Trace Elements in the Human Body

Trace Elements in the Human BodyCHAPTER 1 origination1.Introduction1.1 Trace Elements in Biological SystemIn recent eld scientists from a variety of disciplines have directed their attention in an truculent manner to a long neglected bea of bio chemic interrogation i.e. the role of spook shares for the etiology of disease.Most of the elements indicate in the half-yearly table argon considered to be tip elements. They are defined as motley chemical elements that occur in very runty kernels in the torso of organisms (and are referred to as accompany elements). These elements are essential for many an another(prenominal)(prenominal) physiological and biochemical cropes. A guide element is anelementin a sample that has an average densenessof slight than 100 split per million (ppm) measured in atomic count or less than 100 micrograms per gram (1). Similarly, if the dust needs less than 100 milligram (mg) of an element in a day then it is labelled as a trace element . However, their concentrations may be as low as less than 100 mg of 1 kilogram (kg) of dead em remains weightiness or 65 kg of a body weight of an giving should not contain more than 7 gram (gm) of a trace element (2).1.2. Role of Trace Elements in Human Body in all living organisms possess a certain amount of various trace elements in their body in order to process their body functions right-hand(a)ly. It is improbably authorised that optimum balance level of these elements in every organ, interweave and cell of the human body is maintained that serves as a basal reason to keep an organism healthy and functional. These trace elements thunder mug be in any chemical form much(prenominal)(prenominal) as inorganic salts or as biochemical agents. The trace elements are ubiquitously distributed all all over the earth crest. They wanton away some(prenominal) roles in human body. (However, their role varies,) much(prenominal)(prenominal) as (the element) iron, which is imp ortant for the transportation of oxygen in the body, whereas calcium is the sanctioned component of the bones. Both plants and animals require them for their beseeming functioning, growth, and propagation of their life (3).It is plain that the trace elements are present in the human body in very minute quantity, and if the processes of supply and demand are interrupted overdue to any reason for deterrent example, the intake of these elements is not sustained up to an satisf make upory amount, or the metabolic disorder fails to absorb these elements up to the needful frontier for a chemical reaction (and) the body becomes deficient of these trace elements. In case of deficiency, the body pulmonary tuberculosiss its reserves, but these reserves have to be replenished. The trace elements are the components of various enzymes, hormones and are a part of complicated physiological and biological mechanisms, through which a body generates other biochemicals, and proteins which hel p a be adrift of systems to come out of this demanding state of affairs unscathed. This ability of a body to keep the level of its nutrients and chemical agents within optimum range despite its supply is called homeostasis. This critical process provides the body sufficient reward in order to sustain that pressure, which builds up due to the deficiency of trace elements. However, a lot of misemploy occurs within the body during this turmoil. The frequency of these types of episodes leads the body towards the development of many diseases and makes it vulnerable for the formation of various disorders.Lifestyle, environmental exposure, and feed undersurface directly influence the concentration of trace elements in the body. thither are numerous and essential metabolic activities which can not be instigated without the presence of these trace elements. Such functions may hold protein metabolism, red melody cell production, development of healthy bones and teeth. It may also incl ude growth that depends on thyroid hormones, and proper functioning of nerves and muscleman (functions). Furthermore, fertility, maintenance of the integrity of cell membranes, hair coat growth, and electrical stabilisation of the cell (electrically) involves directly or indirectly certain trace elements for their proper functioning. Additionally, trace elements serve as a component of B-12, which is critical for proper heart functions, regulation of heart beat, and pigmentation. The trace elements are also required for some other functions that carried out inwardly the body of organism such as reproduction, maintenance of fluid balance, (aid in) intercellular communication (which is) needed for organise of to the highest degree proteins and crucial for proper energy processing in the body,( reproduction, act as catalyst,) etc. Another example of such deficiencies or surplusage of the amount of trace elements can be seen in iodine intake, where such a deficiency (or excess (ive )) can lawsuit goiter (an blown-up thyroid gland). This trace element is efficiently concentrated by thyroid glands in fish, amphibians, reptiles, birds, and mammals for the distinctive purpose of producing thyroid hormones (4).It is stated that southeastward can be stored in the cells of body and then become part of the forage series. It starts when carnivorous grazed in the fields where soil is reach with sou-east and consequently the growing crops have attaind a great amount of selenium and eventually high selenium levels become the part of the body of the animals. Initially, selenium was considered to be a harmful element, however with the progression of scientific research and refined consensus has led to the strong belief that selenium is not toxic, and it is essential to several functions in the human body. Such as selenium acts as an antioxidant and sometimes it is present an integral constituent of enzyme glutathione peroxidase (5-6). Regular cellular metabolism is re sponsible for most(prenominal) of the production of reactive oxygen species (ROS) in normal cells. Therefore, ROS are neutralized, engaged, or destroyed by the action of antioxidants. Similarly, the malignant cells also contribute in production of ROS and demonstrate the low levels of antioxidant enzyme in the blood of most cancer patients (7). Beyond, the optimum limit of atomic number 24 in the blood of an organism can be linked with onset of diabetes and cardiovascular disease as hygienic (8).Similarly, selenium influences the development of copious degenerative diseases, and its deficiencies among human beings as salubrious as animals are being recognized worldwide as it has some association with number of pathologies (9).1.3 The Concept of essentialityThose elements that are indispensable, necessary, and incredibly important for the metabolisms of living organisms are called essential elements. It has been widely accepted and established fact that without the presence of these essential trace elements no biochemical metabolism can be lead offd properly, and (on the other hand) the outcome of these chemical reactions does not meet the requirements. Consequently, the concept of essentiality is a leading cause for scientists today to focus their efforts in this field. Furthermore, explore the circumstances through put in data to discern actual facts and reasons for the significance of trace elements required in several metabolic activities in animals. However, special attention must be directed towards how their low or high blood levels, can initiate the development of disease, and the optimum blood levels of these trace elements necessary for the metabolic processes to stay fresh in a proper manner. This is important because some trace metals which are necessary for growth of an organism may be harmful if their detail concentration is even slightly raised.The essential trace elements act as catalyst and the body of an organism can not produce them itself. The solo reference point of these elements in the body is our diet. However, the presence of most of these elements is higher animals is but an expression of geochemical origin or the indicator of environmental contaminations. All cells receive their nourishment from extracellular fluid. The activities of all these trace elements biologically furbish optimum implementation by commencing a series of metabolic reactions in each cell. A lack of any step in the series can lead from mild to severe problems to the health of an organizm.The following elements such as zinc (Zn), copper (Cu), selenium (Se) atomic number 24 (Cr), cobalt (Co), iodine (I), atomic number 25 (Mn), and molybdenum (Mo) are considered to be as essential elements for human body. Although they fiddle incredible roles such as being active sites of enzymes, or obtain the bioactivity of the metabolism though these elements are present in very small amount of the total body weight. The core consequences of low levels of trace elements are the cut activities of the concerned enzymes. An element is recognized as essential when it has a well defined function as a stabilizer, morphological, hormonal or an enzymatic cofactor, when it is always present in tissues and organs in well precise concentration range. When it induces reproducible physiological effects, and when it is possible to prevent and care for consequences due to its deficiency through its supplementation.The effects of the essential elements cannot be in all eradicated by any other element. Nevertheless, another concept of essentiality defines an element as essential when a deficient intake produces an impairment of function. The elimination of an essential trace element produces similar physiological or structural abnormalities apart from type of variety. The restoration of these essential trace elements invalidates or precludes respective(prenominal) abnormalities. Consequently, these abnormalities are accompanied by peculiar(prenominal) biochemical changes that can be prevented or remedied when the deficiency is prevented and remedied and restore the physiological level of that element. The symptoms of deficiency (is) disappear(s) and body functions becomes normal (10-11). Therefore, the physiological levels are restored and the symptoms which indicate such deficiencies are also vanished and the body functions return to their normal state.Trace elements are essential components of biological structures. To deal with this necessity, biological systems have developed the ability to recognize a metal and deliver it to the target without allowing the metal to participate in toxic reactions. Proteins are to begin with responsible for such recognition and transport, and prevent most of the associations of trace elements with other molecules that leads to undesirable chemical modications of these molecules (12).1.4. The Transition Metal atomic number 24 atomic number 24 is the basic element employ in various industrial processes such as paint, construction, chrome plating, (and the) production of stainless steel as well as leather tanning, wood preservation, textile dyes and pigments. Besides the use of atomic number 24 in varieties of industries, trivalent (Cr (III)) and hexavalent (Cr (VI)) atomic number 24 compounds are thought to be the most biologically imperative (13-14). For example, the Cr (III) is an essential dietary mineral in low doses. It is required to potentiate insulin for the normal glucose metabolism (15-16). Since 1971, the internationa citeic Agency for Research on Cancer (IARC) has been interested to categorize carcinogens and visualize occupational association with high rate of cancer risk. Some chemicals used in shoe, tire, and furniture manufacturing, as well as nickel refining, diesel fuel, and dry cleaning have been classified as probable carcinogens. Arsenic, asbestos, benzene, benzidine, chromium, 2-Naphthylene, oils, and vinylchloride inst itute occupational exposures causally associated with cancer in humans.1.4.1. atomic number 24 MetabolismThe chemical science of chromium is very interesting and complicated because of having the capability of possessing various oxidization states. However, chromium (III) and (VI) are the most stable forms that exist in our environment. The chromium (III) and chromium (VI) inter-conversion is influenced by numerous factors, such as the concentrations and type of chromium species, nature of oxidizing or reducing agents. Moreover, the electrochemical behavior of the oxidation and decrease reactions, ambient temperatures and pressure, amount of light, sorbents, acid-base reactions, complexing agents, and precipitation and chemical reactions may also play a pivotal roll in support of establishing a specific chromium oxidation state in certain environmental conditions. chromium can react directly at the site of contact or be absorbed through human tissue. A very important difference is discovered that chromate ion (Cr (VI)) slips away through cellular membranes at an highly faster rate than chromium (III) species (17). atomic number 24 (III) combines directly to transferrin, an iron-transporting protein in the plasma after entering the body from an exogenous source. In contrast, chromium (VI) is outright engaged by erythrocytes after absorption and is reduced to chromium (III) inside the cell. Apart from the source, chromium (III) is extensively distributed within the body and measured for most of the chromium both in plasma or tissues. It has been expounded that the reduction of chromium (VI) does not occur in the plasma. Chromium (VI) enters cells through the phosphate and convert anion-exchange toter pathway. However, most chromium (III) present in the blood pullulate and is stiffly bound to amino acids, and with other organic acids. The plasma proteins, such as globulins may also an attractive target for chromium (III) though a portion of it remain s in plasma for an extended catch of time as well (18).The blood provides a major carrier service for the delivery of chromium to other parts and organs of the body. The substantial concentration of chromium was discovered as a protein-complex in various parts of the human body such as bone marrow, lungs, lymph nodes, spleen, kidney, and liver, though the highest levels of chromium remains in the lungs (19-20). Excretion of chromium takes place primarily through kidneys, with the release of maximum concentration and without leaving traces of it in the organs. However, intimately 10% of an absorbed dose is eliminated by biliary excretion. Nevertheless, minute quantities delivered to hair, nails, milk, and sweat. Chromium usually cleared from blood within hours whereas eradication from the organs of body is not prompt as the half life of chromium is several days. In a study chromium (VI) was administered to volunteers and it was observed that it removed more rapidly from the body th an chromium (III) (21).The reduction of chromium (VI) to chromium (III) has been extensively investigated and it has been observed that the consumed hexavalent chromium is vigorously reduced to the trivalent form by the action of chemicals present in stomach such as gastric fluid (22). However the results of another study show that chromium (VI) is reduced to the chromium (III) form in the red blood cells (RBCs) as well (23). Moreover, during reduction to the trivalent form, chromium may interact with cellular macromolecules, including desoxyribonucleic acid (18) or it may be released slowly from the cell (24).After conducting a series of experiments a group of scientists purposed various routs (routes) by which conversion of chromium (VI) to chromium (III) can occurs inside the body of an organism. They discovered that as curtly as chromium (VI) enters inside the cell it is immediately incorporated by cellular reductants and converts chromium (VI) to the trivalent form. The reduc tants may consist of ascorbic acid, glutathione, and flavoenzymes. The example of glutathione is cytochrome P-450 glutathione reductase and the example of flavoenzymes is riboflavin. However, inter-conversion of one oxidation state to another oxidation of chromium instantly occurs when reducing agent is ascorbate instead of glutathione. At some point during the process of conversion from one oxidation to another oxidation state chromium is capable of producing many other types of unstable complexes as well as free radicals such as hydroxyl group (*OH) and single atom of oxygen (1O2). Besides the production of oxidants, the presence of DNA abrasions were also observed during this series of experiments. For example these abrasions may consist on oxidative damage of DNA, and production of 8-oxo-deoxyguanosine etc. However, it is still mystery whether to characterize the formation of various intermediate chromium complexes as potential carcinogen with respect to chromium (VI) (25-26).1. 4.2. Chromium DeficiencyChromium deficiency has been associated with many factors such as stricken glucose tolerance, fasting hyperglycemia, glucosuria, elevated body fat percentage, decreased lean body mass, maturity-onset diabetes, cardiovascular disease, decreased sperm count, and impaired fertility etc (27). A recent comparative study revealed that supplement chromium (III)-picolinate is an excellent source of chromium towards its own deficiency as compared to chromium (III)-niacin (19). However there is a long list of fresh food and nuts that are purchasable in the market that are considered to be a rich source of chromium (III) such as cereals, spices, fresh vegetables, meats, and fish etc.1.4.3. Chromium ToxicityGenerally the perniciousness of an element is measured on the root of its lethal dose, where the tolerance limit of the body is exhausted and the consequences of high levels of special element appear in the form of signs, symptoms, and medical impairments. These e lements are estimated for their toxicity or carcinogenic potential exclusively by measuring their levels present in the blood of an organism for instance, tin and lead. However, chromium is exceptional among the list of carcinogens due to its versatile nature of retaining various oxidation states such as chromium (IV), chromium (V), chromium (IV), and chromium (III) etc. Therefore, chromium oxidation states have also been taken into account for the evolution of chromium carcinogenicity. For example, friendship of a hazardous waste material is dependent on the concentration of chromium present in the form of chromium (VI) while the other forms of chromium are classified as non carcinogens, according to the United States environmental Protection Agency (USEPA). Furthermore, it has been recommended that the measurement of toxic levels of chromium is also dependent on the availability of biological form of chromium (28).