New approaches to assess selenium status and requirement

The effect of replacing sodium selenite with selenium-chitosan in laying hens on production performance, egg quality, egg selenium concentration, microbial population, immunological response, antioxidant enzymes, and fatty acid composition

The purpose of this study was to investigate into the effects of Se-chitosan and Na selenite supplementation on laying hen production performance, egg quality, egg Se concentration, microbial population, immunological response, antioxidant enzymes activity, and yolk fatty acid profile. Using a 2 × 2 factorial design, 168 27-wk-old laying hens were randomly divided into 4 treatment groups and 7 replications. Se source (Na selenite and Se-chitosan) and Se level (0.3 and 0.6 mg/kg) were used as treatments. Se-chitosan enhanced egg production percentage and egg mass (P < 0.05) when compared with Na selenite. There was an interaction, with 0.6 mg Se-chitosan/kg causing an increase in albumen height, Haugh unit, albumen index, and shell thickness of fresh eggs (P < 0.05). Se-chitosan increased yolk share, yolk color, and shape index of fresh eggs and shape index, albumen index, albumen height, Haugh unit, yolk color, shell thickness, and specific gravity of stored eggs (P < 0.05). The interaction showed that, 0.6 mg Se-chitosan/kg increased albumen Se concentration and decreased the level of malondialdehyde (MDA) in fresh egg yolk compared with 0.3 and 0.6 mg Na selenite/kg (P < 0.05). When compared with Na selenite, Se-chitosan increased the Se concentration in the yolk and decreased level of MDA in stored egg yolk (P < 0.01). When compared with Na selenite, Se-chitosan reduced coliforms (P < 0.01), increased lactic acid bacteria, and the lactic acid bacteria/coliform ratio (P < 0.05). Se-chitosan supplementation increased antibody response to sheep red blood cells and IgM titers and the activities of glutathione peroxidase and superoxide dismutase in plasma (P < 0.05). Furthermore, compared with Na selenite, supplementing diets with Se-chitosan decreased ∑ n-6 PUFA/∑ n-3 PUFA ratio (P < 0.01). In conclusion, Se-chitosan supplementation of laying hen feed improved production performance, egg quality, egg Se concentration, yolk lipid oxidation, microbial population, immune response, antioxidant enzymes activity, and yolk fatty acid profile, with 0.6 mg Se-chitosan/kg supplementation being optimal.

Micronutrient deficiencies in heart failure: Mitochondrial dysfunction as a common pathophysiological mechanism?

Heart failure is a devastating clinical syndrome, but current therapies are unable to abolish the disease burden. New strategies to treat or prevent heart failure are urgently needed. Over the past decades, a clear relationship has been established between poor cardiac performance and metabolic perturbations, including deficits in substrate uptake and utilization, reduction in mitochondrial oxidative phosphorylation and excessive reactive oxygen species production. Together, these perturbations result in progressive depletion of cardiac adenosine triphosphate (ATP) and cardiac energy deprivation. Increasing the delivery of energy substrates (e.g., fatty acids, glucose, ketones) to the mitochondria will be worthless if the mitochondria are unable to turn these energy substrates into fuel. Micronutrients (including coenzyme Q10, zinc, copper, selenium and iron) are required to efficiently convert macronutrients to ATP. However, up to 50% of patients with heart failure are deficient in one or more micronutrients in cross-sectional studies. Micronutrient deficiency has a high impact on mitochondrial energy production and should be considered an additional factor in the heart failure equation, moving our view of the failing myocardium away from an "an engine out of fuel" to "a defective engine on a path to self-destruction." This summary of evidence suggests that supplementation with micronutrients-preferably as a package rather than singly-might be a potential therapeutic strategy in the treatment of heart failure patients.

Selenium Deficiency After Bariatric Surgery, Incidence and Symptoms: a Systematic Review and Meta-Analysis

This study review the prevalence of selenium deficiency after bariatric surgery, incidence, and symptoms. A systematic literature search and meta-analysis was performed in PubMed and Scopus for articles published by November 1, 2021, including the keywords "Roux-en Y gastric bypass", "RYGB", "Omega bypass", "Mini bypass", "One anastomosis gastric bypass", "Bariatric surgery", "Weight loss surgery", "Metabolic surgery", "Gastric bypass", "Loop gastric bypass", "Selenium", "Selenium deficiency", or a combination of aimed tothem in the title or abstract. In this review, nine studies examining a total of 1174 patients were included in this meta-analysis. The mean age of the patients was 41.14 ± 7.69 years. The mean interval between bariatric surgery and selenium deficiency was 40.36 ± 43.29 months. Mean BMI before surgery and at the time of selenium deficiency was 43.68 ± 4.91 kg/m² and 28.41 ± 9.09 kg/m², respectively. Additionally, the results showed a prevalence of 16% and 2% of selenium deficiency at 1- and 2-year follow-up after bariatric surgery, respectively. Symptoms included weakness, myopathy, and cardiomyopathy, loss of muscle mass, erythematous desquamating eruption, lethargy, dyspnea, and bilateral lower extremity pitting edema. Forty percent of studies reported "Selenium orally (100 μg once daily)" as treatment option. A multidisciplinary team of healthcare professionals, including dietitians, should be involved in the bariatric patient's care. As a result, clinicians should encourage patients to take supplements for the rest of their lives, and patients should be monitored after surgery if necessary.

Reference values of trace elements in blood and/or plasma in adults living in Belgium

OBJECTIVES

Trace elements (TEs) from natural and anthropogenic sources are ubiquitous. Essential or not, their relevance for human health and disease is constantly expanding. Biological monitoring is a widely integrated tool in risk assessment both in occupational and environmental settings. However, the determination of appropriate and accurate reference values in the (specific) population is a prerequisite for a correct interpretation of biomonitoring data. This study aimed at determining the reference distribution for TEs (Al, As, Sb, Be, Bi, Cd, Co, Cu, Mn, Hg, Mo, Ni, Pb, Se, Tl, Sn, V, Zn) in the blood and/or plasma of the adult population in Belgium.

METHODS

Blood and plasma samples were analyzed for 178 males and 202 females, recruited according to an a priori selection procedure, by inductively coupled plasma mass spectrometry (ICP-MS).

RESULTS

Reference values were established with high confidence for AsT, Cd, Cu, HgT, Mn, Mo, Pb, Sn, Se, Tl and Zn. Compared to previously published data in the Belgian population, a decreasing time trend is observed for Zn, Cd and Pb. Globally, the results also indicate that the current exposure levels to TEs in the Belgian population are similar to those from other recent national surveys.

CONCLUSIONS

These reference values and limits obtained through validated analytical and statistical methods will be useful for future occupational and/or environmental surveys. They will contribute to decision-making concerning both public health policies but also exposure assessments on an individual scale.

A Clinical Tool to Predict Low Serum Selenium in Patients with Worsening Heart Failure

Selenium is an essential micronutrient, and a low selenium concentration (<100 µg/L) is associated with a poorer quality of life and exercise capacity, and an impaired prognosis in patients with worsening heart failure. Measuring selenium concentrations routinely is laborious and costly, and although its clinical utility is yet to be proven, an easy implemented model to predict selenium status is desirable. A stepwise multivariable logistic regression analysis was performed using routinely measured clinical factors. Low selenium was independently predicted by: older age, lower serum albumin, higher N-terminal pro-B-type natriuretic peptide levels, worse kidney function, and the presence of orthopnea and iron deficiency. A 10-points risk-model was developed, and a score of ≥6 points identified >80% of patients with low selenium (sensitivity of 44%, specificity of 80%). Given that selenium and iron overlap in their physiological roles, we evaluated the shared determinants and prognostic associates. Both deficiencies shared similar clinical characteristics, including the model risk factors and, in addition, a low protein intake and high levels of C-reactive protein. Low selenium was associated with a similar or worse prognosis compared to iron deficiency. In conclusion, although it is difficult to exclude low selenium based on clinical characteristics alone, we provide a prediction tool which identifies heart failure patients at higher risk of having a low selenium status.

Selenium Status after Roux-en-Y Gastric Bypass: Interventions and Recommendations

BACKGROUND

Selenium is an essential element that plays a vital role in maintaining human health and its deficiency can lead to cardiovascular and hypothyroidism complications. In this context, the main concern is about morbidly obese patients who undergo a Roux-en-Y Gastric Bypass (RYGB). Although RYGB leads to 60-70% excess weight loss, micronutrient deficiencies are common after this procedure and can be problematic if not promptly detected. This review will therefore examine the evidence regarding selenium deficiency in RYGB patients, as well its nutritional treatment methods.

METHODS

There were a total of 6 studies regarding RYGB and selenium deficiency, which were retrieved from PUBMED and SCOPUS electronic databases, ranging from 2006 to 2017.

CONCLUSION

Selenium deficiency was observed before and after RYGB. Lifelong supplementation and regular patient monitoring after surgery are recommended.

Bioavailability of selenium (Se) in cattle population in Sri Lanka based on qualitative determination of glutathione peroxidase (GSH-Px) activities

Glutathione Peroxidase activity in whole blood is well correlated with the Selenium (Se) levels in cattle hence can be used effectively to assess the supply of Se to farm animals. In this study, Se status of cattle from five different geographic regions of Sri Lanka were assessed based on glutathione peroxidase (GSH-Px) activity. The GSH-Px activity was determined in whole blood samples collected from 80 cattle from 31 different farms in five districts viz. Kandy, Anuradhapura, Batticoloa, Trincomalee and Jaffna using photometric method. Mean GSH-Px activity was found to be 825, 1239, 1039, 849 and 1307 μkat L^-1 in above districts, respectively while the reference value was considered as 665.4 μkat L^-1. Among the studied animals, insufficient Se levels were detected in 50%, 17%, 9%, 27% and 5%, respectively, from above districts. Kruskal Wallis test indicated a significant variation among the sampled locations with respect to the GSH-Px activity (p = 0.001). Selenium content in pasture and water collected from studied locations varied from 6.0 to 554 μg kg^-1 and < 0.03-1.14 μg L^-1, respectively. The lower Se levels in feeds recorded from Kandy region infer the lower GSH-Px activity in the animals from the same region. This variability may be due to differences in nutrient supply, age and species of cattle, and lactation stage. Although the assessing method has some limitations, the activity of GSH-Px of the samples indirectly confirms that considerable numbers of cattle from Sri Lanka are with insufficient selenium levels.

Micronutrient Assessment in Long-Term Home Parenteral Nutrition Patients

Assessment of micronutrient status of patients requiring long-term parenteral nutrition (PN) continues to be a challenge for clinicians. The scientific literature primarily consists of small studies and case reports. There are no evidence-based guidelines available. Clinicians rely on clinical assessment according to the patient's disease process, medication regimen, physical examination, and history of nutrient intake to determine existence or risk of micronutrient deficiency and toxicity. This paper will examine current scientific evidence and existing recommendations for the micronutrient assessment and management of patients requiring long-term PN.

Reprint of: Nutrition in the Management of Cirrhosis and its Neurological Complications

Malnutrition is a common feature of chronic liver diseases that is often associated with a poor prognosis including worsening of clinical outcome, neuropsychiatric complications as well as outcome following liver transplantation. Nutritional assessment in patients with cirrhosis is challenging owing to confounding factors related to liver failure. The objectives of nutritional intervention in cirrhotic patients are the support of liver regeneration, the prevention or correction of specific nutritional deficiencies and the prevention and/or treatment of the complications of liver disease per se and of liver transplantation. Nutritional recommendations target the optimal supply of adequate substrates related to requirements linked to energy, protein, carbohydrates, lipids, vitamins and minerals. Some issues relating to malnutrition in chronic liver disease remain to be addressed including the development of an appropriate well-validated nutritional assessment tool, the identification of mechanistic targets or therapy for sarcopenia, the development of nutritional recommendations for obese cirrhotic patients and liver-transplant recipients and the elucidation of the roles of vitamin A hepatotoxicity, as well as the impact of deficiencies in riboflavin and zinc on clinical outcomes. Early identification and treatment of malnutrition in chronic liver disease has the potential to lead to better disease outcome as well as prevention of the complications of chronic liver disease and improved transplant outcomes.

Nutrition in the management of cirrhosis and its neurological complications

Malnutrition is a common feature of chronic liver diseases that is often associated with a poor prognosis including worsening of clinical outcome, neuropsychiatric complications as well as outcome following liver transplantation. Nutritional assessment in patients with cirrhosis is challenging owing to confounding factors related to liver failure. The objectives of nutritional intervention in cirrhotic patients are the support of liver regeneration, the prevention or correction of specific nutritional deficiencies and the prevention and/or treatment of the complications of liver disease per se and of liver transplantation. Nutritional recommendations target the optimal supply of adequate substrates related to requirements linked to energy, protein, carbohydrates, lipids, vitamins and minerals. Some issues relating to malnutrition in chronic liver disease remain to be addressed including the development of an appropriate well-validated nutritional assessment tool, the identification of mechanistic targets or therapy for sarcopenia, the development of nutritional recommendations for obese cirrhotic patients and liver-transplant recipients and the elucidation of the roles of vitamin A hepatotoxicity, as well as the impact of deficiencies in riboflavin and zinc on clinical outcomes. Early identification and treatment of malnutrition in chronic liver disease has the potential to lead to better disease outcome as well as prevention of the complications of chronic liver disease and improved transplant outcomes.

Effect of selenate on viability and selenomethionine accumulation of Chlorella sorokiniana grown in batch culture

The aim of this work was to study the effect of Se(+VI) on viability, cell morphology, and selenomethionine accumulation of the green alga Chlorella sorokiniana grown in batch cultures. Culture exposed to sublethal Se concentrations of 40 mg·L⁻¹ (212 μM) decreased growth rates for about 25% compared to control. A selenate EC₅₀ value of 45 mg·L⁻¹ (238.2 μM) was determined. Results showed that chlorophyll and carotenoids contents were not affected by Se exposure, while oxygen evolution decreased by half. Ultrastructural studies revealed granular stroma, fingerprint-like appearance of thylakoids which did not compromise cell activity. Unlike control cultures, SDS PAGE electrophoresis of crude extracts from selenate-exposed cell cultures revealed appearance of a protein band identified as 53 kDa Rubisco large subunit of Chlorella sorokiniana, suggesting that selenate affects expression of the corresponding chloroplast gene as this subunit is encoded in the chloroplast DNA. Results revealed that the microalga was able to accumulate up to 140 mg·kg⁻¹ of SeMet in 120 h of cultivation. This paper shows that Chlorella sorokiniana biomass can be enriched in the high value aminoacid SeMet in batch cultures, while keeping photochemical viability and carbon dioxide fixation activity intact, if exposed to suitable sublethal concentrations of Se.

Selenium concentration and glutathione peroxidase (GSH-Px) activity in serum of cows at different stages of lactation

The aim of the study was to evaluate the activity of glutathione peroxidase (GSH-Px) and the concentration of selenium in Holstein-Friesian cows at different stages of lactation. Selenium was determined spectrofluorimetrically and GSH-Px activity using a Sigma CGP1 Glutathione Peroxidase Cellular Activity Assay kit. Mean serum selenium concentration was highest in early-lactation multiparous cows (0.18 μg/ml) and the lowest in dry cows (0.111 μg/ml). In early lactation, serum selenium concentration was significantly (P ≤ 0.01) higher in multiparous cows than in cows from the other groups. Mean GSH-Px activity in the serum of dry cows was over twice lower than in late-lactation cows (P ≤ 0.01) and over four times lower than in first-calving heifers and multiparous cows in early lactation (P ≤ 0.01). The coefficients of Spearman's rank correlation between GSH-Px activity and selenium concentration in the cows at different stages of lactation were not significant. A significant (P ≤ 0.01) mean positive correlation (0.46) was found between GSH-Px activity and serum selenium concentration for all the cows analysed together. The highest Se concentration and GSH-Px activity found in the serum of cows during the first stage of lactation may suggest that the generation of reactive oxygen species and their derivatives was higher during this period compared to the other stages, thus placing the cows at a greater risk of oxidative stress. It is therefore essential to give particular attention during this period to meeting the cows' requirement for selenium and other feed components that increase, directly or indirectly, the capacity of the body's antioxidant system.

Plasma trace elements levels are not altered by submaximal exercise intensities in well-trained endurance euhydrated athletes

The purpose of this study was to assess the effect of relative exercise intensity on various plasma trace elements in euhydrated endurance athletes. Twenty-seven well-trained endurance athletes performed a cycloergometer test: after a warm-up of 10 min at 2.0 W kg⁻¹, workload increased by 0.5 W kg⁻¹ every 10 min until exhaustion. Oxygen uptake, blood lactate concentration ([La⁻](b)), and plasma ions (Zn, Se, Mn and Co) were measured at rest, at the end of each stage, and 3, 5 and 7 min post-exercise. Urine specific gravity (U(SG)) was measured before and after the test, and subjects drank water ad libitum. Fat oxidation (FAT(OXR)), carbohydrate oxidation (CHO(OXR)), energy expenditure from fat (EE(FAT)), from carbohydrates (EE(CHO)) and total EE (EE(T)) were estimated using stoichiometric equations. A repeated measure (ANOVA) was used to compare plasma ion levels at each exercise intensity level. The significance level was set at P<0.05. No significant differences were found in U(SG) between, before, and after the test (1.014±0.004 vs. 1.014±0.004 g cm⁻³) or in any plasma ion level as a function of intensity. There were weak significant correlations of Zn (r=0.332, P<0.001) and Se (r=0.242, P<0.01) with [La⁻](b), but no relationships were established between [La⁻](b), VO₂, FAT(OXR), CHO(OXR), EE(FAT), EE(CHO), or EE(T) and plasma ion levels. Acute exercise at different submaximal intensities in euhydrated well-trained endurance athletes does not provoke a change in plasma trace element levels, suggesting that plasma volume plays an important role in the homeostasis of these elements during exercise.

Methods of assessment of selenium status in humans: a systematic review

BACKGROUND

To understand the effect of selenium intake on health, it is important to identify sensitive and population-specific biomarkers of selenium status.

OBJECTIVE

The objective of this systematic review was to assess the usefulness of biomarkers of selenium status in humans.

DESIGN

The methods included a structured search strategy on Ovid MEDLINE, EMBASE (Ovid), and Cochrane databases; formal inclusion and exclusion criteria; data extraction into an Access database; validity assessment; and meta-analysis.

RESULTS

The data from 18 selenium supplementation studies (of which 9 were randomized controlled trials and 1 was considered to be at low risk of bias) indicate that plasma, erythrocyte, and whole-blood selenium, plasma selenoprotein P, and plasma, platelet, and whole-blood glutathione peroxidase activity respond to changes in selenium intake. Although there is a substantial body of data for plasma selenium, more large, high-quality, randomized controlled trials are needed for this biomarker, as well as for the other biomarkers, to explore the reasons for heterogeneity in response to selenium supplementation. There was insufficient evidence to assess the usefulness of other potential biomarkers of selenium status, including urinary selenium, plasma triiodothyroxine:thyroxine ratio, plasma thyroxine, plasma total homocysteine, hair and toenail selenium, erythrocyte, and muscle glutathione peroxidase activity.

CONCLUSIONS

For all potentially useful biomarkers, more information is needed to evaluate their strengths and limitations in different population groups, including the effects of varying intakes, the duration of intervention, baseline selenium status, and possible confounding effects of genotype.

Dietary selenium intake is negatively associated with serum sialic acid and metabolic syndrome features in healthy young adults

Low-grade and chronic inflammation related to excessive body weight can increase the risk for type 2 diabetes and cardiovascular disease, whereas the intake of antioxidant nutrients appears to produce anti-inflammatory effects. The purpose of this observational study was to assess the potential relationships between serum SA levels, metabolic syndrome features, and dietary selenium intake to test the hypothesis that this antioxidant micronutrient may also have anti-inflammatory properties in healthy young adults. Forty-three healthy participants with a mean age of 18.0 +/- 0.93 years and a mean body mass index of 22.2 +/- 2.7 kg/m(2) were enrolled. Anthropometric, body composition, and blood pressure determinations were measured as well as serum lipid profile, glucose, insulin, and SA concentrations. Nutritional intake was estimated by a computerized, validated semiquantitative food frequency questionnaire. The findings included a positive correlation between SA and triacylglycerol levels (r = 0.317, P = .038) and a trend to significance with the homeostatic model assessment of insulin resistance index (r = 0.297, P = .053). Moreover, subjects with higher dietary selenium intake showed statistically lower SA levels compared with subjects with lower dietary selenium intake (1.8 +/- 0.4 vs 2.1 +/- 0.4 mmol/L, P = .037), while dietary selenium negatively correlated with SA (r = -0.331, P = .030) and triacylglycerol levels (r = -0.312, P = .041). It can be concluded that a relationship of SA, an inflammatory marker, with metabolic syndrome features such as lipid profile impairment and insulin resistance has been envisaged. In addition, we report (apparently for the first time) a negative association between SA and selenium intake, a recognized antioxidant trace element, in healthy young subjects, reinforcing the view of selenium as a potential anti-inflammatory nutrient.

Distribution and dynamic pathway of selenium species in selenium-deficient mice injected with (82)Se-enriched selenite

In order to elucidate Se metabolism in a living body, (82)Se-enriched selenite was injected intravenously into mice fed Se-adequate and -deficient diets. We studied the time-dependent changes in the distribution of the labeled Se in organs, red blood cells, and plasma. The total Se was determined by flow-injection ICPMS, and Se speciation analysis was conducted by micro-affinity chromatography coupled with low-flow ICPMS. Total Se in almost all organs, including liver, showed the maximum at 1 h after injection. From speciation analysis, exogenous (82)Se as Se-containing proteins other than selenoprotein P (Sel-P) (selenium containing albumin (SeAlb) and extra cellular glutathione peroxidase (eGPx)), peaked at 1 h and quickly decreased from 1 to 6 h after injection, whereas that as Sel-P, peaked at 6 h, and gradually decreased from 6 to 72 h after injection. We found that there were two pathways for the transfer of Se in mice; one was as SeAlb until 1 h after injection, and the other was as Sel-P from 6 to 72 h after injection.

Selenium status of term infants fed selenium-supplemented formula in a randomized dose-response trial

BACKGROUND

The optimal form and dose of selenium supplementation required to achieve indicators of selenium status equivalent to those in breastfed infants are unclear.

OBJECTIVE

The objective was to evaluate the effect of fortifying infant formula (6 microg Se/L) with 2 concentrations of selenate (7 and 15 microg/L) on biochemical indicators of selenium status and growth at 16 wk in term infants.

DESIGN

A randomized dose-response trial was conducted in 3 groups of term infants fed formula with different selenium concentrations [6 microg/L, F+0 (control); 13 microg/L, F+7; and 21 microg/L, F+15] and in a parallel breastfed reference group (BF; 11 +/- 2 microg Se/L).

RESULTS

One hundred sixty-one (47% males) infants completed the 16-wk study. Baseline plasma selenium was 0.3 +/- 0.1 micromol/L. At 16 wk, plasma selenium had increased in all groups (P < 0.001) and was greater (P < 0.01) in the F+7 and F+15 groups and lower (P < 0.05) in the F+0 group than in the BF group. Plasma glutathione peroxidase increased in the F+15 group, decreased in the F+0 group, and, at 16 wk, was lower in the F+0 group than in the other groups (all P < 0.05). Erythrocyte selenium and glutathione peroxidase decreased in all groups (P < 0.05), but the magnitude of the change was greater in the F+0 than in the F+15 group (P < 0.05). There was no effect of selenium supplementation on growth.

CONCLUSIONS

Selenate fortification of formula resulted in an increase in plasma indicators of selenium status relative to indicators observed in infants fed low-selenium-containing formula. Although the erythrocyte indicators decreased in all groups, the 21-microg/L dose (F+15 group) resulted in a smaller decrease and in higher erythrocyte selenium than did the standard formula. Supplementation of low-selenium formula to provide a net selenium concentration close to that found in the breast milk of US women (18 microg/L) may be justified.

Randomized, double-blind, placebo-controlled trial of selenium supplements among HIV-infected pregnant women in Tanzania: effects on maternal and child outcomes

BACKGROUND

In observational studies, adequate selenium status has been associated with better pregnancy outcomes and slowed HIV disease progression.

OBJECTIVE

We investigated the effects of daily selenium supplements on CD4 cell counts, viral load, pregnancy outcomes, and maternal and infant mortality among 913 HIV-infected pregnant women.

DESIGN

In this randomized, double-blind, placebo-controlled trial, eligible women between 12 and 27 wk of gestation were given daily selenium (200 mug as selenomethionine) or placebo as supplements from recruitment until 6 mo after delivery. All women received prenatal iron, folic acid, and multivitamin supplements irrespective of experimental assignment.

RESULTS

The selenium regimen had no significant effect on maternal CD4 cell counts or viral load. Selenium was marginally associated with a reduced risk of low birth weight [relative risk (RR) = 0.71; 95% CI: 0.49, 1.05; P = 0.09] and increased risk of fetal death (RR = 1.58; 95% CI = 0.95, 2.63; P = 0.08), but had no effect on risk of prematurity or small-for-gestational age birth. The regimen had no significant effect on maternal mortality (RR = 1.02; 95% CI = 0.51, 2.04; P = 0.96). There was no significant effect on neonatal or overall child mortality, but selenium reduced the risk of child mortality after 6 wk (RR = 0.43; 95% CI = 0.19, 0.99; P = 0.048).

CONCLUSION

Among HIV-infected women from Dar es Salaam, Tanzania, selenium supplements given during and after pregnancy did not improve HIV disease progression or pregnancy outcomes, but may improve child survival. This trial was registered at clinicaltrials.gov as NCT00197561.

Selenium supplementation prevents the increase in atherogenic electronegative LDL (LDL minus) in the postprandial phase

Evidence is accumulating that postprandial phenomena play a role in atherogenesis. Dietary lipid hydroperoxides that escape from the gastrointestinal barrier can be incorporated into plasma lipoproteins, leading to a modified form of LDL (LDL minus). The present human study was designed to investigate the effect of selenium supplementation on the formation of LDL minus in the postprandial phase. Fourteen healthy subjects ate the same test meal, high in lipid hydroperoxides, at baseline and after 10-day selenium supplementation (110 microg/day). Plasma selenium, LDL minus, LDL resistance to oxidative modification, plasma antioxidants (ascorbic acid, GSH and GPx activity) and MDA were measured in preprandial (time 0) and postprandial (3h) phases. Supplementation did not induce changes in the concentration of selenium in fasting plasma, but, at the same time, it induced a significant decrease in preprandial plasma GPx activity and inhibited the meal-induced increase in GPx activity. Selenium supplementation fully prevented the meal-induced increase in both LDL minus level and LDL susceptibility to oxidation. This study demonstrated the efficacy of selenium in preventing postprandial oxidative stress. The results, obtained on subjects adequately supplied with selenium, suggest that a non-limiting selenium availability counteracts the postprandial formation of the atherogenic form of LDL and provide a rationale for the epidemiological evidence of the inverse correlation between selenium intake and the incidence of chronic and degenerative diseases.

Time course and relationship between plasma selenium concentrations, systemic inflammatory response, sepsis, and multiorgan failure

BACKGROUND

Selenium plays an important role in defence against acute illness. We investigated, in intensive care unit (ICU) patients, the time course of plasma selenium concentrations and their relationship to systemic inflammatory response syndrome (SIRS), organ dysfunction/failure, infection, and ICU outcome.

METHODS

Plasma selenium and laboratory indices of organ dysfunction/failure, tissue inflammation, and infection were measured daily during the ICU stay in 60 consecutive ICU patients, 15 in each of four a priori defined subgroups: ICU controls (no SIRS); uncomplicated SIRS; severe SIRS; and severe sepsis/septic shock.

RESULTS

Plasma selenium concentrations were below standard values for healthy subjects (74 microg litre(-1)) in 55 patients (92%). Selenium concentrations decreased during the ICU stay in all groups, except controls, to a minimum value that was lower in patients with organ failure, particularly in those with infection. The minimum plasma selenium was inversely correlated to admission Acute Physiology and Chronic Health Evaluation II and Simplified Acute Physiology System II scores, indicators of inflammation, and the maximal degree of organ dysfunction/failure during the ICU stay. Plasma selenium was positively correlated with minimum platelet count, minimum plasma antithrombin activity, and protein C activity. In a receiver operator characteristic analysis, SAPS II score [area under the curve (AUC) = 0.903] and minimum selenium concentration (AUC = 0.867) were the strongest predictive factors for ICU mortality.

CONCLUSIONS

In critically ill surgical patients, plasma selenium concentrations are generally low with a greater decrease during the ICU stay in patients with organ failure, especially when attributed to infection. Lower plasma selenium concentrations are associated with more tissue damage, the presence of infection or organ dysfunction/failure, and increased ICU mortality.

Effect of Iodine Status and other Nutritional Factors on Psychomotor and Cognitive Performance of Filipino Schoolchildren

Background

Until 1998, iodine deficiency was a public health problem in the Philippines. A law entitled “An Act Promoting Salt Iodization Nationwide” (ASIN) has been passed and implemented by the government to eliminate iodine deficiency. The contribution of salt iodization, as well as dietary, health, and environmental factors, to improving the intellectual performance of Filipino schoolchildren remains to be determined.

Objective

The objectives of the study were to determine the relationship between iodine status and levels of psychomotor and cognitive performance in first-grade children aged 6 to 10 years, and to examine the extent to which dietary, biochemical, health, and environmental factors contribute to children's mental performance.

Methods

Two hundred ninety children in six classroom sections from a public school in Manila were examined by measurement of urinary iodine excretion (UIE) and thyroid palpation. The median UIE level for each section was determined. Sixty-five children classified as iodine deficient (UIE < 90 μg/L with grade 1 goiter, n = 34) and non-iodine deficient (UIE > 100 μg/L without goiter, n = 31) were given psychomotor and cognitive function tests (Bender–Gestalt and Raven's Colored Progressive Matrices). Scores from the two tests were used to determine each child's general ability percentile rank. Other variables examined were dietary intake (% RDA of nutrients ingested based on two nonconsecutive 24-hour recalls); deficiencies in iron, vitamin A, and selenium; parasitic infection; coliform contamination of drinking water; household use of iodized salt; illness in the past 2 weeks; and wasting and stunting.

Results

Children whose general ability scores were at or above the 50th percentile had higher UIE levels, but the relationship was not significant. Children from sections with higher median UIE levels had higher percentile ranks for general ability (p =.002). Backward logistic regression showed that the variance in deficient and adequate mental performance was explained by dietary intakes that met ≥ 80% of the RDA for energy, protein, thiamin, and riboflavin; the use of iodized salt; child's iodine status; and stunting (R2 =.520, p =.0016). Higher class median UIE was associated with better psychomotor and cognitive performance in children who were tested. Factors that contributed to better performance include higher intakes of energy, protein, thiamin, and riboflavin; household use of iodized salt; normal iodine status; and absence of stunting or chronic malnutrition.

Conclusions

Salt iodization, accompanied by adequate intakes of energy, protein, and foods rich in thiamin and riboflavin, can contribute to improved mental performance in Filipino schoolchildren. Longer-term factors that can contribute to improved performance are achievement of normal iodine status and elimination of protein–energy malnutrition.

Plasma vitamin E and selenium levels in rats with head trauma

BACKGROUND

Free radicals play an important role in brain damage induced by a head trauma. In this study, we examined the prevention of brain damage that occurs after oxidative stress in rats that had undergone an experimental head trauma and the determination of plasma levels of vitamin E and selenium, which are recognized as antioxidant agents.

METHODS

In this study, adult male Sprague-Dawley rats were used. Rats were divided into 2 groups. In the first group (control group, n = 10), pretraumatic plasma selenium and vitamin E levels were investigated and rats were not traumatized. In the second group (trauma group, n = 10), posttraumatic plasma selenium and vitamin E levels were investigated at the 6th and 24th hours in traumatized rats.

RESULTS

In the control group, the plasma selenium level was 107 +/- 8.113 microg/L, whereas vitamin E level was 1.310 +/- 0.048 mg/dL. In the trauma group, the plasma selenium level was 79.93 +/- 3.130 microg/L at the 6th hour and 74.74 +/- 2.947 microg/L at the 24th hour, whereas the vitamin E level was 1.211 +/- 0.056 mg/dL at the 6th hour and 1.136 +/- 0.044 mg/dL at the 24th hour. Normal plasma selenium and vitamin E levels were significantly reduced in the early period after trauma.

CONCLUSION

Because of oxidative stress that occurs directly after a head trauma, vitamin E and selenium depletion occurs in the early period. This condition supports the idea that brain damage can be reduced if decreased antioxidants are replaced when a head trauma occurs. We believe that these findings will guide and assist in future studies to develop clinical management strategies to prevent brain damage induced by head trauma.

Relationship between plasma selenium concentrations and lower genital tract levels of HIV-1 RNA and interleukin type 1beta

OBJECTIVE

To examine the relationship between selenium nutritional status and intermediates of human immunodeficiency virus (HIV)-1 transmission.

DESIGN

Prospective cohort study.

SETTING

A study clinic at Muhimbili National Hospital, Dar es Salaam, Tanzania.

SUBJECTS

A total of 340 HIV-1-infected pregnant women with gestational ages 12-27 weeks.

METHODS

Women's plasma selenium concentrations were determined at enrollment and modeled as tertiles (tertile 1: <114 microg/l (reference); tertile 2: 114-131 microg/l; tertile 3: >131 microg/l). Cervicovaginal lavage specimens were obtained at 36 weeks of gestation to determine HIV-1 RNA and interleukin-1beta (IL-1beta) levels. In subgroup analyses, 123 women with genital tract infections at enrollment were excluded.

RESULTS

Plasma selenium concentrations >or=114 microg/l were related to increased risk of lower-genital shedding of HIV-1 RNA. Excluding women with genital tract infections strengthened the associations (relative risk (RR) tertile 2: 1.46, 95% confidence interval (CI)=1.10, 1.92; RR tertile 3: 1.39, 95% CI=1.05, 1.84). There was evidence for an association between plasma selenium concentrations >or=114 microg/l and increased HIV-1 RNA levels among the entire cohort and after excluding women with genital tract infections. There was no association between plasma selenium and IL-1beta concentrations.

CONCLUSIONS

High selenium status may lead to increased risk of genital HIV-1 shedding, but data from other studies indicate that the evidence is mixed. Results from ongoing selenium trials are awaited to clarify the impact of selenium on HIV-1-related transmission endpoints.

SPONSORSHIP

National Institute of Child Health and Human Development (NICHD R01 32257) and the Fogarty International Center (NIH D43 TW00004).

Factors associated with longitudinal plasma selenium decline in the elderly: the EVA study

Selenium status decreases in elderly populations. Cardiovascular diseases are the primary cause of death in the French elderly, and selenium may protect against cardiovascular diseases. The present work aims to evaluate the relationships between cardiovascular-related risk factors and plasma selenium variability in an elderly population during a 9-year period. Seven hundred fifty-one subjects from the EVA ("Etude du Vieillissement Artériel") study, aged 59 to 71 at baseline, were followed for 9 years. Clinical examinations and lifestyle questionnaires were repeated every 2 years. Plasma selenium determinations were performed at baseline and at the end of the study. The association between the 9-year plasma selenium variability and studied risk factors at baseline or occurring during the follow-up was evaluated by using multivariate linear regression models. After controlling all potential associated factors, age of subjects (P<.01), obesity (P=.02) and occurrence of cardiovascular disease during follow-up (P=.03) increased the longitudinal decline in plasma selenium, whereas gender, education, smoking, alcohol intakes, dyslipidemia, diabetes, hypertension had no effect (P>.05). It may be postulated that obesity and occurrence of cardiovascular events are the main factors associated with plasma selenium fall during ageing. The respective roles played by nutritional and metabolism changes in the mechanism of these associations still need to be explored.

Serum selenium determinants in French adults: the SU.VI.M.AX study

The objective of the present work was to assess the relationship between serum Se concentrations and environmental determinants (i.e. lifestyle, social activity, geographic region, urban status, education, familial status, physical activity, BMI, tobacco, and food and alcohol consumption). Baseline results from 13 017 subjects (7876 women aged 35-60 and 5141 men aged 45-60) who participated in the SU.VI.M.AX (Supplémentation en Vitamines et Minéraux Antioxydants) study were analysed. Fewer than 2 % of the volunteers had a serum Se status under 0.75 micromol/l, which has been quoted as the cut-off of biological Se sub-deficiency. Women had significantly lower serum Se concentrations than men (1.09 (sd 0.19) micromol/l (n 7423) and 1.14 (sd 0.20) micromol/l (n 4915), P<0.0001, respectively). Significant differences in serum Se concentrations were observed between geographic areas. In both sexes, the serum Se concentration increased with alcohol, meat and fish consumption, and decreased with smoking. In premenopausal women, the serum Se concentration was higher in contraceptive-pill users than in non-users. In women only, age was associated with increased serum Se concentrations, and obesity (BMI> or =30 kg/m2) was associated with decreased serum Se levels. In men, we observed a decrease in serum Se concentrations with increased consumption of vegetables and fruits. In conclusion, though few of the volunteers participating in the SU.VI.M.AX study had Se status in the sub-deficiency range, 83 % of women and 75 % of men had serum concentrations below the value considered optimal for glutathione peroxidase activity. The largest Se associations in both sexes were found with regions, smoking, alcohol, meat and fish consumption. Further studies are needed to understand the difference in Se status between genders.

Effects of baseline serum levels of Se on markers of eccentric exercise-induced muscle injury

Inflammation and oxidative stress have been implicated in the mechanism of eccentric exercise-induced muscle injury. This study examined whether baseline serum levels of selenium (Se), a trace element that participates in both antioxidant and anti-inflammatory systems, affects the overall response to injury. Thirteen males performed 36 maximal eccentric actions with the elbow flexors of the non-dominant arm on a motorized dynamometer. Venous blood samples were collected immediately before and after exercise at 2, 24, 48, 72 and 96 hours. Established indicators of muscle damage such as maximum isometric torque (MIT), range of motion (ROM), relaxed arm angle (RANG), flexed arm angle (FANG), arm circumference (CIRC), muscle soreness and serum levels of creatine kinase (CK) and lactate dehydrogenase (LDH) were determined at the same time points. Baseline serum levels of Se were also measured. Complementary data regarding assessment of Se status were retrieved by the use of a semi-quantitative food frequency questionnaire. All measures changed significantly (p<0.05) after exercise. The main finding of this study was that baseline Se serum levels were associated inversely with CK, LDH and FANG and positively with MIT and ROM (p<0.05). These data suggest that beyond overt Se deficiency, suboptimal Se status possibly worsens muscle functional decrements subsequent to eccentric muscle contractions.

Selenium and mortality in the elderly: results from the EVA study

BACKGROUND

Inadequate plasma selenium can adversely affect the maintenance of optimal health; therefore, reported decreases in plasma selenium in an aging population are cause for concern. To further examine this hypothesis, we explored the relationships between plasma selenium and mortality in an elderly population: the EVA (Etude du Vieillissement Artériel) study.

METHODS

The EVA study was a 9-year longitudinal study with 6 periods of follow-up. During the 2-year period from 1991 to 1993 (EVA0), 1389 men and women born between 1922 and 1932 were recruited. The effects of plasma selenium at baseline on mortality were determined by Cox proportional hazards regression analysis, adjusting for the following variables: sociodemographic characteristics, dietary habits, health, and cognitive factors.

RESULTS

During the 9-year follow-up, 101 study participants died. Baseline plasma selenium was higher in individuals who were alive at the end of follow-up [mean (SD), 1.10 (0.20) micromol/L] than in those who died during the follow-up [1.01 (0.20) micromol/L; P <10(-4)]. Mortality rates were significantly higher in individuals with low selenium [increments = 0.2 micromol/L; relative risk (RR) = 1.56 (95% confidence interval, 1.28-1.89)]. After we controlled for various potential confounding factors, this association remained significant [RR = 1.54 (1.25-1.88)]. When the underlying causes of death were considered, we found an association with cancer-related mortality [adjusted RR = 1.79 (1.32-2.44)].

CONCLUSIONS

Even if it is premature to present selenium as a longevity indicator in an elderly population, our results are in accordance those of large, interventional, randomized trials with selenium, which suggest that this essential trace element plays a role in health maintenance in aging individuals.

Impact of vitamin E or selenium deficiency on nematode-induced alterations in murine intestinal function

The effects of deficiencies in the antioxidant nutrients, vitamin E and selenium, on the host response to gastrointestinal nematode infection are unknown. The aim of the study was to determine the effect of antioxidant deficiencies on nematode-induced alterations in intestinal function in mice. BALB/c mice were fed control diets or diets deficient in selenium or vitamin E and the response to a secondary challenge inoculation with Heligmosomoides polygyrus was determined. Egg and worm counts were assessed to determine host resistance. Sections of jejunum were mounted in Ussing chambers to measure changes in permeability, absorption, and secretion, or suspended in organ baths to determine smooth muscle contraction. Both selenium and vitamin E deficient diets reduced resistance to helminth infection. Vitamin E, but not selenium, deficiency prevented nematode-induced decreases in glucose absorption and hyper-contractility of smooth muscle. Thus, vitamin E status is an important factor in the physiological response to intestinal nematode infection and may contribute to antioxidant-dependent protective mechanisms in the small intestine.

Serum selenium and cancer mortality: a nested case-control study within an age- and sex-stratified sample of the Belgian adult population

OBJECTIVE

To study the predictive power of serum selenium with regard to cancer mortality in a large sample of the Belgian population given the lack of coherence in the results of observational epidemiological studies in this domain.

DESIGN

A prospective case-control study within a stratified sample of the Belgian male and female population.

SUBJECTS

A total of 201 cases randomly selected from all cancer deaths (N=343) during a 10-y mortality follow-up of a large age- and sex-stratified sample of the total Belgian population aged 25-74 y were matched for age and gender with 603 controls.

STATISTICS

Conditional logistic regression for both univariate and multivariate analyses using tertile distribution of serum selenium in controls. Odds ratios (ORs) are adjusted for 10 baseline characteristics.

RESULTS

Unadjusted ORs of cancer deaths taking the highest tertile of serum selenium as a reference: in male subjects T1/T3 is 2.2 (CI 1.3-3.7) (P for trend 0.011), whereas in female subjects a nonsignificant OR of 0.8 is observed. In multivariate analyses, no significant modifications of the ORs are observed for the predictive relation of serum selenium with cancer mortality. Besides serum selenium, beta-carotene intake and smoking are independent predictors in male subjects.

CONCLUSIONS

In this nested case-control study of a stratified sample from the Belgian population, serum selenium is an independent predictor of cancer mortality in male subjects only, in a country with rather high serum selenium levels with respect to most other European countries.

Selenium supplementation at low doses contributes to the decrease in heart damage in experimental Trypanosoma cruzi infection

Chagasic patients with cardiomyopathy have low levels of selenium (Se), a fundamental trace element. We evaluated the effect of supplementing infected mice with Se (0.25-16 ppm). Supplementation with 0.25 or 1 ppm Se led to parasitaemia and survival curves similar to those of the control group. Mice treated with 4-16 ppm showed a dose-dependent decrease of parasitaemia, significant for the highest concentration. This was probably due to a direct effect on the parasites, which were lysed after in vitro incubation with Se. Survival rates did not change significantly; however, heart damage was reduced in infected mice supplemented with 4 ppm Se, as indicated by a lower cardiac isoform of creatine kinase levels. Our results imply that Se supplementation does not lead to a general protection during infection, but may help protect the heart from inflammatory damage. The effect of Se supplementation in the course of T. cruzi infection depends on the host-parasite pair employed.

Selenium and iodine supplementation of rural Tibetan children affected by Kashin-Beck osteoarthropathy

BACKGROUND

Kashin-Beck disease is an osteoarthropathy endemic in selenium- and iodine-deficient areas around Lhasa, Tibet.

OBJECTIVE

We assessed the efficacy of selenium supplementation on disease progression.

DESIGN

A double-blind, randomized controlled trial of selenium supplementation was carried out in 324 children aged 5-15 y who had Kashin-Beck disease. Two hundred eighty children received iodized oil before being randomly assigned to receive selenium or placebo, and a control group of 44 subjects was not supplemented at all. Clinical and radiologic signs, selenium status, urinary iodine, and thyroid function were evaluated at baseline and at 12 mo.

RESULTS

The frequencies of joint pain, decreased joint mobility, and radiologic abnormalities were not significantly different between the 3 groups at 12 mo. Height-for-age z scores increased significantly in the subjects who received placebo and iodine or selenium and iodine. In contrast, unsupplemented control subjects did not recover from growth retardation. Serum selenium concentrations at 12 mo were within the reference range and were significantly greater in the selenium-iodine group than in the placebo-iodine group. Serum thyroid hormone concentrations were within the reference ranges after the administration of iodine, and these values were not significantly affected by selenium supplementation.

CONCLUSIONS

The results of this study do not rule out the possibility that selenium may help to prevent the occurrence of Kashin-Beck disease. However, selenium supplementation had no effect on established Kashin-Beck disease, growth, or thyroid function once iodine deficiency was corrected. These results suggest that iodine, but not selenium, deficiency should be corrected in Tibetan children with Kashin-Beck disease.

Trace metals and the elderly

The elderly are at nutritional risk as a result of multiple physiological, social, psychological, and economic factors. Elderly persons have a higher incidence of chronic diseases and associated intake of medications that may affect nutrient utilization. Social and economic conditions can adversely affect dietary choices and eating patterns. Physiological functions naturally decline with age, which may influence absorption and metabolism. Loneliness and reluctance to eat may complicate an already marginal situation. This article reviews specific trace metals in relation to the elderly. Our objectives are to provide Dietary Reference Intakes for older adults, to provide information on presenting features and functional consequences of trace metal deficiency, and to discuss potential effects and/or benefits of trace metal supplementation in the elderly.

Selenium as a 'nutraceutical': how to conciliate physiological and supra-nutritional effects for an essential trace element

PURPOSE OF REVIEW

To review how selenium has been appreciated in nutrition and therapeutics for the last few decades.

RECENT FINDINGS

Selenium is a powerful micronutrient constituting the active centre of about 20 eukaryotic proteins highly relevant in biochemistry, mostly for redox state-regulating properties. This element is now better recognized as a biologically important nutrient. Insufficient dietary intake for satisfying biological requirements in several physiological or pathological conditions has been demonstrated, and it is now established that inadequate intake has adverse consequences for disease susceptibility and the maintenance of optimal health. The 'recommended dietary allowances' for selenium actually seem inadequately defined considering not only the recent evolutions of selenium biochemistry, but also the way in which selenium requirements are estimated. Indeed, the element also seems active at supra-nutritional levels of dietary intake, mostly in the field of cancer prevention, and maybe also at pharmacological levels as an adjuvant treatment of some cancers.

SUMMARY

Selenium perfectly illustrates the concept of 'nutraceutical' and the need for changing paradigms in nutrition. Indeed, intakes for satisfying physiological needs as reflected by classical selenium-dependent biochemical functions (mostly glutathione peroxidase activity) only explain a part of selenium biological potency. Other beneficial effects can be obtained at higher nutritional intakes, which in turn implies specified chemical forms and doses. Studies are under way to document these effects in a more complete and convincing manner.

Selenium status and associated factors in a British National Diet and Nutrition Survey: young people aged 4-18 y

OBJECTIVE

Assessment of selenium status to provide normative reference values, and investigation of associated socio-demographic factors, in a national sample of British young people aged 4-18 y.

SETTING

National Diet and Nutrition Survey-a nationwide cross-sectional sample of young people aged 4-18 y living in mainland Britain in 1997.

METHODS

Selenium status was measured, mainly in fasting blood samples, by plasma selenium concentration in 1127 participants, by red blood cell (RBC) selenium concentration in 1112, and by whole-blood glutathione peroxidase (GPx) activity in 658.

RESULTS

No evidence of severe selenium deficiency or toxicity was observed. Plasma selenium concentration was directly correlated with RBC selenium concentration, and both were associated directly, although less strongly, with GPx activity. Plasma and RBC selenium concentrations increased significantly with age, with RBC concentrations significantly higher in older girls than boys. Region of domicile exhibited a significant relationship. Associations also occurred with parental occupational social class, selenium concentrations being higher in more socially advantaged children. Black and Indian children had considerably higher concentrations than Caucasian children. Concentrations, especially of plasma selenium, were significantly lower in children either (or both) of whose parents were smokers, although, unexpectedly, there was no evidence that children who themselves smoked had lower levels.

CONCLUSIONS

The observed associations between selenium status indices and age, gender, social class, parental smoking and ethnic group indicate a complex network of biological factors which determine selenium concentrations in blood components, and which thus need to be controlled for when using these indices to assess selenium status in young people.

SPONSORSHIP

The survey was commissioned jointly by the Department of Health and the Ministry of Agriculture, Fisheries and Food, whose responsibility has since been transferred to the Food Standards Agency. Support for the further analysis presented in this paper was provided by the Department of Health.

Trypanosoma cruzi: host selenium deficiency leads to higher mortality but similar parasitemia in mice

Selenium is an essential trace element and its deficiency was implicated in heart diseases. We recently showed low Se levels in chronic chagasic patients with cardiomyopathy. Herein, mice were depleted in Se by feeding the mothers with chow containing only 0.005 mg Se/kg and maintaining this diet for offspring, that were further infected with Trypanosoma cruzi. Survival rate was significantly lower in Se deficient than in control mice. Parasitemia was similar in all groups. Necrotic heart lesions were found after infection (high CK-MB levels). No outbreaks of parasite growth were detected in chronic survivors submitted or not to a second Se depletion. The present results confirm our hypothesis that a nutritional deficiency in Se is associated to a higher mortality during T. cruzi infection. The potential beneficial effect of Se supplementation is a perspective. Hypothesis to explain the higher susceptibility of Se-depleted mice to T. cruzi infection are discussed.