Correlations between parameters of body selenium status and peripheral thyroid parameters in the low selenium region

Variability and Seasonal Change of Urinary Selenium, Molybdenum, and Iodine Excretion in Healthy Young Japanese Adults

Selenium (Se), molybdenum (Mo), and iodine (I) are essential trace elements or nutrients and their adequate intake is essential for human health. These elements in foods are easily absorbed from the digestive tract and excreted predominantly into the urine, and their nutritional status is reflected in urinary excretion; however, information on the variability of urinary excretion is limited. To characterize the urinary Se, Mo, and I concentrations and their intra- and inter-individual coefficients of variation (CV), correlation, and seasonal change, spot urine samples were collected from 24 healthy university students, 10 males and 14 females, with the mean age of 20.6 years, for 10 consecutive days in each of the four seasons according to a defined schedule of an interval of 3 months throughout 1 year. The median Se, Mo, and I concentrations for all urine samples (n = 947) were 52.8, 127.0, and 223 μg/L, respectively. The Se and Mo intakes were highest in summer and lowest in spring, while the I intake was highest in autumn and lowest in summer. In all three elements, the intra-individual CVs were smaller than their inter-individual CVs. The log-transformed intra- and inter-individual CVs were 10.5 and 14.7% for Se, 12.3 and 15.1% for Mo, and 15.5 and 18.1% for I. There was no gender difference in Se and I concentrations, while Mo and Mo/Cr values in males were higher than those in females. Our results suggest adequate nutritional status of Se, Mo, and I with a relatively smaller variability of dietary intake except for I in this population.

Role of Selenium Intake for Risk and Development of Hyperthyroidism

PURPOSE

To investigate the importance of dietary selenium (Se) for hyperthyroidism.

METHODS

We performed a more in-depth analysis of a large cross-sectional study of 6152 participants from two counties within the Shaanxi Province, China. These counties are characterized by different habitual Se intake. We investigated the effects of a different dietary Se supply (0.02, 0.18, 0.6, or 2.0 ppm Se) on disease development in a mouse model of Graves disease (GD).

RESULTS

The cross-sectional study revealed a comparable prevalence of hyperthyroidism, irrespective of Se intake, in both counties. However, an unexpected sex-specific difference was noted, and Se deficiency might constitute a risk factor for hyperthyroidism, especially in males. In a mouse model, pathological thyroid morphology was affected, and greater Se intake exerted some protecting effects on the pathological distortion. Circulating thyroid hormone levels, malondialdehyde concentrations, total antioxidant capacity, and the titer of GD-causing TSH receptor autoantibodies were not affected by Se. Expression analysis of the transcripts in the spleen indicated regulatory effects on genes implicated in the immune response, erythropoiesis, and oxygen status. However, the humoral immune response, including the CD4/CD8 or T-helper 1/T-helper 2 cell ratio and the concentration of regulatory T cells, was similar between the experimental groups, despite the difference in Se intake.

CONCLUSIONS

Our data have highlighted a sexual dimorphism for the interaction of Se and thyroid disease risk in humans, with indications of a local protective effects of Se on thyroid gland integrity, which appears not to be reflected in the circulating biomarkers tested.

Plasma Selenium Levels in First Trimester Pregnant Women with Hyperthyroidism and the Relationship with Thyroid Hormone Status

The thyroid gland has the highest selenium (Se) concentration per unit weight among all tissues. The aims of the present study were to evaluate the Se levels in the plasma of hyperthyroidic pregnant women and to investigate the association between maternal plasma Se concentrations and thyroid hormone levels. The study population consisted of 107 pregnant women, 70 healthy pregnant women (group 1) and 37 pregnant women with hyperthyroidism (group 2). The plasma free triiodothyronine (fT3) and free thyroxine (fT4) levels were significantly higher, and the plasma thyroid-stimulating hormone (TSH) and Se levels were significantly lower in group 2 than in group 1 (p < 0.05). A correlation analysis showed a positive correlation between Se and fT4 in group 1 and with TSH in group 2 (p < 0.05). Decreased maternal serum antioxidant trace element Se in hyperthyroidic pregnant women compared with normal pregnant women supported the hypothesis that hyperthyroidism was associated with decreased antioxidant response.

Instrumental neutron activation analysis and statistical approach for determining baseline values of essential and toxic elements in hairs of high school students

The possibility to have reference values in clinical chemistry is really important and hair is an ideal tissue for tracing human health conditions. This study performed on 131 hair samples of high school students gives a better knowledge of element levels (i.d., As, Cd, Cr, Cu, Fe, Hg, Mn, S, Sb, Se, Sn and Zn) in subjects not exposed to specific contamination. A nuclear analytical technique, Instrumental Neutron Activation Analysis, has been employed for determining such species. These data can be used as tentative reference values in human hairs. The ratios among metals give important considerations on the general aspect of human health: the reference value represents an evaluation of the essential metabolic functions whereas an imbalance could be a factor influencing the rising of some pathologies, even if it is not an index of particular metabolic deficiency. A comparison with Italian studies shows a good agreement whereas some little discrepancies are evident with International studies. Further, a statistical approach (cluster analysis, Canonical Discriminant Analysis) was applied for determining the reference values. Taking in account these reference values a relationship with the environmental and pollutant compartments was studied confirming the starting hypothesis.

Correlations of trace element levels in the diet, blood, urine, and feces in the Chinese male

In order to explore the associations between trace elements in dietary intake and the other three biological media (blood, urine, or feces) and inter-element interactions among the latter, we simultaneously collected 72-h diet duplicates, whole blood, and 72-h urine and feces from 120 free-living healthy males in China. Correlations among the toxic (cadmium [Cd], lead [Pb]), and nutritionally essential (zinc [Zn], copper [Cu], iron [Fe], manganese [Mn], selenium [Se], iodine [I]) elements were evaluated using Spearman rank correlation analysis based on analytical data determined by inductively coupled plasma-mass spectrometry. Dietary Cd intakes were highly correlated with the fecal Cd and blood Cd levels. Inverse correlations were found for Fe-Cd and Fe-Pb in both diet versus blood and diet versus feces. Cd-Zn and Cd-Se were significantly directly correlated in the urine and feces. Cd-Se and Pb-Se were negatively correlated in blood. In addition, there existed an extremely significant association between urinary Se and urinary I. Moreover, the other two highly direct correlations were found for Se-Fe and for I-Fe in urine. Improved knowledge regarding their mutual associations is considered to be of fundamental importance to understand more the complex interrelationships in trace element metabolism.

Iodine, selenium, and other trace elements in urine of pregnant women

The purpose of this work was to determine trace element levels in urine and evaluate possible associations between urinary iodine concentration (UIC), other trace elements (Cr, Cu, Fe, Mn, Na, Se, Zn), toxic elements (Cd, Pb), anthropometrical measures (body weight and height), glycemic indices (serum insulin and glucose), and several parameters related to thyroid function (thyroid stimulating hormone, free thyroxine, antithyroid peroxidase antibodies, thyroid volume, and thyroid echogenicity) in pregnant women. One hundred sixty-nine participants were recruited. The whole study group, originating from Krakow region, comprised three subgroups belonging to three trimesters: I trimester (n = 28), II trimester (n = 83), and III trimester (n = 58). Trace elements were determined using inductively coupled plasma mass/(atomic emission) spectrometry. Partial least square model was used to reveal correlation structure between parameters investigated, as well as a possible causal relationship between dependent parameters and potentially explanatory parameters. Results obtained for trace and toxic elements in urine were comparable with results of other authors, although the study group was not homogenous. We confirmed (1) low iodine excretion in pregnant women, (2) the existence of statistically significant correlation between UIC and urinary selenium, and (3) lack of correlation between latter parameter and typical indices of thyroid function. Urinary selenium correlated with other urinary trace elements, but physiological significance of this finding remains uncertain. The fact that a large number of pregnant women fail to meet dietary recommendations for iodine is the major reason for concern.

Selenoenzymes, laboratory parameters, and trace elements in different types of thyroid tumor

This study was performed to investigate selenoenzyme activities and trace element concentrations in thyroid tissues, with reference to other parameters routinely used to characterize thyroid function. This was to reveal relevant parameters as possible additional markers of tumor grade, clinical course, and prognosis of thyroid disorders. The tissue samples were obtained during surgical treatment (total or near total thyroidectomy) of 122 patients with different types of thyroid tumor. For most of the investigated parameters in different groups of patients, we did not find statistically significant differences. In the majority of cases, thyroid benign or malignant tumors were not accompanied by significant derangement of the gland selenoenzymes and of either intrathyroidal or plasma concentration of selenium. Nevertheless, types I and II iodothyronine deiodinases were the most promising (among selenoenzymes) targets for diagnoses and possibly therapy of thyroid tumors. Higher activities of both enzymes in cases with Graves' disease, as compared with other thyroid lesions, suggest their involvement in the pathogenesis of this condition. Patients with struna nodosa had higher levels of thyroid Zn, Cu, and Pb as compared with papillary carcinoma subjects and also a higher level of Cu than follicular carcinoma cases. The above diagnostics may play a similar role to some of the general thyroid function indices, TSH, anti-TG, anti-TPO, and calcitonin, which can partially distinguish between various thyroid tumors. In conclusion, some of selenium status markers, when accompanied with general parameters, and trace elements can serve as factors with pathophysiologic relevance and be helpful in the identification of malignant disease. Multivariate statistical methods should be employed to tackle a broad array of thyroid tumor diagnostic data in a short time. Partial least squares model and other pattern recognition methods seem to be the most appropriate methods for that task. The miniaturization of all the steps of complex analytical procedure should be developed in a way to allow its completion as sensitive, robust, and efficient for use of the small quantity of material provided by fine-needle biopsy.

Selenium and hormone interactions in female patients with Hashimoto disease and healthy subjects

OBJECTIVE

To examine the correlation structure of parameters expressing selenium status, sex hormones secretion and thyroid function in a group of patients with Hashimoto disease and healthy female subjects.

METHOD

Partial Least Square modeling was applied to parameters under study.

RESULTS

The correlations between relevant parameters were confirmed. Selenoenzyme glutathione peroxidase (GPX3) an progesterone played the most significant roles among factors contributing to thyroid stimulating hormone and free thyroxine regulation. Additionally, a correlation between GPX3 and estradiol was also observed which is in agreement with results reported by other authors. Patients with Hashimoto disease had lower glutathione peroxidase activities than healthy subjects.

CONCLUSION

The integrated multivariate approach applied to a new group of patients dissimilar to the previous one, was validated by statistical adequacy as well ass meaningful interpretation.

Selenium status and cardiovascular risk profile in healthy adult Saudi males

The purpose of this research was to investigate the relationship between selenium levels, thyroid function and other coronary risk factors in 140 Saudi subjects without overt coronary heart disease stratified by age. Demographic data and serum fasting lipid profile, glucose, thyroid function tests, selenium status and dietary intake was assessed. The relationships between selenium status, thyroid function and cardiovascular risk factors were assessed by univariate and multivariate analysis. The results showed that thyroid hormone levels did not differ with age. Erythrocyte glutathione peroxidase (GPx) levels were significantly higher in the youngest vs. oldest tertile (p<0.0001). Selenium and iodine intake did not differ significantly with age tertile, but the average intake for the population sample was below the estimated average requirements for both elements. Serum lipoprotein (a) concentrations correlated with selenium (r = 0.417, p<0.0001) and TSH (r = 0.172, p<0.05). After adjustment for confounding variables; serum fT₄ and erythrocytes GPx remained significant determinants of serum TSH levels, whilst serum selenium and TSH were determinants of serum fT₄ levels. Serum Lp(a), a coronary risk factor, was strongly related to measures of selenium status. A significant relationship between measures of selenium status and thyroid function was found. Serum Lp(a) a known risk factor for cardiovascular disease was also related to selenium status in our population.

Selenium status, sex hormones, and thyroid function in young women

The aim of the study was to identify those parameters characterising selenium status and sex hormones secretion, which are responsible for the changes in indicators of thyroid function, and to reveal the correlation structure of parameters expressing selenium status, sex hormones secretion and thyroid function, if any exist. The general approach in this work was essentially the same as in our previous report (cf. [Zagrodzki P, Ratajczak R, Wietecha-Posłuszny R. The interaction between selenium status, sex hormones, and thyroid metabolism in adolescent girls during the luteal phase of their menstrual cycle. Biol Trace Elem Res 2007; 120: 51-60]), but the study group and parameters' spectrum were different. Thirty-six women aged 23.5+/-0.6 years were investigated. The parameters of interest were: plasma selenium concentration (Se) and plasma glutathione peroxidase activity (GPX3) (indicators of selenium status); serum estradiol (E2), progesterone (P4), follicle-stimulating hormone (FSH), luteotropic hormone (LH), and age of menarche (indicators of sex hormones secretion); thyroid-stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), anti-thyroid peroxidase antibodies in serum (anti-TPO), and thyroid volume (indicators of thyroid function). Our findings show that Se, GPX3, P4, LH, FSH, TSH and fT4 were interrelated. The pairs of parameters: GPX3 and P4; LH and FSH exhibited the strongest associations. The thyroid function parameters were mainly influenced by GPX3 and P4. Partial least-squares method corroborated our hypothesis about the existence of complex interactions among selenium status, sex hormones secretion, and thyroid function in healthy young women in the luteal phase.

The effect of selenium on thyroid status in a population with marginal selenium and iodine status

The effects of Se on thyroid metabolism in a New Zealand population are investigated, including (a) the relationship between Se and thyroid status, and (b) the effect of Se supplementation on thyroid status. The data used come from two cross-sectional studies of Se, I, thyroid hormones and thyroid volume (studies 1 and 4), and three Se intervention studies in which thyroid hormones, Se and glutathione peroxidase (GPx) activities were measured (studies 2, 3 and 5). There were no significant correlations between Se status and measures of thyroid status after controlling for sex at baseline or after supplementation in any of the studies. When data from study 4 were divided into two groups according to plasma Se, plasma thyroxine (T4) was lower in males with higher plasma Se levels (P=0·009). Se supplementation increased plasma Se and GPx activity, but produced only small changes in plasma T4and triiodothyronine (T3):T4ratio. In study 2, there was a significant reduction in plasma T4(P=0·0045). In studies 3 and 5 there were small decreases in plasma T4and a small increase in the T3:T4ratio, which were not significantly different from placebo groups. Lack of significant associations between plasma Se and thyroid status, and only small changes in T4suggest that Se status in New Zealand is close to adequate for the optimal function of deiodinases. Adequate plasma Se may be approximately 0·82–0·90 μmol/l, compared with 1·00–1·14 μmol/l for maximal GPx activities.

The interaction between selenium status, sex hormones, and thyroid metabolism in adolescent girls in the luteal phase of their menstrual cycle

The objective of the present work was to study all physiological relationships among selenium status (SeS), sex hormones secretion (SH), and thyroid metabolism (ThM) in healthy adolescent girls, at one time. Forty-four girls aged 13.4-16.6 years (mean age, 14.5 +/- 0.5 years) entered the statistical model. Parameters reflecting SeS: plasma selenium concentration (Se) and plasma glutathione peroxidase activity (GPX3); SH: serum estradiol (E2) and progesterone (P4); age of menarche (AoM); and ThM: thyroid stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), antithyroid peroxidase antibodies (anti-TPO) in serum, and thyroid volume (ThV), were determined, and the interactions between them were evaluated by means of the partial least squares method (PLS). PLS method was, for the first time, successfully applied to the problem of selenium and hormone interactions and revealed that selenium status and female reproductive system are interrelated and affect thyroid physiology in adolescent girls in the luteal phase. The strongest associations were revealed for the pairs of parameters, Se and fT4/fT3, Se and P4, the modest ones for the pairs, Se and ThV, P4 and fT4/fT3, Se and AoM, and P4 and AoM. There was no correlation between E2, GPX3, and TSH, and any other considered parameter. Se and P4 had the greatest influence on ThM parameters.

Selenium, the thyroid, and the endocrine system

Recent identification of new selenocysteine-containing proteins has revealed relationships between the two trace elements selenium (Se) and iodine and the hormone network. Several selenoproteins participate in the protection of thyrocytes from damage by H(2)O(2) produced for thyroid hormone biosynthesis. Iodothyronine deiodinases are selenoproteins contributing to systemic or local thyroid hormone homeostasis. The Se content in endocrine tissues (thyroid, adrenals, pituitary, testes, ovary) is higher than in many other organs. Nutritional Se depletion results in retention, whereas Se repletion is followed by a rapid accumulation of Se in endocrine tissues, reproductive organs, and the brain. Selenoproteins such as thioredoxin reductases constitute the link between the Se metabolism and the regulation of transcription by redox sensitive ligand-modulated nuclear hormone receptors. Hormones and growth factors regulate the expression of selenoproteins and, conversely, Se supply modulates hormone actions. Selenoproteins are involved in bone metabolism as well as functions of the endocrine pancreas and adrenal glands. Furthermore, spermatogenesis depends on adequate Se supply, whereas Se excess may impair ovarian function. Comparative analysis of the genomes of several life forms reveals that higher mammals contain a limited number of identical genes encoding newly detected selenocysteine-containing proteins.

Selenium and the control of thyroid hormone metabolism

Thyroid hormone synthesis, metabolism and action require adequate availability of the essential trace elements iodine and selenium, which affect homeostasis of thyroid hormone-dependent metabolic pathways. The three selenocysteine-containing iodothyronine deiodinases constitute a novel gene family. Selenium is retained and deiodinase expression is maintained at almost normal levels in the thyroid gland, the brain and several other endocrine tissues during selenium deficiency, thus guaranteeing adequate local and systemic levels of the active thyroid hormone T(3). Due to their low tissue concentrations and their mRNA SECIS elements deiodinases rank high in the cellular and tissue-specific hierarchy of selenium distribution among various selenoproteins. While systemic selenium status and expression of abundant selenoproteins (glutathione peroxidase or selenoprotein P) is already impaired in patients with cancer, disturbed gastrointestinal resorption, unbalanced nutrition or patients requiring intensive care treatment, selenium-dependent deiodinase function might still be adequate. However, disease-associated alterations in proinflammatory cytokines, growth factors, hormones and pharmaceuticals modulate deiodinase isoenzyme expression independent from altered selenium status and might thus pretend causal relationships between systemic selenium status and altered thyroid hormone metabolism. Limited or inadequate supply of both trace elements, iodine and selenium, leads to complex rearrangements of thyroid hormone metabolism enabling adaptation to unfavorable conditions.

Selenium and iodine intakes and status in New Zealand and Australia

Most New Zealand soils contain relatively low concentrations of the anionic trace elements F, I and Se. Some areas of Australia also have a history of I deficiency. In view of current interest in establishing nutrient reference intakes for Se and I in New Zealand and Australia, it is timely to review current understanding of the intakes and status of these two elements. In spite of a recent increase in Se status, the status of New Zealanders remains low compared with populations of many other countries and may still be considered marginal, although the clinical consequences of the marginal Se status are unclear. There are no recent reports of blood Se levels in Australia, but earlier reports indicate that they were generally greater than those of New Zealanders. Similarly, the consequences of decreasing I status in Australia and New Zealand are unclear. Mild I deficiency in New Zealand has resulted in enlarged thyroid glands indicating an increased risk of goitre. Currently there is little evidence, however, of any associated clinical disease. Public health recommendations to reduce salt intake, together with the reduction in I content of dairy products, are likely to result in further decreases in the I status of New Zealand and Australian residents. Some action is needed to prevent this decline and it may be necessary to consider other means of fortification than iodized salt. The consequences of possible interactions between Se and I in human nutrition are also unclear and no practical recommendations can be made.

Assessment of requirements for selenium and adequacy of selenium status: a review

OBJECTIVE

The intent of this review is to evaluate the scientific evidence for the assessment of adequacy of selenium status and of the requirements for selenium. From this evidence, attempts have been made to define levels of plasma selenium and dietary selenium intake, which could be used for the assessment of deficiency or adequacy of selenium status.

METHOD

The first section briefly reviews the methods for assessment of selenium status. The second section outlines the requirements for selenium based on a number of criteria, and how these have been translated into recommended intakes of selenium. In the final section, levels of plasma selenium and dietary intake based on different criteria of adequacy have been proposed.

RESULTS AND CONCLUSION

The minimum requirement for selenium is that which prevents the deficiency disease, Keshan disease. The recommended intakes of selenium have been calculated from the requirement for optimum plasma glutathione peroxidase (GPx) activity that must, because of the hierarchy of selenoproteins, also take account of the amounts needed for normal levels of other biologically necessary selenium compounds. Whether optimal health depends upon maximization of GPx or other selenoproteins, however, has yet to be resolved, and the consequences of less-than-maximal GPx activities or mRNA levels need investigation. Intakes, higher than recommended intakes, and plasma selenium concentrations that might be protective for cancer or result in other additional health benefits have been proposed. There is an urgent need for more large-scale trials to assess any such beneficial effects and to provide further data on which to base more reliable estimates for intakes and plasma selenium levels that are protective.

Urinary selenium and iodine during pregnancy and lactation

The New Zealand environment is low in selenium and iodine, and is therefore ideally suited for the study of these anionic trace elements. The aim of this study was to determine urinary excretion of selenium and iodine during pregnancy and postpartum as part of an investigation of the influence of pregnancy and lactation on selenium metabolism in women of low selenium status. In a double-blind placebo-controlled study, 35 women in the earliest stages of pregnancy and 17 non-pregnant women were recruited in Dunedin, New Zealand. Eighteen pregnant women received 50 microg selenium as L-selenomethionine, while the others received a placebo daily during pregnancy and 12 months postpartum. The non-pregnant women received the supplement, serving as a positive control. Blood samples and twenty-four hour urine samples were collected monthly during pregnancy and at 3, 6, and 12 months postpartum for analysis of selenium and iodine. Selenium content in plasma and urinary excretion of selenium fell during pregnancy; however, total excretion of selenium was greater during pregnancy than postpartum. Urinary iodine excretion was much lower than reported previously in New Zealand. Due to large intra- and inter-subject variability, no trends in iodide excretion were observed. Factors which influence urinary excretion of selenium include dietary intake, but more closely, plasma concentrations of selenium (which is probably related to total selenium pool), creatinine excretion and therefore lean body mass, and glomerular filtration rate. The exact mechanism and sequence of events remains unclear and future studies incorporating new speciation techniques are necessary.

Characterization of selenium status of inhabitants in the region Usti nad Orlici, Czech Republic by INAA of blood serum and hair and fluorimetric analysis of urine

Selenium is an essential trace element and its insufficient status may cause serious health complications for both individuals and the whole populations. To investigate the selenium status of the subpopulation in northeastern Bohemia represented by the region Ustí nad Orlicí, 253 serum, 469 urine, and 31 hair samples from 470 randomly selected volunteers between 6 and 65 yr of age have been analyzed for selenium concentration. Serum and hair Se were detected by instrumental neutron activation analysis (means: 55 +/- 11 micrograms Se/L sera, 0.268 +/- 0.040 microgram Se/g hair). Urine Se was measured by fluorimetry (12 +/- 5 micrograms Se/L urine) with coanalyses of Lyphocheck urine, SRM Urine 2670, and Seronorm urine for quality control of the method. Results proved significant age-dependent differences, but gender differences were not significant. The frequency plot of serum Se proved maximal frequencies in adults between 55 and 70 micrograms Se/L and in children in the range 45-55 micrograms Se/L. The same plots of urine Se for both age groups showed maximal frequency in the limits 8-15 micrograms Se/L. All indices used (Se in serum, urine, and hair) confirmed mild to severe selenium deficiency in the population of the region.

An evaluation of urinary measures of iodine and selenium status

The aim of this study was to establish methodology for a survey of the iodine and selenium status of New Zealand residents, more specifically to investigate the correlation between fasting or random casual urine samples and 24 hour urines for iodine and selenium excretion. Sixty-two (31 M, 31 F) adults collected casual, fasting and 24 hour urine samples for analysis of iodide, selenium and creatinine. Plasma and serum samples were collected for analysis of selenium and glutathione peroxidase activity. Results indicated that fasting urine samples, but not casual urines, may give a reasonable estimate of urinary output of iodine and selenium on a population basis, but that 24 hour urines are necessary for diagnosis of iodine deficiency in an individual and for research purposes. The results for iodine also give no support for expressing iodine as the iodide-creatinine ratio, although there was some indication that the selenium-creatinine ratio might be useful. Significant correlations between total daily excretion of selenium and iodine and also for urinary concentrations of the two trace elements in fasting and in 24 hour urine specimens may reflect a relationship of selenium and iodine to body size which may have implications for dietary requirements of these trace elements. Alternatively the correlations may reflect a relationship between dietary intake of the two trace elements in a country in which food concentrations are low, and this needs further investigation.

Selenium and glutathione peroxidase activity in Hungarian children

Selenium (Se) in plasma, whole blood and erythrocytes as well as glutathione peroxidase (GSH-Px) activity in plasma and erythrocytes were investigated in 161 healthy Hungarian children aged 1-15 years. Se was determined by AAS with hydride generation. The estimation of GSH-Px activity was performed in plasma with tertbutyl-hydroperoxide (t-BOOH) and in erythrocytes with hydrogen peroxide (H2O2) as acceptor substrates. The Se content in plasma (0.63 +/- 0.12 mumol/L), whole blood (0.81 +/- 0.14 mumol/L) and erythrocytes (1.14 +/- 0.26 mumol/L, the GSH-Px activity in plasma (87 +/- 19 U/L) and erythrocytes (5.93 +/- 1.04 U/gHb) was low in Hungarian children in comparison to values for children from other European countries. Samples from a rural area in southeast Hungary showed even lower Se content than samples from an industrial city in the northwest or from the capital. The Se in plasma and whole blood as well as GSH-Px activity in the plasma exhibited a clear age dependency. There was a good correlation between plasma Se and GSH-Px activity in all children (r = 0.633, p < 0.001). In addition, in children from the northwestern city and from the capital a correlation was found between Se content and GSH-Px activity of erythrocytes (r = 0.625, p < 0.001). There is no indication that the high mortality in young Hungarian adults from cardiovascular diseases is mainly caused by a low Se supply because there are no corresponding findings in the surrounding countries of southeastern or central eastern Europe with similar low Se states.