6.2. Salt metabolism

Metabolism of water, as already noted, is intimately connected with the salt metabolism. Salt is not only part of the structural elements of cells and tissues, but it also participates in a variety of metabolic processes between the cells and intercellular fluid. They activate a number of enzymatic systems, play a vital role as necessary components of all biological fluids and enable normal functioning of the body. In the largest amount, mineral compounds (Ca, Mg, F, and P) are part of the bone tissue and teeth. Calcium and magnesium in the bones are in the form of phosphates, and some carbonates and fluoride. Calcium and magnesium are in the ionized state of the cells of other tissues, blood plasma and all body fluids. Parts of the cations (especially Ca²⁺ and Mg²⁺) are presented in the body in the associated with proteins form. This part of the cations is not osmotically active and is not involved in the activation of enzyme systems.

Calcium (Ca) is macroelement plays an important role in the functioning of muscle tissue, the myocardium, nervous system and skin. In ionized form (Ca²⁺) it circulates in the blood and interstitial fluid; it takes part in the regulation of neuromuscular conduction, vascular tone, hormone production, capillary permeability, reproductive function, blood clotting; it prevents the deposit of toxins, heavy metals and radioactive elements in the body. The normal serum calcium content is 92.2-110.2 mg/kg.

Magnesium (Mg) is the main intracellular element. It activates enzymes that regulate carbohydrate metabolism, stimulates the production of proteins, regulates the storage and release of energy in ATP, reduces the stimulation of nerve cells, relaxes heart muscle. Normally, the serum content of P is 17-29.2 mg/kg.

Phosphorus (P) is an important nutrient element found in the body not only in the form of inorganic phosphate salts, but it is also a part of nucleoproteins and nucleotides, phosphoproteins, phosphatides, carbohydrates phosphoric esters, etc. Phosphorus is essential for the normal functioning of the nervous system (ensures the conduction of a nerve impulse), bones and muscles (it provides muscle contraction). It is involved in cell growth, cell division, storage and use of genetic information; it reduces vascular permeability and blood cholesterol levels.

Sodium and potassium are found in the body mostly in the form of ions in all tissues. Sodium is found in extracellular fluids (blood plasma, lymph, digestive juices, and exudates), in the form of salts – chloride, phosphate and bicarbonate. Potassium, on the contrary, usually dominates the contents of cells.

Sodium (Na) is a macroelement, electrolyte; it plays a very important role in water and salt metabolism, regulation of neuromuscular activity and renal function. The serum content of Na is normally 2900-3588 mg/kg.

Potassium (K) is the most important element, electrolyte and activator of function of several enzymes. K regulates the intracellular metabolism, the metabolism of water and salts, and supports the osmotic pressure and acid-base state of the body; promotes normal functioning of the muscle,is involved in conducting nerve impulses to muscles; promotes excretion of water and sodium; it also activates several enzymes and is involved in important metabolic processes (energy production, synthesis of glycogen, proteins, glycoproteins); moreover it is involved in the regulation of the process of insulin secretion by cells of the pancreas; supports smooth muscle cell sensitivity to the vasoconstrictor action of angiotensin. he serum content of K is normally 135.7-207.117 mg/kg.

Sulfur (S) is a part of almost all the proteins of the body. There is especially a lot of sulfur in proteins of supporting tissues, such as keratin in hair that differs by high content of amino acid cystine. Sulfur is found in the body in the tripeptide glutathione, vitamins, hormones (oxytocin), etc.

Chlorine (C1) is located in the body mostly in the form of an anion of Na, K, Ca and Mg salts. Anions of chlorine are the most important osmotically active ions of blood plasma, lymph, cellular content, cerebrospinal fluid, etc.

Apart from the above salts other elements are also always found in small amounts in the human body.

Cobalt (Co) is required for the body to participate in the process of hematopoiesis, activation of a number of vital enzymes, the functioning of the nervous system, the processes of tissue regeneration, production of thyroid hormones, maturation and development of cells and factors of the immune system, and brain antistress protection. Cobalt is a part of a molecule of vitamin B₁₂. The normal serum content of Co is within 0.07-0.12 mg/kg.

Silicon (Si) is a micro element, the maximum content of it is observed in the skin and in solid tissues – enamel, hair, nails and bones. Silicon plays an important role as a structural component of connective tissue. Normally, the serum content of Si is in the range from 0-3.5 mg/kg.

Manganese (Mn) is vital micro element; it is involved in the functioning of more than 30 enzymes. Manganese is responsible for many processes in the body: synthesis and metabolism of neurotransmitters in the central nervous system; formation of bone and connective tissues, the immune response; it regulates the activity of antioxidant enzymes, insulin and lipid metabolism, the metabolism of thyroid hormones, estrogens. Manganese is necessary for the regulation of metabolism of vitamins C, E, B group, as well as choline. Manganese is a part of the active site of many enzymes; it plays an important role in protecting the body from the harmful effects of peroxide radicals. Normally, the serum content of Mn is 0.01-0.02 mg/kg.

Iron (Fe) is micro element which is closely associated with copper (Cu) and zinc (Zn). Iron is a part of more than 70 proteins and enzymes, hemoglobin, cytochromes, redox enzymes. Iron is essential for the normal functioning of the immune system, bone formation, nervous system, for the gastrointestinal tract, endocrine glands. The main functions of Fe in the body are: electron transport (cytochromes, iron-sulphur proteins); transport and deposition of oxygen (myoglobin and hemoglobin); participation in the formation of active sites of redox enzymes (oxidases, hydroxylases, SOD); activation of lipid peroxidation, pre-prepared by copper ions; transport and deposition of iron (transferrin, ferritin, hemosiderin, lactoferrin); participation in DNA synthesis and cell division; participation in the synthesis of prostaglandins, thromboxanes, leukotrienes and collagen; participation in the metabolism of hormones of the adrenal medulla; participation in the metabolism of aldehydes, xanthine; participation in the catabolism of aromatic amino acids, peroxides. Normally, the serum content of Fe is 0.6-1.8 mg/kg.

Copper (Cu) is a micro element that plays an important role in the regulation of redox processes, and hematopoiesis, the formation of connective tissue. It is involved in the synthesis of hemoglobin and red blood cell production; it is vital for normal bone development, the integrity of the cardiovascular system (hardening of blood vessels and heart muscle). Copper forms elastin; copper is necessary for normal functioning of the immune system; it plays an important role in the development of myelin. Copper is extremely important for iron absorption, controls cholesterol, glucose and uric acid levels. Copper is closely related to zinc and iron. Normally, the serum content of Cu – 0.7-1.4 mg/kg.

Zinc (Zn) is essential micro element that is needed for fission and cell growth, protein and nucleic acid synthesis, regeneration and detoxification processes and immune protection. Most of the zinc in the adult's body is found in muscles, bones and skin. Zinc provides a function of the nervous system (memory, mental capacity, intellectual capacity, taste, smell, vision), the immune system (T-cell immunity, local immunity of the skin and mucous membranes) and reproductive organs (synthesis of sex hormones). Zinc controls the contractility of muscles, needed for protein synthesis (liver), digestive enzymes and insulin (pancreas), detoxification (alcohol, radioactive elements, toxic metals and various chemical agents). Particularly children are in need of zinc, because it regulates the growth of human and influence on his mental and physical development; it has a direct impact on the formation of collagen tissue and skeleton; it plays an important role in the formation of hormones. Zinc is closely associated with copper and iron. Normally, the serum content of Zn is 0.02-1.2 mg/kg.

Selenium (Se) is vital ultra-micro element: it provides antioxidant and disintoxication protection of the body; trophic functions in the central and peripheral nervous system; it involved in maintaining of the nutrition of the skin, cornea and lens, hair and nails. Selenium works synergistically with vitamin E, protects sperm from pollutants and ensures their mobility. Normally, the serum content of Se is 0.14-0.22 mg/kg.

Iodine(I), aluminum (A1), cadmium (Cd), arsenic (As), nickel (Ni), lead (Pb), titanium (Ti), chromium (Cr), barium (Ba), lithium (Li) are also important elements for the functioning of the human body.

Despite the fact that the daily need of the human body in the macro-and micronutrients is often expressed in small parts of a milligram, a number of diseases of metabolic disorders can appear with complete elimination of them from food.

For example, in iron deficiency such pathological conditions are developed as acute and chronic blood loss, hypochromic anemia, and myoglobin deficient cardiomyopathy and atonia of skeletal muscles, inflammation and atrophic changes of the mucous membranes of mouth, nose; esophagopathy, chronic gastroduodenitis, and immunodeficiency states.

With the deficit of potassium such diseases occur as degeneration and diffuse cardionecrosis with dilatation of the cavities of the heart, arrhythmias, nephrosis with sclerosis of the renal tubules, muscular dystrophy and generalized weakness, hallucinations.

The most characteristic manifestations of cobalt deficiency are anemia, abnormal menstrual cycle in women, degenerative changes in the spinal cord, hypo-pigmentation of the skin.

With the deficit of silicon, the non-specific body resistance to various deseases including cancer becomes lower. In children, low levels of silicon can be evidence of degenerative changes, increased fragility and lack of elasticity of blood vessels.

Magnesium deficiency is a common phenomenon for people exposed to chronic stress, common in chronic fatigue syndrome, diabetes mellitus.

Lack of manganese in the body leads to disruption of glucose metabolism in insulin-dependent type of diabetes, hypocholesterolemia, delayed growth of hair and nails, increased convulsive readiness, allergoses, dermatitis, disturbance of cartilage formation, osteoporosis. Manganese deficiency also states in various forms of anemia, reproductive dysfunction, stunted growth, reduced body weight.

Copper deficiency negatively affects the absorption of iron, hemapoiesis, the processes of myelination in the nervous tissue, strengthens propensity for bronchial asthma, allergodermatosis, cardiomyopathy, and to vitiligo; it affects the condition of the connective tissue.

People with a deficiency of zinc are usually often suffered from catarrhal and infectious diseases for long time. Zinc-deficient states are characterized by reduced appetite, anemia, allergies, hyperactivity, dermatitis, underweight, decreased visual acuity, hair loss, and delayed puberty in boys, the loss of the ability of sperm to ovum fertilization in men.

Selenium deficiency gives decreased immunity, increased propensity to inflammatory diseases, decreased liver function, cardiomyopathy, diseases of the skin, hair and nails; atherosclerosis, cataracts, reproductive failure, growth retardation, pulmonary pathology, the rapid aging of the body. Selenium deficiency accelerates the development of atherosclerosis, coronary heart disease, the risk of myocardial infarction. It is proved that there is relationship between selenium deficiency and the frequency of sudden infant death syndrom. The likelihood of male infertility is also increased with selenium deficiency. There is also a relationship between cancer of stomach, prostate, colon and breast cancer and lack of Se.

Minerals and salts are involved in maintaining of osmotic pressure in body fluids on a certain level; they play an important role in the formation of buffer systems of tissue and blood.