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This review discusses biologic roles, metabolism, and clinical aspects of three essential trace elements, zinc, copper, and selenium. Clinical situations that result in disturbed trace element metabolism, and signs or symptoms that may suggest a trace element problem are listed. Important issues for trace element assay development are emphasized, and examples of pediatric reference ranges provided.
The role of micronutrients in parenteral nutrition include the following: (1) Whenever artificial nutrition is indicated, micronutrients, i.e., vitamins and trace elements, should be given from the first day of artificial nutritional support. (2) Testing blood levels of vitamins and trace elements in acutely ill patients is of very limited value. By using sensible clinical judgment, it is possible to manage patients with only a small amount of laboratory testing. (3) Patients with major burns or major trauma and those with acute renal failure who are on continuous renal replacement therapy or dialysis quickly develop acute deficits in some micronutrients, and immediate supplementation is essential. (4) Other groups at risk are cancer patients, but also pregnant women with hyperemesis and people with anorexia nervosa or other malnutrition or malabsorption states. (5) Clinicians need to treat severe deficits before they become clinical deficiencies. If a patient develops a micronutrient deficiency state while in care, then there has been a severe failure of care. (6) In the early acute phase of recovery from critical illness, where artificial nutrition is generally not indicated, there may still be a need to deliver micronutrients to specific categories of very sick patients. (7) Ideally, trace element preparations should provide a low-manganese product for all and a manganese-free product for certain patients with liver disease. (8) High losses through excretion should be minimized by infusing micronutrients slowly, over as long a period as possible. To avoid interactions, it would be ideal to infuse trace elements and vitamins separately: the trace elements over an initial 12-h period and the vitamins over the next 12-h period. (9) Multivitamin and trace element preparations suitable for most patients requiring parenteral nutrition are widely available, but individual patients may require additional supplements or smaller amounts of certain micronutrients, depending on their clinical condition.
Trace element deficiencies, toxicities and imbalances in man are more difficult to relate to geochemical factors than they are in farm animals. The reasons for this are discussed and examples of such differences between man and grazing animals presented. The most convincing evidence of a geochemical causal link with human disease comes from the incidence and distribution of endemic goitre. The influence of technological developments upon this relation is discussed. Other associations between the physical environment, including the air and drinking water, and to health are given and critically examined in relation to the criteria necessary to distinguish between association and causation. The nature and extent of man-made modifications of the natural geochemical environment through technological change are discussed in relation to intakes of Fe, I, Zn, Pb and Se and their relation, in turn, to human health and disease. The currently proposed permissible limits or maximum tolerances of potentially toxic elements are presented, and the importance to these tolerances of the chemical and physical forms of the element and their metabolic interactions with other elements is emphasized.
OBJECTIVES: Dietary intake by the general population of trace elements related to human health is not well known. Therefore, values for zinc, copper, manganese, chromium, selenium, molybdenum, cobalt and aluminum were estimated from food intake data from the 1993 Tottori Prefecture Nutritional Survey. For each element, consumption by the individual person was compared to the recommended dietary allowance (RDA) and the tolerable upper intake level (UL). METHODS: Daily intake of trace elements by individuals was calculated from food intake data of 1993 Tottori Prefecture Nutrition Survey by computer program written by visual C++ using the trace element food table published by Suzuki (1993) and compared with RDA and UL values. RESULTS: 1. The percentage of people whose intake of zinc was lower than the RDA was 72.0%. Those for copper and manganese were 69.8% and 39.2%, respectively. Persons aged over 60 years consumed less of those trace elements. 2. Few people had a chromium intake lower than the RDA. The same was the case for molybdenum and selenium. However, 9.2% of people had on intake of chromium in excess of the UL, and for manganese, molybdenum and selenium the figures were 0.7%, 81.6% and 9.6%, respectively. 3. The major sources of the trace elements were cereals, fish, meats, vegetables and beans. CONCLUSIONS: It is necessary to investigate the reason for the low intake of zinc, copper and manganese. It is also to be recommended that food tables for trace elements be produced to feel compliance with the RDA and UL for trace elements.
Although trace elements have been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS) for a long time, new evidence has connected familial ALS with the metalloenzyme copper-zinc superoxide dismutase, thus reinforcing the study of their metabolism. This work presents the results of serum and cerebrospinal fluid levels of copper, zinc, manganese and magnesium, by atomic absorption spectrophotometry. Statistically significant decreased cerebrospinal fluid and serum copper levels were found in patients compared to the control group (20.25 +/- 7.09 vs. 30.86 +/- 16.02 SD micrograms/l and 913.21 +/- 165.55 vs. 1020.17 +/- 197.76 SD micrograms/l) while serum manganese levels were found to be increased in patients (3.59 +/- 0.89 SD micrograms/l) compared to controls (3.03 +/- 1.23 SD micrograms/l). Zinc and magnesium levels were unchanged. Our findings indicate an essential trace element imbalance in the disease.
We compared trace element status in multiple sclerosis (MS) patients (n = 27) with and without treatment with corticosteroids and groups of healthy subjects. Concentrations of plasma ceruloplasmin, selenium, and zinc and erythrocyte (RBC) glutathione peroxidase, Se, and Zn were similar in all groups. RBC copper concentrations were significantly lower in MS patients than in control subjects (mean +/- SEM: 0.048 +/- 0.005 vs 0.060 +/- 0.002 mumol/g Hb) because of decreased RBC Cu with steroid therapy. RBC Zn-Cu ratios were significantly higher (14.9 +/- 1.0 vs 10.1 +/- 0.3) in MS patients than in control subjects, differing in both groups of MS patients. In MS and control subjects, RBC Cu correlated significantly with RBC Zn (r = 0.56, 0.49). Disease acuity and disability had no effect on trace-mineral status. These data suggest that in MS there is altered Cu and Zn homeostasis that may cause or result from the disease and is influenced by corticosteroid therapy. Systemic trace element alterations might provide clinically useful markers of MS.
Abnormalities of trace elements such as aluminum, silicon, zinc, manganese and nickel were found in chronic hemodialysis (HD) patients. The relationship between serum concentration of trace elements and complications such as anemia bone disease, neurological disorder and nutritional disorder in 100 chronic HD patients was examined. Serum Al and Si levels were very high in these patients, and were negatively correlated with indicators of anemia such as RBC, hemoglobin and hematocrit values. Serum Al and Si levels in the HD patients with peripheral neurological disorder (excluding encephalopathy) and with bone disease were significantly high. The levels of serum Zn, Mn and Ni were low, and were correlated with total serum protein levels. In summary, in order to prevent some complications in chronic HD patients, it is very important to regulate levels of trace elements.
The relation between trace elements and human health has been scarcely studied. With respect to cardiovascular diseases and hypertension attention has mostly focused on arsenic, cobalt, copper, chromium, fluorine, manganese, vanadium, zinc, selenium, silicon, cadmium, and lead. Environmental contamination can influence organ concentrations through long-term, low-level effects. This article reviews the present knowledge obtained by epidemiological, biochemical and cell biological studies. Attention is paid to interpretation problems due to the complexity of biochemical interactions with proteins of various sorts which determine metabolic processes and to the occurrence of detoxification mechanisms in which trace elements interact. This can also lead to strong variations in individual vulnerability. In general, the elements selenium, copper, zinc, chromium, and manganese seem to counteract the development of cardiovascular diseases, whereas cadmium and may be lead seem to stimulate it. Effects of arsenic, silicon and fluorine are unclear and for cobalt absent. The intensity of these effects on public health is difficult to measure, but is as yet probably limited except in extra-ordinary situations.
Knowledge of trace element requirements of infants with phenylketonuria (PKU) fed a semisynthetic diet is limited. Three infants with PKU detected early were studied longitudinally in classical balance studies for 72 h, under domestic conditions, at the ages of 2, 5, 8, 12 and 16 weeks. Iron, copper and manganese concentrations in the diet and faeces were determined by atomic absorption spectroscopy. The median concentrations in the diet (4.8 mg Fe/L, 1.7 mg Cu/L, 0.43 mg Mn/L) exceed those in human milk. This is mainly due to supplementation of the amino acid preparation used. The increased intake led to a significantly higher daily retention of Cu and Mn from the PKU-diet fed, with a median of 0.17 mg Cu/kg and 6.4 micrograms Mn/kg body weight; the median retention of Fe was 0.24 mg Fe/kg. Our results confirmed the doubts about the suitability of the present trace element supplementation in formula for infants with PKU during the first four months of life.
Effect of environment and dietary habits on trace element contents in human scalp hair has been investigated in the present work. Trace elements were detected with neutron activation technique. It was found that diet and environment contribute largely towards the trace elements in human body. Further trace elements Te, Lu, Ba, Cs, Yb, Re, Hf, In and Ir were detected for the first time in human scalp hair.
BACKGROUND: Trace elements--zinc, copper and selenium are part of antioxidant enzymes, superoxide dismutase (SOD) and glutathione peroxidase (GHPx). In renal diseases changes in the trace element metabolism may influence the equilibrium in the antioxidant defence system and enhance the toxic effect of reactive oxygen molecules. METHODS AND RESULTS: The authors examined in 53 children with chronic neprophathies (34 with chronic glomerulonephritis, 11 with chronic renal failure and 8 children included in a chronic dialyzation programme) zinc and selenium in blood and urine and antioxidant enzymes SOD and GHPx in red blood cells. The lowest SOD activity (737 +/- 219 U/g Hb, p < 0.01) and serum zinc concentration (12.9 +/- 3.2, p < 0.05) were found in children in the terminal stage of uraemia, GHPx was as compared with the group of healthy children elevated in all groups of sick children. In dialysed children GHPx was highest (p < 0.01) and correlated with urinary selenium concentrations (r = -0.86, p < 0.05). The SOD activity depended on the serum copper concentrations (r = 0.78, p < 0.05). The highest renal zinc and selenium excretion was recorded in patients with glomerulonephritis (p < 0.05). CONCLUSIONS: The results support the hypothesis on a causal relationship between trace elements and antioxidant enzymes.
OBJECTIVE: To investigate fetal exposure to toxic metals [lead (Pb), cadmium (Cd)] and fetal levels of trace elements [zinc (Zn), copper (Cu), and iron (Fe)] in newborns from an industrial city. Relationships between meconium mineral contents and parental occupation and location of residence were also tested. METHOD: The meconium mineral contents of 117 healthy newborn infants were measured by flame atomic absorption spectrophotometer. RESULTS: The median concentrations (interquartile range) of toxic metals and trace elements in the meconium were as follows: Pb: 46.5 (1,399) microg/g dry weight (wt), Cd: 2.3 (55.6) microg/g dry wt; Zn: 234 (3,049) microg/g dry wt; Cu: 11.8 (818.7) microg/g dry wt, and Fe 105 (2,980) microg/g dry wt. All the meconium samples contained both toxic metals and trace elements. The proportions of trace elements in the meconium samples with concentration higher than 100 microg/g dry wt of the substances tested were Zn 90%, Cu 64%, and Fe 53%. There were significantly positive correlations between the concentrations of toxic metals and trace elements. Also there were positive correlations between the levels of Zn, Fe, and parental occupations, and between the level of Fe and location of residence of the parents (proximity to the petroleum refinery or the dye industries). CONCLUSION: All the meconium samples were positive for toxic metals, and thus may reflect environmental pollution in the city. The occupation environments and the location of the family residence are linked with levels of trace elements in meconium.
It is very important to detect trace elements for kilmberlite. Through improving the working conditions of X-ray fluorescence spectrometer and optimizing the analytical conditions, the determination method of trace elements, such as Sc, Cr, Ni, Y, Nb, La, in kimberlite was worked out. The method has been successfully applied to the determination of trace elements in over 2 thousand samples of kimberlite from Liaoning province. The detection limits of the method were relatively low (the detection limit of Sc droped from 9.54 to 2.83 micrograms.g-1 and the detection limit of La droped from 21.68 micrograms.g-1 to 9.18 micrograms.g-1), i.e. 2.83, 2.15, 2.20, 1.17, 1.05 and 9.18 micrograms.g-1 for Sc, Cr, Ni, Y, Nb and La, respectively. The precision of the method was very high with 2.10%-7.09% of RSD (n = 20). Compared with ICP spectrometry this method is satisfactory. The method has proven to be simple and rapid with low cost and high efficiency.
The feasibility of producing and certifying new certified reference materials (CRMs) for trace elements in honey was investigated. Preliminary steps for preparation of candidate materials are performed at the Institute for Reference Materials and Measurements, Joint Research Centre of the European Commission (EC-JRC-IRMM). Two different types of honey, Acacia and Eucalyptus, were tested for determination of 10 trace elements. To each type of honey was added a given amount of high purity deionized water to obtain aqueous solutions with an acceptable degree of homogeneity which would require only minimal manipulation before analysis. Average values obtained for the trace elements by means of inductively coupled plasma-based techniques were as follows (in microg/ kg +/- SD): Acacia honey, As, 1.10+/-0.20; Cd, 0.328+/-0.035; Cr, 1.90+/-0.22; Cu, 67.0+/-5; Fe, 215+/-30; Hg, < 0.75; Mn, 82.1+/-6.2; Ni, 21.0 3.0; Pb, 2.30+/-0.25; Se, 9.10+/-1.2; Zn, 167+/-22; Eucalyptus honey, As, 5.99+/-0.10; Cd, 0.592+/-0.074; Cr, 1.50+/-0.07; Cu, 219 24; Fe, 1008+/-114; Hg, <0.75; Mn, 1009+/-51; Ni, 11.3+/-1.5; Pb, 5.00+/-0.40; Se, 5.60+/-0.91; Zn, 791+/-91. When these 2 pilot materials are ready, the certification project will be launched in full compliance with current rules set by EC-JRC-IRMM. If the project is successful, the new CRMs will be put primarily at the disposal of the National Reference Laboratories for trace elements.
Trace element analyses were performed on the livers of 52 and the heart muscle of 19 stillborn dairy calves. All calves originated from one herd and ranged in age from 260 days of gestation up to one day old. In the liver the trace element concentrations (mg/kg fresh weight) were as follows: Fe: 181.3 +/- 173.5; Zn: 74.6 +/- 37.7; Cu: 98.1 +/- 42.6; Mn: 1.4 +/- 0.36 and in the heart: Fe: 54.1 +/- 10.6; Zn: 16.3 +/- 3.8; Cu: 2.5 +/- 0.99; Mn: 0.42 +/- 0.07. Calves from heifers had lower Cu values. The relationship between trace element concentration and content and liver and heart weight is discussed, as are aspects of bioavailability and storage mechanisms as well as clinical signs of trace metal deficiencies.
OBJECTIVE: To explore the relationship between the changes of trace elements and lymphatic metastasis in gastric carcinoma. METHODS: Trace elements including Fe, Mg, Mn, Ca, Cu, Zn, Se were measured in primary gastric carcinoma and regional lymph nodes from 40 patients with gastric carcinoma, and compared among the primary tumor, metastatic, and non-metastatic nodes. RESULTS: There were no significant differences in the contents of Fe, Mg, Mn and Ca among primary gastric tumors, regional lymph nodes with or without metastasis (P=0.372 - 0.741, P > 005), and no significant differences in the contents of all 7 trace elements between primary tumors and metastatic lymph nodes (P=0.15 - 0.59, P > 005). Compared with metastatic lymph nodes, the contents of Zn, Se significantly decreased, while Cu and Cu/Zn significantly increased (P=0.001 - 0.009, P< 0.01) in non-metastatic lymph nodes. The content of Zn in N2 positive lymph nodes was significant lower than that in N1 positive nodes (P=0.027). There were no significant difference in the contents of all 7 elements between intestinal type and diffuse type (P=0.149 - 0.758, P > 0.05). CONCLUSIONS: Lymphatic metastasis of gastric cancer is concomitant with the changes of trace elements, and the changes of Zn, Cu, Se may be related with lymphatic metastasis.
Variations in trace element concentration in the head and facial hair of five individuals with ever-increasing amounts of white hair were examined. Hair was collected from the scalp, cheeks, and chin from one donor on a regular basis since 1984. Samples were separated into white and pigmented fractions, and analyzed at SLOWPOKE-Toronto by INAA for the short-lived, isotope-producing elements Br, Ca, Cl, Cu, I, Mg, Mn, Na, S, and Zn. Temporal concentration variations of these elements over time, and variations of the elemental concentrations in pigmented and white hair were established.
Trace elements trapped in glaciers are important indicators for the characterization of past biogeochemical cycles, the identification of numerous sources and their varying strength, and thus indirectly provide insight into past climate variations. However, this necessitates highly resolved and continuous records of trace elements in ice. To obtain records corresponding to these requirements, a continuous ice-core melting (CIM) device was coupled to an inductively coupled plasma sector field mass spectrometer (ICP-SFMS). Accuracy of this newly developed method was tested by replicate analysis of longitudinally cut ice-core sections (reproducibility) and by comparing results of the continuous method with the conventional decontamination and analysis procedure. The new, fast method is suited to accurately determine concentrations of a number of elements, such as Li, Na, Mg, Ca, Mn, Co, Br, Sr, Mo, and Tl. However, for 18 elements (including Al and lanthanides) observed concentrations were underestimated when analyzed using the continuous method. Possible explanations of these low concentrations are (i) incomplete dissolution of mineral dust particles contained in the ice resulting from a delayed acidification step and/or (ii) adsorption of dissolved trace elements or mineral dust particles on the surface of the ice melting device.