing recurrent events and/or cause-specific mortality) prevention or therapeutic (treatment to improve quality of life, limit complications, and/or provide rehabilitation) studies, and determined positive outcomes in 8 of 20 primary prevention studies, 10 of 34 secondary prevention studies, and 6 out of 16 therapeutic studies. Seven of the eight RCTs with a positive outcome in primary prevention included participants in a population where malnutrition is frequently described. These results suggest that analyses of potential risks from antioxidant supplementation should be placed in the context of a benefit/risk ratio.
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Affiliation(s)
- Hans K. Biesalski
- Department of Biological Chemistry and Nutritional Science, University of Hohenheim, Garbenstrasse 28, D-70593 Stuttgart, Germany;
| | - Tilman Grune
- Department of Nutritional Toxicology, Friedrich Schiller University Jena, Dornburger Strasse 24, D-07743 Jena, Germany;
| | - Jana Tinz
- Department of Biological Chemistry and Nutritional Science, University of Hohenheim, Garbenstrasse 28, D-70593 Stuttgart, Germany;
| | - Iris Zöllner
- Department of Epidemiology, Baden-Wuerttemberg State Health Office, Nordbahnhofstr. 135, D-70191 Stuttgart, Germany;
| | - Jeffrey B. Blumberg
- Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111, USA;
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210
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Ekström AM, Serafini M, Nyrén O, Wolk A, Bosetti C, Bellocco R. Dietary quercetin intake and risk of gastric cancer: results from a population-based study in Sweden. Ann Oncol 2010; 22:438-43. [PMID: 20688844 DOI: 10.1093/annonc/mdq390] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND To study the impact of the dietary antioxidant quercetin on risk of gastric adenocarcinoma. PATIENTS AND METHODS Using data from a large Swedish population-based case-control study of gastric cancer (505 cases and 1116 controls), we studied the association between quercetin and risk of anatomic (cardia/noncardia) and histological (intestinal and diffuse) subtypes of gastric cancer. RESULTS We found strong inverse associations between quercetin and the risk of noncardia gastric adenocarcinoma, with an adjusted odds ratio (OR) of 0.57 (95% confidence interval 0.40-0.83) for the highest quintile (≥11.9 mg) of daily quercetin intake relative to the lowest quintile of intake (<4 mg quercetin/day), supported by a significant decreasing linear trend (P value < 0.001). Similar findings were observed for the intestinal and diffuse subtype. For cardia cancer, we found a less evident and nonsignificant inverse relationship. The protection of quercetin appeared to be stronger among female smokers, with the OR leveled of at values <0.2 in quintiles 3-5 (>6 mg quercetin/day). CONCLUSIONS High dietary quercetin intake is inversely related to the risk of noncardia gastric adenocarcinoma, and the protection appears to be particularly strong for women exposed to oxidative stress, such as tobacco smoking.
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Affiliation(s)
- A M Ekström
- Division of Global Health/IHCAR, Department of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden.
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211
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Bjelakovic G, Gluud LL, Nikolova D, Bjelakovic M, Nagorni A, Gluud C. Meta-analysis: antioxidant supplements for liver diseases - the Cochrane Hepato-Biliary Group. Aliment Pharmacol Ther 2010; 32:356-67. [PMID: 20497142 DOI: 10.1111/j.1365-2036.2010.04371.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Several liver diseases have been associated with oxidative stress. Accordingly, antioxidants have been suggested as potential therapeutics for various liver diseases. The evidence supporting these suggestions is equivocal. AIM To assess the benefits and harms of antioxidant supplements for patients with liver diseases. METHODS We identified trials through electronic and manual searches until August 2009. We included randomized trials comparing antioxidant supplements (beta-carotene, vitamin A, C, E and selenium) vs. placebo or no intervention for autoimmune liver diseases, viral hepatitis, alcoholic liver disease and cirrhosis (any aetiology). Random-effects and fixed-effect meta-analyses were conducted. Results were presented as relative risks (RR), or mean difference (MD), both with 95% confidence intervals (CI). RESULTS Twenty randomized trials with 1225 participants were included. The trials assessed beta-carotene (3 trials), vitamin A (2 trials), vitamin C (9 trials), vitamin E (15 trials) and selenium (8 trials). The majority of the trials had high risk of bias and showed heterogeneity. Overall, the assessed antioxidant supplements had no significant effect on all-cause mortality [relative risk (RR) 0.84, 95% confidence interval (CI) 0.60-1.19, I(2) = 0%] or liver-related mortality (RR 0.89, 95% CI 0.39-2.05, I(2) = 37%). Stratification according to the type of liver disease assessed did not affect the conclusions. Antioxidant supplements significantly increased the activity of gamma glutamyl transpeptidase (MD 24.21 IU/L, 95% CI 6.67-41.75, I(2) = 0%). CONCLUSIONS We found no evidence to support or refute antioxidant supplements in patients with liver disease. Antioxidant supplements may increase liver enzymes.
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Affiliation(s)
- G Bjelakovic
- Centre for Clinical Intervention Research, Copenhagen University Hospital, Rigshospitalet, Denmark.
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212
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Singh PP, Chandra A, Mahdi F, Roy A, Sharma P. Reconvene and reconnect the antioxidant hypothesis in human health and disease. Indian J Clin Biochem 2010; 25:225-43. [PMID: 21731194 PMCID: PMC3001844 DOI: 10.1007/s12291-010-0078-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2010] [Accepted: 07/20/2010] [Indexed: 02/07/2023]
Abstract
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.
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Affiliation(s)
- P. P. Singh
- Department of Biochemistry, Era’s Lucknow Medical College & Hospital, Sarfarazganj, Lucknow, UP India
| | - Anu Chandra
- Department of Biochemistry, Era’s Lucknow Medical College & Hospital, Sarfarazganj, Lucknow, UP India
| | - Farzana Mahdi
- Department of Biochemistry, Era’s Lucknow Medical College & Hospital, Sarfarazganj, Lucknow, UP India
| | - Ajanta Roy
- Department of Biochemistry, Era’s Lucknow Medical College & Hospital, Sarfarazganj, Lucknow, UP India
| | - Praveen Sharma
- Department of Biochemistry, Era’s Lucknow Medical College & Hospital, Sarfarazganj, Lucknow, UP India
- Department of Biochemistry, SMS Medical College, Jaipur, India
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213
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Krishnaswamy R, Devaraj SN, Padma VV. Lutein protects HT-29 cells against Deoxynivalenol-induced oxidative stress and apoptosis: prevention of NF-kappaB nuclear localization and down regulation of NF-kappaB and Cyclo-Oxygenase-2 expression. Free Radic Biol Med 2010; 49:50-60. [PMID: 20347963 DOI: 10.1016/j.freeradbiomed.2010.03.016] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 03/02/2010] [Accepted: 03/16/2010] [Indexed: 12/23/2022]
Abstract
Increasing evidence suggests that oxidative stress is closely linked to toxic responses in cells. The tricothecene mycotoxin, Deoxynivalenol (DON), primarily affects cells of the immune system and the GI tract. DON's cytotoxicity is closely linked to intracellular ROS, and it exerts its toxic effect by a mechanism known as ribotoxic stress response, which drives both cytokine expressions at low dosages and apoptosis at high dosages. Studies to alleviate DON's toxicity are sparsely reported in literature. In the present study, the cytoprotective effect of lutein, was tested in HT-29 cells against DON-induced oxidative stress and cytotoxicity. MTT assay revealed IC(20) values of DON at 250 ng/ml. Pre-treatment of cells with 10 microM lutein resulted in 95% cell viability. Lutein combated DON-induced oxidative stress and downregulated expression of inflammatory genes, NF-kappaB and COX-2. Lutein also prevented DON-induced migration of NF-kappaB into the nucleus, as measured by immunofluorescence. Morphological studies by Electron microscopy and Cell cycle analysis by flow cytometry indicated that lutein prevented DON-induced apoptosis. The results of the present study demonstrate for the first time that lutein exerts a cytoprotective role in DON-induced toxicity.
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Affiliation(s)
- Rajashree Krishnaswamy
- School of Biotechnology and Genetic Engineering, Bharathiar University, Coimbatore - 641046, India
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214
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Abstract
Selenium is an essential element with remarkable chemical properties. The similarity to sulphur results in a number of chemical interactions mainly connected to thiols and redox processes. The element modulates cell growth; in low concentrations it is absolutely required for growth and an essential component of serum free growth media. However moderate to high concentrations potently inhibit cell growth. The inhibitory effects are tumour specific and selenium induces apoptosis in malignant cells at concentrations that do not affect the viability of normal cells. Depending on concentration and chemical form selenium may prevent or treat tumour disease. Selenium supplementation has been found to be of value in preventing hepatocellular cancer by hepatitis B, in reducing the incidence of liver cancer in general and in decreasing mortality of colorectal, lung and prostate cancer. This review focuses on the current knowledge of the preventive effects of selenium with special emphasis on major human tumours. The unique chemical properties along with metabolism and preventive mechanisms are also discussed.
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Affiliation(s)
- Mikael Björnstedt
- Division of Pathology, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge F46, 141 86 Stockholm, Sweden
| | - Aristi P. Fernandes
- Division of Pathology, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge F46, 141 86 Stockholm, Sweden
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215
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Chan AT, Giovannucci EL. Primary prevention of colorectal cancer. Gastroenterology 2010; 138:2029-2043.e10. [PMID: 20420944 PMCID: PMC2947820 DOI: 10.1053/j.gastro.2010.01.057] [Citation(s) in RCA: 411] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2009] [Revised: 01/10/2010] [Accepted: 01/14/2010] [Indexed: 02/07/2023]
Abstract
Colorectal cancer has been strongly associated with a Western lifestyle. In the past several decades, much has been learned about the dietary, lifestyle, and medication risk factors for this malignancy. Although there is controversy about the role of specific nutritional factors, consideration of dietary pattern as a whole appears useful for formulating recommendations. For example, several studies have shown that high intake of red and processed meats, highly refined grains and starches, and sugars is related to increased risk of colorectal cancer. Replacing these factors with poultry, fish, and plant sources as the primary source of protein; unsaturated fats as the primary source of fat; and unrefined grains, legumes and fruits as the primary source of carbohydrates is likely to lower risk of colorectal cancer. Although a role for supplements, including vitamin D, folate, and vitamin B6, remains uncertain, calcium supplementation is likely to be at least modestly beneficial. With respect to lifestyle, compelling evidence indicates that avoidance of smoking and heavy alcohol use, prevention of weight gain, and maintenance of a reasonable level of physical activity are associated with markedly lower risks of colorectal cancer. Medications such as aspirin and nonsteroidal anti-inflammatory drugs and postmenopausal hormones for women are associated with substantial reductions in colorectal cancer risk, though their utility is affected by associated risks. Taken together, modifications in diet and lifestyle should substantially reduce the risk of colorectal cancer and could complement screening in reducing colorectal cancer incidence.
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216
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Lhoste EF, Bruneau A, Bensaada M, Cherbuy C, Philippe C, Bruel S, Sutren M, Rabot S, Guyot S, Duée PH, Latino-Martel P. Apple proanthocyanidins do not reduce the induction of preneoplastic lesions in the colon of rats associated with human microbiota. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:4120-4125. [PMID: 20205389 DOI: 10.1021/jf904010a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Since the gut microbiota metabolizes various dietary constituents unabsorbed by the small intestine and modulates colon function, it plays an essential role in colon carcinogenesis. First, we have developed a model of human microbiota-associated rats (HMA), fed a human-type diet and injected with 1-2,dimethylhydrazine (DMH). We observed that the number and size of DMH-induced aberrant crypt foci (ACF) were significantly higher in HMA rats than in germ-free or conventional rats. Second, we used this model to assess the protective effect of an apple proanthocyanidin-rich extract (APE) on colon carcinogenesis. In this model, ACF number and multiplicity were not reduced by APE at 0.001% and 0.01% in drinking water. They were higher with APE 0.1% than with APE 0.01%. Therefore, the cross-talk between human microbiota and the colon epithelium should be taken into account in carcinogenesis models. Moreover, attention should be paid prior to using proanthocyanidin extracts as dietary supplements for humans.
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Affiliation(s)
- Evelyne F Lhoste
- INRA, UR910 Unite d'Ecologie et Physiologie du Systeme Digestif, Institut National de la Recherche Agronomique (INRA), Jouy-en-Josas, France
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217
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Selenius M, Rundlöf AK, Olm E, Fernandes AP, Björnstedt M. Selenium and the selenoprotein thioredoxin reductase in the prevention, treatment and diagnostics of cancer. Antioxid Redox Signal 2010; 12:867-80. [PMID: 19769465 DOI: 10.1089/ars.2009.2884] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Selenium is an essential element that is specifically incorporated as selenocystein into selenoproteins. It is a potent modulator of eukaryotic cell growth with strictly concentration-dependant effects. Lower concentrations are necessary for cell survival and growth, whereas higher concentrations inhibit growth and induce cell death. It is well established that selenium has cancer preventive effects, and several studies also have shown that it has strong anticancer effects with a selective cytotoxicity on malignant drug-resistant cells while only exerting marginal effects on normal and benign cells. This cancer-specific cytotoxicity is likely explained by high affinity selenium uptake dependent on proteins connected to multidrug resistance. One of the most studied selenoproteins in cancer is thioredoxin reductase (TrxR) that has important functions in neoplastic growth and is an important component of the resistant phenotype. Several reports have shown that TrxR is induced in tumor cells and pre-neoplastic cells, and several commonly used drugs interact with the protein. In this review, we summarize the current knowledge of selenium as a potent preventive and tumor selective anticancer drug, and we also discuss the potential of using the expression and modulation of the selenoprotein TrxR in the diagnostics and treatment of cancer.
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Affiliation(s)
- Markus Selenius
- Division of Pathology, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden
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218
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Babar M, Abdel-Latif MMM, Ravi N, Murphy A, Byrne PJ, Kelleher D, Reynolds JV. Pilot translational study of dietary vitamin C supplementation in Barrett's esophagus. Dis Esophagus 2010; 23:271-6. [PMID: 19930402 DOI: 10.1111/j.1442-2050.2009.01027.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The transcription factor Nuclear factor kappa B (NF-kappaB) is central to the regulation of genes encoding for mediators of inflammation and carcinogenesis. In the esophagus, NF-kappaB is progressively activated from inflammation to Barrett's metaplasia and adenocarcinoma. Vitamin C, an antioxidant, can inhibit NF-kappaB in in vitro models, and the aim of this study was to prospectively assess the effect of supplemental vitamin C on NF-kappaB and associated cytokines in patients with Barrett's esophagus. Twenty-five patients with long-segment Barrett's and specialized intestinal metaplasia received dietary vitamin C (1000 mg/day) orally for four weeks, and had pre- and post-vitamin C endoscopic biopsies. NF-kappaB activity (activated p50 and p65 subunits) of nuclear extracts was assessed using the Active Motif NF-kappaB assay, and cytokines and growth factors were measured using the Evidence Investigator biochip array. NF-kappaB and related pro-inflammatory cytokines and growth factors (IL-8, VEGF, IL-10) were activated in all Barrett's tissue pre-treatment. Down-regulation in activated NF-kappaB and cytokines was observed in 8/25 (35%) patients. Dietary vitamin C supplementation may down-regulate pro-inflammatory markers in a subset of Barrett's patients. Further studies with larger numbers of endpoints will be needed to further evaluate this effect.
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Affiliation(s)
- M Babar
- Department of Clinical Surgery, Trinity Centre for Health Sciences, St. James's Hospital, Dublin, Ireland
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219
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Carroll C, Cooper K, Papaioannou D, Hind D, Tappenden P, Pilgrim H, Booth A. Meta-analysis: folic acid in the chemoprevention of colorectal adenomas and colorectal cancer. Aliment Pharmacol Ther 2010; 31:708-18. [PMID: 20085565 DOI: 10.1111/j.1365-2036.2010.04238.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Folic acid has been identified as a possible agent for the chemoprevention of colorectal cancer. AIM To assess the effectiveness of folic acid in reducing the recurrence of adenomas (precursors of colorectal cancer) among populations with a history of adenomas and the incidence of colorectal cancer within average-risk populations. METHODS Systematic review of randomized controlled trials comparing folic acid alone, or with other agents, vs. placebo. Eight databases were searched for relevant trials. Meta-analysis was performed. RESULTS The literature search retrieved 3785 citations. Six studies met the inclusion criteria. Meta-analysis of three studies in individuals with a history of adenomas showed no statistically significant difference in the relative risk of adenoma recurrence (RR 0.93, P = 0.27). A sensitivity analysis of the two higher quality trials changed the direction of effect (RR 1.16, P = 0.11). Meta-analysis of three trials in general populations demonstrated no statistically significant effect on the relative risk of colorectal cancer (RR 1.13, P = 0.54). In all three analyses, outcome event rates were higher in individuals receiving folic acid. CONCLUSION There is no evidence that folic acid is effective in the chemoprevention of colorectal adenomas or colorectal cancer for any population.
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Affiliation(s)
- C Carroll
- Health Economics and Decision Science, School of Health and Related Research, University of Sheffield, Sheffield, UK.
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220
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How increased oxidative stress promotes longevity and metabolic health: The concept of mitochondrial hormesis (mitohormesis). Exp Gerontol 2010; 45:410-8. [PMID: 20350594 DOI: 10.1016/j.exger.2010.03.014] [Citation(s) in RCA: 531] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Revised: 03/09/2010] [Accepted: 03/19/2010] [Indexed: 12/23/2022]
Abstract
Recent evidence suggests that calorie restriction and specifically reduced glucose metabolism induces mitochondrial metabolism to extend life span in various model organisms, including Saccharomyces cerevisiae, Drosophila melanogaster, Caenorhabditis elegans and possibly mice. In conflict with Harman's free radical theory of aging (FRTA), these effects may be due to increased formation of reactive oxygen species (ROS) within the mitochondria causing an adaptive response that culminates in subsequently increased stress resistance assumed to ultimately cause a long-term reduction of oxidative stress. This type of retrograde response has been named mitochondrial hormesis or mitohormesis, and may in addition be applicable to the health-promoting effects of physical exercise in humans and, hypothetically, impaired insulin/IGF-1-signaling in model organisms. Consistently, abrogation of this mitochondrial ROS signal by antioxidants impairs the lifespan-extending and health-promoting capabilities of glucose restriction and physical exercise, respectively. In summary, the findings discussed in this review indicate that ROS are essential signaling molecules which are required to promote health and longevity. Hence, the concept of mitohormesis provides a common mechanistic denominator for the physiological effects of physical exercise, reduced calorie uptake, glucose restriction, and possibly beyond.
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221
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Abstract
The interaction between nutrition and infection was the subject of important work by several groups in the 1960s. The explosion of knowledge in immunology, including innate immunity, has led to increased understanding of the impact of nutrition on host defence, but much more work needs to be done in this area. In the last decade an increasing volume of work has opened up the previously obscure world of human endogenous flora. This work suggests that the microbiome, the total genetic pool of the microbiota, contributes to the already complex interaction between nutrition and infectious disease. The established concept that nutritional status, host defence and infection all impact on each other now has to be expanded into a multiple interaction, with the microbiota interacting with all three other elements. There is good evidence that the microbiome programmes host defence and drives a metabolome that impacts on energy balance, and indeed on some micronutrients. In turn, host defence shapes the microbiome, and nutritional status, particularly micronutrient status, helps determine several elements of host defence. While interventions in this area are in their infancy, the understanding of interactions that already have an enormous impact on global health is now at a threshold. The present review explores the evidence for these interactions with a view to putting potential interventions into the context of a conceptual framework.
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222
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Gutteridge JM, Halliwell B. Antioxidants: Molecules, medicines, and myths. Biochem Biophys Res Commun 2010; 393:561-4. [DOI: 10.1016/j.bbrc.2010.02.071] [Citation(s) in RCA: 264] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Accepted: 02/11/2010] [Indexed: 11/26/2022]
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223
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Yang MH, Chuang CM, Hsieh CL, Wang HE, Chen KC, Chiu WT, Shih CM, Peng RY. Modeling of the in vivo kinetics of antioxidants delineates suitable parameters for selecting potential antioxidant adjuvants for cancer therapy. PHARMACEUTICAL BIOLOGY 2010; 48:306-317. [PMID: 20645818 DOI: 10.3109/13880200903127375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
To find in vivo behaviors of an antioxidant when used as an adjuvant cancer therapy, a more detailed integrated pharmacokinetic scheme is needed. Major reaction parameters associated with the sequential routes from ingestion to decay of an antioxidant were used in mathematical analysis, which included absorption rate coefficient k(a), quenching rate coefficient of the antioxidant k(q1) and tissue quenching rate coefficient k(r). The model was then treated with computer simulation using cited decay rate coefficients and some assumed parameters. When intestinal absorption rate coefficient k(a) becomes larger, retention time of antioxidant in plasma would be prolonged. moreover, k(a) had no effect on either quenching ability of antioxidants or tissue recovering capability. in quenching plasma ROS, the larger the quenching coefficient k(q1), the shorter peak- and the life-times would be for the secondary free radicals that are formed in primary quenching. Conclusively, it is suggestive to prescribe an antioxidant therapy with an appropriate values of k(a) and larger values of k(q1).
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Affiliation(s)
- Ming-Hua Yang
- Department of Food and Nutrition, Hungkuang University, Shalu County, Taichung Hsien, Taiwan
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224
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Velimirov A, Huber M, Lauridsen C, Rembiałkowska E, Seidel K, Bügel S. Feeding trials in organic food quality and health research. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2010; 90:175-182. [PMID: 20355028 DOI: 10.1002/jsfa.3805] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Feeding experiments comparing organically and conventionally produced food are performed to assess the overall impact on the animals' health as a model for the effects experienced by the human consumers. These experiments are based on systems research and characterized by their focus on production methods, whole food testing and procedures in accordance with the terms of organic farming. A short review of such experiments shows that the majority of these tests revealed effects of the organically produced feed on health parameters such as reproductive performance and immune responses. Systems research is not just about simple cause-effect chains, but rather about the pluralism of interactions in biological networks; therefore, the interpretation of the outcome of whole food experiments is difficult. Furthermore, the test diets of organic and conventional origin can be constituted in different ways, compensating for or maintaining existing differences in nutrient and energy contents. The science-based results suggest positive influences from organic feeds, but there is still a need for confirmation in animals and, finally, in humans. For this purpose animal feeding trials with feed from different production systems should be conducted, with the aims to define health indicators and to establish biomarkers as a basis for future dietary intervention studies in humans.
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225
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Abstract
Hepatitis C virus (HCV) infection causes chronic hepatitis, which can progress to cirrhosis and hepatocellular carcinoma (HCC). The incidence of hepatocellular carcinoma in the United States tripled between 1975 and 2005, and is expected to increase further, and to remain elevated for more than 20 years. Curing hepatitis C infection in patients with cirrhosis through treatment with peginterferon and ribavirin reduces the risk of developing hepatocellular carcinoma. Several noncurative treatments also appear to reduce the risk of hepatocellular carcinoma in patients with chronic hepatitis C. Prospective studies report a reduced incidence of hepatocellular carcinoma among patients treated with a mixture of carotenoids with or without myo-inositol, with vitamin K₂, or with polyprenoic acid (an acyclic retinoid). Uncontrolled and/or retrospective studies have reported beneficial effects of treatment with Sho-saiko-to, glycyrrhizin and ursodeoxycholic acid on hepatocellular carcinoma incidence. Meta-analyses of epidemiologic studies show a reduced risk of hepatocellular carcinoma among liver disease patients who drink two or more cups of coffee per day. Numerous agents prevent or reduce hepatocarcinogenesis in animal models. An ongoing Phase II clinical trial is evaluating S-adenosylmethionine (SAMe) as a potential chemopreventive agent in hepatitis C cirrhosis. Overall, these data suggest that chemoprevention of hepatocellular carcinoma in patients with chronic hepatitis C is an achievable objective.
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Affiliation(s)
- Timothy R Morgan
- Gastroenterology Section, VA Long Beach Healthcare System, Long Beach, CA 90822, USA.
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226
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Mustacich DJ, Leonard SW, Patel NK, Traber MG. Alpha-tocopherol beta-oxidation localized to rat liver mitochondria. Free Radic Biol Med 2010; 48:73-81. [PMID: 19819327 PMCID: PMC2818260 DOI: 10.1016/j.freeradbiomed.2009.10.024] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Revised: 09/21/2009] [Accepted: 10/04/2009] [Indexed: 12/14/2022]
Abstract
Approximately 40% of Americans take dietary supplements, including vitamin E (alpha-tocopherol). Unlike other fat-soluble vitamins, alpha-tocopherol is not accumulated to toxic levels. Rather tissue levels are tightly regulated, in part via increased hepatic metabolism and excretion that could, theoretically, alter metabolism of drugs, environmental toxins, and other nutrients. To date, in vivo subcellular location(s) of alpha-tocopherol metabolism have not been identified. The proposed pathway of alpha-tocopherol metabolism proceeds via omega-hydroxylation to 13'-OH-alpha-tocopherol, followed by successive rounds of beta-oxidation to form alpha-CEHC. To test the hypothesis that alpha-tocopherol omega-hydroxylation occurs in microsomes while beta-oxidation occurs in peroxisomes, rats received daily injections of vehicle, 10 mg alpha-tocopherol, or 10 mg trolox/100 g body wt for 3 days, and then microsomes, mitochondria, and peroxisomes were isolated from liver homogenates. Homogenate alpha-tocopherol levels increased 16-fold in alpha-tocopherol-injected rats, while remaining unchanged in trolox- or vehicle-injected rats. Total alpha-tocopherol recovered in the three subcellular fractions represented 93+/-4% of homogenate alpha-tocopherol levels. In alpha-tocopherol-injected rats, microsome alpha-tocopherol levels increased 28-fold, while mitochondria and peroxisome levels increased 8- and 3-fold, respectively, indicating greater partitioning of alpha-tocopherol to the microsomes with increasing liver alpha-tocopherol. In alpha-tocopherol-injected rats, microsome 13'-OH-alpha-tocopherol levels increased 24-fold compared to controls, and were 7-fold greater than 13'-OH-alpha-tocopherol levels in peroxisome and mitochondrial fractions of alpha-tocopherol-injected rats. An unexpected finding was that alpha-CEHC, the end product of alpha-tocopherol metabolism, was found almost exclusively in mitochondria. These data are the first to indicate a mitochondrial role in alpha-tocopherol metabolism.
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Affiliation(s)
- Debbie J Mustacich
- Linus Pauling Institute, 571 Weniger Hall, Oregon State University, Corvallis, OR 97331, USA.
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227
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Molecular, genetic and epigenetic pathways of peroxynitrite-induced cellular toxicity. Interdiscip Toxicol 2009; 2:219-28. [PMID: 21217858 PMCID: PMC2984115 DOI: 10.2478/v10102-009-0020-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 09/25/2009] [Accepted: 10/01/2009] [Indexed: 02/07/2023] Open
Abstract
Oxidative stress plays a key role in the pathogenesis of cancer and many metabolic diseases; therefore, an effective antioxidant therapy would be of great importance in these circumstances. Nevertheless, convincing randomized clinical trials revealed that antioxidant supplementations were not associated with significant reduction in incidence of cancer, chronic diseases and all-cause mortality. As oxidation of essential molecules continues, it turns to nitro-oxidative stress because of the involvement of nitric oxide in pathogenesis processes. Peroxynitrite damages via several distinctive mechanisms; first, it has direct toxic effects on all biomolecules and causes lipid peroxidation, protein oxidation and DNA damage. The second mechanism involves the induction of several transcription factors leading to cytokine-induced chronic inflammation. Finally, it causes epigenetic perturbations that exaggerate nuclear factor kappa-B mediated inflammatory gene expression. Lessons-learned from the treatment of several chronic disorders including pulmonary diseases suggest that, chronic inflammation and glucocorticoid resistance are regulated by prolonged peroxynitrite production.
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228
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Southworth LK, Owen AB, Kim SK. Aging mice show a decreasing correlation of gene expression within genetic modules. PLoS Genet 2009; 5:e1000776. [PMID: 20019809 PMCID: PMC2788246 DOI: 10.1371/journal.pgen.1000776] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Accepted: 11/18/2009] [Indexed: 12/22/2022] Open
Abstract
In this work we present a method for the differential analysis of gene co-expression networks and apply this method to look for large-scale transcriptional changes in aging. We derived synonymous gene co-expression networks from AGEMAP expression data for 16-month-old and 24-month-old mice. We identified a number of functional gene groups that change co-expression with age. Among these changing groups we found a trend towards declining correlation with age. In particular, we identified a modular (as opposed to uniform) decline in general correlation with age. We identified potential transcriptional mechanisms that may aid in modular correlation decline. We found that computationally identified targets of the NF-ΚB transcription factor decrease expression correlation with age. Finally, we found that genes that are prone to declining co-expression tend to be co-located on the chromosome. Our results conclude that there is a modular decline in co-expression with age in mice. They also indicate that factors relating to both chromosome domains and specific transcription factors may contribute to the decline. There is mounting evidence that mammalian aging is marked by increased gene transcriptional variation. This trend was shown not only by studying gene expression in single cells (Bahar et al. 2006), but at the coarse tissue resolution as well (Somel et al. 2006; Li et al. 2009). These led us to believe that looking at absolute changes in expression level alone may not tell the whole story of transcriptional changes in age. Instead the story may be in the more subtle changes in the coordination of expression among multiple genes. For this reason, we decided to look at changes in co-expression relationships with age. To this end, we developed a methodology for differential co-expression network analysis for the comparison gene co-expression on a global scale. We applied this methodology to compare co-expression between young (16-month) and old (24-month) mice. This allowed us to find both gene groups whose coordination appear to be affected by age and to propose potential mechanisms for the change. We believe our work is of broad importance because it represents a different paradigm for looking not only at aging but also at any complex condition or disease—away from changes in individual genes towards changes in gene relationships.
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Affiliation(s)
- Lucinda K. Southworth
- Biomedical Informatics, Stanford University, Stanford, California, United States of America
| | - Art B. Owen
- Statistics, Stanford University, Stanford, California, United States of America
| | - Stuart K. Kim
- Developmental Biology, Stanford University, Stanford, California, United States of America
- * E-mail:
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229
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Symposium on ‘Geographical and geological influences on nutrition’ Factors controlling the distribution of selenium in the environment and their impact on health and nutrition. Proc Nutr Soc 2009; 69:119-32. [DOI: 10.1017/s0029665109991807] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Se is essential to human and animal health but can be toxic in excess. An interest in its geochemistry has developed alongside a greater understanding of its function in a number of health conditions. Geology exerts a strong control on the Se status of the surface environment; low-Se rock-types (0·05–0·09 mg Se/kg) make up the majority of rocks occurring at the Earth's surface, which in turn account for the generally low levels of Se in most soils. However, there are exceptions such as associations with sulfide mineralisation and in some types of sedimentary rocks (e.g. black shales) in which contents of Se can be much higher. Baseline geochemical data now enable a comparison to be made between environmental and human Se status, although a direct link is only likely to be seen if the population is dependent on the local environment for sustenance. This situation is demonstrated with an example from the work of the British Geological Survey in the Se-deficiency belt of China. The recent fall in the daily dietary Se intake in the UK is discussed in the context of human Se status and declining use of North American wheat in bread making. Generally, US wheat has ten times more Se than UK wheat, attributed to the fact that soils from the wheat-growing belt of America are more enriched in Se to a similar order of magnitude. In agriculture effective biofortification of crops with Se-rich fertilisers must be demonstrably safe to the environment and monitored appropriately and baseline geochemical data will enable this process to be done with confidence.
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230
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Gomez-Cabrera MC, Viña J, Ji LL. Interplay of oxidants and antioxidants during exercise: implications for muscle health. PHYSICIAN SPORTSMED 2009; 37:116-23. [PMID: 20048548 DOI: 10.3810/psm.2009.12.1749] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Muscle contraction results in generation of reactive oxygen and nitrogen species (RONS) at a rate determined by the intensity, frequency, and duration of the exercise protocols. Strenuous exercise causes oxidation of protein, lipid, and DNA, release of cytosolic enzymes, and other signs of cell damage; however, only exhaustive exercise is detrimental. Indeed, the regulation of vascular tone, the excitation-contraction coupling, growth, and differentiation in skeletal muscle, are governed in part by RONS. This is accomplished by RONS interaction with redox-sensitive transcription factors, leading to increased gene expression of antioxidant enzymes, cytoprotective proteins, and other enzymes involved in muscle metabolic functions. However, high levels of RONS generation are known to cause oxidative stress, activate certain pathogenic pathways, and accelerate aging. This article reviews research from the past decades on the interplay of oxidants and antioxidants in skeletal muscle, with particular reference to increased contractile activity. Adaptation of muscle to increased oxidative stress and the potential mechanisms involved will be highlighted. The role of redox-controlled cell signaling in skeletal muscle health and function is also described.
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231
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Use of dietary supplements in the European Prospective Investigation into Cancer and Nutrition calibration study. Eur J Clin Nutr 2009; 63 Suppl 4:S226-38. [DOI: 10.1038/ejcn.2009.83] [Citation(s) in RCA: 170] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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232
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Schleicher RL, Carroll MD, Ford ES, Lacher DA. Serum vitamin C and the prevalence of vitamin C deficiency in the United States: 2003-2004 National Health and Nutrition Examination Survey (NHANES). Am J Clin Nutr 2009; 90:1252-63. [PMID: 19675106 DOI: 10.3945/ajcn.2008.27016] [Citation(s) in RCA: 306] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Vitamin C (ascorbic acid) may be the most important water-soluble antioxidant in human plasma. In the third National Health and Nutrition Examination Survey (NHANES III, 1988-1994), approximately 13% of the US population was vitamin C deficient (serum concentrations <11.4 micromol/L). OBJECTIVE The aim was to determine the most current distribution of serum vitamin C concentrations in the United States and the prevalence of deficiency in selected subgroups. DESIGN Serum concentrations of total vitamin C were measured in 7277 noninstitutionalized civilians aged > or =6 y during the cross-sectional, nationally representative NHANES 2003-2004. The prevalence of deficiency was compared with results from NHANES III. RESULTS The overall age-adjusted mean from the square-root transformed (SM) concentration was 51.4 micromol/L (95% CI: 48.4, 54.6). The highest concentrations were found in children and older persons. Within each race-ethnic group, women had higher concentrations than did men (P < 0.05). Mean concentrations of adult smokers were one-third lower than those of nonsmokers (SM: 35.2 compared with 50.7 micromol/L and 38.6 compared with 58.0 micromol/L in men and women, respectively). The overall prevalence (+/-SE) of age-adjusted vitamin C deficiency was 7.1 +/- 0.9%. Mean vitamin C concentrations increased (P < 0.05) and the prevalence of vitamin C deficiency decreased (P < 0.01) with increasing socioeconomic status. Recent vitamin C supplement use or adequate dietary intake decreased the risk of vitamin C deficiency (P < 0.05). CONCLUSIONS In NHANES 2003-2004, vitamin C status improved, and the prevalence of vitamin C deficiency was significantly lower than that during NHANES III, but smokers and low-income persons were among those at increased risk of deficiency.
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Affiliation(s)
- Rosemary L Schleicher
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA.
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233
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Edeas M. Anti-oxydants, controverses et perspectives : comment expliquer l'échec des études cliniques utilisant des anti-oxydants. ACTA ACUST UNITED AC 2009; 203:271-80. [DOI: 10.1051/jbio:2009031] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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234
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Wingler K, Schmidt HHHW. Good stress, bad stress--the delicate balance in the vasculature. DEUTSCHES ARZTEBLATT INTERNATIONAL 2009; 106:677-84. [PMID: 19946436 DOI: 10.3238/arztebl.2009.0677] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Accepted: 10/22/2009] [Indexed: 12/14/2022]
Abstract
BACKGROUND Radicals have important physiological functions, for example, in immune defense and vasoprotection. However, they are also potentially dangerous waste products of cellular metabolism and they can contribute to the development of many different diseases. METHOD Selective literature review. RESULTS The scientific understanding of radicals has not yet led to any therapeutic application. For many years, scavenging already formed radicals with antioxidants was considered to be the most promising therapeutic approach, but clinical trials based on this principle have yielded mostly negative results. Thus, entirely new approaches are needed. The goal should be to prevent the formation of harmful radicals, or to treat radical-related damage if it has already occurred. New diagnostic tools have the potential to identify those patients that are most likely to benefit from this form of treatment, as well as to document its success. CONCLUSIONS A new generation of cardiovascular drugs is being developed for the prevention or the mechanism-based treatment of vascular damage caused by oxidative stress. This new therapy should go hand in hand with new diagnostics, in accordance with the principle of individualized medicine.
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Affiliation(s)
- Kirstin Wingler
- Monash University, Department of Pharmacology, Centre for Vascular Health, Melbourne, Australien
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235
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Giustarini D, Dalle-Donne I, Tsikas D, Rossi R. Oxidative stress and human diseases: Origin, link, measurement, mechanisms, and biomarkers. Crit Rev Clin Lab Sci 2009; 46:241-81. [DOI: 10.3109/10408360903142326] [Citation(s) in RCA: 305] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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236
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Koren E, Lipkin J, Klar A, Hershkovitz E, Ginsburg I, Kohen R. Total oxidant-scavenging capacities of plasma from glycogen storage disease type Ia patients as measured by cyclic voltammetry, FRAP and luminescence techniques. J Inherit Metab Dis 2009; 32:651. [PMID: 19728140 DOI: 10.1007/s10545-009-1242-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Revised: 07/09/2009] [Accepted: 07/13/2009] [Indexed: 12/14/2022]
Abstract
It has been suggested that the very low incidence of atherosclerosis in glycogen storage disease type Ia (GSD Ia) subjects might be attributed to elevated levels of uric acid, one of the potent low molecular- weight antioxidants found in plasma. The present communication describes a use of two analytical methods-cyclic voltammetry and ferric reducing ability of plasma-and also two chemiluminescence methods to evaluate the total oxidant-scavenging capacities (TOSC) of plasma from GSD Ia patients. Our results verified the elevation of TOSC in GSD Ia patients and we propose the inclusion of luminescence and cyclic voltammetry assays as reliable methods for estimating TOSC in a variety of clinical disorders. Our findings with the cyclic voltammetry method add support to the assumption that the elevated uric acid levels might be the main contributor to plasma antioxidant capacity and possible protection against atherosclerosis.
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Affiliation(s)
- E Koren
- Department of Pharmaceutics, School of Pharmacy, Richard and Jean Zarbin Chair in Medical Studies, Hebrew University, Hadassah Faculty of Medicine, Jerusalem, 91120, Israel
| | - J Lipkin
- Department of Pediatrics, Bikur Cholim General Hospital, Jerusalem, Israel
| | - A Klar
- Department of Pediatrics, Bikur Cholim General Hospital, Jerusalem, Israel
| | - E Hershkovitz
- Pediatric Endocrinology & Metabolic Unit, Soroka Medical University Center, Beer Sheva, Israel
| | - I Ginsburg
- Faculty of Dental Medicine, Institute for Dental Sciences, Hebrew University, Hadassah Medical Center, Jerusalem, Israel
| | - R Kohen
- Department of Pharmaceutics, School of Pharmacy, Richard and Jean Zarbin Chair in Medical Studies, Hebrew University, Hadassah Faculty of Medicine, Jerusalem, 91120, Israel.
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Dotan Y, Pinchuk I, Lichtenberg D, Leshno M. Decision Analysis Supports the Paradigm That Indiscriminate Supplementation of Vitamin E Does More Harm than Good. Arterioscler Thromb Vasc Biol 2009; 29:1304-9. [DOI: 10.1161/atvbaha.108.178699] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Objectives—
For many years, the prevailing concept was that LDL oxidation plays a central role in atherogenesis. As a consequence, supplementation of antioxidants, particularly vitamin E, became very popular. Unfortunately, however, the major randomized clinical trials have yielded disappointing results on the effects of vitamin E on both mortality and morbidity. Moreover, recent meta-analyses have concluded that vitamin E supplementation increases mortality. This conclusion has raised much criticism, most of it relating to three issues: (1) the choice of clinical trials to be included in the meta-analyses; (2) the end point of these meta-analyses (only mortality); and (3) the heterogeneity of the analyzed clinical trials with respect to both population and treatment. Our goal was to bring this controversy to an end by using a Markov-model approach, which is free of most of the limitations involved in using meta-analyses.
Methods and Results—
We used a Markov model to compare the vitamin E supplemented virtual cohorts with nonsupplemented cohorts derived from published randomized clinical trials that were included in at least one of the major meta-analyses. The difference between the virtual supplemented and nonsupplemented cohorts is given in terms of a composite end point denoted quality-adjusted life year (QALY). The vitamin E supplemented virtual cohort had 0.30 QALY (95%CI 0.21 to 0.39) less than the nontreated virtual cohort.
Conclusions—
Our study demonstrates that in terms of QALY, indiscriminate supplementation of high doses of vitamin E is not beneficial in preventing CVD. Selective supplementation of vitamin E to individuals under oxidative stress requires further investigation.
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Affiliation(s)
- Yedidya Dotan
- From the Department of Physiology and Pharmacology (Y.D., I.P., D.L.) and the Faculty of Management and School of Medicine (M.L.), Tel Aviv University, Sackler Faculty of Medicine, Israel
| | - Ilya Pinchuk
- From the Department of Physiology and Pharmacology (Y.D., I.P., D.L.) and the Faculty of Management and School of Medicine (M.L.), Tel Aviv University, Sackler Faculty of Medicine, Israel
| | - Dov Lichtenberg
- From the Department of Physiology and Pharmacology (Y.D., I.P., D.L.) and the Faculty of Management and School of Medicine (M.L.), Tel Aviv University, Sackler Faculty of Medicine, Israel
| | - Moshe Leshno
- From the Department of Physiology and Pharmacology (Y.D., I.P., D.L.) and the Faculty of Management and School of Medicine (M.L.), Tel Aviv University, Sackler Faculty of Medicine, Israel
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Zhang Q, Pi J, Woods CG, Andersen ME. A systems biology perspective on Nrf2-mediated antioxidant response. Toxicol Appl Pharmacol 2009; 244:84-97. [PMID: 19716833 DOI: 10.1016/j.taap.2009.08.018] [Citation(s) in RCA: 157] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Revised: 08/07/2009] [Accepted: 08/18/2009] [Indexed: 12/13/2022]
Abstract
Cells in vivo are constantly exposed to reactive oxygen species (ROS) generated endogenously and exogenously. To defend against the deleterious consequences of ROS, cells contain multiple antioxidant enzymes expressed in various cellular compartments to scavenge these toxic species. Under oxidative stresses, these antioxidant enzymes are upregulated to restore redox homeostasis. Such an adaptive response results from the activation of a redox-sensitive gene regulatory network mediated by nuclear factor E2-related factor 2. To more completely understand how the redox control system is designed by nature to meet homeostatic goals, we have examined the network from a systems perspective using engineering approaches. As with man-made control devices, the redox control system can be decomposed into distinct functional modules, including transducer, controller, actuator, and plant. Cells achieve specific performance objectives by utilizing nested feedback loops, feedforward control, and ultrasensitive signaling motifs, etc. Given that endogenously generated ROS are also used as signaling molecules, our analysis suggests a novel mode of action to explain oxidative stress-induced pathological conditions and diseases. Specifically, by adaptively upregulating antioxidant enzymes, oxidative stress may inadvertently attenuate ROS signals that mediate physiological processes, resulting in aberrations of cellular functions and adverse consequences. Lastly, by simultaneously considering the two competing cellular tasks-adaptive antioxidant defense and ROS signaling-we re-examine the premise that dietary antioxidant supplements is generally beneficial to human health. Our analysis highlights some possible adverse effects of these widely consumed antioxidants.
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Affiliation(s)
- Qiang Zhang
- Division of Computational Biology, The Hamner Institutes for Health Sciences, 6 Davis Drive, Research Triangle Park, NC 27709, USA.
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239
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Bacteria Coated by Polyphenols Acquire Potent Oxidant-Scavenging Capacities. Exp Biol Med (Maywood) 2009; 234:940-51. [DOI: 10.3181/0901-rm-22] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Several microbial species, including probiotic lactic acid bacteria, have the ability to irreversibly bind a large variety of polyphenols (flavonoids) and anthocyanidins found in many colored fruits and vegetables and to enhance their total oxidant-scavenging capacities (TOSC). The binding of flavonoids to microbial surfaces was further increased by the cationic polyelectrolytes ligands poly-L-histidine, chlorhexidine and Copaxone®. This phenomenon was confirmed visually, by the FRAP, DPPH, cyclic voltammetry, Folin-Ciocalteu as well as by luminol-dependent chemiluminescence techniques employed to assay TOSC. The possibility is considered that clinically, microbial cells in the oral cavity and in the gastro intestinal tract, complexed with antioxidant polyphenols from nutrients and with cationic ligands, might increase the protection of mammalian cells against damage induced by excessive generation of reactive oxygen species during infections and inflammation.
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240
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Pasupathi P, Saravanan G, Chinnaswamy P, Bakthavathsalam G. Glutathione, glutathione-dependent enzymes and antioxidant status in gastric carcinoma patients. J Appl Biomed 2009. [DOI: 10.32725/jab.2009.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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241
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Reactive oxygen intermediate-induced pathomechanisms contribute to immunosenescence, chronic inflammation and autoimmunity. Mech Ageing Dev 2009; 130:564-87. [PMID: 19632262 DOI: 10.1016/j.mad.2009.07.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Revised: 06/07/2009] [Accepted: 07/15/2009] [Indexed: 02/07/2023]
Abstract
Deregulation of reactive oxygen intermediates (ROI) resulting in either too high or too low concentrations are commonly recognized to be at least in part responsible for many changes associated with aging. This article reviews ROI-dependent mechanisms critically contributing to the decline of immune function during physiologic - or premature - aging. While ROI serve important effector functions in cellular metabolism, signalling and host defence, their fine-tuned generation declines over time, and ROI-mediated damage to several cellular components and/or signalling deviations become increasingly prevalent. Although distinct ROI-associated pathomechanisms contribute to immunosenescence of the innate and adaptive immune system, mutual amplification of dysfunctions may often result in hyporesponsiveness and immunodeficiency, or in chronic inflammation with hyperresponsiveness/deregulation, or both. In this context, we point out how imbalanced ROI contribute ambiguously to driving immunosenescence, chronic inflammation and autoimmunity. Although ROI may offer a distinct potential for therapeutic targeting along with the charming opportunity to rescue from deleterious processes of aging and chronic inflammatory diseases, such modifications, owing to the complexity of metabolic interactions, may carry a marked risk of unforeseen side effects.
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242
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Myung SK, Kim Y, Ju W, Choi HJ, Bae WK. Effects of antioxidant supplements on cancer prevention: meta-analysis of randomized controlled trials. Ann Oncol 2009; 21:166-79. [PMID: 19622597 DOI: 10.1093/annonc/mdp286] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND This meta-analysis aimed to investigate the effect of antioxidant supplements on the primary and secondary prevention of cancer as reported by randomized controlled trials. METHODS We searched Medline (PubMed), Excerpta Medica database, and the Cochrane Review in October 2007. RESULTS Among 3327 articles searched, 31 articles on 22 randomized controlled trials, which included 161 045 total subjects, 88 610 in antioxidant supplement groups and 72 435 in placebo or no-intervention groups, were included in the final analyses. In a fixed-effects meta-analysis of all 22 trials, antioxidant supplements were found to have no preventive effect on cancer [relative risk (RR) 0.99; 95% confidence interval (CI) 0.96-1.03). Similar findings were observed in 12 studies on primary prevention trials (RR 1.00; 95% CI 0.97-1.04) and in nine studies on secondary prevention trials (RR 0.97; 95% CI 0.83-1.13). Further, subgroup analyses revealed no preventive effect on cancer according to type of antioxidant, type of cancer, or the methodological quality of the studies. On the other hand, the use of antioxidant supplements significantly increased the risk of bladder cancer (RR 1.52; 95% CI 1.06-2.17) in a subgroup meta-analysis of four trials. CONCLUSIONS The meta-analysis of randomized controlled trials indicated that there is no clinical evidence to support an overall primary and secondary preventive effect of antioxidant supplements on cancer. The effects of antioxidant supplements on human health, particularly in relation to cancer, should not be overemphasized because the use of those might be harmful for some cancer.
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Affiliation(s)
- S-K Myung
- Center for Cancer Prevention and Detection, National Cancer Center, Goyang, Korea.
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243
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Oikawa S, Nagao E, Sakano K, Kawanishi S. Mechanism of oxidative DNA damage induced by capsaicin, a principal ingredient of hot chili pepper. Free Radic Res 2009; 40:966-73. [PMID: 17015277 DOI: 10.1080/10715760600827483] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Although capsaicin exhibits antitumor activity, carcinogenic potential has also been reported. To clarify the mechanism for expression of potential carcinogenicity of capsaicin, we examined DNA damage induced by capsaicin in the presence of metal ion and various kinds of cytochrome P450 (CYP) using 32P-5'-end-labeled DNA fragments. Capsaicin induced Cu(II)-mediated DNA damage efficiently in the presence of CYP1A2 and partially in the presence of 2D6. CYP1A2-treated capsaicin caused double-base lesions at 5'-TG-3', 5'-GC-3' and CG of the 5'-ACG-3' sequence complementary to codon 273, a hotspot of p53 gene. DNA damage was inhibited by catalase and bathocuproine, a Cu(I) chelator, suggesting that reactive species derived from the reaction of H2O2 with Cu(I) participate in DNA damage. Formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine was significantly increased by CYP1A2-treated capsaicin in the presence of Cu(II). Therefore, we conclude that Cu(II)-mediated oxidative DNA damage by CYP-treated capsaicin seems to be relevant for the expression of its carcinogenicity.
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Affiliation(s)
- Shinji Oikawa
- Mie University Graduate School of Medicine, Department of Environmental and Molecular Medicine, Mie, Japan
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244
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Huerta JM, González S, Fernández S, Patterson AM, Lasheras C. Lipid peroxidation, antioxidant status and survival in institutionalised elderly: A five-year longitudinal study. Free Radic Res 2009; 40:571-8. [PMID: 16753834 DOI: 10.1080/10715760600580470] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Oxidative stress has been related to ageing and risk of death. To determine whether oxidative status was associated with all-cause risk of death we carried out a prospective study in 154 non-smoking Spanish elderly without major illness. Baseline glutathione peroxidase (GPx) and superoxide dismutase (SOD) were analysed in plasma and erythrocytes. alpha-tocopherol, beta-carotene, lycopene and retinol were determined in serum samples and malondialdehyde (MDA), as a lipid peroxidation marker, in plasma. Mean survival time was 4.3 years. A total of 31 death cases (20.1%) occurred during the follow-up. Plasma-MDA predicted mortality independently of all other variables, while erythrocyte-SOD (e-SOD), beta-carotene and alpha-tocopherol were positively associated with survival. alpha-tocopherol and MDA were revealed as independent predictors in a joint survival model, being the group with low MDA and high alpha-tocopherol that with the lowest mortality. In conclusion, a higher risk of death was associated with increased lipid peroxidation and lower antioxidant defenses.
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Affiliation(s)
- José M Huerta
- Departamento de Biología Funcional, Area de Fisiología. Facultad de Medicina, Universidad de Oviedo, Julián Clavería s/n, Oviedo 33006, Spain
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Duarte TL, Lunec J. ReviewPart of the Series: From Dietary Antioxidants to Regulators in Cellular Signalling and Gene ExpressionReview: When is an antioxidant not an antioxidant? A review of novel actions and reactions of vitamin C. Free Radic Res 2009; 39:671-86. [PMID: 16036346 DOI: 10.1080/10715760500104025] [Citation(s) in RCA: 212] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Vitamin C (or ascorbic acid) is regarded as the most important water-soluble antioxidant in human plasma and mammalian cells which have mechanisms to recycle and accumulate it against a concentration gradient, suggesting that the vitamin might also have important intracellular functions. In this review we summarize evidence from human trials that have attempted an association between vitamin C supplementation and an effect on biomarkers of oxidative DNA damage. Most studies reviewed herein showed either a vitamin C-mediated reduction in oxidative DNA damage or a null effect, whereas only a few studies showed an increase in specific base lesions. We also address the possible beneficial effects of vitamin C supplementation for the prevention of cancer and cardiovascular disease. Finally, we discuss the contribution of cell culture studies to our understanding of the mode of action of vitamin C and we review recent evidence that vitamin C is able to modulate gene expression and cellular function, with a particular interest in cell differentiation.
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Affiliation(s)
- Tiago L Duarte
- Pharmaceutical Sciences Research Division, Kings College London University
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246
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Morante M, Sandoval J, Gómez-Cabrera MC, Rodríguez JL, Pallardó FV, Viña JR, Torres L, Barber T. Vitamin E deficiency induces liver nuclear factor-κB DNA-binding activity and changes in related genes. Free Radic Res 2009; 39:1127-38. [PMID: 16298738 DOI: 10.1080/10715760500193820] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The biological functions of vitamin E have been classically attributed to its property as a potent inhibitor of lipid peroxidation in cellular membranes. However, in 1991, Azzi's group first described that alpha-tocopherol inhibits smooth muscle cell proliferation in a protein kinase C (PKC)-dependent way, demonstrating a non-antioxidant cell signalling function for vitamin E. More recently, the capacity of alpha-tocopherol to modulate gene expression with the implication of different transcription factors, beyond its antioxidant properties, has also been established. This study was to determine the effect of vitamin E-deficiency on liver nuclear factor-kappa B (NF-kappaB) DNA-binding activity and the response of target antioxidant-defense genes and cell cycle modulators. Rats were fed either control diet or vitamin-E free diet until 60 or 90 days after birth. Vitamin E-deficiency enhanced liver DNA-binding activity of NF-kappaB [electrophoretic mobility-shift assay, (EMSA)] and up-regulated transcription of gamma-glutamylcysteine synthetase (gamma-GCSM; gamma-GCSC), cyclin D1 and cyclin E. We also showed down-regulation of p21(Waf1/Cip1) transcription. Western-blot analysis demonstrated that gamma-glutamylcysteine synthetase catalytic subunit (gamma-GCSC) and cyclin D1 showed a similar pattern to that found in the RT-PCR analysis. Moreover, chromatin immunoprecipitation (ChIP) assay demonstrated that NF-kappaB directly regulates transcription of gamma-GCS (both subunits) and cyclin D1 through the binding of NF-kappaB to the corresponding gene promoters, which was enhanced in vitamin E-deficiency. These findings show that vitamin E-deficiency induces significant molecular regulatory properties in liver cells with an altered expression of both antioxidant-defense genes and genes that control the cell cycle and demonstrate that liver NF-kappaB activation is involved in this response. Our results emphasize the importance of maintaining an adequate vitamin E consumption not only to prevent liver oxidative damage but also in modulating signal transduction.
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Affiliation(s)
- María Morante
- Universitat de València, Departamentos de Bioquímica y Biología Molecular y Fisiología, València, Spain
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Wu J, Salisbury C, Graham R, Lyons G, Fenech M. Increased consumption of wheat biofortified with selenium does not modify biomarkers of cancer risk, oxidative stress, or immune function in healthy Australian males. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2009; 50:489-501. [PMID: 19365873 DOI: 10.1002/em.20490] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Increased intake of selenium (Se) may reduce the risk of degenerative diseases including cancer but excessive intake may be toxic. Wheat is a major source of dietary Se in humans. However, the effect of Se from wheat that is agronomically biofortified with Se on biomarkers of human health status is unknown. This study aimed to investigate whether improving Se status, by increased dietary intake of Se-biofortified wheat, affects biomarkers of cancer risk, cardiovascular disease risk, oxidative stress, and immune function in healthy South Australian men. A 24-week placebo-controlled double-blind intervention was performed in healthy older men (n = 62), with increased dose of Se intake every 8 weeks. Wheat was provided as 1, 2, and 3 puffed wheat biscuits, during weeks 1-8, 9-16, and 17-24, respectively. Blood was collected to measure a wide range of disease risk biomarkers. Consumption of Se-biofortified wheat was found to increase plasma Se concentration from a baseline level of 122 to 192 microg/L following intake of three biscuits/day, which provided 267 microg Se. Platelet glutathione peroxidase, chromosome aberrations, and DNA damage in lymphocytes measured using the cytokinesis-block micronucleus cytome assay and with the Comet assay, plasma F2-isoprostanes, protein carbonyls, plasma C-reactive protein, and leukocyte number were unaffected by the improved Se status. Improvement of Se status by consumption of Se-biofortified wheat did not substantially modify the selected biomarkers of degenerative disease risk and health status in this apparently selenium-replete cohort of healthy older men in South Australia.
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Affiliation(s)
- Jing Wu
- Nutritional Genomics and Genome Damage Diagnostics Laboratory, CSIRO Human Nutrition, Food Science Australia, Adelaide, South Australia, Australia
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Buscemi S, Verga S, Batsis JA, Tranchina MR, Belmonte S, Mattina A, Re A, Rizzo R, Cerasola G. Dose-dependent effects of decaffeinated coffee on endothelial function in healthy subjects. Eur J Clin Nutr 2009; 63:1200-5. [DOI: 10.1038/ejcn.2009.51] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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249
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Borrás C, Stvolinsky S, López-Grueso R, Fedorova T, Gambini J, Boldyrev A, Viña J. Low in vivo brain glucose consumption and high oxidative stress in accelerated aging. FEBS Lett 2009; 583:2287-93. [DOI: 10.1016/j.febslet.2009.06.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Revised: 05/26/2009] [Accepted: 06/09/2009] [Indexed: 02/07/2023]
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Abstract
OBJECTIVES Using the population-based cancer registry in Jejudo, we found that Jejudo had lower incidence in stomach cancer than other regions in Korea. The aim of this study was to evaluate reasons for this difference. METHODS Citrus is the leading agricultural production in Jejudo, suggesting that lower cancer incidence in Jejudo could be explained by citrus fruit intake. We evaluated this hypothesis with quantitative systematic review (QSR). RESULTS Stomach cancer incidence was significantly lower, with a summary odds ratio (SOR) after QSR of 0.72 [95% CI=0.64-0.81]. In addition, the SOR of pancreatic cancer tended to be lower at 0.83 [95% CI=0.70-0.98]. The SOR of prostate cancer was slightly higher at 1.03 [0.89-1.19]. CONCLUSIONS Quantitative systematic reviews for the effect of citrus fruit intake on cancer occurrence suggested that lower cancer incidence in Jejudo could be explained by intake of citrus fruits.
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Affiliation(s)
- Jong-Myon Bae
- Department of Preventive Medicine, Cheju National University College of Medicine, Jejudo, Republic of Korea.
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