- Email: [email protected]
Serum sample levels of selenium and copper in healthy volunteers living in Rio de Janeiro city
The Science of the Total Environment 301 (2003) 51–54
Serum sample levels of selenium and copper in healthy volunteers living in Rio de Janeiro city ´ Sergio da Cunhaa,*, Francisco Manes Albanesi Filhob,1, Domingos Senra Anteloc, ´ Mario Miranda de Souzac a
˜ 184, Meier, ´ Pedro Ernesto University Hospital, Rio de Janeiro State University, Rua Aquidaba, CEP 20720-291 Rio de Janeiro, RJ, Brazil b Rio de Janeiro State University Medical Sciences School, Rio de Janeiro, Brazil c Rio de Janeiro State University Geology School, Rio de Janeiro, Brazil Received 28 February 2002; accepted 5 July 2002
Abstract The objective of this study was to analyze the serum sample levels of selenium and copper in healthy volunteers living in the city Rio de Janeiro. Thirty individuals were submitted for nutritional assessment, electrocardiogram, echocardiogram, and serum selenium and copper analysis through hydride generation and flame atomic absorption spectrometry, respectively. The accuracy and precision of these methods were evaluated using certified reference materials. None of the studied individuals was undernourished; 53% were overweight and 13.3% were slightly obese. The mean serum selenium level was 73.18"9.9 mgyl (56.50–94.50 mgyl). Among women it was 76.28"8.7 mgyl and in men 72.23"10.24 mgyl (Ps0.35). Among non-white individuals the mean was 73.12"12.57 mgyl and in the white individuals it was 73.20"9.11 mgyl (Ps0.98). The mean serum level of copper was 1.09"0.39 mgyl (0.56–1.80 mgyl). The mean found in women was 0.99"0.22 mgyl and in the men 1.13"0.43 mgyl (Ps0.42). In non-white individuals it was 1.36"0.48 mgyl and in white individuals was 1.00"0.31 mgyl (Ps0.02). The authors concluded that selenium and copper serum levels observed in this study were similar to those found in other cities. 䊚 2002 Elsevier Science B.V. All rights reserved. Keywords: Serum selenium; Serum copper; Trace elements
1. Introduction Selenium (Se) is a component of the enzyme glutathione peroxidase (Rotruck et al., 1973). This enzyme controls the intracellular level of hydrogen peroxide, reducing the formation of active oxygen species that can induce lipid peroxidation, with *Corresponding author. E-mail address: [email protected] (S. da Cunha). 1 Cardiology Professor.
consequent damage to the cellular membranes (Burk and Levander, 1999). The importance of Se in the human nutrition was emphasized in 1979, when Chinese scientists reported that its supplementation prevented the development of a cardiomyopathy, known as Keshan disease, in children who lived in areas were the soil was poor in Se (Keshan Disease Research Group, 1979). Other reported cases about cardiomyopathy caused by Se deficiency refer, in most cases, to patients submit-
0048-9697/03/$ - see front matter 䊚 2002 Elsevier Science B.V. All rights reserved. PII: S 0 0 4 8 - 9 6 9 7 Ž 0 2 . 0 0 2 9 0 - 5
52
S. da Cunha et al. / The Science of the Total Environment 301 (2003) 51–54
ted to prolonged parenteral nutrition without the reposition of that element, or patients with acquired immunodeficiency syndrome and with severe malnutrition (Fleming et al., 1982; Quercia et al., 1984; Duorkin et al., 1989). The recommended dietary allowances of Se in the USA are 55 mgyday for women and 70 mgyday for men. There are regions in which the soil shows deficiency of Se such as Finland, New Zealand, and the eastcoast of the USA and China (Burk and Levander, 1999). This is the reason why all the researches that analyzed the normal serum sample level in various countries showed numbers that oscillated from 41.73 mgyl, in Finland, to 158.26 mgyl, in Canada (Lockitch, 1989). There is not available information of any similar research referring to the Brazilian population. Copper (Cu) is also an essential element for the human organism, being part of the structure of various enzymes, especially superoxide-dismutase, which also participates in the cleaning up of free oxygen radicals from the intracellular environment ´ (Terres-Martos et al., 1997). The USA National Research Council defined the safe level of daily ingestion as 1.5–3.0 mg. The adequacy of copper ingestion has been questioned in the healthy population (Milne et al., 1980; Reiser et al., 1985). Among the most important foodstuffs are shellfish, nuts, seeds, legumes, and the bran and germ ´ portions of grains, liver and innards (Terres-Martos et al., 1997). The copper restriction in rats’ diet resulted in cardiomyopathy (Medeiros et al., 1993). The purpose of this research was to detect the mean serum sample levels of Se and Cu in healthy volunteers who live in the city of Rio de Janeiro. 2. Material and methods Thirty healthy volunteers were studied (Table 1). All of them were submitted for medical history, physical exam, assessment of nutritional status, biochemical exams, electrocardiogram and echocardiogram. The levels of Se and Cu in the serum samples were determined through hydride generation and flame atomic absorption spectrometry, respectively, according to techniques described in previous stud-
Table 1 Age, sex and skin color of the studied volunteers Total
30 volunteers
Mean age
39.63
Sex
Skin color
m
f
White
Non-white
23
7
22
8
Abbreviations: Msmean (years); msmale; and fsfemale.
´ ies (Navarro et al., 1995; Terres-Martos et al., 1997). The blood samples were taken between 08.00 and 09.00 h, after 12 h of fasting. The serum samples were stocked frozen up to the day of analysis. The accuracy and the precision of the methods were tested with the use of two serum samples with standardized concentrations of Se and Cu, internationally recognized: (1) contox trace metal serum control (Kaulson Lab, Inc., NJ, USA); (2) seronorm trace elements serum, produced by SERO AS, Billingstad, Norway. The results were expressed as mean"S.D. The comparison of the means obtained from both sexes and races (white and non-white individuals) was done using Student’s t-test. The research was approved by the Pedro Ernesto University Hospital Research Ethics Committee. 3. Results The medical history and physical examination ruled out the presence of disease in the studied group. None of the individuals showed any digestive symptom indicative of nutrient malabsorption. The mean body mass index (BMI) was 26.2 kgy m2 (19.9–31.2 kgym2). Most of the patients presented overweight (53.3%). Four individuals (13.3%) presented slight obesity. None of the volunteers presented undernorishment. There were no significant alterations of electrolytes, glycemia, renal or hepatic function exams, electrocardiography or echocardiography. The accuracy and precision of the methods used for selenium and copper serum analyses are presented in Table 2. The mean serum sample selenium level was 73.18"9.9 mgyl (56.50–94.50 mgyl). Among women the mean was 76.28"8.7 mgyl, and among men 72.23"10.24 mgyl (Ps 0.35). In non-white individuals the mean was
S. da Cunha et al. / The Science of the Total Environment 301 (2003) 51–54
73.12"12.57 mgyl and in whites was 73.20"9.11 mgyl, (Ps0.98). The mean serum sample copper level was 1.09"0.39 mgyl (0.56–1.80 mgyl). In the women’s group the mean was 0.99"0.22 mgy l and among men was 1.13"0.43 mgyl (Ps0.42). Among non-white individuals it was 1.36"0.48 mgyl and in whites was 1.00"0.31 mgyl (Ps 0.02). 4. Discussion The studied individuals did not show caloric proteic undernutrition. Most of them showed overweight and obesity, and this is in accordance with the reality of occidental societies (World Health Organization, 1997). It was not the intention to exclude obese individuals since, even among them, it was expected to find specific micronutrient deficiencies. The mean serum selenium level observed in this study (73.18"9.9 mgyl) was similar to the one described by Navarro et al. (1995) in Spain (74.90 mgyl), and it is among the lowest ones registered in some other cities (Table 3), though above the levels registered in Finland and in New Zealand, regions in which the soil showed to be poor in selenium. It was not significantly different between both sexes and races. Navarro et al. (1995), used the medium correlation factor of various countries (1.51) for the estimation of the daily intake of Se. This factor is the result of the division of the serum Se concentration by the amount of Se ingested in the daily diet of each country. Thus, in the volunteers analyzed in this study, a mean selenium daily intake of 50.47 mg was obtained among the women, and 47.83 mg among the men. Considering the American RDA, which recom-
53
Table 3 Comparison of the mean serum levels of selenium, among adults of different countries (as mentioned by Lockitch, 1989), with the one observed in this study Region
mgyl
Finland (Helsinki) New Zealand (Dunedin) Brazil (Rio de Janeiro) W. Germany (Mainz) Sweden (Lund) Italy (Rome) Japan (Hiroshima) USA (Mort. Gr.) England (Southampton) Canada (Toronto)
41.73 47.24 73.18 81.10 85.03 89.76 97.63 110.23 115.74 158.26
1 mgs0.0127 mmol.
mends a daily Se intake of 50 mg for women and 70 mg for men, we concluded that the diet was adequate only in the first case. Despite the report of Inoko et al. (1998), of one case of cardiomyopathy related to a serum selenium level of 62 mgyl, the most frequent levels mentioned in the literature are below 50 mgyl (Fleming et al., 1982; Oster et al., 1983; Lockitch, 1989) and in the regions of China with reported cases of cardiomyopathy, the levels were less than 30 mgyl (Lockitch, 1989). However, we do not know the effects that intermediate serum levels can cause in the aggravation of the cardiomyopathy already installed and of other etiology. The mean serum sample copper level observed in this research (1.09"0.39 mgyl) is similar to ´ the one described by Terres-Martos et al. (1997), which was 1.10 mgyl and, as in these authors’ study, no significant difference between sexes was observed. There was a significant difference
Table 2 Accuracy and precision of selenium and copper analyses Material
Selenium (mgyl)
Seronorm NIST-RM 3149
Copper (mgyl)
Contox RM-0148
Concentration
Accuracy (%)
Precision R.S.D. (%)
Certified
Measured
80.00"13
81.92"4.37
102.40
5.3
0.78"12
0.77"0.03
98.71
3.8
Abbreviations: R.S.D.srelative standard deviation; NISTsNational Institute of Standards; and RMsreference material.
54
S. da Cunha et al. / The Science of the Total Environment 301 (2003) 51–54
between the mean serum levels of non-white and white individuals (Ps0.02), a fact not revealed in previous literature. It is worth emphasizing the small number of women and non-white volunteers in the present study, becoming necessary to enlarge these numbers for adequate conclusions. The mean copper serum level observed in this study is similar to the ones described in other places, such as: USAs0.91"0.06 mgyl in the women and 0.90"0.03 mgyl in the men (Lukaski et al., 1990); Japans0.98"0.11 mgyl (Yoshida et al., 1993); Slovakias1.10"0.19 mgyl in men and 1.17"0.17 mgyl in women (Magalova et al., 1994); and Australias0.98 mgyl (Mira et al., 1989). The city of Rio de Janeiro, situated in the southeast of Brazil, has a population of approximately six million inhabitants, representing a small part of the country’s population, estimated to be 160 million inhabitants. Therefore, the number of individuals studied does not allow the extension of the results to the whole population. Besides, the diversity of nourishment sources of Rio de Janeiro city, including imported foods, makes it difficult to determine the influence of the content of Se in the Brazilian soil over the serum levels that were observed. References Burk RF, Levander OA. Selenium. In: Shils ME, Olson J, Shike M, editors. Modern nutrition in health and disease, 9th. Baltimore: Willians & Willians, 1999. p. 265 –276. Duorkin BM, Antonecchia PP, Smith F, Weiss L, Davidian M, Rubin D, Rosenthal WS. Reduced cardiac selenium content in the acquired imunodeficiency syndrome. J Parent Ent Nut 1989;13:644 –647. Fleming CR, Lie JT, Maccall JT, O’Brien JF, Baillie EE, Thistle JL. Selenium deficiency and fatal cardiomyopathy in a patient on home parenteral nutrition. Gastroenterology 1982;83:689 –693. Inoko M, Konishi T, Matsusue S, Kobashi Y. Midmural fibrosis of left ventricle due to selenium deficiency. Circulation 1998;98:2638 –2639.
Keshan Disease Research Group. Observations on effect of sodium selenite in prevention of Keshan disease. Chin Med J Engl 1979;92:471 –476. Lockitch G. Selenium: clinical significance and analytical concepts. Crit Rev Clin Lab Sci 1989;27:483 –541. Lukaski HC, Hoverson BS, Gallagher SK, Bolouchuk WW. Physical training and copper, iron and zinc status of swimmers. Am J Clin Nutr 1990;51:1093 –1099. Magalova T, Batkova A, Bederova A, Kajaba I, Puchonova I. Serum copper and zinc in industrial centers in Slovakia. Biol Trace Elem Res 1994;40:225 –235. Medeiros DM, Davidson J, Jenkins JE. A unified perspective on copper deficiency and cardiomyopathy. Proc Soc Exp Biol Med 1993;203:262 –273. Milne DB, Johnson PE, Klevay LM. Effects of copper intake on balance, absorption, and status indices of copper in men. Nutr Res 1980;10:975 –986. Mira M, Stewart PM, Abraham SF. Vitamin and trace element status of women with disordered eating. Am J Clin Nutr 1989;50:940 –944. ´ ´ ´ Navarro M, Lopez H, Ruiz ML, Gonzalez S, Perez V, Lopez MC. Determination of selenium in serum by hydride generation atomic absorption spectrometry for calculation of daily dietary intake. Sci Total Environ 1995;175:245 –252. Oster O, Prellwitz W, Kasper W, Meinertz T. Congestive cardiomyopathy and selenium content of serum. Clin Chim Acta 1983;128:125 –132. Quercia RA, Korn S, O’Neill D, Dougherty JE, Ludwig M, Schweizer R, Sigman R. Selenium deficiency and fatal cardiomyopathy in a patient receiving long-term home parenteral nutrition. Clin Pharm 1984;3:531 –535. Reiser S, Smith JC, Mertz W, Holbrook JT, Scholfield DJ, Powell AS. Indices of copper status in humans consuming a typical American diet containing either fructose or starch. Am J Clin Nutr 1985;42:242 –251. Rotruck JT, Pope AL, Ganther HE, Swanson AB, Hafeman DG, Hoekstra WG. Selenium: biochemical role as a component of glutatione peroxidase. Science 1973;179:588 – 590. ´ ´ M, Martın-Lagos ´ ´ Terres-Martos C, Navarro-Alarcon F, Lopez ´ G, Lopez-Martinez MC. Determination of copper levels in serum of healthy subjects by atomic absorption spectrometry. Sci Total Environ 1997;198:97 –103. World Health Organization. Obesity: preventing and managing the global epidemic. Report of WHO Consultation on obesity. Geneva: WHO, 1997. Yoshida D, Ykeda Y, Nakazawa S. Quantitative analysis of copper, zinc and copperyzinc ratio in selected human brain tumors. J Neurooncol 1993;16:109 –115.
Serum sample levels of selenium and copper in healthy volunteers living in Rio de Janeiro city ´ Sergio da Cunhaa,*, Francisco Manes Albanesi Filhob,1, Domingos Senra Anteloc, ´ Mario Miranda de Souzac a
˜ 184, Meier, ´ Pedro Ernesto University Hospital, Rio de Janeiro State University, Rua Aquidaba, CEP 20720-291 Rio de Janeiro, RJ, Brazil b Rio de Janeiro State University Medical Sciences School, Rio de Janeiro, Brazil c Rio de Janeiro State University Geology School, Rio de Janeiro, Brazil Received 28 February 2002; accepted 5 July 2002
Abstract The objective of this study was to analyze the serum sample levels of selenium and copper in healthy volunteers living in the city Rio de Janeiro. Thirty individuals were submitted for nutritional assessment, electrocardiogram, echocardiogram, and serum selenium and copper analysis through hydride generation and flame atomic absorption spectrometry, respectively. The accuracy and precision of these methods were evaluated using certified reference materials. None of the studied individuals was undernourished; 53% were overweight and 13.3% were slightly obese. The mean serum selenium level was 73.18"9.9 mgyl (56.50–94.50 mgyl). Among women it was 76.28"8.7 mgyl and in men 72.23"10.24 mgyl (Ps0.35). Among non-white individuals the mean was 73.12"12.57 mgyl and in the white individuals it was 73.20"9.11 mgyl (Ps0.98). The mean serum level of copper was 1.09"0.39 mgyl (0.56–1.80 mgyl). The mean found in women was 0.99"0.22 mgyl and in the men 1.13"0.43 mgyl (Ps0.42). In non-white individuals it was 1.36"0.48 mgyl and in white individuals was 1.00"0.31 mgyl (Ps0.02). The authors concluded that selenium and copper serum levels observed in this study were similar to those found in other cities. 䊚 2002 Elsevier Science B.V. All rights reserved. Keywords: Serum selenium; Serum copper; Trace elements
1. Introduction Selenium (Se) is a component of the enzyme glutathione peroxidase (Rotruck et al., 1973). This enzyme controls the intracellular level of hydrogen peroxide, reducing the formation of active oxygen species that can induce lipid peroxidation, with *Corresponding author. E-mail address: [email protected] (S. da Cunha). 1 Cardiology Professor.
consequent damage to the cellular membranes (Burk and Levander, 1999). The importance of Se in the human nutrition was emphasized in 1979, when Chinese scientists reported that its supplementation prevented the development of a cardiomyopathy, known as Keshan disease, in children who lived in areas were the soil was poor in Se (Keshan Disease Research Group, 1979). Other reported cases about cardiomyopathy caused by Se deficiency refer, in most cases, to patients submit-
0048-9697/03/$ - see front matter 䊚 2002 Elsevier Science B.V. All rights reserved. PII: S 0 0 4 8 - 9 6 9 7 Ž 0 2 . 0 0 2 9 0 - 5
52
S. da Cunha et al. / The Science of the Total Environment 301 (2003) 51–54
ted to prolonged parenteral nutrition without the reposition of that element, or patients with acquired immunodeficiency syndrome and with severe malnutrition (Fleming et al., 1982; Quercia et al., 1984; Duorkin et al., 1989). The recommended dietary allowances of Se in the USA are 55 mgyday for women and 70 mgyday for men. There are regions in which the soil shows deficiency of Se such as Finland, New Zealand, and the eastcoast of the USA and China (Burk and Levander, 1999). This is the reason why all the researches that analyzed the normal serum sample level in various countries showed numbers that oscillated from 41.73 mgyl, in Finland, to 158.26 mgyl, in Canada (Lockitch, 1989). There is not available information of any similar research referring to the Brazilian population. Copper (Cu) is also an essential element for the human organism, being part of the structure of various enzymes, especially superoxide-dismutase, which also participates in the cleaning up of free oxygen radicals from the intracellular environment ´ (Terres-Martos et al., 1997). The USA National Research Council defined the safe level of daily ingestion as 1.5–3.0 mg. The adequacy of copper ingestion has been questioned in the healthy population (Milne et al., 1980; Reiser et al., 1985). Among the most important foodstuffs are shellfish, nuts, seeds, legumes, and the bran and germ ´ portions of grains, liver and innards (Terres-Martos et al., 1997). The copper restriction in rats’ diet resulted in cardiomyopathy (Medeiros et al., 1993). The purpose of this research was to detect the mean serum sample levels of Se and Cu in healthy volunteers who live in the city of Rio de Janeiro. 2. Material and methods Thirty healthy volunteers were studied (Table 1). All of them were submitted for medical history, physical exam, assessment of nutritional status, biochemical exams, electrocardiogram and echocardiogram. The levels of Se and Cu in the serum samples were determined through hydride generation and flame atomic absorption spectrometry, respectively, according to techniques described in previous stud-
Table 1 Age, sex and skin color of the studied volunteers Total
30 volunteers
Mean age
39.63
Sex
Skin color
m
f
White
Non-white
23
7
22
8
Abbreviations: Msmean (years); msmale; and fsfemale.
´ ies (Navarro et al., 1995; Terres-Martos et al., 1997). The blood samples were taken between 08.00 and 09.00 h, after 12 h of fasting. The serum samples were stocked frozen up to the day of analysis. The accuracy and the precision of the methods were tested with the use of two serum samples with standardized concentrations of Se and Cu, internationally recognized: (1) contox trace metal serum control (Kaulson Lab, Inc., NJ, USA); (2) seronorm trace elements serum, produced by SERO AS, Billingstad, Norway. The results were expressed as mean"S.D. The comparison of the means obtained from both sexes and races (white and non-white individuals) was done using Student’s t-test. The research was approved by the Pedro Ernesto University Hospital Research Ethics Committee. 3. Results The medical history and physical examination ruled out the presence of disease in the studied group. None of the individuals showed any digestive symptom indicative of nutrient malabsorption. The mean body mass index (BMI) was 26.2 kgy m2 (19.9–31.2 kgym2). Most of the patients presented overweight (53.3%). Four individuals (13.3%) presented slight obesity. None of the volunteers presented undernorishment. There were no significant alterations of electrolytes, glycemia, renal or hepatic function exams, electrocardiography or echocardiography. The accuracy and precision of the methods used for selenium and copper serum analyses are presented in Table 2. The mean serum sample selenium level was 73.18"9.9 mgyl (56.50–94.50 mgyl). Among women the mean was 76.28"8.7 mgyl, and among men 72.23"10.24 mgyl (Ps 0.35). In non-white individuals the mean was
S. da Cunha et al. / The Science of the Total Environment 301 (2003) 51–54
73.12"12.57 mgyl and in whites was 73.20"9.11 mgyl, (Ps0.98). The mean serum sample copper level was 1.09"0.39 mgyl (0.56–1.80 mgyl). In the women’s group the mean was 0.99"0.22 mgy l and among men was 1.13"0.43 mgyl (Ps0.42). Among non-white individuals it was 1.36"0.48 mgyl and in whites was 1.00"0.31 mgyl (Ps 0.02). 4. Discussion The studied individuals did not show caloric proteic undernutrition. Most of them showed overweight and obesity, and this is in accordance with the reality of occidental societies (World Health Organization, 1997). It was not the intention to exclude obese individuals since, even among them, it was expected to find specific micronutrient deficiencies. The mean serum selenium level observed in this study (73.18"9.9 mgyl) was similar to the one described by Navarro et al. (1995) in Spain (74.90 mgyl), and it is among the lowest ones registered in some other cities (Table 3), though above the levels registered in Finland and in New Zealand, regions in which the soil showed to be poor in selenium. It was not significantly different between both sexes and races. Navarro et al. (1995), used the medium correlation factor of various countries (1.51) for the estimation of the daily intake of Se. This factor is the result of the division of the serum Se concentration by the amount of Se ingested in the daily diet of each country. Thus, in the volunteers analyzed in this study, a mean selenium daily intake of 50.47 mg was obtained among the women, and 47.83 mg among the men. Considering the American RDA, which recom-
53
Table 3 Comparison of the mean serum levels of selenium, among adults of different countries (as mentioned by Lockitch, 1989), with the one observed in this study Region
mgyl
Finland (Helsinki) New Zealand (Dunedin) Brazil (Rio de Janeiro) W. Germany (Mainz) Sweden (Lund) Italy (Rome) Japan (Hiroshima) USA (Mort. Gr.) England (Southampton) Canada (Toronto)
41.73 47.24 73.18 81.10 85.03 89.76 97.63 110.23 115.74 158.26
1 mgs0.0127 mmol.
mends a daily Se intake of 50 mg for women and 70 mg for men, we concluded that the diet was adequate only in the first case. Despite the report of Inoko et al. (1998), of one case of cardiomyopathy related to a serum selenium level of 62 mgyl, the most frequent levels mentioned in the literature are below 50 mgyl (Fleming et al., 1982; Oster et al., 1983; Lockitch, 1989) and in the regions of China with reported cases of cardiomyopathy, the levels were less than 30 mgyl (Lockitch, 1989). However, we do not know the effects that intermediate serum levels can cause in the aggravation of the cardiomyopathy already installed and of other etiology. The mean serum sample copper level observed in this research (1.09"0.39 mgyl) is similar to ´ the one described by Terres-Martos et al. (1997), which was 1.10 mgyl and, as in these authors’ study, no significant difference between sexes was observed. There was a significant difference
Table 2 Accuracy and precision of selenium and copper analyses Material
Selenium (mgyl)
Seronorm NIST-RM 3149
Copper (mgyl)
Contox RM-0148
Concentration
Accuracy (%)
Precision R.S.D. (%)
Certified
Measured
80.00"13
81.92"4.37
102.40
5.3
0.78"12
0.77"0.03
98.71
3.8
Abbreviations: R.S.D.srelative standard deviation; NISTsNational Institute of Standards; and RMsreference material.
54
S. da Cunha et al. / The Science of the Total Environment 301 (2003) 51–54
between the mean serum levels of non-white and white individuals (Ps0.02), a fact not revealed in previous literature. It is worth emphasizing the small number of women and non-white volunteers in the present study, becoming necessary to enlarge these numbers for adequate conclusions. The mean copper serum level observed in this study is similar to the ones described in other places, such as: USAs0.91"0.06 mgyl in the women and 0.90"0.03 mgyl in the men (Lukaski et al., 1990); Japans0.98"0.11 mgyl (Yoshida et al., 1993); Slovakias1.10"0.19 mgyl in men and 1.17"0.17 mgyl in women (Magalova et al., 1994); and Australias0.98 mgyl (Mira et al., 1989). The city of Rio de Janeiro, situated in the southeast of Brazil, has a population of approximately six million inhabitants, representing a small part of the country’s population, estimated to be 160 million inhabitants. Therefore, the number of individuals studied does not allow the extension of the results to the whole population. Besides, the diversity of nourishment sources of Rio de Janeiro city, including imported foods, makes it difficult to determine the influence of the content of Se in the Brazilian soil over the serum levels that were observed. References Burk RF, Levander OA. Selenium. In: Shils ME, Olson J, Shike M, editors. Modern nutrition in health and disease, 9th. Baltimore: Willians & Willians, 1999. p. 265 –276. Duorkin BM, Antonecchia PP, Smith F, Weiss L, Davidian M, Rubin D, Rosenthal WS. Reduced cardiac selenium content in the acquired imunodeficiency syndrome. J Parent Ent Nut 1989;13:644 –647. Fleming CR, Lie JT, Maccall JT, O’Brien JF, Baillie EE, Thistle JL. Selenium deficiency and fatal cardiomyopathy in a patient on home parenteral nutrition. Gastroenterology 1982;83:689 –693. Inoko M, Konishi T, Matsusue S, Kobashi Y. Midmural fibrosis of left ventricle due to selenium deficiency. Circulation 1998;98:2638 –2639.
Keshan Disease Research Group. Observations on effect of sodium selenite in prevention of Keshan disease. Chin Med J Engl 1979;92:471 –476. Lockitch G. Selenium: clinical significance and analytical concepts. Crit Rev Clin Lab Sci 1989;27:483 –541. Lukaski HC, Hoverson BS, Gallagher SK, Bolouchuk WW. Physical training and copper, iron and zinc status of swimmers. Am J Clin Nutr 1990;51:1093 –1099. Magalova T, Batkova A, Bederova A, Kajaba I, Puchonova I. Serum copper and zinc in industrial centers in Slovakia. Biol Trace Elem Res 1994;40:225 –235. Medeiros DM, Davidson J, Jenkins JE. A unified perspective on copper deficiency and cardiomyopathy. Proc Soc Exp Biol Med 1993;203:262 –273. Milne DB, Johnson PE, Klevay LM. Effects of copper intake on balance, absorption, and status indices of copper in men. Nutr Res 1980;10:975 –986. Mira M, Stewart PM, Abraham SF. Vitamin and trace element status of women with disordered eating. Am J Clin Nutr 1989;50:940 –944. ´ ´ ´ Navarro M, Lopez H, Ruiz ML, Gonzalez S, Perez V, Lopez MC. Determination of selenium in serum by hydride generation atomic absorption spectrometry for calculation of daily dietary intake. Sci Total Environ 1995;175:245 –252. Oster O, Prellwitz W, Kasper W, Meinertz T. Congestive cardiomyopathy and selenium content of serum. Clin Chim Acta 1983;128:125 –132. Quercia RA, Korn S, O’Neill D, Dougherty JE, Ludwig M, Schweizer R, Sigman R. Selenium deficiency and fatal cardiomyopathy in a patient receiving long-term home parenteral nutrition. Clin Pharm 1984;3:531 –535. Reiser S, Smith JC, Mertz W, Holbrook JT, Scholfield DJ, Powell AS. Indices of copper status in humans consuming a typical American diet containing either fructose or starch. Am J Clin Nutr 1985;42:242 –251. Rotruck JT, Pope AL, Ganther HE, Swanson AB, Hafeman DG, Hoekstra WG. Selenium: biochemical role as a component of glutatione peroxidase. Science 1973;179:588 – 590. ´ ´ M, Martın-Lagos ´ ´ Terres-Martos C, Navarro-Alarcon F, Lopez ´ G, Lopez-Martinez MC. Determination of copper levels in serum of healthy subjects by atomic absorption spectrometry. Sci Total Environ 1997;198:97 –103. World Health Organization. Obesity: preventing and managing the global epidemic. Report of WHO Consultation on obesity. Geneva: WHO, 1997. Yoshida D, Ykeda Y, Nakazawa S. Quantitative analysis of copper, zinc and copperyzinc ratio in selected human brain tumors. J Neurooncol 1993;16:109 –115.