Trace metal concentrations in two New Zealand talitrid amphipods: effects of gender and reproductive state and implications for biomonitoring

This is the first in-depth investigation of whether the gender or reproductive state of talitrid amphipods affects the bioaccumulation of trace metals. Concentrations of copper, zinc, and cadmium were measured in the beach flea Transorchestia chiliensis (Milne-Edwards) and the sand hopper Talorchestia quoyana (Milne-Edwards) (Amphipoda: Talitridae) from sites in and near the Avon-Heathcote Estuary, Christchurch, New Zealand. For T. chiliensis, the whole body trace metals concentrations (μg g⁻¹) were generally similar for nonbrooding, brooding, and brooding females that had the embryos removed. Where there were differences between female groups (3 out of 15 samples), concentrations in nonbrooding females were below those for brooding females. The trace metal concentrations of separated embryos did not follow those of their mothers. The body zinc concentration was similar for males and females. For copper and cadmium, body concentrations for females were higher than males at the two most contaminated sites. Cadmium body concentrations were similar between sites, and the lowest concentrations were from amphipods from one of the Estuary sites rather than the reference site. In T. quoyana, the trace metal concentrations in nonbrooding female and male sand hoppers were similar for copper and zinc, but cadmium concentrations were higher in nonbrooding females than in males. Copper and zinc concentrations within amphipod body tissues did not reflect those in the sediment or their food. The implications of these results are discussed in relation to previous studies and the use of beach fleas and sand hoppers as metal biomonitors. The beach flea T. chiliensis is recommended as a suitable trace metal biomonitor in New Zealand coastal waters with the potential to be affected by anthropogenic trace metal contamination.     

Serum trace elements and fat-soluble vitamins A and E in healthy pre-school children from a Venezuelan rural community.

Zn (SZn), Cu (SCu), Fe (SFe), vitamin A (SVA) and vitamin E (SVE) were measured in blood serum samples of 85 healthy pre-school children aged 2-6 yr. from the rural community of Canaguá, Mérida State, Venezuela. The relationship between these biochemical indexes was also investigated. The mean serum concentrations of zinc, copper, iron, vitamin A and vitamin E were 0.74 +/- 0.25, 1.18 +/- 0.30, 0.76 +/- 0.20, 0.30 +/- 0.15 and 5.87 +/- 0.43 mg/L, respectively. There was a tendency for SZn to increase with age, whereas SCu and SVA decreased. There was no significant difference in serum trace elements and fat-soluble vitamin concentration between males and females in the different age groups. SFe tended to be lower than that reported in the literature. However, the age groups studied showed no statistically significant sex- and age-related differences. The present study shows that there is a complex interaction between SZn, SCu, SFe, SVA, SVE and age of the children. Multiple regression analysis showed serum zinc was strongly related to serum copper, and serum iron. Serum vitamin A was strongly related to serum zinc and serum vitamin E, whereas serum vitamin E was strongly related to serum zinc, serum copper, and serum vitamin A. On the other hand, our observations also suggest that more detailed studies of these metals and fat-soluble vitamins should be carried out, and that the study should include nutritional surveys, metabolic balances and associations between SZn, SCu, SFe, SVA and SVE and anthropometric variables (height, weight, body mass index and skinfold thickness).     

Determination of iron, copper, zinc, magnesium and selenium in plasma and erythrocytes in neurosurgical patients.

A direct method for determination of Fe, Cu, Zn, Mg and Se in erythrocytes was developed. The aim of the present study was to establish a method for examining perioperative levels of the above mentioned elements simultaneously in erythrocytes and plasma by atomic absorption spectrophotometry in 11 patients undergoing neurosurgery for acute spinal nerve compressions because of intervertebral disk prolapses. Reference values for erythrocytes were 11.49 +/- 3.48 mmol/mmol Hb; 0.82 +/- 0.087 mmol/mmol Hb; 9.01 +/- 2.20 mmol/mmol Hb; 0.104 +/- 0.032 mmol/mmol Hb; 0.07 +/- 0.050 mmol/mmol Hb for iron, copper, zinc, magnesium, and selenium, respectively. Postoperative erythrocyte concentrations did not differ significantly compared to those obtained preoperatively and remained within the reference ranges perioperatively. For plasma the following reference values were used: 19.0 +/- 8.0 mmol/l (Fe); 20.1 +/- 8.2 mmol/l (Cu); 15.4 +/- 4.6 mmol/l (Zn); 0.9 +/- 0.15 mmol/l (Mg); 1.02 +/- 0.3 mmol/l (Se). There was a significant decrease in the concentration of copper in plasma (13.41 +/- 3.46 mmol/l, p < 0.1) and zinc (10.73 +/- 2.73 mmol/l, p < 0.1) immediately postoperative, iron (10.56 +/- 3.91 mmol/l, p < 0.1) and zinc on day 1 (11.28 +/- 1.88 mmol/l, p < 0.10), and a significant postoperative increase of copper on day 5 (18.81 +/- 3.97 mmol/l, p < 0.1), postoperatively. The mean plasma concentrations of iron, copper, zinc magnesium and selenium remained within the reference ranges during the entire period.     

Measurement of zinc, copper, manganese, and iron concentrations in hair of pituitary dwarfism patients using flameless atomic absorption spectrophotometry

Pituitary dwarfism (hGHD) is known to be associated with trace element deficiency, which causes improper functioning of the involved endocrine system. Previously, we reported on the head hair concentrations of zinc, copper, manganese, and iron from a total of 418 normal subjects (154 male and 264 female). In this report, we analyzed the head hair concentrations of the same four trace metals of 103 hGHD children (60 male and 43 female) under treatment with human growth hormone (hGH). These subjects ranged in age from 5 to 18 yr. The results were compared with 338 agematched normal subjects (120 male and 218 female). Both male and female hGHD showed approx 1.7 times higher zinc concentrations than normal subjects. Cheruvanky et al. reported a similar trend but with a slightly lower difference between hGHD and normal subjects. The average copper content in the hair of both male and female subjects also showed higher values for the hGHD than for the normal subjects, a trend similar to the values reported by Teraoka et al. In the case of manganese, the concentrations in hair of the hGHD were approx 50% of the values in the normal subjects. Head hair concentrations of iron in the hGHD were commensurate with the normal subjects. Because the content of trace elements in hair varies with the age of subjects, as a control, we investigated the head hair concentration of zinc from 20 healthy girls ranging in age from 10 to 18 yr. The average zinc concentration decreased from 10 to 12 yr, but no clear relation to age was observed from 13 yr and older. These trends were similar to our previous report. The zinc concentration in hair and body weight gain over a year was negatively correlated. The age variation in the content of zinc, copper, manganese, and iron in hair was measured comparing hGHD with the normal subjects in various ages. Concerning the zinc-level variation of hGHD and normal subjects, there were conspicuous differences between hGHD and normal subjects. For copper, the variations in concentration with age were similar to zinc. Regarding the age variations for manganese, hGHD had lower concentrations in hair compared to the normal subjects throughout adolescence (11–18 yr). We have studied the effects between the hair and these trace element concentrations in hGHD before and after hGH administration. These results suggest that hGH affects the metabolism of these trace elements.     

Zinc and copper of fetal organs during the second trimester of pregnancy

In fetus with a mean gestational age of 18 weeks (range 15-25, n = 14), zinc and copper concentrations in liver, femur, rib, and skeletal muscle were measured. Zinc and copper concentrations are highest in liver. A trend of decreasing liver zinc concentrations during gestational age is suggested. Zinc concentrations are significantly correlated with copper concentrations in liver and in femur, suggesting steady growth in both organs. Femur zinc values rank ca. 30% of those in liver, femur copper, ca. 2%. Zinc or copper concentrations in rib are of the same levels as in skeletal muscle. Their concentration for zinc ranks ca. 20%, for copper, ca. 5% of the values in liver. All zinc and copper values are lower than reported in third trimester fetal organs. Calculated zinc/copper molar ratios are distinctive for the various organs: in liver, 6 +/- 1, in femur, 73 +/- 8, and in soft tissues, 26 +/- 3. Calculated ratios from published values obtained from the third trimester of pregnancy show that the ratios in liver and skeletal muscle maintain these levels. The zinc/copper molar ratio can serve as an internal reference in zinc and/or copper measurements.     

The relationship between zinc and copper status and lipid levels in African-Americans

Studies examining the role of zinc and copper nutriture as risk factors for cardiovascular disease in European Americans have produced conflicting results. This study assessed the associations between zinc and copper status and serum lipid levels in an adult African-American community. A cross-sectional study was conducted on 600 individuals (233 males, 367 females) from 25 to 65 yr of age using a random sampling design in a small city in Alabama. Anthropometric, dietary, and serum zinc, copper, and lipid measurements were made. The mean serum zinc and copper levels and dietary zinc intake were similar to that reported previously for European Americans. There were no significant associations between serum zinc, copper, or zinc/copper ratio and total serum cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), or triglyceride levels. For males, there was a small but significant association between dietary zinc and the total cholesterol/HDL-C ratio (r=−0.17, p=0.03). Similarly, females taking either zinc supplements or a multivitamin including zinc had higher HDL-C values than nonsupplementing females. Further prospective studies of the relationship between zinc status and lipid levels in African Americans are needed to verify these results.     

Indices of iron and copper status during experimentally induced,marginal zinc deficiency in humans

This study examined the effect of diet-induced, marginal zinc deficiency for 7 wks in 15 men (aged 25.3 +/- 3.3 yrs; mean +/- SD) on selected indices of iron and copper status. The regimen involved low-zinc diets based on egg albumin and soy protein with added phytate and calcium such that mean [phytate]/[Zn] and [phytate] X [Ca]/[Zn] molar ratios were 209 and 4116, respectively, for 1 wk, followed by 70 and 2000, respectively, for 6 wks. Subjects were then repleted with 30 mg Zn/d for 2 wks. Plasma copper, Cu,Zn-superoxide dismutase (Cu,Zn-SOD) activity in plasma and red blood cells (RBC), hemoglobin, hematocrit, and serum ferritin were determined weekly on fasting blood samples. Significant reductions (p less than 0.05) after 7 wks in RBC Cu,Zn-superoxide dismutase (49.5 +/- 7.2 vs 33.6 +/- 6.3 U/mg Hb) and serum ferritin (69.2 +/- 38.7 vs 53.8 +/- 33.7 micrograms/L) occurred; no comparable decline was noted for plasma Cu, hemoglobin, or hematocrit. Significant (p less than 0.05) but less consistent changes were also observed in plasma superoxide dismutase activity. None of the changes were associated with the decreases in plasma, urinary and hair zinc concentrations, and alkaline phosphatase activity in RBC membranes. Results indicate that the biochemical iron and copper status of the subjects was marginally impaired, probably from the dietary regimen that induced marginal zinc deficiency.     

Tryptophan, copper and zinc in hair of healthy subjects. Correlation with differences in hair pigmentation

Tryptophan, copper and zinc levels were determined in the hair of 300 healthy subjects divided by sex, age and hair colour. Sex influences tryptophan content in hair, the levels of this amino acid being higher in males than in females. Tryptophan is also higher in infancy (2-5 years) and in both males and females aging around 80 years and over. Hair colour also influences tryptophan levels, which increase from fair to black hair. Copper levels are similar in hair of both males and females, while those of zinc are higher in women. Age influences the distribution of these two metals in human hair. Copper contents in hair of males are higher at the age 20-40 years. In females, values decrease over the age of 60 years. Instead, zinc levels are higher between 20 and 60 years in males, and between 13 and 19 years in females. As regards hair colour, copper is slightly higher in black hair in males and in fair hair in females, and lower in white hair in both sexes. Zinc values appear to be higher in red and lower in white hair in males. In females they are higher in black hair.     

Prevalence of zinc deficiency in junior high school students of Tehran City

Zinc deficiency is a health problem in many communities especially among adolescents because of pubertal growth sprout. This investigation was carried out to determine the epidemiology of zinc deficiency in junior high school students in Tehran City in 1997. This cross-sectional study was performed on 881 students (452 males and 429 females) with the mean age of 13.2±1.0 yr, who were selected by multistage random sampling method. Plasma, erythrocyte, and hair zinc levels were assayed by flame atomic absorption spectrophotometry. Anthropometric and demographic characteristics were measured and recorded on a questionnaire. Dietary intakes were evaluated by a 24-h recall method. Zinc deficiency was defined as having at least two indices from indices of erythrocyte, plasma, and hair zinc below 10 μg/mL, 100 μg/dL, and 125 μg/g of hair, respectively. The results showed that zinc deficiency prevalence was 31.1% (confidence interval: 28–34.4%). Zinc deficiency was 65%, 49%, and 1.3% based on plasma, erythrocyte, and hair zinc levels, respectively. The mean ± SD for plasma, erythrocyte, and hair zinc concentration, height-for-age, as well as weight-for-age Z scores were 95.2±17.7 μg/dL, 10.3±2.3 μg/mL, 239.4±54.4 μg/g, −0.40±0.92, and 0.12±0.91, respectively. As for dietary intake compared with the RDA, 50% of the subjects consumed less than 50% of their requirement for zinc RDA based on a 24-h dietary recall. Zinc intake in subjects was 7.5±3.7 μg, that in boys was higher than in girls. Correlation coefficients between zinc status indices were very weak. There was neither a linear nor nonlinear relationship between biochemical parameters and nutritional zinc intake. It is concluded that almost one-third to one-half of the subjects would be considered zinc deficient.     

Zinc and copper modulate differentially the P2X4 receptor

The rat ATP P2X4 receptor was expressed in Xenopus laevis oocytes to assess the effect of zinc and copper as possible regulators of purinergic mechanisms. ATP applied for 20 s evoked an inward cationic current with a median effective concentration (EC50) of 21.4+/-2.8 microM and a Hill coefficient (nH) of 1.5+/-0.1. Coapplication of ATP plus 10 microM zinc displaced leftward, in a parallel fashion, the ATP concentration-response curve, reducing the EC50 to 8.4+/-1.8 microM (p < 0.01) without altering the receptor nH. The zinc potentiation was fast in onset, easily reversible, and voltage-independent and did not require metal preexposure. The zinc EC50 was 2-5 microM, with a bell-shaped curve. At concentrations of 100-300 microM, zinc produced less potentiation, and at 1 mM, it inhibited 50% the ATP current. The effect of zinc was mimicked by cadmium. In contrast, copper inhibited the ATP-evoked currents in a time- and concentration-dependent fashion, reducing the maximal current (Imax) without altering the EC50. The copper-induced inhibition was slow in onset, slowly reversible, and voltage-independent. Whereas coapplication of 300 microM copper plus ATP reduced Imax to 36.2+/-5%, the coapplication of, or 60-s preexposure by, 10 microM copper reduced Imax to 79+/-9.2% (p < 0.05) and 39.6+/-8.7% (p < 0.01), respectively. The inhibition was noncompetitive in nature and mimicked by mercury. Cobalt, barium, and manganese did not modify significantly the ATP-evoked current, demonstrating metal specificity. The simultaneous 1-min preapplication of both metals revealed that the 10 microM zinc-induced potentiation was obliterated by 10 microM copper, whereas 30 microM copper not only reduced the potentiation, but inhibited the ATP response. Following coapplication of both metals for 20 s with ATP, at least 100 microM copper was required to counteract the 10 microM zinc-induced potentiation. The simultaneous preincubation with both metals provided evidence for a noncompetitive interaction. We hypothesize the existence of metal binding site(s), which are most likely localized in the extracellular domain of the P2X4 receptor structure. These sites are selective and accessible to extracellular metal applications and bind micromolar concentrations of metals. The present results are compatible with the working hypothesis that trace metals, such as copper and zinc, are physiological modulators of the P2X4 receptor. The modulation of brain purinergic transmission by physiologically and toxicologically relevant trace metal cations is highlighted.     

Obesity and low back pain

Obesity and low back pain (LBP) are common health problems among patients attending Primary Health Care (PHC) in general practice at the United Arab Emirates (UAE). The objective of this study was to determine whether obesity is associated with low back pain. A cross-sectional face-to-face interview questionnaire survey was conducted. The questionnaire was a modified version of the Roland-Morris Scale for evaluating back disability. The interviews were conducted in Arabic by qualified nurses. A multi-stage stratified sample 1,103 UAE national aged 25-65 years, who attended PHC clinics for any reason, were invited to participate but only 802 subjects were eligible to be included for the statistical analysis. The data were analyzed using univariate and multivariate statistical methods. Of the 802 subjects, 428 (53.4%) were males and 374 (46.6%) were females. The mean age of the males was 40.5 +/- 11.5 years and females was 38.2 +/- 10.5 years (p = 0.004). The mean BMI of the males was 26.4 +/- 7.4 and females was 27.8 +/- 5.6 (p = 0.002). The overall prevalence of LBP in the present study was 64.9% (95% confidence interval, 61.0-68.8) and respectively, 56.1% in males and 73.8% in females. The results revealed that there was association between BMI and some socio-demographic variables with the respect of with low back pain. Back pain had more influence on the life style habits on females than in males. Stepwise multiple regression analysis showed that only age (p < 0.0001), educational level (p = 0.001), gender (p = 0.002), place of living (p = 0.019), BMI (p < 0.0001), and housing condition (p = 0.02) had significant effect on the presence of LBP in patients. The present study showed that obesity is moderately associated with low back pain.     

Urinary levels of metallothioneins and metals in subjects from a semiindustrialized area in Tarragona Province of Spain

The monitoring of heavy metals is important if adverse effects on health are to be avoided. In humans, metallothionein (MT) has been used as a biomonitor for the assessment of cadmium (Cd). In the present study, subjects drawn from the population of Tarragona Province (NE Spain) were investigated. Urinary MT, zinc (Zn), and copper (Cu) concentrations, corrected for creatine concentrations, were determined in 625 samples from healthy subjects aged between 10 and 65 yr. Mean values of MT and Cu in females were higher than those in males, with levels of 29.5 (23.8) vs. 22.7 (24.9) μg MT/creatinine (p<0.001) and 4.8 (6.1) vs 3.4 (4.9) μg Cu/g creatinine (p<0.001). No differences between males and females were observed with respect to urinary Zn: 78.0 (66.4) vs 73.0 (85.5) μg/g creatinine, respectively (p=0.332). Significantly higher MT, Zn, and Cu values were observed in the females aged 15–19 yr and, in the age group of 50–54 yr, only in the Zn and Cu values, when compared with those in males. Significant positive correlations of MT vs Zn and Cu as well as correlations of Zn vs Cu levels were observed in both genders. The present findings confirm the proposed role of MT as a biomonitor of mineral status.     

Heavy metals in relation to the biology of the mummichog, Fundulus heteroclitus

Heavy metal levels of cadmium, copper, mercury, manganese, and zinc were examined in the mummichog, Fundulus heteroditus from industrialized and non-industrialized environments. With one exception, the environment with the highest trace metal in its waters, had the fishes with the highest metal concentration. Except for mercury, the concentration factor varied inversely with the metal concentrations of the fish and water, suggesting a possible regulatory mechanism for metals in the tissues of mummichogs from environments with high metal concentrations. There was an inverse relationship between standard length and concentrations of zinc, manganese, copper and cadmium in whole male and female fishes. The viscera contained significantly greater concentrations of these metals than somatic muscle tissue. There were also significant differences between males and females with respect to whole-body zinc and copper concentrations, but no sex differences for manganese and cadmium.     

Trace element status in Saudi patients with established atherosclerosis

BACKGROUND: Traditional coronary risk factors do not fully explain variations in the incidence of cardiovascular disease (CVD). Epidemiological studies have implicated perturbations in selenium, copper, and zinc metabolism in the aetiology of CVD. However, these studies have been principally undertaken in Caucasian populations, in whom trace element intake is generally sufficient. METHOD: We have measured serum and urine selenium, copper, and zinc; and superoxide dismutase, glutathione peroxidase, and lipid peroxide concentrations in 130 Saudi male subjects with established CVD, and 130 age-matched controls. RESULTS: Diabetes mellitus, positive smoking habit (p<0.0001 for both), and hypertension (p<0.05) were more prevalent among CVD patients. Urinary copper (p<0.0001) and zinc (p<0.05) were higher among controls. Serum selenium concentrations were lower among CVD patients (p<0.001), and a high proportion (52%) had selenium levels below 79mug/L compared to controls (22%) (p<0.0001). Conditional logistic regression analysis, showed the characteristics differentiating CVD patients from controls were serum zinc (odds ratio (OR) 0.92, confidence interval (CI) 0.85-0.99, p<0.05), serum copper/zinc ratio (OR 0.31, CI 0.10-0.96), serum selenium (OR 0.07, CI 0.02-0.31, p<0.0001), and urine selenium (OR 3.34, CI 1.40-7.99, p<0.01). CONCLUSION: Measures of trace metals status appear to be associated with the risk of atherosclerosis in a Saudi male population.     

The relationship between established coronary risk factors and serum copper and zinc concentrations in a large Persian Cohort

IntroductionThe relationship between demographic and biochemical characteristics, including several established coronary risk factors, and serum copper and zinc was assessed in a large Iranian population sample.Materials and methodsA group of 2233 individuals, 15–65 years of age [1106 (49.5%) males and 1127 (50.5%) females] was recruited from residents of the Greater Khorasan province in northeast of Iran. Demographic data were collected using questionnaires. Coronary risk factors were determined using standard protocols, and trace elements were measured in serum using atomic absorption spectroscopy.ResultsDegree of glucose tolerance and smoking habit were not associated with serum zinc and copper levels. Serum copper levels were significantly higher in obese and hypertensive than in normal subjects (p<0.001). In the whole group and for the female subgroup, serum zinc (p<0.01) and copper (p<0.001) were both significantly lower in individuals with normal versus high levels of low-density lipoprotein cholesterol.A strong positive correlation was found between serum copper and body mass index (BMI) (r=0.85, p<0.001). Weaker positive associations were found between serum copper and calculated 10 years’ coronary risk (r=0.11, p<0.001). Serum zinc/copper ratio was strongly inversely associated with calculated 10 years’ coronary risk (r=?0.10, p<0.001). The partial Eta squared (PES) values for factors determining serum zinc were hypertension (0.007, p=0.01) and BMI (0.004, p=0.01); and for serum copper, they were gender (0.02, p=0.001), hypertension (0.004, p=0.009), and 10 years’ coronary risk for men (0.003, p=0.03) and women (0.002, p=0.07).ConclusionSignificant associations between serum trace element concentrations and several coronary risk factors, including calculated 10 years’ coronary risk scores, were found.     

Influences of calorie restriction and age on energy expenditure in the rhesus monkey

Caloric restriction (CR) is known to retard the aging process, and a marker of aging is decreased energy expenditure (EE). To assess longitudinal effects of CR on EE in rhesus monkeys (Macaca mulatta), data from 41 males (M) and 26 females (F) subjected to 9 or 15 yr of CR were studied. EE and body composition of monkeys 11-28 yr of age were measured using indirect calorimetry and dual X-ray absorptiometry. Total EE (24-h EE) was divided into daytime (day EE), nighttime (night EE), and daytime minus nighttime (D - N EE). M calorie-restricted monkeys showed a lower 24-h EE (means +/- SD = 568 +/- 96 kcal/day, P < 0.0001) than controls (C; 630 +/- 129 kcal/day). Calorie-restricted M had a lower night EE (difference = 36 kcal P < 0.0001) compared with C M, but after adjusting for FFM and FM, night EE was not different between calorie-restricted and C males (P = 0.72). The 24-h EE decreased with age (13 kcal decrease/yr, P < 0.0001), but there was no difference between CR and C. Adjusted for FFM and FM, D - N EE decreased with age (9 kcal/yr, P < 0.0001), with no interaction with age (P = 0.72). The F were compared with age-matched M selected from the male cohort. F had a lower 24-h EE (496 +/- 84 kcal/day) than M (636 +/- 139 kcal/day) (P < 0.0001). Adjusting for FFM and FM, night EE was lower in F compared with M (difference = 18 kcal, P = 0.077). Night EE did not differ between calorie-restricted and C younger monkeys after adjusting for FFM and FM. In conclusion, CR did not alter the age-related decrease in EE with CR.     

Effect of zinc supplementation on serum leptin levels and insulin resistance of obese women

Leptin is thought to be a lipostatic signal that contributes to body weight regulation. Zinc might play an important role in appetite regulation and its administration stimulates leptin production. However, there are few reports in the literature on its role on leptin levels in the obese population. The present work assesses the effect of zinc supplementation on serum leptin levels in insulin resistance (IR). A prospective double-blind, randomized, clinical, placebo-controlled study was conducted. Fifty-six normal glucose-tolerant obese women (age: 25-45 yr, body mass index [BMI] = 36.2 +/- 2.3 kg/m2) were randomized for treatment with 30 mg zinc daily for 4 wk. Baseline values of both groups were similar for age, BMI, caloric intake, insulin concentration, insulin resistance, and zinc concentration in diet, plasma, urine, and erythrocytes. Insulin and leptin were measured by radioimmunoassay and IR was estimated by the homeostasis model assessment (HOMA). The determinations of zinc in plasma, erythrocytes, and 24- h urine were performed by using atomic absorption spectrophotometry. After 4 wk, BMI, fasting glucose, and zinc concentration in plasma and erythrocyte did not change in either group, although zinc concentration in the urine increased from 385.9 +/- 259.3 to 470.2 +/- 241.2 +/- microg/24 h in the group with zinc supplementation (p < 0.05). Insulin did not change in the placebo group, whereas there was a significant decrease of this hormone in the supplemented group. HOMA also decreased from 5.8 +/- 2.6 to 4.3 +/- 1.7 (p < 0.05) in the zinc-supplemented group but did not change in the placebo group. Leptin did not change in the placebo group. In the zinc group, leptin was 23.6 +/- 12.3 microg/L and did not change. More human data from a unique population of obese individuals with documented insulin resistance would be useful in guiding future studies on zinc supplementation (with higher doses or longer intervals) or different measures.     

Sex differences in abdominal, gluteal, and thigh LPL activity

Lipoprotein lipase (LPL) activity is necessary for adipocytes to take up triglycerides from the circulation, and regional differences in LPL activity could help determine regional fat storage. LPL activity has been reported to increase as a function of fat cell size, but this issue has not been extensively evaluated in different depots comparing sexes. Our objective was to determine whether sex alters the relationship between LPL activity and fat cell size. Subcutaneous adipose tissue biopsies were taken from the abdomen and thigh after an overnight fast and 1 h after a meal in 65 females (BMI 25.4 +/- 0.8, means +/- SE) and 41 males (BMI 23.7 +/- 0.3); gluteal adipose samples were obtained in 47 of the females and 27 of the males. Fat cell size was greater in females than males in thigh (P < 0.005) and gluteal (P < 0.05) regions but not in the abdomen. There was a relationship between fasting LPL activity/fat cell and fat cell size in females (abdomen r2 = 0.52, P < 0.0001; gluteal r2 = 0.23, P < 0.005; thigh r2 = 0.19, P < 0.005). In males, this relationship was seen only in the abdomen (r2 = 0.51, P < 0.0001) and thigh (r2 = 0.17, P < 0.05). Males and females had a significantly different relationship in the thigh only in the fasted state. Similar results were found in the fed state, although the strength of the relationship decreased in the abdominal regions for females only. This suggests fundamental differences in the regulation of triglyceride uptake between males and females and adipose regions.     

Associations between Serum C-reactive Protein and Serum Zinc, Ferritin, and Copper in Guatemalan School Children

Inflammation affects trace nutrient concentrations, but research on copper and particularly in children is limited. We assessed associations between serum C-reactive protein (CRP) and zinc, iron, copper, and other biomarkers (alkaline phosphatase, hemoglobin, and albumin), in 634 healthy 6- to 11-year-old Guatemalan schoolchildren. CRP was measured by a standardized, high-sensitive method. For significant associations with CRP, we stratified nutrient concentrations across categories of CRP and compared concentrations above and below several CRP cutoff points (0.5, 1, 3, 5, and 10 mg/L), and then adjusted values using correction factors (ratios of geometric means of the nutrients in the low and high groups). Prevalence of serum zinc (<65 μg/dL0, ferritin (<15 μg/L), and copper (<90 μg/dL) deficiency were 21%, 2.1%, and 23.8%, respectively. Median (25th and 75th percentiles) CRP was 0.56 (0.26 and 1.54) mg/L. CRP concentration was positively associated with ferritin and copper concentrations (r = 0.23 and 0.29, respectively; P < 0.0001) but not with zinc and other biomarkers (P > 0.05). Regardless of CRP cutoffs, high (> cutoff) vs. low (≤ cutoff) CRP levels had higher ferritin and copper concentrations and lower prevalence of copper deficiency of <90 μg/dL (P < 0.05). Adjustment for inflammation had the greatest influence on recalculated prevalence for the CRP 0.5 mg/L cutoff. The low ferritin prevalence hardly changed (from 2.1% to 2.5%) while the low copper prevalence changed appreciably (from 23.8% to 31.2%). In conclusion, CRP was positively associated with ferritin and copper but not with zinc concentrations. Adjustment for inflammation had little effect on low ferritin prevalence, low to begin with, and a large impact on low copper prevalence. High-sensitive CRP methods and the use of very low CRP cutoffs may be more accurate than traditional CRP methods in the adjustment of serum copper concentrations for inflammation in healthy school children.     

High intensity physical exercise induced effects on plasma levels of copper and zinc

Physical exercise leads to many metabolic, cardiovascular, and muscular changes in the body. The trace elements (TE) zinc and copper are directly involved, as enzymatic cofactors, in many of these processes, especially those related to nutrients metabolism, oxygen transport, and formation of usable energy. The effects of high-intensity physical exercise on plasma levels of CU²⁺ and Zn²⁺ in 19 subjects are investigated (9 males and 10 females). Plasma copper concentration decreases, and plasma zinc concentration increases, after exercise, in both sexes. After 30 min recovery, both TE concentration values shifts-toward rest values in both sexes. These results only partially agree with literature data, probably because we used the treadmill exercise, which makes many muscles work, whereas other authors made their subjects perform a cycloergometer exercise. Physical exercise causes a marked redistribution of TE (copper and zinc) between body stores, bloodstream, and tissues. The condition of high metabolism may lead to a deficiency of TE, requiring supplementation in order to maintain high level performance.