Trace Elements to Humans

Vanadium is an essential trace element to humans it is also essential to tunicates. However, these marine organisms concentrate vanadium within their blood cells, where the element is present in molar concentrations and the term trace element is no longer appropriate. 

Zinc is an essential trace element to human health. It plays an important role in membrane stabilization and in cell protection against oxidative stress because it is p>art of structure of superoxide dismutase, the main enzyme in endogenous control of some types of free oxygen radicals. It also inhibits transition metals, such as copper and iron, from ptroducing reactive types of oxygen (Powell, 2000). This metal is also essential for DNA and RNA polymerase, which has an important effect in hepatic regeneration (Sato et al., 2005). 

Copper is the third most abundant trace element in humans, after iron and zinc (Underwood, 1977). It is critical to a variety of proteins with functions ranging from electron transfer to oxygen transport to active chemistry, such as insertion of oxygen in a substrate. Table I is a selected list of copper-containing proteins. 

Trace elements in human teeth and bone can be used to reconstruct dietary patterns in prehistoric populations. Several methods have been used to generate chemical data for prehistoric human bone. Among these methods INAA of solid bone and ICP-MS and ICP-ES of solutions have been used most often (33-35). With INAA, portions of bone or teeth are cleaned, sealed in vials, and irradiated to provide data for 8-10 elements. Samples analyzed by ICP-MS are digested in acid prior to analysis. In both cases, sample preparation is cumbersome. 

Toulsen et al. (1994) appear to use the term reference interval as synonymous with reference range. In a paper titled Trace element reference values. . . , the authors emphasize that knowledge of the reference intervals (baseline data) for the trace elements in human body fluids and tissues is of paramount importance. ... 

Nickel, atomic number 28, is a transition metal with a variety of essential uses in alloys, catalysts, and other applications. It is strongly suspected of being an essential trace element for human nutrition, although definitive evidence has not yet established its essentiality to humans. A nickel-containing urease metalloenzyme has been found in the jack bean. 

In the initial studies of trace elements of human skin cross sections, a Ca profile evolved which was increasing from the basal, germinative level of the epidermis toward the horny layer. The drastic concentration drop of Ca concentration down to threshold values at the border of the stratum germinativum and the stratum corneum was a particularly interesting feature.15-17 Only a few years later this finding could be correlated to the fact that a Ca concentration >0.1 mmol was essential if a fully cornified stratum corneum was to be obtained in cell culture. This relationship between Ca and terminal differentiation of the epidermal cells was verified in a PIXE study of epidermal cell cultures.18... 

Iyengar V, Woittiez J. 1988. Trace elements in human clinical specimens Evaluation of literature data to identify reference values. ClinChem 34(3) 474-481. 

Inductively Coupled Plasma Atomic Emission Spectrometry ICP-AES is a technique half-way between FAAS and ET-AAS in terms of detection power. Among all ICP-AES features its robustness against matrix effects and its ability to carry out multielemental analysis predominate as the most advantageous [76-80], Multielemental analysis has also been successfully used to establish reference values [6, 76, 81-84] for many major and trace essential elements in different matrices of biological and nutritional interest, particularly in milk samples [81-83], Reference values for minor and trace element in human milk are collected in Table 13.8. 

E. Coni, A. Stacchini, S. Caroli, P. Falconieri, Analytical approach to obtaining reference values for minor and trace elements in human milk, J. Anal. Atom. Spectrom., 5 (1990), 581-586. 

As detailed in the earlier chapter on milk, from an analytical viewpoint the total determination of trace elements in human milk samples as such is still an open issue because decomposition, preconcentration, and storage of trace analytes in solutions are often a source of concern. The accuracy of the analytical results can, in fact, be endangered by these pretreatments. There are relatively few methods for such total direct analytical determinations, and in many cases they are still inadequate to meet the needs of the analyst. 

Zinc is the second most important of the essential trace elements for humans. It is a constituent of some enzymes, such as carbonic anhydrase. Zinc is sufficiently abundant that deficiencies of zinc are unknown. The highest levels of zinc are found in shellfish, which may contain 400 ppm. The level of zinc in cereal grains is 30 to 40 ppm. When acid foods such as fruit juices are stored in galvanized containers, sufficient zinc may be dissolved to cause zinc poisoning. The zinc in meat is tightly bound to the myofibrils and has been speculated to influence meat s water-binding capacity (Hamm 1972). 

Secondly there is a need to exploit fully the high sensitivity of ETA—AAS to measure the distribution of elements among proteins and other species separated from sera and from cellular material and to measure the sub-cellular distribution of elements. These techniques will undoubtedly provide a most useful means of studying the role of trace elements in human disorders. 

A. Chatt et al. Scalp hair as a monitor of community exposure to environmental pollutants. Hair, Trace Elements Sr Human Illness. A.C. Brown and R. Crouse, Editors. Praeger Publishers, New York, 1980, pp. 46-73. 

Use and exposure Selenium is an essential trace element for human health. However, acute and prolonged periods of exposure to high concentrations of selenium compounds cause adverse health effects in humans. The symptoms include garlicky breath irritation of eyes, skin, nose, and throat visual disturbances headache nausea vomiting chills fever weakness violent cough bitter metallic taste in the mouth nose bleeds dyspnea bronchial spasms bronchitis pulmonary edema gastrointestinal tract disturbance ... 

S. J. A. Fatemi, F. H. A. Kadir, D. J. Williamson, and G. R. Moore, Adv. Inorg. Chem., 1991, 26, 409 R. B. Frankel and R. P. Blakemore eds, Iron Biominerals , Plenum Press, New York, 1991 Subcommittee on Iron, Division of Medical Sciences Assembly of Life Sciences, National Research Council, Iron , University Park Press, Baltimore, 1978 E. J. Underwood, Trace Elements in Human and Animal Nutrition , 2nd edn., Academic Press, New York, 1962 R. Crichton, Inorganic Biochemistry of Iron Metabolism, From Molecular Mechanisms to Clinical Consequences , 2nd edn., Wiley, New York, 2001. 

Several approaches have /been used to determine absorption of trace elements in humans. The most frequently used method has been balance studies, in which the amount of a mineral ingested is compared with the amount eliminated in the feces. However, absorption calculated from total mineral eliminated in fecal collections generally differs greatly from true absorption, since some of the mineral eliminated in the feces is of endogenous origin (1). A number of other difficulties with metabolic balance studies, such as variation in intestinal transit time and inadequate analytical precision, limit their usefulness and often result in conflicting results (2). 

Diplock, A, T. (1987). Trace elements in human health with special reference to selenium. Am. /. Ci n. Nufr. 45,1313-1322. 

Other authors in this volume have addressed the importance of trace and ultratrace quantities of various substances as they relate to nutritional, environmental, and occupational aspects of human health. This chapter will focus more on the development and application of a specific analytical procedure, based on inductively coupled plasma-atomic emission spectrometry (ICP-AES), for the rapid, simultaneous determination of a number of trace elements in human urine. 

Iodine is an essential trace element in human nutrition, and iodides are often added to table salt. This iodized salt prevents iodine deficiency, which leads to the enlargement of the thyroid gland in the neck (a condition called goiter). 

Properties Distinctive reddish color. D 8.96, mp 1083C, bp 2595C. Ductile, excellent conductor of electricity. Complexing agent, coordination numbers 2 and 4. Dissolves readily in nitric and hot concentrated sulfuric acids in hydrochloric and dilute sulfuric acids slowly, but only when exposed to the atmosphere. More resistant to atmospheric corrosion than iron, forming a green layer of hydrated basic carbonate. Readily attacked by alkalies. A necessary trace element in human diet, and a factor in plant metabolism. Essentially nontoxic in elemental form. Noncombustible, except as powder. 

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