External quality assessment schemes for inorganic elements in the clinical laboratory: Lessons from the OELM scheme.

Measurements of inorganic elements in clinical laboratories produce results used for the diagnosis, the treatment and the monitoring of deficiencies or overloads. The main objective of External Quality Assessment Schemes is to verify, on a regular frequency, that clinical laboratory results correspond to the quality requirement for patient care. Therefore, External Quality Assessment Schemes represent an essential component of a laboratory's quality management system. However, External Quality Assessment Schemes within the same analytical field remain heterogeneous for different reasons such as samples, determination of assigned value, acceptable limits, content of the reports. The aim of this review was to describe and illustrate some major critical aspects of External Quality Assessment Schemes based on Occupational and Environmental Laboratory Medicine external quality assessment scheme experience.

Selenium status and fungi in the protein-losing enteropathy of persistent diarrhea.

BACKGROUND AND OBJECTIVES: A vicious cycle of infection, malabsorption, and malnutrition has been implicated in the perpetuation of diarrheal disease. This study examined whether persistent diarrhea is associated with changes in selenium status and stool alpha-1 antitrypsin (AAT) concentration. METHODS AND STUDY DESIGN: This cross-sectional study included 30 children aged 1-12 years with persistent diarrhea who were hospitalized in Cipto Mangunkusumo Hospital and Fatmawati Hospital, Jakarta, and 30 apparently healthy children who were matched by age and sex and lived in a rural area of Jakarta. Clinical examinations, blood routine tests, erythrocyte glutathione peroxidase (GPX) activity and plasma selenium levels as well as AAT in fresh stool samples were performed in all the subjects. RESULTS: Of 30 children with persistent diarrhea, 17 had moderate malnutrition and 13 had severe malnutrition. The mean plasma selenium was significantly lower in children with persistent diarrhea than in children without diarrhea (86.0 µg/L [95% CI: 76.1-95.9] vs 110 µg/L [95% CI: 104-116, p<0.0001). The mean stool AAT concentration was significantly higher in children with persistent diarrhea than in those without diarrhea (115 mg/dL [95% CI: 38.5-191] vs 16 mg/dL [95% CI: 4.0-13.5, p<0.0001]). Selenium correlated with AAT (p=0.05). Fecal fungi were persistently present. CONCLUSIONS: Although selenium status in both groups was optimal for the obtained plasma GPX activity, children with persistent diarrhea exhibited lower plasma selenium levels. This study suggests that the decrease in the plasma selenium level may be the consequence of protein loss and that fungi may be involved.

The effects of di(2-ethylhexyl) phthalate and/or selenium on trace element levels in different organs of rats.

Di(2-ethylhexyl)phthalate (DEHP), a widely used plasticizer for synthetic polymers, is known to have endocrine disruptive potential, reproductive toxicity, and induces hepatic carcinogenesis in rodents. Selenium (Se) is a component of several selenoenzymes which are essential for cellular antioxidant defense and for the functions of mammalian reproductive system. The present study was designed to investigate the effects of DEHP exposure on trace element distribution in liver, testis, and kidney tissues and plasma of Se-deficient and Se-supplemented rats. Se deficiency was produced by feeding 3-week old Sprague-Dawley rats with ≤0.05mg Se/kg diet for 5 weeks, and supplementation group were on 1mg Se/kg diet. DEHP treated groups received 1000mg/kg dose by gavage during the last 10 days of feeding period. Se, zinc (Zn), copper (Cu), iron (Fe) and manganese (Mn) levels were measured by inductively coupled plasma mass spectrometry (ICP-MS). Se supplementation caused significant increases in hepatic, renal, and testicular Se levels. With DEHP exposure, plasma Se and Zn, kidney Se, Cu and Mn levels were significantly decreased. Besides, liver Fe decreased markedly in all the DEHP-treated groups. Liver and kidney Mn levels decreased significantly in DEHP/SeD group compared to both DEHP and SeD groups. These results showed the potential of DEHP exposure and/or different Se status to modify the distribution pattern of essential trace elements in various tissues, the importance of which needs to be further evaluated.

Six-day selenium supplementation led to either UVA-photoprotection or toxic effects in human fibroblasts depending on the chemical form and dose of Se.

Selenium (Se) is an essential trace element with a narrow safety zone and unclear effects on skin photoageing. The aim of this work was to investigate the photoageing properties of sodium selenite or selenomethionine (SeMet) after a long term (6 days) Se supplementation in normal human skin fibroblasts (NHSF) subjected to ultraviolet-A (UVA) irradiation inducing 30% cell death. The uptake, toxicity and antioxidant effects of sodium selenite and SeMet were compared to better understand their photoageing properties. SeMet uptake was better than sodium selenite and their uptake by fibroblasts was not via an actively transport process. Sodium selenite induced a higher toxicity than SeMet. At 5 µM, sodium selenite inhibited cell proliferation associated with a blockage in the G2 phase and induced DNA fragmentation leading to caspase-3-dependent apoptosis cell death. At low doses (<1 µM), SeMet and sodium selenite induced glutathione peroxidase-1 (GPX1) activity and selenoproteinW1 (SEPW1) transcript expression but metalloproteinase (MMP)-1 was only induced by sodium selenite. SeMet and sodium selenite did not protect NHSFs from UVA-induced cell death. However, SeMet decreased malondialdehyde (MDA) and protected NHSFs from UVA-induced MMP1 and MMP3. We then observed a large difference in terms of photoprotection according to selenium forms. SeMet may be a potential agent for the prevention and treatment of skin photoageing.

Midlife iron status is inversely associated with subsequent cognitive performance, particularly in perimenopausal women.

The link between iron status and cognition has been established in infants and children, yet evidence in adults is scant and heterogeneous. We examined sex- and menopause-specific cross-time associations of iron status with cognition in the French Supplémentation en Vitamines et Minéraux Antioxydants Study cohort (1539 men, 1431 pre-/perimenopausal women, 962 postmenopausal women). Serum ferritin and hemoglobin data were obtained in 1995. Cognition was assessed after a mean of 13 y through 6 validated instruments, including the RI-48 cued recall test, phonemic and semantic fluency tasks, forward and backward digit span tasks, and a trail-making test. The standardized individual test scores were summed to form a composite cognitive performance measure. Associations between ferritin and hemoglobin and subsequent cognitive performance were examined through multivariable linear regression. Among men, no significant associations were observed. In postmenopausal women, an inverse association was found between ferritin and phonemic fluency (adjusted ß: -0.11; 95% CI: -0.21, -0.01). Significant inverse associations between ferritin and both the composite cognitive measure (adjusted ß: -0.09; 95% CI: -0.17, -0.00) and the forward digit span scores (adjusted ß: -0.13; 95% CI: -0.22, -0.03) were observed only among premenopausal women aged ≥ 46 y at baseline. No significant findings with hemoglobin emerged. This study supports an inverse association between midlife iron status and subsequent cognitive performance that is sex- and menopause-dependent. Given the urgent need for prevention research on age-related disorders, future investigations of iron status and cognition are warranted. The study is registered at www.clinicaltrials.gov as NCT00272428.

Long-term selenium supplementation in HaCaT cells: importance of chemical form for antagonist (protective versus toxic) activities.

The beneficial effect of selenium (Se) on cancer is known to depend on the chemical form, the dose and the duration of the supplementation. The aim of this work was to explore long term antagonist (antioxidant versus toxic) effects of an inorganic (sodium selenite, Na2SeO3) and an organic (seleno-L-methionine, SeMet) forms in human immortalized keratinocytes HaCaT cells. HaCaT cells were supplemented with Na2SeO3 or SeMet at micromolar concentrations for 144 h, followed or not by UVA radiation. Se absorption, effects of UVA radiation, cell morphology, antioxidant profile, cell cycle processing, DNA fragmentation, cell death triggered and caspase-3 activity were determined. At non-toxic doses (10 µM SeMet and 1 µM Na2SeO3), SeMet was better absorbed than Na2SeO3. The protection of HaCaT from UVA-induced cell death was observed only with SeMet despite both forms increased glutathione peroxidase-1 (GPX1) activities and selenoprotein-1 (SEPW1) transcript expression. After UVA irradiation, malondialdehyde (MDA) and SH groups were not modulated whatever Se chemical form. At toxic doses (100 µM SeMet and 5 µM Na2SeO3), Na2SeO3 and SeMet inhibited cell proliferation associated with S-G2 blockage and DNA fragmentation leading to apoptosis caspase-3 dependant. SeMet only led to hydrogen peroxide production and to a decrease in mitochondrial transmembrane potential. Our study of the effects of selenium on HaCaT cells reaffirm the necessity to take into account the chemical form in experimental and intervention studies.

Selenium and cognitive impairment: a brief-review based on results from the EVA study.

Preventing cognitive impairment and dementia in the elderly is a major public health challenge for our century and all hypotheses should be explored. Selenium (Se) is one of the factors that may affect the risk of cognitive decline. Its importance in the health and aging process has been documented. Because of the potential of selenoproteins to protect against oxidative stress, Se raises significant expectations for the prevention of chronic diseases including cancer, cardiovascular disease, and type 2 diabetes conditions commonly associated with oxidative stress. Thus, the relationships between Se and cognitive impairment or dementia can be examined through vascular risk factors for dementia, with particular interest in diabetes and dyslipidemia. In addition, in cases of Se deficiency, the brain is the organ that remains Se replete the longest suggesting that Se plays an important role in brain functions. This article presents results obtained in the frame of a longitudinal study on Se and cognitive impairment. They are consistent with the hypothesis that low Se status is a risk factor for cognitive decline even after taking into account vascular risk factors. The concomitant evolution between plasma Se decrease over a 9-year period and cognitive decline suggested that optimal Se status is potentially important to maintain neuropsychological functions in aging people. However, as our understanding of Se biology is incomplete, epidemiological studies are needed to define the groups of population that could benefit from Se supplementation.

Reproductive toxicity of di(2-ethylhexyl) phthalate in selenium-supplemented and selenium-deficient rats.

Phthalates are abundantly produced plasticizers, and di(ethylhexyl) phthalate (DEHP) is the most widely used derivative in various consumer products and medical devices. Animal studies show that DEHP and various other phthalates cause reproductive and developmental toxicity. Although the evidences are limited, it seems reasonable that DEHP may have a potential for similar adverse effects in humans. Such concerns are increasing, particularly for the developing reproductive system of male infants and children. By taking into account the essentiality of selenium (Se) in testicular structure and functions and the high prevalence of inadequate Se intake in various part of the world, this study was designed to investigate the testicular toxicity of DEHP in Se-deficient male rats and to examine the possible preventive effects of Se supplementation on phthalate toxicity. Se deficiency was generated by feeding 3-week-old Sprague-Dawley rats with a ≤0.05 Se mg/kg diet for 5 weeks. Supplementation groups were on a 1 mg Se/kg diet, and DEHP-treated groups received a 1,000 mg/kg dose by gavage during the last 10 days of the feeding period. Testicular histopathology, sperm count and motility, and sperm morphology were examined, and plasma levels of sex hormones were measured. Toxicity and antiandrogenic effects of DEHP were evidenced by disturbed testicular histology and spermatogenesis, diminished testosterone, leutinizing hormone (LH) and follicle stimulating hormone (FSH) levels, and sperm motility. The effects of DEHP were much more pronounced in Se-deficient rats, whereas Se supplementation was found to be protective, reflecting its regulating role in cellular redox equilibrium.

Selenium supplementation ameliorates static magnetic field-induced disorders in antioxidant status in rat tissues.

The aim of this study was to investigate the effect of selenium supplementation on the antioxidant enzymatic system (such as GPx, GR and SOD), GSH and selenium level in liver, kidney, muscle and brain of static magnetic field (SMF) exposed rats. Male adult rats were divided into control rats (n=6), SMF-exposed rats (128 mT; 1h/day for 5 days), selenium-treated rats (Na(2)SeO(3), 0.2mg/l, in drinking water for 4 weeks) and co-exposed rats (selenium for 4 weeks and SMF during the last 5 consecutive days). Sub-acute exposure to SMF induces a decrease of selenium levels in kidney, muscle and brain. Our results also revealed a decrease of GPx activities in kidney and muscle. By contrast, SMF exposure increased total GSH levels and total SOD activities in liver, while glutathione reductase activity is unaffected. Selenium supplementation in SMF-exposed rats restored selenium levels in kidney, muscle and brain and elevated the activities of GPx in kidney and muscle to those of control group. In the liver, selenium supplementation failed to bring down the elevated levels of total GSH and SOD activity. Our investigations suggested that sub-acute exposure to SMF altered the antioxidant response by decreasing the level of total selenium in kidney, muscle and brain. Interestingly, selenium supplementation ameliorates antioxidant capacity in rat tissues exposed to SMF.

Trace elements status in multinodular goiter.

Importance of iodine and selenium in thyroid metabolism is well known, but the roles of other essential trace elements including copper, zinc, manganese and iron on thyroid hormone homeostasis remain unclear. The aim of this study was to investigate the status of those trace elements in benign thyroid diseases and evaluate possible links between trace element concentrations and thyroid hormones. The study group was composed of 25 patients with multinodular goiter. Concentrations of thyroid hormones (plasma-free thyroxine, FT(4); free triiodothyronine, FT(3); and thyrotropin, TSH), selenium, copper, zinc, manganese and iron in plasma, and urinary iodine were determined. The results were compared with those of a healthy control group (n=20) with no thyroid disorder. A mild iodine deficiency was observed in the patients with multinodular goiter whereas urinary iodine levels were in the range of "normal" values in healthy controls. All patients were euthyroid, and their thyroid hormone concentrations were not significantly different from the control group. Plasma selenium, zinc and iron concentrations did not differ from controls, while copper and manganese levels were found to be significantly higher in the patients with multinodular goiter indicating links between these trace elements and thyroid function and possibly in development of goiter. Besides iodine, there was a significant correlation between plasma copper concentration and FT(3)/FT(4) ratio.

Plasma selenium and risk of dysglycemia in an elderly French population: results from the prospective Epidemiology of Vascular Ageing Study.

BACKGROUND: A preventive role of selenium on the risk of diabetes has been reported and ascribed to the "insulin-like" activity of selenium and the antioxidant properties of the selenoenzymes. By contrast, data from cross-sectional studies and clinical trials have suggested an adverse effect of high selenium status and selenium supplementation on type-2 diabetes risk. Given these controversial results, we investigated prospectively the relationship between baseline plasma selenium concentration and occurrence of dysglycemia (impaired fasting glucose or type 2 diabetes) in an elderly French cohort. METHODS: The Epidemiology of Vascular Ageing (EVA) study (n = 1389, 59-71 years) is a 9-year longitudinal study in which, fasting plasma glucose was measured at baseline, 2, 4 and 9 years. Analyses were performed on 1162 participants with complete data. RESULTS: At baseline plasma selenium mean levels were 1.08 (0.21) mumol/l in men and 1.10 (0.20) mumol/l in women. During the 9-year follow-up, 127 cases of dysglycemia occurred. A significant interaction was found between plasma selenium and sex. Risk of dysglycemia was significantly lower in men with plasma selenium in the highest tertile (T3:1.19-1.97) compared to those in the lowest tertile (T1:0.18-1.00) [HR = 0.48 (0.25-0.92)], but no significant relationship was observed in women. After controlling for socio-demographic factors, lifestyle factors, cardiovascular diseases, body mass index, hypertension and lipid profile, plasma selenium remained marginally significantly associated with occurrence of dysglycemia in men [T3 vs. T1, HR = 0.50 (0.24-1.04)] and unrelated in women. CONCLUSIONS: This prospective study suggests a sex-specific protective effect of higher selenium status at baseline on later occurrence of dysglycemia.

Effects of long-term antioxidant supplementation and association of serum antioxidant concentrations with risk of metabolic syndrome in adults.

BACKGROUND: Limited observational evidence suggests lower antioxidant concentrations in individuals with the metabolic syndrome (MetS); few randomized controlled trials have addressed the effect of multiple antioxidants on the risk of MetS. OBJECTIVE: The objective was to examine the effect of antioxidant supplementation for 7.5 y on the incidence of MetS and the epidemiologic association between baseline serum antioxidant concentrations and the prospective risk of MetS. DESIGN: Adults (n = 5220) participating in the SUpplementation en VItamines et Minéraux AntioXydants (SU.VI.MAX) primary prevention trial were randomly assigned to receive a supplement containing a combination of antioxidants (vitamins C and E, beta-carotene, zinc, and selenium) at nutritional doses or a placebo. Subjects were free of MetS at baseline and were followed for 7.5 y. RESULTS: Antioxidant supplementation for 7.5 y did not affect the risk of MetS. Baseline serum antioxidant concentrations of beta-carotene and vitamin C, however, were negatively associated with the risk of MetS; the adjusted odds ratios (and 95% CIs) for the highest compared with the lowest tertile were 0.34 (0.21, 0.53; P for trend = 0.0002) and 0.53 (0.35, 0.80; P for trend = 0.01), respectively. Baseline serum zinc concentrations were positively associated with the risk of developing MetS; the adjusted odds ratio (and 95% CI) for the highest compared with the lowest tertile was 1.81 (1.20, 2.72; P for trend = 0.01). CONCLUSIONS: The experimental finding of no beneficial effects of antioxidant supplementation in a generally well-nourished population is consistent with recent reports of a lack of efficacy of antioxidant supplements. However, the relations observed between the risk of MetS and baseline serum antioxidant concentrations, which probably reflect associations with overall dietary patterns, do support the current recommendations to consume antioxidant-rich foods. This trial was registered at clinicaltrials.gov as NCT00272428.

Zinc supplementation does not alter plasma homocysteine, vitamin B12 and red blood cell folate concentrations in French elderly subjects.

BACKGROUND/AIMS: In ageing, low folates and vitamin B12 status are frequent and can explain the increase of plasma homocysteine level. Zinc is involved in the folates and vitamin B12 metabolism with opposite actions. The aim of this study was to investigate the effects of zinc supplementation on homocysteine and vitamin B12 plasma levels as well as red blood cell folate level in French ageing subjects participating in the ZENITH study. METHODS: Apparently healthy middle-aged (55-70 years) and free-living older (70-85 years) subjects were enrolled. They were randomly allocated to three groups: 0, 15 or 30 mg Zn per day for 6 months as zinc gluconate in addition to their usual dietary intake. RESULTS: At baseline, plasma homocysteine levels (15.2+/-3.5 micromol/L) in older people were higher than in the middle-aged subjects (12.7+/-2.7 micromol/L) and was negatively correlated with vitamin B12 values (p=0.0036, r=-0.215) and with RBC folate levels (p<0.0001, r=-0.30). These results are in agreement with previous data. However, we found no correlation between the biomarkers of zinc status and homocysteine, vitamin B12 or folate levels at baseline. Moreover, 6-month zinc supplementation did not modify homocysteine, vitamin B12 and RBC folate values in either of the groups. CONCLUSIONS: Zinc supplementation at moderate doses do not lead to deleterious effect on folate or vitamin B12 status in ageing healthy free-living people, but does not have any beneficial effects on homocysteine metabolism either.

Fibrates but not statins increase plasma selenium in dyslipidemic aged patients--the EVA study.

This secondary analysis of "Etude du Vieillissement Artériel" (EVA) study reports the effect of fibrates and statins on plasma selenium concentration and its 9-year change in free-living dyslipidemic elderly. Dyslipidemic patients were categorized in three sub-groups according to final low-density lipoprotein (LDL)-cholesterol level or hypolipidemic treatment: non-treated dyslipidemic (LDL-cholesterol >4.41 mmol/L, n=84); dyslipidemics who were treated exclusively by fibrates (n=47) or by statins (n=25) whatever their serum LDL-cholesterol concentration. The influence of lipid-lowering treatments on plasma selenium concentrations and its 9-year change was evaluated by analysis of variance (ANOVA) and multivariate linear regression models taking into account cardiovascular risk and changes in lipid-profile parameters. Multivariate linear regression indicated that the plasma selenium decline was associated with the longitudinal variation in LDL (beta=-0.039+/-0.019, p=0.04) and high-density lipoprotein (HDL)-cholesterol concentrations (beta=0.187+/-0.059, p=0.002) but not with triglycerides (beta=-0.018+/-0.031, p=0.57). During the 9-year follow-up, similar plasma selenium declines were observed in all the sub-groups (p=0.33) despite plasma selenium levels being higher in fibrate users and lower in statin users (p=0.0004). The mechanisms underlying these data are not yet totally understood, but considering the risk of selenium deficiency in the elderly and its relationship with poor health status further clinical trial is needed to verify the proposed hypotheses.

Burn-induced oxidative stress is altered by a low zinc status: kinetic study in burned rats fed a low zinc diet.

As an initial subdeficient status of zinc, considered as an essential antioxidant trace element, is frequent in burned patients, we aim to assess the effects of low zinc dietary intakes on burn-induced oxidative stress, in an animal model. After 8 weeks of conditioning diets containing 80 ppm (control group) or 10 ppm of zinc (depleted group), Wistar rats were 20% TBSA burned and sampled 1-10 days after injury. Kinetic evolutions of zinc status, plasma oxidative stress parameters, and antioxidant enzymes were also studied in blood and organs. The zinc-depleted diet induced, before injury, a significant decrease in zinc bone level and the increase of oxidative stress markers without stimulation of antioxidant enzyme activity. After burn, more markedly in zinc depleted animals than in controls, zinc levels decreased in plasma and bone, while increasing in liver. The decrease of thiol groups and GSH/GSSG ratio and the depression of GPx activity in liver are also moderately emphasized. Nevertheless, depleted zinc status could not be considered as determining for oxidative damages after burn injury. Further investigations must also be done to enlighten the mechanism of beneficial effects of zinc supplementation reported in burned patients.

Quality specifications for the determination of copper, zinc, and selenium in human serum or plasma: evaluation of an approach based on biological and analytical variation.

BACKGROUND: Trace element external quality assessment schemes monitor laboratory performance and provide a stimulus for improvement in accuracy. However, monitoring of participant performance varies according to the scheme and can lead to conflicting conclusions. METHODS: Quality specifications based on biological intra- and interindividual variability were calculated and compared to those currently used by various trace element external quality assessment schemes for plasma or serum copper, zinc, and selenium concentrations. For this purpose, we evaluated results reported by participating laboratories in different schemes, at key concentrations, using z scores. RESULTS: Minimal quality specifications developed from the biological intra- and interindividual variability were, for Cu, +/-0.84 micromol/L or 12% of the assigned target concentration, whichever is greater; for Zn, +/-1.20 micromol/L or 15% of the assigned target concentration, whichever is greater; and for Se, +/-0.072 micromol/L or 12% of the assigned target concentration, whichever is greater. Reported performance of the participating laboratories depended on analyte, concentration, and the selected quality specification. In addition, the most commonly used methods for the determination of Cu, Zn, and Se may give different results. CONCLUSIONS: The proposed minimal quality specifications based on biological variation are generally slightly less stringent than those currently in use, although they do not drastically change the performance evaluation in the different schemes. These specifications are a first step in the harmonization of practices among the schemes and remain to be evaluated.

Effect of low dose antioxidant vitamin and trace element supplementation on the urinary concentrations of thromboxane and prostacyclin metabolites.

OBJECTIVE: This trial evaluated the effect of antioxidant supplementation on the urinary excretion of 11-dehydro TXB(2)/2,3 dinor 6 keto PGF(1alpha) ratio, a marker of the pathogenesis of thrombosis and arteriosclerosis. METHODS: This study was a randomised, double-blind, placebo-controlled trial involving 186 presumably healthy volunteers. One hundred received a multi-antioxidant supplementation and 86 a placebo for two years. Blood zinc, selenium, beta-carotene, vitamin C and E and urinary excretion of 11-dehydro TXB(2) and 2,3 dinor 6 keto PGF(1alpha) were measured. RESULTS: Baseline subject characteristics did not differ between the two groups. Blood zinc, selenium, and beta-carotene concentrations significantly increased between baseline and two years in the multi-antioxidant supplementation group supporting subject compliance (p < 0.05). At two years, the median urinary 11-dehydro TXB(2)/2,3 dinor 6 keto PGF(1alpha) ratio was significantly lower in the multi-antioxidant supplementation group (3.4 versus 2.78, p = 0.015). Serum selenium concentration was the only antioxidant studied that was significantly related to the urinary 11-dehydro TXB(2)/2,3 dinor 6 keto PGF(1alpha) ratio. CONCLUSIONS: These results support the hypothesis that a low-dose multi-antioxidant supplementation may contributes to a reduction in platelet activation which is beneficial for cardiovascular function.

Age- and sex-dependent effects of long-term zinc supplementation on essential trace element status and lipid metabolism in European subjects: the Zenith Study.

Given the key role of Zn in many physiological functions, optimal Zn status could be a predictive parameter of successful ageing. However, the benefit of Zn supplementation is still a matter of debate since Zn supplementation has been reported to be associated with the alteration of Cu status and lipid metabolism. As part of the Zenith Project, the present study aimed to investigate, in free-living healthy European middle-aged and older subjects, the effect of Zn supplementation on the biochemical status of Zn, Fe and Cu and on lipid profile. Volunteers aged 55-70 (n 188) and 70-85 (n 199) years old participated in a double-blinded, randomised study and received a daily placebo, or Zn as 15 or 30 mg for 6 months. Zn supplementation did not significantly modify erythrocyte Zn levels or erythrocyte Cu,Zn-superoxide dismutase activity. But Zn supplementation at 15 or 30 mg/d for 6 months increased significantly serum Zn levels and Zn urinary excretion with no major adverse effects on Fe and Cu status or on lipid metabolism. However, Zn supplementation at 30 mg/d showed some age- and sex-dependent alterations in Fe status or lipid profile. Therefore, with respect to the key role of an optimal Zn status in successful ageing, Zn supplementation at 15 mg/d, when necessary, could be safely proposed regarding lipids and the risk of interaction with Fe and Cu.

Relationships between selenium, lipids, iron status and hormonal therapy in women of the SU.VI.M.AX cohort.

Significant differences in serum selenium concentration according to contraceptive treatment and age have been evidenced in women of the SU.VI.M.AX cohort. This study aimed at verifying the physiopathological hypothesis that the observed increase in serum selenium concentration could be related to serum lipid increase and/or bleeding decrease. Women were divided into six groups: menopausal with or without hormonal replacement therapy; non-menopausal using contraceptive pills; intrauterine device; other contraceptive treatment or no contraceptive treatment. Adjusted linear regression indicated positive associations between selenium and apolipoprotein A1 (r(2) from 0.038 to 0.074, p<0.07 depending on groups) or ferritin in serum (r(2) from 0.032 to 0.075, p<0.07 depending on groups). These relationships could explain the differences observed according to hormonal treatment and age in the SU.VI.MAX study.