Effects of a multivitamin mineral supplement on zinc and copper status during pregnancy

The effect of a multivitamin-mineral supplement was investigated during pregnancy according to a double-blind protocol by determining zinc and copper in maternal plasma, mononuclear and polynuclear zinc and copper at the third, sixth, eighth, and ninth months of gestation. The subjects were supplemented from the first trimester until delivery. A significant decrease was observed in plasma zinc that varied from 11.5 μmol/L to 10.8 μmol/L in the supplemented group (n=29) and from 11 μmol/L to 10 μmol/L in the placebo group (n=33) at 3 and 9 mo of gestation, respectively. In contrast, plasma copper levels increased in a way depending upon the stage of gestation in both groups: from 24.7 to 28.2 μmol/L in the treated group and from 24.9 to 30.9 μmol/L in the placebo group at 3 and 9 mo of gestation, respectively, but the difference was only significant in the placebo group. No difference between groups was observed in mononuclear and polynuclear zinc or copper levels. These trace elements were also determined in cord blood at delivery. There were no statistically significant differences in zinc and copper concentration found in placebo group and supplemented group. Finally, the beneficial effect of supplementation on muscular cramps and appearance of vergetures was noted.     

Serum and liver zinc,copper, and iron in chicks infected withEimeria acervulina orEimeria tenella

Two-wk-old broiler chicks were inoculated via crop intubation withEimeria acervulina at two doses: 10⁵ or 10⁶ sporulated oocysts/bird or withEimeria tenella at a dose of 10⁵ sporulated oocysts/bird. Serum and liver samples were collected on days 3 and 6 post-inoculation (PI). There were no significant changes in serum or liver zinc, copper, and iron concentrations in any of the infected groups by 3 d PI. However, on d 6, PI serum protein was significantly reduced in all of the infected groups compared to their pair-fed controls. The chicks infected withE. tennella had significantly reduced serum zinc (1.20 vs 1.77 μg/mL) and iron (0.44 vs 1.28 μg/mL) concentrations and significantly elevated serum copper (0.28 vs 0.17 μg/mL) and ceruloplasmin levels (20.33 vs 11.11 μg/mL) compared to their pair-fed counterparts. Those chicks infected withE. acervulina (10⁶ oocysts/bird) exhibited significantly reduced serum iron concentration by 6 days PI (0.90 vs 1.14 μg/mL). Liver zinc was significantly increased in the chicks infected withE. tenella (349 vs 113 μg/g dry liver wt), as was copper (24 vs 19 μg/g), whereas liver iron concentration was significantly reduced (172 vs 243 μg/g) compared to pair-fed controls. At both dose levels, the chicks infected withE. acervulina exhibited a significant reduction in liver iron by 6 d PI. Hepatic cytosol metals generally reflected whole tissue levels. Metallothionein (MT)-bound zinc was significantly elevated in the chicks infected withE. tenella. Iron bound to a high molecular weight, heat-stable protein fraction (presumably cytoplasmic ferritin) was significantly reduced in chicks infected withE. acervulina, as well as those infected withE. tenella. Collectively, the changes in serum zinc, copper, and iron concentrations, as well as the changes in hepatic zinc and MT-zinc concentrations in the chicks infected withE. tenella were similar to changes evoked during an acute phase response to infection. It is possible that a secondary bacterial infection or inflammation stemming from erosion of the lining of the cecum may play a role in the response of trace element metabolism to theE. tenella infection. Mentions of a trademarkr, proprietary product or specific equipment does not consitute a guarantee or warranty by the US Department of Agriculture and does not imply its approval to the exclusion of other products.     

Trace-elements status in camels

Data relating to trace-elements status in camels is scarce, from both a clinical and biochemical point of view. Clinical deficiency or toxicity has rarely been described in this species. However, there is a some evidence that camels are sensitive to trace element disorders in the same way as other ruminants. For example, copper deficiency in camels has been reported in East Africa. Normal plasma level is comparable to cattle (70–120 mg/100 mL). Camels appear to maintain zinc levels at a lower value than other domestic ruminants (<60μg/100 mL). Iron metabolism is more active in the liver than in the spleen. Data concerning manganese levels are possibly unreliable. Some cases of selenium deficiency (white muscle disease) have been reported. No data are available for cobalt status in camels. Finally, camels appear to be more sensitive to iodine deficiency than the other domestic ruminants.     

Zinc,copper, selenium,and glutathione peroxidase in blood of 11-yr-old dunedin,New Zealand children

Blood was obtained from 564 11-yr-old children who had participated since birth in a multidisciplinary health and development study. Serum zinc concentration did not differ between the boys and the girls (mean±SD: 91=17 μg/100 mL,n=453). Five-6% of serum zinc values were low; although there was a weak correlation with height, none of the boys with low values were below the 10th percentile for height for this group. Serum copper concentration (112±24 μg/100 mL,n=454) was unrelated to sex, height, weight, body mass index, socioeconomic status (SES), or iron status. Blood selenium concentration (49±10 ng/mL,n=564) was lower than previously reported for Dunedin children; it was higher in children in the lower SES categories. The data represent normal values for healthy, 11-yr-old NZ children.     

Effect of dietary nickel and iron on the trace element content of rat liver

The level and/or form of dietary iron, dietary nickel, and the interaction between them affected the trace element content of rat liver. Livers were from the offspring of dams fed diets containing 10–16 ng, or 20 μg, of nickel/g. Dietary iron was supplied as ferric chloride (30 μg/g) or ferric sulfate (30 μg, or 60 μg). In nickel-deprived rats fed 60 μg of iron/g of diet as ferric sulfate, at age 35 days, levels of iron and zinc were depressed in liver and the level of copper was elevated. At age 55 days, iron was still depressed, copper was still elevated, but zinc also was elevated. In rats fed 30 μg of iron/g of diet as ferric chloride, liver iron content was higher in nickel-deprived than in nickel-supplemented rats at 30, but not at 50, days of age. Also manganese and zinc were lower in nickel-deprived than in nickel-supplemented rats at age 35 days if their dams had been on experiment for an extended period of time (i.e., since age 21 days). Thus, the levels of copper, iron, manganese, and zinc in liver were affected by nickel deprivation, but the direction and extent of the affects depended upon the iron status of the rat.     

Maternal and neonatal scalp hair concentrations of zinc, copper, cadmium, and lead

Postpartum scalp hair samples from 82 term-pregnancy mother/neonate pairs were analyzed for their concentration of zinc (Zn), copper (Cu), cadmium (Cd), and lead (Pb), using inductively coupled plasma-mass spectrometry. Maternal and neonatal Zn concentrations had geometric means (and 99% confidence intervals) of 122.5 μg/g (117.9–131.5 μg/g) and 146.9 μg (141.5–156.7 μg/g) respectively. Corresponding Cu values were 18.4 μg/g (17.6–23.8 μg/g) and 6.7 μg/g (6.3–7.6 μg/g). Those of Cd were 0.49 μg/g (0.47–0.69 μg/g) in the mothers and 0.57 μg/g (0.55–0.86 μg/g) in the neonates. For Pb, they were 7.95 μg/g (7.60–9.32 μg/g) and 4.56 μg/g (4.39–5.56 μg/g). Cigaret smoking, despite its relatively low prevalence (19.5%), was associated with lower Zn and higher Cd and Pb concentrations and in lower Zn/Cd and Zn/Pb molar concentration ratios. Smoking also altered interelemental relationships, particularly those of Zn with Cd and Pb and those between Cd and Pb. Smoking frequency appeared to show negative dose-response effects on maternal and neonatal Zn concentrations, Zn/Pb molar concentration ratios, and birth weight. Mothers with a history of oral contraceptive (OC) usage had significantly higher Cu concentrations and lower Zn/Cu molar concentration ratios than nonusers, with the highest Cu concentrations and lowest Zn/Cu values being associated with third-generation OCs. No similar effects were elicited in the respective neonatal Cu concentrations. Neither alcohol consumption nor prenatal supplementation with iron and/or folic acid had discernible effects on the maternal or neonatal elemental concentrations. The data from this study suggest that in a given population of term-pregnancy mothers and neonates, significant interindividual variations in hair trace element concentrations can occur, irrespective of commonality of general environment, and that lifestyle factors, including cigaret smoking and OC usage history, can be significant contributory factors to such variations. The data are discussed in relation to the effects of smoking-associated exposure to Cd and Pb exposure on Zn availability for placental transfer, as well as on the quantitative maternal Zn supply levels to the fetus resulting from the known tendency of smokers to have lower dietary intakes of Zn. The higher Cu concentrations in OC users are discussed in relation to altered Cu metabolism, characterized by increased synthesis of the Cu-binding protein, ceruloplasmin, as an acute-phase antioxidant response to altered lipid profile and increased lipid oxidation.     

Metabolism and Tissue Distribution of Trace Elements in Broiler Chickens' Fed Diets Containing Deficient and Plethoric Levels of Copper,Manganese, and Zinc

Supplementation of broiler diets with copper, manganese, and zinc at levels higher than that stipulated by the National Research Council 1994 reportedly improved live weight, feed conversion, and cured leg abnormality supposedly caused by inadequate intake of Mn and Zn. The objective of the study was to ascertain the effects of plethoric supplementation of copper (Cu), manganese (Mn), and zinc (Zn) on performance and metabolic responses in broiler chickens. The study also aimed to discriminate the responses of the birds when the mineral elements were supplemented either in an inorganic or in an organic form. Cobb 400 broiler chickens (1-day old, n = 300) were assigned to three dietary treatments each containing nine replicates with ten birds for 39 days. The treatments included a control in which the diet was devoid of supplemental trace elements and treatments supplemented with an inorganic trace element premix (ITM) and supplemented with a combination of the inorganic and an organic trace element premix (OTM). The ITM contained (per kilogram) copper, 15 g; iron, 90 g; manganese, 90 g; zinc, 80 g (all as sulfated salts); iodine (as potassium iodide), 2 g; and selenium (as sodium selenite), 0.3 g. The OTM on the other hand, contained copper, 2.5 g; iron, 15 g; manganese, 15 g; zinc, 13.33 g; and chromium, 0.226 g (all as protein chelates). Plethoric supplementation of trace elements improved live weight gain and feed/gain ratio (p < 0.05). Leg abnormality developed in the 16% of the control group of birds but not in the supplemented group. Metabolizability of dry matter, organic matter, and protein was higher (p < 0.01) in the ITM and OTM groups. Excretion of Cu, Fe, and Zn decreased (p < 0.1) due to supplementation of the trace elements leading to increased apparent absorption of the said mineral elements (p < 0.01). Concentration of the concerned trace elements in serum, liver, and composite muscle samples was higher (p < 0.05) in the ITM and OTM dietary groups indicating an increased deposition of the said mineral elements due to supplementation. Although the study revealed subtle difference between the inorganic and organic mineral premixes with regards to the parameters mentioned above, it became apparent that it is possible to reduce excretion of these trace elements by a judicious escalation in the level of supplementation. The results of the present investigation further revealed that the trace mineral requirement of broiler chickens suggested by the National Research Council may not be optimum to support the maximum growth potential of the high yielding strains, and it is reasonable to consider a review of the current NRC recommendations to meet the needs of the modern birds.     

Significance of serum trace element status in patients with rheumatic heart disease

It is known that certain trace elements can affect various heart diseases. In this study, we aimed to evaluate the changes in concentrations of certain serum trace elements in patients with chronic rheumatic heart disease (RHD). Serum analysis of selenium (Se), zinc (Zn), and copper (Cu) trace elements was assayed by atomic absorption spectrophotometry. RHD patients had significantly lower serum concentrations of Se and Zn than control subjects (p<0.05 and p<0.001, respectively). However, the serum Cu concentration was significantly higher in RHD patients than in controls (1.93±0.59 μg/L vs 1.06±0.29 μg/L; p<0.001). Similarly, the Cu/Zn ratio in RHD patients was higher than in control subjects (4.70±0.92 vs 1.68±0.45; p<0.001). Additionally, no significant correlation was found among these trace element concentrations and the functional capacity classes (p>0.05). RHD patients had decreased serum Se and Zn element concentrations and increased serum Cu element concentration. We suggest that Se and Zn deficiency might be contributory factors in the development of rheumatic heart disease, and a high Cu concentration and a high Cu/Zn ratio might reflect an ongoing inflammatory process in this disease.     

Effects of Multivitamin/Mineral Supplementation on Trace Element Levels in Serum and Follicular Fluid of Women Undergoing in Vitro Fertilization (IVF)

We investigated effects of multivitamin/mineral supplementation on element levels in serum and follicular fluid of women undergoing IVF. We used three groups in this study. The first group was used as an age-matched and nonpregnant control (n = 13). Group 2 (n = 30) constituted the IVF group and women in the third group who were undergoing IVF also received a multivitamin/mineral tablet daily for 45 days. Follicular fluid and serum selenium and zinc levels and follicular fluid copper levels were lower in IVF patients than in controls although follicular fluid aluminum and iron levels were higher in IVF patients than in controls. However, follicular fluid and serum aluminum, copper, zinc and selenium levels, and serum magnesium levels were higher in the multivitamin/mineral group than in the IVF group although follicular fluid iron levels were lower in the multivitamin/mineral group than in the IVF group. In conclusion, we observed that copper, zinc, and selenium in serum and follicular fluid decreased in women undergoing IVF. Multivitamin/mineral supplementation in serum and follicular fluid of women undergoing IVF normalized the trace element levels.     

The effect of variable magnesium intake on potential factors influencing endurance capacity

Rats fed a magnesium (MG) deficient diet have a lower endurance capacity than rats fed Mg adequate diets. The current study evaluates the effects of marginal, moderate, and severe Mg deficiencies on physiological and biochemical changes that may contribute to the reduced endurance capacity of Mg deficient rats. Variable levels of dietary Mg (400, 200, 100, 50 μg/g) were fed for 23 d to 5-wk-old male Osborne-Mendel rats. Indirect blood pressure and heart rate were measured during dietary treatment. Forty-eight hours after an endurance test, rats were killed and sampled for plasma glucose, insulin, and triglyceride levels. Organ weights, mineral and trace element concentrations, and carcass composition were determined. Blood pressure was lower in rats fed 50 and 100 ppm Mg during the first half of the study than in controls (400 ppm Mg). There were no significant differences in blood pressure among groups at the end of the study. Heart rate was not affected by dietary Mg intake. Plasma insulin was lowered by decreasing dietary Mg; however, plasma glucose and triglyceride concentrations were not affected by dietary Mg intake. Rats fed 100 and 50 ppm Mg diets had significantly higher calcium concentrations in plasma and gastrocnemius muscle than controls. Dietary Mg variably affected tissue trace element (iron, zinc, copper, and manganese) concentrations but did not affect Mg concentrations in any organ studied. Body composition was significantly altered by dietary Mg intake. In conclusion, variable Mg intake differentially affects the parameters evaluated. Thus, the decreased endurance capacity of the Mg deficient rat is apparently not the result of a single biochemical lesion but is likely to be multifactorial.     

Regional distribution of metallothionein, zinc, and copper in the brain of different strains of rats

The regional brain distribution of metallothionein (MT), zinc, and copper in the brain was determined in nine anatomical regions (olfactory bulb, cortex, corpus striatum, hippocampus, thalamus plus hypothalamus, pons plus medulla oblongata, cerebellum, midbrain, and white matter) and was compared between two different strains of rat (Sprague-Dawley [SD] and Lewis). No significant difference was observed in the whole-brain MT level between the two strains (17.8 ± 3.4 μg/g in SD rats and 20.3 ± 2.3 μg/g in Lewis rats). In SD rats, however, MT was more highly expressed in the white matter than in the other regions studied. In contrast, MT concentration was highest in the cortex and lowest in the olfactory bulb in Lewis rats. The MT levels in the cortex, corpus striatum, hippocampus, and thalamus plus hypothalamus were significantly lower in SD rats than in Lewis rats. In both strains, the olfactory bulb contained markedly higher levels of both zinc and copper than the other regions (27.9 ±6.8 μg/g zinc in SD rats and 27.6 ± 6.9 μg/g zinc in Lewis rats, and 5.2 ± 1.5 μg/g copper in SD rats and 11.1 ± 4.8 μg/g copper in Lewis rats). The next high-est zinc levels were seen in the hippocampus, whereas the next highest copper levels were in the corpus striatum in both SD and Lewis rats. The high levels of zinc and copper in the olfactory bulb were not accompanied by concomitant high MT concentrations. These results indicate that the strain of rat as well as the anatomical brain region should be taken into account in MT and metal distribution studies. However, the highest concentrations of zinc and copper in olfactory bulb were common to both SD and Lewis rats. The discrepancy between MT and the metal levels in olfactory bulb suggests a role for other proteins in addition to MT in the homeostatic control of zinc and copper.     

Selenium depletion in patients on home parenteral nutrition

Severe selenium (Se) depletion was found in nine patients receiving long-term home parenteral nutrition because of short bowel syndrome. Plasma Se ranged from 0–0.51 (median 0.21 μmol/L) and erythrocyte Se ranged from 0.7–2.6 (median 1.8 μmol/gHgb), which was significantly lower than in the controls. Glutathione peroxidase (GSHPx) in plasma and erythrocytes was also decreased. After bolus injections with 200 μg Se/d in the form of sodium selenite for 4 mo, followed by 100 μg/d for 8 mo, plasma Se increased to values slightly but significantly higher than in the controls. Erythrocyte Se reached normal levels in most of the patients after 4 mo substitution, but it remained lower than in the controls. Following Se supplementation, plasma and erythrocyte GSHPx did not differ between patients and controls. These data suggest that all patients receiving long-term parenteral nutrition because of short bowel syndrome should receive at least 100 μg sodium selenite/d when given as bolus injections to avoid Se depletion.     

Trace Elements Status in Selenium-Deficient Rats—Interaction with Cadmium

Although the metabolic and toxicological interactions between essential element selenium (Se) and toxic element cadmium (Cd) have been reported for a long time, the experimental studies explored mostly acute, high-dose interactions. Limited data are available regarding the effects of Se-deficiency on toxicokinetics of cadmium, as well as on the levels of key trace elements—copper, zinc, and iron. In the present study, male and female Wistar weanling rats (n = 40/41) were fed either Se-deficient or Se-adequate diet (<0.06 or 0.14 mg Se per kilogram diet, respectively) for 12 weeks, and from week 9 were drinking water containing 0 or 50 mg Cd/l as cadmium chloride. At the end of the 12-week period, trace element concentrations were estimated by AAS. Selenium-deficient rats of both genders showed significantly lower accumulation of cadmium in the liver, compared to Se-adequate rats. Zinc and iron hepatic levels were not affected by Se-deficiency. However, a significant elevation of copper was found in the liver of Se-deficient rats of both genders. Cadmium supplementation increased zinc and decreased iron hepatic level, regardless of Se status and decreased copper concentration in Se-adequate rats. Se-deficiency was also found to influence the effectiveness of cadmium mobilization in male rats.     

Evaluation of copper toxicity in isolated human peripheral blood mononuclear cells and it's attenuation by zinc: ex vivo

Copper and zinc act as a cofactor of over 300 mammalian proteins. Both have same electronic configuration therefore they are antagonist at higher individual concentration. The present study was designed with the aim to investigate the mechanisms pertaining to toxic effects of copper on human peripheral blood mononuclear cells (PBMCs) and to evaluate the cytoprotective effect of zinc on copper-induced cytotoxicity. The copper uptake into PBMCs was progressively increased with increasing concentration of metal in the growth medium. However, no significant effect on copper uptake was observed in the presence of zinc. Cell proliferation rate was decreased with increasing copper concentration. Interestingly, the proliferation rate of zinc treated PBMCs remained nearly the same as that of control cells. LD₅₀ of copper (115 μM) was increased six times (710 μM) in presence of zinc for PBMCs. At higher concentrations of copper (> 100 μM) decrease level of GSH was noticed. Increased levels of metallothionein in PBMCs were observed in response to zinc. DNA fragmentation studies also showed that copper produced DNA fragmentation at LD₅₀ (115 μM). Subsequently, zinc showed protection against DNA fragmentation caused by copper. Cell structure of PBMCs at LD₅₀ (115 μM copper) showed membrane bound cystic spaces and mitochondria having disrupted cristae and few myelin figures. In presence of zinc at LD₅₀ of copper (115 μM) cells showed improvement in mitochondrial structure and membrane bound cystic spaces. Taken together, the results of our study demonstrates that zinc play an important role in prevention of copper toxicity in peripheral blood mononuclear cells.     

The antimutagenic effect of selenium on 7,12-dimethylbenz(a)anthracene and metabolites in the amesSalmonella/microsome system

The antimutagenic effect of selenium as sodium selenite, sodium selenate, selenium dioxide, and seleno-methionine was studied in the AmesSalmonella/microsome mutagenicity test using 7,12-dimethylbenz(a)anthracene (DMBA) and some of its metabolites. Selenium (20 ppm) as sodium selenite reduced the number of histidine revertants on plates containing up to 100 μg DMBA/plate. Increasing concentrations of selenium as sodium selenite, sodium selenate, and selenium dioxide up to 40 ppm Se progressively decreased the number of revertants caused by 50 μg DMBA. DMBA and its metabolites 7-hydroxymethyl-12-methylbenz(a)anthracene, 12-hydroxymethyl-7-methylbenz(a)anthracene, and 3-hydroxy-7,12-dimethylbenz(a)anthracene were mutagenic forSalmonella typhimurium TA100 in the presence of an S-9 mixture. Selenium supplementation as Na₂SeO₃ reduced the number of revertants induced by these metabolites to background levels. The antimutagenic effect of inorganic selenium compounds cannot be explained by toxicity of selenium as determined by viability tests withSalmonella typhimurium TA100. Selenium supplementation in all forms examined, except sodium selenate, decreased the rate of spontaneous reversion. Selenium as sodium selenate was slightly mutagenic at concentrations of 4 ppm or less. Higher concentration of Na₂SeO₄ inhibited the mutagenicity of DMBA. The present studies support the anticarcinogenic potential of selenium and indicate that form and concentration are important factors in this trace element's efficacy.     

Zinc and copper in Indian patients of tuberculosis

The effectiveness and success of antitubercular therapy is mainly measured by identifying the organism in sputum. In certain patients, especially in geriatric patients, available tuberculosis tests are not satisfactory and do not provide enough information on the effectiveness of antitubercular therapy, as the symptoms might be confused with the existing symptoms of ongoing diseases. Therefore, 60 diagnosed and randomly selected patients with tuberculosis were included into this study. The patients with other associated diseases likely to influence serum copper and zinc were not included in the study. The estimations of serum copper and zinc were done in healthy volunteers and in tubercular patients before the start of treatment and after 4 wk of antitubercular treatment. The average plasma concentration of serum copper and zinc in healthy volunteers were 102±20 μg/dL and 96±18 μg/dL respectively. In tuberculosis patients, serum copper and zinc levels were 123.65±9.98 μg/dL and 64.14±3.97 μg/dL, respectively, before the start of treatment, which came down to 116.23±4.27 μg/dL and 74.31±3.60 μg/dL, respectively, after 4 wk of antitubercular treatment.     

Serum Iron,Zinc, and Copper Concentration in Premature Graying of Hair

Premature graying of hair with unclear etiology, which is known as premature canities, is a common cause of referrals to the dermatologists. We assessed the relationship between serum iron, copper, and zinc concentrations with premature canities. This study was conducted on patients under 20 years old suffering from premature canities, having a minimum of ten gray hair fibers, and referring to university hospitals of Isfahan (Iran). The results were compared with age–sex-matched controls. Demographic data and disease characteristics were recorded for two groups. We studied serum iron, copper, and zinc concentrations of 66 patients and 66 controls using atomic absorption and Ferrozine methods. The mean age of studied cases was 17.8 ± 2.0 years, and the mean age of the onset of canities was 15.5 ± 3.2 years with no significant difference between males and females (P > 0.05). Serum copper concentration was significantly lower in patients compared with controls (90.7 ± 37.4 vs. 105.3 ± 50.2 μg/dL, P = 0.048), but serum iron concentration was significantly lower in controls compared to patients (88.8 ± 39.5 vs. 108.3 ± 48.4 μg/dL, P = 0.008). Also, there was no significant difference between patients and controls in serum zinc concentration (114.8 ± 67.8 vs. 108.2 ± 49.9 μg/dL, P = 0.285). According to these results, among copper, zinc, and iron, a low serum copper concentration may play a role in premature graying of hairs in our society. Further studies are needed to find the underlying mechanism of this relationship.     

Effects of germanium and silicon on bone mineralization

The chemical properties of Ge are similar to Si. This study investigated whether Ge can substitute for, or is antagonistic to, Si in bone formation. Sixty male weanling Sprague-Dawley rats were randomly assigned to treatment groups of 12 and 6 in a 2×4 factorially arranged experiment. The independent variables were, per gram fresh diet, Si (as sodium metasilicate) at 0 or 25 μg and Ge (as sodium germanate) at 0, 5, 30 or 60 μg. Results confirmed that Ge does not enhance Si deprivation and provided evidence that Ge apparently can replace Si in functions that influence bone composition. When Si was lacking in the diet, calcium and magnesium concentrations of the femur were decreased; this was reversed by feeding either Ge and/or Si. Similar effects were found for zinc, sodium, iron, manganese, and potassium of vertebra. There were some responses to Si deprivation that Ge could not reverse: Ge did not increase femur copper, sodium, or phosphorus or decrease molybdenum of vertebra, effects that were eveked by Si supplementation. Additionally, some findings suggested that 60 μg Ge/g diet could be a toxic intake for the rat. On the other hand, some responses induced by Ge indicate that this element may be acting physiologically other than as a substitute for Si. Germanium itself affected bone composition. Germanium supplementation decreased Si and molybdenum in the femur and increased DNA in tibia. Regardless of the amount of Si fed, animals fed 30 μg Ge/g diet had increased tibial DNA compared to animals fed 0 or 60 μg Ge; however, tibial DNA of animals fed 30 μg Ge was not statistically different from those animals fed 5 μg Ge. Thus, Ge may be of nutritional importance.     

Changes in trace element concentrations in hair of growing children

Head hair concentrations of zinc, copper, manganese, and iron from a total of 418 subjects (154 male and 264 female) aged between 6 mo and 20 yr were measured mainly with flameless atomic absorption spectrophotometry. Only zinc analysis of a part of the female samples (n=140) were analyzed with inductively coupled plasma-atomic emission spectrometry. The two analytical methods showed close agreement. The mean concentration of copper and manganese were significantly higher in male subjects than in female subjects. The trace element concentrations in hair varied with the subject’s age. Zinc concentration in hair decreased from 6 mo to 14 yr in the male subjects and decreased from 6 mo to 12 yr in the female subjects. Then, the concentrations increased gradually to 20 yr in the both sexes. Age-dependent variations of copper and manganese concentrations in hair showed similar trends to those of zinc. The results of this study suggest that a higher concentration in the diet of these trace elements may be required for growing children, especially in the period of adolescence.     

Plasma Zinc,Copper, and Serum Thyroid Hormones and Insulin Levels After Zinc Supplementation Followed by Placebo in Competitive Athletes

Intense physical activity is associated with biological adaptations involving hormones and trace elements. Zinc supplementation may affect plasma copper concentration, thyroid-stimulating hormone (TSH), thyroid hormones, insulin, and glucose homeostasis, but data in athletes are scarce. The aim of this study was to evaluate in competitive athletes (cyclists, n = 7, 32 ± 8 years) the effect of zinc supplementation (22 mg/day as zinc gluconate) during 30 days, and discontinuation using placebo (maltodextrin) during the following 30 days, on plasma zinc and copper concentrations, serum thyroid hormones, insulin and glucose levels, and HOMA2-IR. Compared to baseline, plasma zinc and Zn:Cu plasma ratio increased, but plasma copper decreased after zinc supplementation (day 30) and discontinuation (day 60) (p < 0.05). Zn supplementation and discontinuation had no effect on TSH, T3, and T4. Fasting serum insulin and HOMA2-IR increased (27% and 47%, respectively) on day 60 compared to baseline (p = 0.03), suggesting a delayed effect of zinc supplementation. Moreover, plasma zinc was positively associated with serum insulin (r = 0.87, p = 0.009) and HOMA2-IR (r = 0.81, p = 0.03) after zinc supplementation (day 30), indicating that supplemental zinc may impair glucose utilization in cyclists.