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Aydemir D, Salman N, Karimzadehkhouei M, Alaca BE, Turan B, Ulusu NN. Evaluation of the Effects of Aging on the Aorta Stiffness in Relation with Mineral and Trace Element Levels: an Optimized Method via Custom-Built Stretcher Device. Biol Trace Elem Res 2021; 199:2644-2652. [PMID: 32918713 DOI: 10.1007/s12011-020-02380-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 09/07/2020] [Indexed: 01/03/2023]
Abstract
Aortic stiffness represents the major cause of aging and tightly associated with hypertension, atherosclerosis, cardiovascular diseases, and increased mortality. Mechanical characteristics of the aorta play a vital role in the blood flow, circulation, systolic pressure, and aortic stiffness; however, the correlation of trace element and mineral levels with aortic stiffness has not been studied before. Balance in the trace elements and minerals is vital for the biological functions; however, natural aging may alter this balance. Thus, after measuring aortic stiffness of aged and young rat aortas by a custom-built stretcher device, trace element and mineral levels were evaluated via ICP-MS. Also, biomarkers of aging including blood pressure, arterial pressure glucose, insulin levels, and histochemical parameters were investigated as well. Aortic stiffness, blood glucose, plasma insulin, systolic, diastolic, and mean arterial pressure significantly increased by aging in the aorta of aged rats compared with the young ones. Also, Fe, Al, Co, Ni, Zn, Sr, Na, Mg, and K levels increased in the aged aorta samples compared with the young aorta samples of rats. Increased levels of the indicated elements may be correlated with the development and progression of aortic stiffness and vascular complications. Thus, possible mechanisms correlating aortic stiffness with the imbalance in the trace element and mineral levels should be further investigated.
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Affiliation(s)
- Duygu Aydemir
- School of Medicine, Department of Medical Biochemistry, Koç University, Sariyer, 34450, Istanbul, Turkey
- Koç University Research Center for Translational Medicine (KUTTAM), Sariyer, 34450, Istanbul, Turkey
| | - Naveed Salman
- Department of Mechanical Engineering, Koç University, Rumelifeneri Yolu, Sariyer, 34450, Istanbul, Turkey
| | - Mehrdad Karimzadehkhouei
- Department of Mechanical Engineering, Koç University, Rumelifeneri Yolu, Sariyer, 34450, Istanbul, Turkey
| | - B Erdem Alaca
- Department of Mechanical Engineering, Koç University, Rumelifeneri Yolu, Sariyer, 34450, Istanbul, Turkey
- Surface Science and Technology Center (KUYTAM), Koç University, Rumelifeneri Yolu, Sariyer, 34450, Istanbul, Turkey
| | - Belma Turan
- Faculty of Medicine, Department of Biophysics, Ankara University, 06100, Ankara, Turkey
| | - Nuriye Nuray Ulusu
- School of Medicine, Department of Medical Biochemistry, Koç University, Sariyer, 34450, Istanbul, Turkey.
- Koç University Research Center for Translational Medicine (KUTTAM), Sariyer, 34450, Istanbul, Turkey.
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2
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Lossow K, Kopp JF, Schwarz M, Finke H, Winkelbeiner N, Renko K, Meçi X, Ott C, Alker W, Hackler J, Grune T, Schomburg L, Haase H, Schwerdtle T, Kipp AP. Aging affects sex- and organ-specific trace element profiles in mice. Aging (Albany NY) 2020; 12:13762-13790. [PMID: 32620712 PMCID: PMC7377894 DOI: 10.18632/aging.103572] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 06/13/2020] [Indexed: 12/18/2022]
Abstract
A decline of immune responses and dynamic modulation of the redox status are observed during aging and are influenced by trace elements such as copper, iodine, iron, manganese, selenium, and zinc. So far, analytical studies have focused mainly on single trace elements. Therefore, we aimed to characterize age-specific profiles of several trace elements simultaneously in serum and organs of adult and old mice. This allows for correlating multiple trace element levels and to identify potential patterns of age-dependent alterations. In serum, copper and iodine concentrations were increased and zinc concentration was decreased in old as compared to adult mice. In parallel, decreased copper and elevated iron concentrations were observed in liver. The age-related reduction of hepatic copper levels was associated with reduced expression of copper transporters, whereas the increased hepatic iron concentrations correlated positively with proinflammatory mediators and Nrf2-induced ferritin H levels. Interestingly, the age-dependent inverse regulation of copper and iron was unique for the liver and not observed in any other organ. The physiological importance of alterations in the iron/copper ratio for liver function and the aging process needs to be addressed in further studies.
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Affiliation(s)
- Kristina Lossow
- Department of Molecular Nutritional Physiology, Institute of Nutritional Sciences, Friedrich Schiller University Jena, Jena, Germany.,Department of Food Chemistry, Institute of Nutritional Science, University of Potsdam, Nuthetal, Germany.,German Institute of Human Nutrition, Nuthetal, Germany.,TraceAge-DFG Research Unit on Interactions of Essential Trace Elements in Healthy and Diseased Elderly, Potsdam-Berlin-Jena, Germany
| | - Johannes F Kopp
- Department of Food Chemistry, Institute of Nutritional Science, University of Potsdam, Nuthetal, Germany.,TraceAge-DFG Research Unit on Interactions of Essential Trace Elements in Healthy and Diseased Elderly, Potsdam-Berlin-Jena, Germany
| | - Maria Schwarz
- Department of Molecular Nutritional Physiology, Institute of Nutritional Sciences, Friedrich Schiller University Jena, Jena, Germany.,TraceAge-DFG Research Unit on Interactions of Essential Trace Elements in Healthy and Diseased Elderly, Potsdam-Berlin-Jena, Germany
| | - Hannah Finke
- Department of Food Chemistry, Institute of Nutritional Science, University of Potsdam, Nuthetal, Germany
| | - Nicola Winkelbeiner
- Department of Food Chemistry, Institute of Nutritional Science, University of Potsdam, Nuthetal, Germany.,TraceAge-DFG Research Unit on Interactions of Essential Trace Elements in Healthy and Diseased Elderly, Potsdam-Berlin-Jena, Germany
| | - Kostja Renko
- Institute for Experimental Endocrinology, Charité University Medical School Berlin, Berlin, Germany.,German Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - Xheni Meçi
- Institute for Experimental Endocrinology, Charité University Medical School Berlin, Berlin, Germany
| | - Christiane Ott
- German Institute of Human Nutrition, Nuthetal, Germany.,DZHK German Centre for Cardiovascular Research, Berlin, Germany
| | - Wiebke Alker
- TraceAge-DFG Research Unit on Interactions of Essential Trace Elements in Healthy and Diseased Elderly, Potsdam-Berlin-Jena, Germany.,Department of Food Chemistry and Toxicology, Technische Universität Berlin, Berlin, Germany
| | - Julian Hackler
- TraceAge-DFG Research Unit on Interactions of Essential Trace Elements in Healthy and Diseased Elderly, Potsdam-Berlin-Jena, Germany.,Institute for Experimental Endocrinology, Charité University Medical School Berlin, Berlin, Germany
| | - Tilman Grune
- German Institute of Human Nutrition, Nuthetal, Germany
| | - Lutz Schomburg
- TraceAge-DFG Research Unit on Interactions of Essential Trace Elements in Healthy and Diseased Elderly, Potsdam-Berlin-Jena, Germany.,Institute for Experimental Endocrinology, Charité University Medical School Berlin, Berlin, Germany
| | - Hajo Haase
- TraceAge-DFG Research Unit on Interactions of Essential Trace Elements in Healthy and Diseased Elderly, Potsdam-Berlin-Jena, Germany.,Department of Food Chemistry and Toxicology, Technische Universität Berlin, Berlin, Germany
| | - Tanja Schwerdtle
- Department of Food Chemistry, Institute of Nutritional Science, University of Potsdam, Nuthetal, Germany.,TraceAge-DFG Research Unit on Interactions of Essential Trace Elements in Healthy and Diseased Elderly, Potsdam-Berlin-Jena, Germany.,German Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - Anna P Kipp
- Department of Molecular Nutritional Physiology, Institute of Nutritional Sciences, Friedrich Schiller University Jena, Jena, Germany.,TraceAge-DFG Research Unit on Interactions of Essential Trace Elements in Healthy and Diseased Elderly, Potsdam-Berlin-Jena, Germany
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Loomba R, Filippini T, Chawla R, Chaudhary R, Cilloni S, Datt C, Singh S, Dhillon KS, Vinceti M. Exposure to a high selenium environment in Punjab, India: Effects on blood chemistry. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 716:135347. [PMID: 31843317 DOI: 10.1016/j.scitotenv.2019.135347] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 10/31/2019] [Accepted: 11/01/2019] [Indexed: 06/10/2023]
Abstract
Many studies have shown that overexposure to environmental selenium may exert a wide pattern of adverse effects on human health, but much uncertainty still surrounds some of them as well as the exact amounts of exposure involved. In particular, very few studies have addressed the possible changes in blood chemistry following high selenium exposure. In a Northeastern part of Punjab, India, very high soil selenium content has been documented, with a value exceeding 2 mg/kg (up to 5) as compared with the <0.5 mg/kg selenium content characterizing the surrounding referent areas. In seven villages located in that seleniferous areas, we carried out a survey by recruiting volunteers and sampling blood, hair and nail specimens. We administered a questionnaire to the participants and analyzed the specimens for the selenium, along with a series of biochemical and haematological parameters in blood. We included 680 adult volunteers (267 men and 413 women), who showed median selenium levels of 171.30 µg/L in serum, 1.25 µg/g in hair, and 5.7 µg/g in nails. Overall, increasing selenium exposure tended to correlate with higher levels of total cholesterol, albumin, free triiodothyronine, deionidase activity, and with red cell and platelet counts. After stratifying the subjects according to category of selenium exposure, we observed a dose-response relation between serum selenium and risk of high total cholesterol, and between hair selenium and risk of high total and low-density lipoprotein cholesterol, high pancreatic lipase, altered thyroid-stimulating hormone and free triiodothyronine levels. Nail selenium exposure category positively correlated with risk of high alanine-aminotransferase, altered albumin levels, high pancreatic lipase and low levels of thyroid-stimulating hormone. Chronic selenium overexposure appears to adversely affect lipid profiles and pancreatic, liver, and thyroid function, with selenium biomarkers having different abilities to predict such effects.
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Affiliation(s)
- Rinchu Loomba
- Christian Medical College & Hospital, Ludhiana, India
| | - Tommaso Filippini
- CREAGEN - Environmental, Genetic and Nutritional Epidemiology Research Center, University of Modena and Reggio Emilia, Reggio Emilia, Italy
| | - Rajinder Chawla
- Christian Medical College & Hospital, Ludhiana, India; Accuscript Consultancy, Ludhiana, India
| | | | - Silvia Cilloni
- CREAGEN - Environmental, Genetic and Nutritional Epidemiology Research Center, University of Modena and Reggio Emilia, Reggio Emilia, Italy
| | - Chander Datt
- ICAR-National Dairy Research Institute, Karnal, India
| | | | | | - Marco Vinceti
- CREAGEN - Environmental, Genetic and Nutritional Epidemiology Research Center, University of Modena and Reggio Emilia, Reggio Emilia, Italy; Department of Epidemiology, Boston University School of Public Health, Boston, MA, United States.
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Vinceti M, Filippini T, Del Giovane C, Dennert G, Zwahlen M, Brinkman M, Zeegers MPA, Horneber M, D'Amico R, Crespi CM. Selenium for preventing cancer. Cochrane Database Syst Rev 2018; 1:CD005195. [PMID: 29376219 PMCID: PMC6491296 DOI: 10.1002/14651858.cd005195.pub4] [Citation(s) in RCA: 121] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND This review is the third update of the Cochrane review "Selenium for preventing cancer". Selenium is a naturally occurring element with both nutritional and toxicological properties. Higher selenium exposure and selenium supplements have been suggested to protect against several types of cancer. OBJECTIVES To gather and present evidence needed to address two research questions:1. What is the aetiological relationship between selenium exposure and cancer risk in humans?2. Describe the efficacy of selenium supplementation for cancer prevention in humans. SEARCH METHODS We updated electronic searches of the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 2), MEDLINE (Ovid, 2013 to January 2017, week 4), and Embase (2013 to 2017, week 6), as well as searches of clinical trial registries. SELECTION CRITERIA We included randomised controlled trials (RCTs) and longitudinal observational studies that enrolled adult participants. DATA COLLECTION AND ANALYSIS We performed random-effects (RE) meta-analyses when two or more RCTs were available for a specific outcome. We conducted RE meta-analyses when five or more observational studies were available for a specific outcome. We assessed risk of bias in RCTs and in observational studies using Cochrane's risk assessment tool and the Newcastle-Ottawa Scale, respectively. We considered in the primary analysis data pooled from RCTs with low risk of bias. We assessed the certainty of evidence by using the GRADE approach. MAIN RESULTS We included 83 studies in this updated review: two additional RCTs (10 in total) and a few additional trial reports for previously included studies. RCTs involved 27,232 participants allocated to either selenium supplements or placebo. For analyses of RCTs with low risk of bias, the summary risk ratio (RR) for any cancer incidence was 1.01 (95% confidence interval (CI) 0.93 to 1.10; 3 studies, 19,475 participants; high-certainty evidence). The RR for estimated cancer mortality was 1.02 (95% CI 0.80 to 1.30; 1 study, 17,444 participants). For the most frequently investigated site-specific cancers, investigators provided little evidence of any effect of selenium supplementation. Two RCTs with 19,009 participants indicated that colorectal cancer was unaffected by selenium administration (RR 0.99, 95% CI 0.69 to 1.43), as were non-melanoma skin cancer (RR 1.16, 95% CI 0.30 to 4.42; 2 studies, 2027 participants), lung cancer (RR 1.16, 95% CI 0.89 to 1.50; 2 studies, 19,009 participants), breast cancer (RR 2.04, 95% CI 0.44 to 9.55; 1 study, 802 participants), bladder cancer (RR 1.07, 95% CI 0.76 to 1.52; 2 studies, 19,009 participants), and prostate cancer (RR 1.01, 95% CI 0.90 to 1.14; 4 studies, 18,942 participants). Certainty of the evidence was high for all of these cancer sites, except for breast cancer, which was of moderate certainty owing to imprecision, and non-melanoma skin cancer, which we judged as moderate certainty owing to high heterogeneity. RCTs with low risk of bias suggested increased melanoma risk.Results for most outcomes were similar when we included all RCTs in the meta-analysis, regardless of risk of bias. Selenium supplementation did not reduce overall cancer incidence (RR 0.99, 95% CI 0.86 to 1.14; 5 studies, 21,860 participants) nor mortality (RR 0.81, 95% CI 0.49 to 1.32; 2 studies, 18,698 participants). Summary RRs for site-specific cancers showed limited changes compared with estimates from high-quality studies alone, except for liver cancer, for which results were reversed.In the largest trial, the Selenium and Vitamin E Cancer Trial, selenium supplementation increased risks of alopecia and dermatitis, and for participants with highest background selenium status, supplementation also increased risk of high-grade prostate cancer. RCTs showed a slightly increased risk of type 2 diabetes associated with supplementation. A hypothesis generated by the Nutritional Prevention of Cancer Trial - that individuals with low blood selenium levels could reduce their risk of cancer (particularly prostate cancer) by increasing selenium intake - has not been confirmed. As RCT participants have been overwhelmingly male (88%), we could not assess the potential influence of sex or gender.We included 15 additional observational cohort studies (70 in total; over 2,360,000 participants). We found that lower cancer incidence (summary odds ratio (OR) 0.72, 95% CI 0.55 to 0.93; 7 studies, 76,239 participants) and lower cancer mortality (OR 0.76, 95% CI 0.59 to 0.97; 7 studies, 183,863 participants) were associated with the highest category of selenium exposure compared with the lowest. Cancer incidence was lower in men (OR 0.72, 95% CI 0.46 to 1.14, 4 studies, 29,365 men) than in women (OR 0.90, 95% CI 0.45 to 1.77, 2 studies, 18,244 women). Data show a decrease in risk of site-specific cancers for stomach, colorectal, lung, breast, bladder, and prostate cancers. However, these studies have major weaknesses due to study design, exposure misclassification, and potential unmeasured confounding due to lifestyle or nutritional factors covarying with selenium exposure beyond those taken into account in multi-variable analyses. In addition, no evidence of a dose-response relation between selenium status and cancer risk emerged. Certainty of evidence was very low for each outcome. Some studies suggested that genetic factors might modify the relation between selenium and cancer risk - an issue that merits further investigation. AUTHORS' CONCLUSIONS Well-designed and well-conducted RCTs have shown no beneficial effect of selenium supplements in reducing cancer risk (high certainty of evidence). Some RCTs have raised concerns by reporting a higher incidence of high-grade prostate cancer and type 2 diabetes in participants with selenium supplementation. No clear evidence of an influence of baseline participant selenium status on outcomes has emerged in these studies.Observational longitudinal studies have shown an inverse association between selenium exposure and risk of some cancer types, but null and direct relations have also been reported, and no systematic pattern suggesting dose-response relations has emerged. These studies suffer from limitations inherent to the observational design, including exposure misclassification and unmeasured confounding.Overall, there is no evidence to suggest that increasing selenium intake through diet or supplementation prevents cancer in humans. However, more research is needed to assess whether selenium may modify the risk of cancer in individuals with a specific genetic background or nutritional status, and to investigate possible differential effects of various forms of selenium.
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Affiliation(s)
- Marco Vinceti
- Boston University School of Public HealthDepartment of Epidemiology715 Albany StreetBoston, MAUSA02118
- University of Modena and Reggio EmiliaResearch Center in Environmental, Nutritional and Genetic Epidemiology (CREAGEN), Department of Biomedical, Metabolic and Neural SciencesVia Campi 287ModenaItaly41125
| | - Tommaso Filippini
- University of Modena and Reggio EmiliaResearch Center in Environmental, Nutritional and Genetic Epidemiology (CREAGEN), Department of Biomedical, Metabolic and Neural SciencesVia Campi 287ModenaItaly41125
| | - Cinzia Del Giovane
- University of BernInstitute of Primary Health Care (BIHAM)Gesellschaftsstrasse 49BernSwitzerland3012
- University of Modena and Reggio EmiliaCochrane Italy, Department of Diagnostic, Clinical and Public Health MedicineVia del Pozzo, 71ModenaItaly41100
| | - Gabriele Dennert
- University of Applied Sciences DortmundSocial Medicine and Public Health with Focus on Gender and Diversity, Department of Applied Social SciencesEmil‐Figge‐Str. 44DortmundGermanyD‐44227
| | - Marcel Zwahlen
- University of BernInstitute of Social and Preventive Medicine (ISPM)Finkelhubelweg11BernSwitzerland3012
| | - Maree Brinkman
- Nutrition Biomed Research InstituteDepartment of Nutritional Epidemiology and Clinical StudiesArgyle Place SouthMelbourneVictoriaAustralia3053
- Chairgroup of Complex Genetics and Epidemiology, School for Nutrition and Translational Research in Metabolism, Care and Public Health Research InstituteUnit of Nutritional and Cancer EpidemiologyMaastricht UniversityMaastrichtNetherlands
| | | | - Markus Horneber
- Paracelsus Medical University, Klinikum NurembergDepartment of Internal Medicine, Division of Oncology and HematologyProf.‐Ernst‐Nathan‐Str. 1NurembergGermanyD‐90419
| | - Roberto D'Amico
- University of Modena and Reggio EmiliaCochrane Italy, Department of Diagnostic, Clinical and Public Health MedicineVia del Pozzo, 71ModenaItaly41100
| | - Catherine M Crespi
- University of California Los AngelesBiostatisticsFielding School of Public Health650 Charles Young Drive South, A2‐125 CHS, Box 956900Los AngelesCaliforniaUSA90095‐6900
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Forte G, Deiana M, Pasella S, Baralla A, Occhineri P, Mura I, Madeddu R, Muresu E, Sotgia S, Zinellu A, Carru C, Bocca B, Deiana L. Metals in plasma of nonagenarians and centenarians living in a key area of longevity. Exp Gerontol 2014; 60:197-206. [DOI: 10.1016/j.exger.2014.10.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 09/26/2014] [Accepted: 10/30/2014] [Indexed: 10/24/2022]
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Vinceti M, Dennert G, Crespi CM, Zwahlen M, Brinkman M, Zeegers MPA, Horneber M, D'Amico R, Del Giovane C. Selenium for preventing cancer. Cochrane Database Syst Rev 2014; 2014:CD005195. [PMID: 24683040 PMCID: PMC4441528 DOI: 10.1002/14651858.cd005195.pub3] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND This review is an update of the first Cochrane publication on selenium for preventing cancer (Dennert 2011).Selenium is a metalloid with both nutritional and toxicological properties. Higher selenium exposure and selenium supplements have been suggested to protect against several types of cancers. OBJECTIVES Two research questions were addressed in this review: What is the evidence for:1. an aetiological relation between selenium exposure and cancer risk in humans? and2. the efficacy of selenium supplementation for cancer prevention in humans? SEARCH METHODS We conducted electronic searches of the Cochrane Central Register of Controlled Trials (CENTRAL, 2013, Issue 1), MEDLINE (Ovid, 1966 to February 2013 week 1), EMBASE (1980 to 2013 week 6), CancerLit (February 2004) and CCMed (February 2011). As MEDLINE now includes the journals indexed in CancerLit, no further searches were conducted in this database after 2004. SELECTION CRITERIA We included prospective observational studies (cohort studies including sub-cohort controlled studies and nested case-control studies) and randomised controlled trials (RCTs) with healthy adult participants (18 years of age and older). DATA COLLECTION AND ANALYSIS For observational studies, we conducted random effects meta-analyses when five or more studies were retrieved for a specific outcome. For RCTs, we performed random effects meta-analyses when two or more studies were available. The risk of bias in observational studies was assessed using forms adapted from the Newcastle-Ottawa Quality Assessment Scale for cohort and case-control studies; the criteria specified in the Cochrane Handbook for Systematic Reviews of Interventions were used to evaluate the risk of bias in RCTs. MAIN RESULTS We included 55 prospective observational studies (including more than 1,100,000 participants) and eight RCTs (with a total of 44,743 participants). For the observational studies, we found lower cancer incidence (summary odds ratio (OR) 0.69, 95% confidence interval (CI) 0.53 to 0.91, N = 8) and cancer mortality (OR 0.60, 95% CI 0.39 to 0.93, N = 6) associated with higher selenium exposure. Gender-specific subgroup analysis provided no clear evidence of different effects in men and women (P value 0.47), although cancer incidence was lower in men (OR 0.66, 95% CI 0.42 to 1.05, N = 6) than in women (OR 0.90, 95% CI 0.45 to 1.77, N = 2). The most pronounced decreases in risk of site-specific cancers were seen for stomach, bladder and prostate cancers. However, these findings have limitations due to study design, quality and heterogeneity that complicate interpretation of the summary statistics. Some studies suggested that genetic factors may modify the relation between selenium and cancer risk-a hypothesis that deserves further investigation.In RCTs, we found no clear evidence that selenium supplementation reduced the risk of any cancer (risk ratio (RR) 0.90, 95% CI 0.70 to 1.17, two studies, N = 4765) or cancer-related mortality (RR 0.81, 95% CI 0.49 to 1.32, two studies, N = 18,698), and this finding was confirmed when the analysis was restricted to studies with low risk of bias. The effect on prostate cancer was imprecise (RR 0.90, 95% CI 0.71 to 1.14, four studies, N = 19,110), and when the analysis was limited to trials with low risk of bias, the interventions showed no effect (RR 1.02, 95% CI 0.90 to 1.14, three studies, N = 18,183). The risk of non-melanoma skin cancer was increased (RR 1.44, 95% CI 0.95 to 1.17, three studies, N = 1900). Results of two trials-the Nutritional Prevention of Cancer Trial (NPCT) and the Selenium and Vitamin E Cancer Trial (SELECT)-also raised concerns about possible increased risk of type 2 diabetes, alopecia and dermatitis due to selenium supplements. An early hypothesis generated by NPCT that individuals with the lowest blood selenium levels at baseline could reduce their risk of cancer, particularly of prostate cancer, by increasing selenium intake has not been confirmed by subsequent trials. As the RCT participants were overwhelmingly male (94%), gender differences could not be systematically assessed. AUTHORS' CONCLUSIONS Although an inverse association between selenium exposure and the risk of some types of cancer was found in some observational studies, this cannot be taken as evidence of a causal relation, and these results should be interpreted with caution. These studies have many limitations, including issues with assessment of exposure to selenium and to its various chemical forms, heterogeneity, confounding and other biases. Conflicting results including inverse, null and direct associations have been reported for some cancer types.RCTs assessing the effects of selenium supplementation on cancer risk have yielded inconsistent results, although the most recent studies, characterised by a low risk of bias, found no beneficial effect on cancer risk, more specifically on risk of prostate cancer, as well as little evidence of any influence of baseline selenium status. Rather, some trials suggest harmful effects of selenium exposure. To date, no convincing evidence suggests that selenium supplements can prevent cancer in humans.
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Affiliation(s)
- Marco Vinceti
- University of Modena and Reggio EmiliaDepartment of Diagnostic, Clinical and Public Health MedicineVia Campi 287ModenaItaly41125
| | - Gabriele Dennert
- University of Applied Sciences DortmundSocial Medicine and Public Health with Focus on Gender and Diversity, Department of Applied Social SciencesEmil‐Figge‐Str. 44DortmundGermanyD‐44227
| | - Catherine M Crespi
- University of California Los AngelesBiostatisticsFielding School of Public Health650 Charles Young Drive South, A2‐125 CHS, Box 95690090095‐6900USALos Angeles
| | - Marcel Zwahlen
- University of BernInstitute of Social and Preventive MedicineFinkelhubelweg11BernSwitzerland3012
| | - Maree Brinkman
- Cancer Council VictoriaCancer Epidemiology Centre615 St Kilda RdMelbourneAustralia3004
| | | | - Markus Horneber
- Paracelsus Medical University, Klinikum NurembergDepartment of Internal Medicine, Division of Oncology and HematologyProf.‐Ernst‐Nathan‐Str. 1NurembergGermanyD‐90419
| | - Roberto D'Amico
- University of Modena and Reggio EmiliaItalian Cochrane Centre, Department of Diagnostic, Clinical and Public Health MedicineVia del Pozzo 71ModenaItaly41124
| | - Cinzia Del Giovane
- University of Modena and Reggio EmiliaItalian Cochrane Centre, Department of Diagnostic, Clinical and Public Health MedicineVia del Pozzo 71ModenaItaly41124
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Zhou X, Smith AM, Failla ML, Hill KE, Yu Z. Estrogen status alters tissue distribution and metabolism of selenium in female rats. J Nutr Biochem 2011; 23:532-8. [PMID: 21684133 DOI: 10.1016/j.jnutbio.2011.02.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Revised: 11/05/2010] [Accepted: 02/18/2011] [Indexed: 11/26/2022]
Abstract
A reported association between estrogen and selenium status may be important in the regulation of selenium metabolism. In this study, the effect of estrogen status on the metabolism of orally administered (75)Se-selenite and tissue selenium status was investigated. Female Sprague-Dawley rats were bilaterally ovariectomized at 7 weeks of age and implanted with either a placebo pellet (OVX) or pellet containing estradiol (OVX+E2), or were sham operated (Sham). At 12 weeks of age, 60 µCi of (75)Se as selenite was orally administered to OVX and OVX+E2 rats. Blood and organs were collected 1, 3, 6 and 24 h after dosing. Estrogen status was associated with time-dependent differences in distribution of (75)Se in plasma, red blood cell (RBC), liver, heart, kidney, spleen, brain and thymus and incorporation of (75)Se into plasma selenoprotein P (Sepp1) and glutathione peroxidase (GPx). Estrogen treatment also significantly increased selenium concentration and GPx activity in plasma, liver and brain, selenium concentration in RBC and hepatic Sepp1 and GPx1 messenger RNA. These results suggest that estrogen status affects tissue distribution of selenium by modulating Sepp1, as this protein plays a central role in selenium transport.
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Affiliation(s)
- Xiaodong Zhou
- Interdisciplinary PhD Program in Nutrition, The Ohio State University, Columbus, OH 43210, USA.
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Abstract
BACKGROUND Selenium is a trace element essential to humans. Higher selenium exposure and selenium supplements have been suggested to protect against several types of cancers. OBJECTIVES Two research questions were addressed in this review: What is the evidence for1. an aetiological relationship between selenium exposure and cancer risk in women and men?2. the efficacy of selenium supplementation for cancer prevention in women and men? SEARCH STRATEGY We searched electronic databases and bibliographies of reviews and included publications. SELECTION CRITERIA We included prospective observational studies to answer research question (a) and randomised controlled trials (RCTs) to answer research question (b). DATA COLLECTION AND ANALYSIS We conducted random effects meta-analyses of epidemiological data when five or more studies were retrieved for a specific outcome. We made a narrative summary of data from RCTs. MAIN RESULTS We included 49 prospective observational studies and six RCTs. In epidemiologic data, we found a reduced cancer incidence (summary odds ratio (OR) 0.69 (95% confidence interval (CI) 0.53 to 0.91) and mortality (OR 0.55, 95% CI 0.36 to 0.83) with higher selenium exposure. Cancer risk was more pronouncedly reduced in men (incidence: OR 0.66, 95% CI 0.42 to 1.05) than in women (incidence: OR 0.90, 95% CI 0.45 to 1.77). These findings have potential limitations due to study design, quality and heterogeneity of the data, which complicated the interpretation of the summary statistics.The RCTs found no protective efficacy of selenium yeast supplementation against non-melanoma skin cancer or L-selenomethionine supplementation against prostate cancer. Study results for the prevention of liver cancer with selenium supplements were inconsistent and studies had an unclear risk of bias. The results of the Nutritional Prevention of Cancer Trial (NPCT) and SELECT raised concerns about possible harmful effects of selenium supplements. AUTHORS' CONCLUSIONS No reliable conclusions can be drawn regarding a causal relationship between low selenium exposure and an increased risk of cancer. Despite evidence for an inverse association between selenium exposure and the risk of some types of cancer, these results should be interpreted with care due to the potential limiting factors of heterogeneity and influences of unknown biases, confounding and effect modification.The effect of selenium supplementation from RCTs yielded inconsistent results. To date, there is no convincing evidence that selenium supplements can prevent cancer in men, women or children.
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Affiliation(s)
- Gabriele Dennert
- Institut für Transdisziplinäre Gesundheitsforschung, Berlin, Germany
| | - Marcel Zwahlen
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
| | - Maree Brinkman
- Department of General Practice, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Marco Vinceti
- Department of Public Health Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Maurice P A Zeegers
- Unit of Genetic Epidemiology, Department of Public Health & Epidemiology, Birmingham, UK
| | - Markus Horneber
- Medizinische Klinik 5-Schwerpunkt Onkologie/Haematologie, Klinikum Nord, Nuernberg, Germany
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Méplan C. Trace elements and ageing, a genomic perspective using selenium as an example. J Trace Elem Med Biol 2011; 25 Suppl 1:S11-6. [PMID: 21145717 DOI: 10.1016/j.jtemb.2010.10.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Accepted: 10/26/2010] [Indexed: 01/09/2023]
Abstract
Trace elements are key regulators of metabolic and physiological pathways known to be altered during the ageing process and therefore have the capacity to modulate the rate of biological ageing. Optimal intake is required to maintain homeostasis and to increase cell protection. Deficiencies are associated with specific illnesses. However the contribution of commonly observed life-long sub-optimal intakes of trace elements to the development and severity of age-related chronic diseases is less appreciated. Additionally, reduce intake of several trace elements has been shown to be particularly challenging for elderly people. This review will use selenium as an example to illustrate how a trace element can influence ageing and how the Omics technologies could help to study the effect of trace elements on the ageing process. Although transcriptomics and proteomics approaches in animal models have so far enabled us to identify downstream targets of trace elements in pathways related to age-related diseases processes, future approaches of combining nutrigenomics with longevity studies in humans will help us to identify mechanisms whereby trace elements affect the ageing process.
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Affiliation(s)
- Catherine Méplan
- Institute for Cell and Molecular Biosciences and Human Nutrition Research Centre, The Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne NE24HH, UK.
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