Why does the body need calcium and phosphorus? Mineral metabolism disorders. Calcium and Vitamin D
Features of calcium absorptionIt is not enough just to use calcium, the main thing is to absorb it! Calcium is a hard-to-digest substance. Calcium is found in foodstuffs mainly in the form of sparingly soluble salts (phosphates, carbonates, oxalates, etc.). For example, only 13.4% of the calcium found in carrots is absorbed by the body. You need to eat 700 g of carrots to get 1/4 part daily allowance calcium. Its digestibility largely depends on the accompanying substances in the composition of food.
The solubility of calcium salts increases with acidic environment stomach, but dissolved ions are to some extent rebound and precipitated into the jejunum and ileum where the pH is closer to neutral. Did you know that a person at the age of 60 can only produce 25% of the amount of stomach acid that they produced at the age of 20? Therefore, the need for calcium only increases with age. gastrointestinal tract food components (glucose, fatty acids, phosphorus and oxalates) bind to calcium, forming complexes. In general, absorption of calcium supplements (especially less soluble ones) is improved when taken with food. This may be because food stimulates gastric secretions and motility, and dietary sources of calcium become more particulate and soluble.
Dietary fiber reduces the absorption of calcium. Several components dietary fiber bind calcium. Hemicellulose inhibits calcium absorption.
Phytic acid ( component plants) binds calcium into an insoluble form. Phytic acid is especially rich in cereals - rye, wheat, oats, however, during the fermentation of the dough under the action of the phytase contained in yeast, phytic acid is split.
Dark green, leafy vegetables are often relatively high content calcium. But calcium absorption is often hindered by oxalic acid. Combining with oxalic acid, calcium gives water-insoluble compounds that are components of kidney stones. These are sorrel, rhubarb, spinach, beets. Low content foods oxalic acid (White cabbage, broccoli, turnip) - good sources calcium. The absorption of calcium from cabbage is as high as from milk.
Insufficient amount of protein in the diet impairs the absorption of calcium. The stimulating effect of proteins is probably due to the fact that the amino acids released during their hydrolysis form well-soluble complexes with calcium. diet, rich in protein possibly induce calciuria. Calciuria causes a negative calcium balance, but it does not lead to a compensatory increase in the efficiency of calcium absorption in the intestine. The same person has large diurnal fluctuations in urinary calcium levels due to the calciuretic effect food products. Digested carbohydrates and protein have a calciuretic effect that is linearly related to intake of these substances, but relatively independent of calcium intake. For every additional 50 g of dietary protein, 60 mg of calcium is lost in the urine. High level phosphorus content in some proteins reduces, but does not eliminate its calciuretic effect. The calciuretic effect of protein leads to a decrease in renal reabsorption of calcium, which is not compensated by an increase in its absorption in the intestine. Hence, rich in proteins diet in adults results in a negative calcium balance.
Calcium is absorbed from the intestines in the form of complexes with fatty and bile acids. The optimal ratio is 10-15 mg of calcium per 1 g of fat. Calcium absorption is facilitated by a sufficient content of unsaturated fatty acids. Insufficient and excessive amounts of fats, especially those rich in saturated fatty acids (cooking fats, lamb, beef lard, etc.), impair calcium absorption. With insufficient intake of fat, too few calcium salts of fatty acids are formed, giving soluble complex compounds with bile acids. When excessive fatty foods not enough bile acids to carry everything calcium salts fatty acids into a soluble state, and a significant part of Ca is excreted in the feces. The excretion of Ca also depends on the nature of the diet. A diet with a predominance of food products with an acidic reaction of the environment (meat, cereals, bread) leads to the excretion of Ca in the urine. With the predominance of alkaline products (fruits, vegetables, dairy products) in the diet, Ca is excreted mainly with feces.
An important factor influencing Ca absorption is the amount of phosphorus and magnesium in the diet.
The most favorable ratio of calcium to magnesium in the diet is 2:1. A ratio close to this is found in following products- sardines, Atlantic herring, eggplant, cucumbers, lettuce, garlic, beans, pears, apples, grapes, raspberries, porcini mushrooms. If there is little magnesium, the formation of stones, calcification of blood vessels, calcium is deposited in atherosclerotic plaques. Magnesium is essential for calcium absorption in the kidneys and urinary tract. Magnesium deficiency stimulates PTH, leading to increased bone resorption and increased renal Ca excretion. Magnesium competes with Ca for bile acids, so an excess of magnesium negatively affects Ca absorption. In addition, magnesium is part of the enzymes necessary for the metabolism in cartilage and bone tissue.
The best ratio of calcium to phosphorus in adults is 2:1.2-1.8. A ratio close to this is characteristic of cottage cheese, cucumbers, garlic, and grapes. If Ca is supplied more than phosphorus, then the bone tissue does not form normally, problems arise in the calcification of blood vessels, the formation of calculi in the kidneys, gallbladder. And if, on the contrary, more than necessary phosphorus is supplied, Ca is washed out of the bones and its absorption decreases.
The absorption of calcium is also affected by potassium, the excess of which impairs its absorption, because. Potassium, like magnesium, competes with Ca for bile acids.
Difficult calcium absorption: chocolate, excessive consumption of sugar, excess coarse fiber foods. Tea is not compatible with any trace element.
Coca-Cola, Pepsi-Cola, Fanta and other similar drinks contain acid sodium phosphate (Ca antagonist, prevents it from being absorbed), their pH = 2.2-2.5, to neutralize them, the body uses Ca, which is washed out of bone tissue .
Caffeine also increases urinary calcium loss. Abuse of coffee and alcohol can be the causes of calcium deficiency, as part of it is excreted in the urine.
Lactose increases calcium absorption. Lactose, being fermented, maintains in the intestines low values pH, which prevents the formation of insoluble phosphorus-calcium salts.
Along with vitamins A, C, D, E, K, the following elements can increase the level of calcium in the body: Fe, Mg, Mn, Cu, P, Si, as well as protein, gastric juice(HCl), pancreatic enzymes and Lactobacillus acidophilus.
Silicon cross-links bone tissue collagen. Zinc and chromium play an important role in the energy supply of bones, which is necessary for bone tissue growth. Boron affects the synthesis of estradiol, selenium with iodine - on the synthesis of hormones thyroid gland. Vitamin E affects the condition of membranes, including bone tissue.
A serious enemy of Ca and P is aluminum. Aluminum ions are able to replace Ca ions and thereby cause major changes in Sa exchange. A person gets too much of this metal by using aluminum cookware, drinking juice from aluminum-coated bags or canned beer.
In food modern man calcium deficiency is significant, especially for urban residents, whose diet is dominated by refined foods, semi-finished products, etc. suffice it to say that the main source of calcium - dairy products - get on the table of a city dweller significantly depleted in calcium: in 1 liter of fresh natural milk(from a cow) contains 1400 ml of calcium, and in pasteurized, and even more so, sterilized, from which cottage cheese and cheese are made at dairies, only 140 mg. The modern city dweller receives, in good case, only a third of daily requirement calcium.
It is recommended to take any Ca products at night, which is explained circadian rhythm bone resorption. Resorption is suppressed only by the evening intake of Ca, while the morning intake does not give a significant effect.
Many people, especially the elderly, eat cottage cheese, cheese for breakfast, believing that this The best way enrich your body with Ca and P. Resorption of Ca and P bone tissue carried out in the evening and at night. So, if you ate fish or cheese for breakfast, then you should not count on them. beneficial effect. Ca and P either do not get into the blood from the intestines at all, or, due to their lack of demand, the bone tissue will settle in the kidneys in the form of oxalate stones. The point is also that in the morning corticosteroid hormones are produced and delivered to the blood, which block the absorption of Ca and P from the intestines into the blood. Therefore, products containing Ca and P are best taken in 2/2 days, for dinner.
It must be remembered that calcium is lost during heat treatment(for example, when cooking vegetables - 25%). Losses will be negligible if the water in which the vegetables were boiled is used (for example, broth or gravy).
The lower the fat content of dairy products, the higher the Ca content.
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Osteoporosis
Chronic problems of Lewis (constitutional, acquired or hereditary). Deep phases of degeneration of the genitourinary sphere. Compensatory course:
In the morning: Arnika-12, Glonoin-12, Veratrum album-12.
In the afternoon: Phosphorus-12, Calcarea Fluorica-12, Barita Carbonica-12.
In the evening: 1). Hina-12, Lycopodium-12; 2). Lachesis-12, Mercury biyod-12.
The course is designed for three months.
Calcium metabolism is mainly based on the functions of the bladder, without the correction of which (removal of dysfunction) it is useless to try to fix it.
By the way, at the beginning of the last century, medicine realized that calcium is an important element in the body - this is bones, and metabolism, and the potassium-sodium pump (and this is water exchange in all phases - cells, lymph, tissues). Therefore, most diseases, and severe systemic ones, are either significantly alleviated or completely cured when the calcium balance is restored, therefore the slogan “all diseases are from a lack of calcium” was quickly voiced and applied. At the same time, the general calcification of the population (in Europe) went on a large scale, so much so that it reached the intake of 100-200 g of calcium per day - firstly, calcium is just chalk, the composition, let’s say, is inexpensive, and secondly, the idea “the faster – so much the better”, plus the citizens’ own initiative. I must say that the deterioration of health went very quickly, up to deaths (by the way, by default it was assumed that chalk is a neutral substance, let's say, it is not a poison), after which the whole company was curtailed (all this happened for a maximum of six months). And here's the problem. Let's imagine that our body is tuned to receive all the necessary elements from food products, i.e. we have a kind of “factory” in our body, which is obliged to absorb and process calcium. Lack of calcium - it is clear that the factory is not working well. Accordingly, with a sharp increase in load (loading of equipment), the effect was completely opposite - the equipment was worn out, and instead of increasing the rate, it simply failed. So, before increasing the load, it was first necessary to repair the “factory”, or normalize calcium metabolism - to activate the processes for its absorption. Therefore, it is impossible to increase the dose of calcium without stimulating the metabolism - the effect is strictly negative.
The exchange of calcium, especially fluoride, is stimulated by a simple preparation Calcarea fluorica (in general, calcium fluoride). About the last one. Since, again, calcium is an important element, after the crisis with the intake of chalk (for several years) another boom began - one of the German pharmaceutical companies began to produce and recommend to the population for use the same homeopathic calcium, only not fluoric, but carbonic . Since, as you and I know, this drug normalizes calcium metabolism in the body - the first effect was very successful - it was here that a large-scale improvement in well-being and healing of citizens began - the effect is clear to us. About a year later, the reverse process suddenly began - aggravations and deterioration began, after which one citizen from Holland even sued the company. At the same time, the German company was an honest manufacturer and did not refuse its claims - they themselves did not understand what was the reason that the drug had ceased to act in the right way. But it turned out that after the first year of selling the drug, which at the beginning was made according to the classical homeopathic scheme (for which a chalk particle was taken from the middle layer of chalk deposits and dynamized), they decided to improve the composition. The German mind suggested one simple idea - it is clear that they did not take pure calcium from the earth - there was a lot of pollution and related elements. Then they decided to improve the preparation and began to make homeopathy from chemically obtained calcium, assuming that pure calcium is much better than natural. But the result was exactly the opposite. Since then, all homeopathy has been prepared only from ecological components (no chemistry), and this preparation in German pharmacology began to be referred to as Calcarea Austermani - a homeopathic preparation obtained from natural calcium (marine sediments).
Therefore, to normalize the exchange, we need the following course:
First dose: Hina-12, Kantaris-12, Calcarea fluorica-12 - 2 peas each.
The second reception: Hina-12, Kantaris-12, Calcarea carbonica-12 - 2 peas each.
The third dose: Hina-12, Kantaris-12, Calcarea phosphorica-12 - 2 peas each.
The time of taking the drugs is from 21.00 to 23.00, it should be taken alternately, starting with the drugs of the first group, the next day - the drugs of the second group, and then the third, then the first again - and so on.
calcium metabolism
The functions of calcium in the body include:
Structural (bones, teeth);
signaling (intracellular second messenger-intermediary);
enzymatic (coenzyme of blood coagulation factors);
Neuromuscular (control of excitability, release of neurotransmitters, initiation of muscle contraction).
the main role in the metabolism of calcium in the human body belongs to the bone tissue. In the bones, calcium is represented by phosphates - Ca3 (PO4) 2 (85%), carbonates - CaCO3 (10%), salts of organic acids - citric and lactic (about 5%). Outside the skeleton, calcium is contained in the extracellular fluid and is practically absent in the cells. The composition of the dense bone matrix, along with collagen, includes calcium phosphate, a crystalline mineral compound close to Ca10(PO4)6(OH)2 hydroxyapatite. Part of Ca2+ ions is replaced by Mg2+ ions, a small part of OH– ions is replaced by fluorine ions, which increase bone strength. The mineral components of bone tissue are in a state of chemical equilibrium with calcium and phosphate ions in the blood serum. Bone tissue cells can accelerate the deposition or, conversely, the dissolution of mineral components with local changes in pH, the concentration of Ca2+, HPO42- ions, and chelating compounds (D. Metzler, 1980). The body of an adult contains 1-2 kg of calcium, 98% of which is in the skeleton (A. White et al., 1981). It makes up about 2% of body weight (about 30 mol). In the blood, the level of calcium is 9-11 mg / 100 ml (2.2-2.8 mmol / l), in the extracellular fluid - about 20 mg / 100 ml. The regulation of calcium exchange between extra- and intracellular fluid is carried out by parathyroid hormone, calcitonin, 1,25-dioxycholecalciferol. With a decrease in the concentration of calcium ions, the secretion of parathyroid-stimulating hormone (PTH) increases, and osteoclasts increase the dissolution of mineral compounds contained in the bones. PTH simultaneously increases the reabsorption of Ca2+ ions in the renal tubules. As a result, the level of calcium in the blood serum rises. With an increase in the content of calcium ions, calcitonin is secreted, which reduces the concentration of Ca2+ ions due to the deposition of calcium as a result of the activity of osteoblasts. Vitamin D is involved in the regulation process, it is required for the synthesis of calcium-binding proteins necessary for the absorption of Ca2+ ions in the intestine and its reabsorption in the kidneys. A constant supply of vitamin D is necessary for the normal course of calcification processes. Changes in the level of calcium in the blood can be caused by thyroxine, androgens, which increase the content of Ca2 + ions, and glucocorticoids, which reduce it. Ca2+ ions bind many proteins, including some proteins of the blood coagulation system. The proteins of the coagulation system contain calcium-binding sites, the formation of which depends on vitamin K.
In food calcium is found mainly in the form of calcium phosphate, which enters the body. In nature, calcium occurs in the form of carbonate, oxalate, tartrate, phytic acid (as part of cereals).
calcium deficiency in the body is often associated with the low solubility of most of its salts.
With bad the solubility of calcium salts, the authors link the calcification of the walls of the arteries, the formation of stones in the gallbladder, renal pelvis and tubules.
calcium phosphates dissolve easily in gastric contents. Maximum calcium absorption occurs in the proximal small intestine and decreases in the distal.
Share of assimilation calcium is more significant in children (compared to adults), in pregnant and lactating women. Calcium absorption decreases with age, with vitamin D deficiency.
In blood plasma contains fractions of protein-bound (non-diffusing) calcium (0.9 mmol/l) and diffusing: ionized (1.1-1.4 mmol/l) and non-ionized (0.35 mmol/l). Biologically active is ionized calcium, it penetrates into cells through membranes, the non-ionized form is associated with proteins (albumin), carbohydrates and other compounds. Inside the cells, the concentration of free calcium is low. Thus, the total concentration of Ca2+ ions in the cytoplasm of erythrocytes is about 3 μM, of which less than 1 μM is free ions. The concentration gradient of calcium ions on opposite sides of the membrane (from 102 to 105) is maintained by a calcium pump. The very slow back diffusion of ions into the cell opposes the operation of the pump. Ca2+ refers to secondary messengers - intracellular substances, the concentration of which is controlled by hormones, neurotransmitters, extracellular signals. Low levels of calcium in cells are maintained by calcium pumps (calcium ATPases) and sodium-calcium exchangers. High activation of Mg2+-, Ca2+-ATPase is associated with conformational changes in the calcium pump leading to Ca2+ transfer. A sharp increase in the calcium content in the cell occurs when calcium channels or intracellular calcium depots are opened (the concentration rises to 500–1000 nM at 10–100 nM in an unstimulated cell). The opening of channels can be caused by membrane depolarization, the action of signaling substances, neurotransmitters (glutamate, ATP), second messengers (inositol-1,4,5-triphosphate, cAMP) (J. Kolman, K. G. Rem, 2000). The level of calcium in cells increases (5-10 times) in the form of short-term fluctuations (high concentrations of calcium have a cytotoxic effect). In cell organelles and cytoplasm of cells there are a large number of proteins that can bind calcium and act as a buffer. The action of calcium is mediated by "calcium sensors" - special calcium-binding proteins - annexin, calmodulin, troponin. Calmodulin is present in all cells and, when four calcium ions are bound, it passes into an active form that can interact with proteins. C2+ affects the activity of enzymes, ion pumps, cytoskeletal components due to the activation of calmodulin.
Hypoalbuminemia does not affect the level of ionized calcium, which varies in a narrow range and thus ensures the normal functioning of the neuromuscular apparatus. With an increase in pH, the proportion of bound calcium increases. In alkalosis, hydrogen ions dissociate from the albumin molecule, which leads to a decrease in the concentration of calcium ions. This can cause clinical symptoms of hypocalcemia, despite the fact that the concentration of total calcium in plasma is not changed. The reverse picture (an increase in the concentration of calcium ions in plasma) is observed in acute acidosis. Globulins also bind calcium, although to a lesser extent than albumin.
The constituent components of the regulation of calcium in blood plasma include:
Skeleton (calcium reservoir)
· kidneys;
excretion of calcium through the intestines with bile;
parathyroid hormone, calcitonin (their secretion is determined by the level of calcium in the plasma);
1,25-dioxycholecalciferol.
Extracellular pool calcium is renewed approximately 33 times during the day (W. J. Marshall, 2002), passing through the kidneys, intestines and bones. And even a small change in any of these fluxes has a significant effect on the concentration of calcium in the extracellular fluid, including blood plasma. Calcium, which is part of the secrets of the digestive tract, is partially reabsorbed along with dietary calcium.
Exchange disorders calcium are accompanied by impaired phosphate metabolism and are clinically manifested in changes in the bone skeleton and neuromuscular excitability.
There is an inverse relationship between the content of calcium and phosphorus in the blood serum (a simultaneous increase is observed in hyperparathyroidism, a decrease in rickets in children). With an increased content of phosphorus in food, non-absorbable tribasic calcium phosphate is formed in the gastrointestinal tract. The daily requirement for calcium in an adult is 20-37.5 mmol (0.8-1.5 g), in pregnant and lactating women it is twice as high (MA Bazarnova et al., 1986). 35 mmol of calcium enters the alimentary canal daily, but only half is absorbed, 50 times slower than sodium, but more intense than iron, zinc, manganese. Absorption occurs in the small intestine (maximum in the duodenum 12). Calcium gluconate and lactate are best absorbed. The absorption optimum is observed at pH=3.0. Calcium combines with fatty and bile acids and enters the liver through the portal vein. Vitamin D contributes to transport through the enterocyte membrane into the blood. Absorption decreases with a lack of phosphates (the calcium / phosphorus ratio is important). Absorption is affected by the concentration of Na +, the activity of alkaline phosphatase, Mg2 + -, Ca2 + -ATPase, the content of calcium-binding protein. Calcium is normally excreted from the body through the intestines. Every day, it is secreted into the alimentary canal by the salivary, gastric and pancreas glands and about 25 mmol of Ca2+ is excreted (M. A. Bazarnova et al., 1986). Excretion of calcium with feces persists even with a calcium-free diet (as part of bile). About 270 mmol Ca2+ is filtered in the kidneys per day. 90% of the calcium filtered in the kidneys is reabsorbed, therefore, in general, little is excreted in the urine (excretion increases with an increase in the concentration of calcium in the blood and leads to the formation of kidney stones). Daily excretion ranges from 1.5 to 15 mmol and depends on the circadian rhythm (maximum in the morning), hormone levels, acid-base state, nature of food (carbohydrates increase calcium excretion). With the resorption of the mineral backbone of bones, calcium reabsorption decreases. Bones are a reservoir of calcium: in hypocalcemia, calcium comes from the bones and, conversely, in hypercalcemia, it is deposited in the skeleton.
Calcium ions are important for the course of many processes:
neuromuscular excitation;
muscle contraction;
blood clotting;
permeability of cell membranes;
activity of many enzymes and lipid peroxidation.
Main sources of calcium - milk, dairy products (cottage cheese, hard cheeses), fish, eggs. It is also found in green vegetables and nuts. One of the sources of calcium is drinking water (up to 350-500 mg in 1 liter). With drinking water comes 10-30% of calcium (V. I. Smolyar, 1991). The bioavailability of calcium is improved by fermented milk products, animal proteins, and reduced by dietary fiber, alcohol, caffeine, excess fat (insoluble compounds are formed), phosphates, oxalates. The increased content of magnesium and potassium in food inhibits the absorption of calcium: they compete with calcium for bile acids. Vitamin D supplements promote calcium absorption. In the treatment of osteoporosis, along with the appointment of calcium preparations, it is necessary to replenish the deficiency of proteins, calciferol, and vitamins.
Hypercalcemia - the result of increased intake of calcium into the extracellular fluid from resorbable bone tissue or from food in conditions of reduced renal reabsorption. The most common cause of hypercalcemia (90% of cases) is primary hyperparathyroidism, malignant neoplasms. Often hypercalcemia is not clinically manifested. Rare causes of hypercalcemia include (W. Klatter, 1995) granulomatous diseases (including sarcoidosis), hypervitaminosis D, thyrotoxicosis, the use of thiazide diuretics, lithium preparations, milk-alkali syndrome, prolonged immobility, hereditary hypocalciuric hypercalcemia, renal failure. Clinical symptoms of hypercalcemia include:
lack of appetite, nausea, vomiting, abdominal pain (gastric and duodenal ulcer develops, pancreatitis), constipation;
weakness, fatigue, weight loss, muscle weakness;
personality changes, impaired concentration, drowsiness, coma;
arrhythmias, shortening of the Q-T interval on the ECG;
Nephrocalcinosis, renal calculi, vascular calcification, cornea;
polyuria, dehydration, kidney failure.
Most frequent the reason for the decrease in total serum calcium concentration is hypoalbuminemia.
calcium metabolism in the body is not disturbed if the content of free calcium is within the normal range. The concentration of free calcium in serum decreases with hypoparathyroidism, resistance to parathyroid hormone (pseudohypoparathyroidism), avitaminosis D, renal failure, severe hypomagnesemia, hypermagnesemia, acute pancreatitis, skeletal muscle necrosis (rhabdomyolysis), tumor decay, multiple transfusions of citrate blood. Clinical manifestations of hypocalcemia include: paresthesia, numbness, muscle cramps, laryngeal spasm, behavioral abnormalities, stupor, positive symptoms of Chvostek and Trousseau, prolongation of the QT interval on the ECG, cataracts. Moderate hypocalcemia may be asymptomatic.
Hypercalciuria develops with increased dietary calcium intake, an overdose of vitamin D (resorption in the intestine increases), tubular disorders (idiopathic hypercalciuria, renal tubular acidosis), with increased bone tissue breakdown (myeloma, bone tumors, phosphate diabetes, osteoporosis, hyperparathyroidism).
hypocalciuria observed with hypoparathyroidism, hypovitaminosis D, hypocalcemia, decreased glomerular filtration.
The role of phosphorus in the human body
In the body of an adult human contains about 670 g of phosphorus (1% of body weight), which is necessary for bone formation and cellular energy metabolism. 90% of phosphorus, like calcium, is found in the skeleton - bones and teeth (MA Bazarnova et al., 1986). Together with calcium, they form the basis of bone solids. In the bones, phosphorus is represented by sparingly soluble calcium phosphate (2/3) and soluble compounds (1/3). Most of the rest of the phosphorus is inside the cells, 1% - in the extracellular fluid. Therefore, the level of phosphorus in the blood serum does not allow us to judge its total content in the body.
Phosphates are structural elements of bone tissue, are involved in the transfer of energy in the form of macroergic bonds (ATP, ADP, creatine phosphate, guanine phosphate, and others). Phosphorus and sulfur are two elements in the human body that are part of various macroergic compounds. With the participation of phosphoric acid, glycolysis, glycogenesis, and fat metabolism are carried out. Phosphorus is included in the structure of DNA, RNA, which provide protein synthesis. It is involved in oxidative phosphorylation, which results in the formation of ATP, the phosphorylation of certain vitamins (thiamine, pyridoxine, and others). Phosphorus is also important for the functioning of muscle tissue (skeletal muscle and heart muscle). Inorganic phosphates are part of the buffer systems of plasma and tissue fluid. Phosphorus activates the absorption of calcium ions in the intestine. The daily need for phosphorus is 30 mmol (900 mg), in pregnant women it increases by 30-40%, during lactation - twice (MA Bazarnova et al., 1986). According to V. I. Smolyar (1991), the need for phosphorus in adults is 1600 mg per day, in children - 1500-1800 mg per day.
Into the human body phosphorus comes from plant and animal foods in the form of phospholipids, phosphoproteins and phosphates.
in herbal products (in particular, in legumes) contains a lot of phosphorus, but its digestibility is low. An important source of it is meat and fish. In the stomach and intestines, phosphoric acid is split off from organic compounds. Absorption of 70-90% of phosphorus occurs in the small intestine. It depends on the concentration of phosphorus in the intestinal lumen, the activity of alkaline phosphatase (its inhibition reduces the absorption of phosphorus). Alkaline phosphatase activity is increased by vitamin D, and phosphate absorption is increased by parathyroid hormone. The absorbed phosphorus enters the liver, participates in the processes of phosphorylation, is partially deposited in the form of mineral salts, which then pass into the blood and are used by bone and muscle tissue (creatine phosphate is synthesized). The normal course of ossification processes and the maintenance of a normal bone structure depend on the exchange of phosphates between blood and bone tissue.
Phosphorus in the blood is in the form of four compounds: inorganic phosphate, organic phosphate esters, phospholipids and free nucleotides. In blood plasma, inorganic phosphorus is present in the form of orthophosphates, but its serum concentration is estimated directly (1 mg% phosphorus = 0.32 mmol / l phosphate). It penetrates through semi-impermeable membranes, is filtered in the renal glomeruli. The concentration of inorganic pyrophosphate in blood plasma is 1-10 µmol/L. The content of inorganic phosphorus in the blood plasma of adults is 3.5-4 mg phosphorus / 100 ml, it is slightly higher in children (4-5 mg / 100 ml) and in women after menopause. Plasma also contains hexose phosphates, triose phosphates, and others. The skeleton is a reservoir of inorganic phosphorus: with a decrease in its content in plasma, it comes from the skeleton and, conversely, is deposited in the skeleton with an increase in its concentration in plasma. It is recommended to determine the concentration of phosphorus in the blood serum on an empty stomach: food rich in phosphorus increases it, and carbohydrates, glucose infusion - reduce it. Phosphorus is excreted from the body through the intestines and kidneys in the form of calcium phosphate. With urine, 2/3 of soluble mono- and disubstituted sodium and potassium phosphates and 1/3 of calcium and magnesium phosphates are excreted. In the kidneys, about 208 mmol of phosphate is filtered per day, 16-26 mmol is excreted. The ratio of mono- and disubstituted salts of phosphorus depends on the acid-base state. With acidosis, monosubstituted phosphates are excreted 50 times more than disubstituted ones. With alkalosis, disubstituted salts of phosphates are intensively formed and released.
Parathyroid hormone reduces the level of phosphorus in the blood serum, inhibiting its reabsorption in the proximal and distal tubules, increasing excretion in the urine. Calcitonin has a hypophosphatemic effect, reducing reabsorption and increasing excretion. 1,25 (OH) 2D3, enhancing the absorption of phosphate in the intestine, increases its level in the blood, promotes the fixation of phosphorus-calcium salts by bone tissue. Insulin stimulates the entry of phosphate into the cells and thereby reduces its content in the blood serum. Growth hormone increases phosphate reabsorption, vasopressin - excretion.
Phosphorus and calcium metabolism are closely interconnected. It is believed (V. I. Smolyar, 1991) that the ratio between phosphorus and calcium equal to 1: 1-1.5 is optimal for joint assimilation from food. Hypercalcemia, by reducing the secretion of parathyroid hormone, stimulates the reabsorption of phosphates. Phosphate can combine with calcium and lead to calcium deposition in tissues and hypocalcemia.
In case of violation of the exchange phosphorus is found to increase and decrease it in the blood. Hyperphosphatemia is often observed in renal failure, occurs in hypoparathyroidism, pseudohypoparathyroidism, rhabdomyolysis, tumor decay, metabolic and respiratory acidosis. Hyperphosphatemia inhibits the hydroxylation of 25-hydroxycalciferol in the kidneys. Moderate hypophosphatemia is not accompanied by significant consequences. Severe hypophosphatemia (less than 0.3 mmol / l (1 mg%) is accompanied by impaired function of erythrocytes, leukocytes, muscle weakness (the formation of ATP, 2,3-diphosphoglycerate is impaired). It is observed with alcohol abuse and withdrawal, respiratory alkalosis, malabsorption in bowel, taking phosphate binders, resuming food intake after fasting, overeating, severe burns, treatment of diabetic ketoacidosis (W. Clutter, 1995) In diabetic ketoacidosis, hypophosphatemia is not a sign of depletion of phosphate reserves Moderate hypophosphatemia (1.0-2 .5 mg%) can be observed with glucose infusion, vitamin D deficiency in food or a decrease in its absorption in the intestine, with hyperparathyroidism, acute tubular necrosis, after kidney transplantation, with hereditary hypophosphatemia, Fanconi syndrome, paraneoplastic osteomalacia, an increase in the volume of extracellular fluid. alkalosis can cause hypophosphatemia by stimulating phosphofructokinase activity and the formation of phosphorylated glycolysis intermediates. Chronic hypophosphatemia leads to rickets and osteomalacia.
hypophosphatemia manifested by loss of appetite, malaise, weakness, paresthesia in the extremities, pain in the bones. Hypophosphaturia is observed in osteoporosis, hypophosphatemic renal rickets, infectious diseases, acute yellow liver atrophy, decreased glomerular filtration, increased phosphorus reabsorption (with PTH hyposecretion).
Hyperphosphaturia observed with increased filtration and reduced reabsorption of phosphorus (rickets, hyperparathyroidism, tubular acidosis, phosphate diabetes), hyperthyroidism, leukemia, poisoning with salts of heavy metals, benzene, phenol.
Homeostasis of calcium and phosphate
hypocalcemia stimulates the secretion of parathyroid hormone and thereby increases the production of calcitriol. As a result, the mobilization of calcium and phosphates from the bones, their intake from the intestines, increases. Excess phosphate is excreted in the urine (PTH has a phosphaturic effect), and calcium reabsorption in the renal tubules increases, and its concentration in the blood normalizes. Hypophosphatemia is accompanied by increased secretion of calcitriol alone. An increase in plasma concentration under the action of calcitriol leads to a decrease in the secretion of parathyroid hormone. Hypophosphatemia leads to stimulation of the absorption of phosphate and calcium in the intestine. Excess calcium is excreted in the urine, since calcitriol increases calcium reabsorption to a small extent (compared to PTH). As a result of the described processes, the normal concentration of phosphate in the blood plasma is restored regardless of the concentration of calcium.
Phosphorus is not only one of the most common elements of the earth's crust (its content is 0.08-0.09% of its mass, and the concentration in sea water is 0.07 mg / l), but phosphorus is also present in every cell of the body, and, Together with calcium, phosphorus is the most abundant mineral in the body.
- a macronutrient, which makes up 1% of the total body weight of a person, it is required by every cell of the body for normal functioning. Phosphorus is present in living cells in the form of ortho- and pyrophosphoric acids; it is part of nucleotides, nucleic acids, phosphoproteins, phospholipids, coenzymes, and enzymes. Phosphorus, in the form of phosphate compounds, is present in cells and tissues throughout the body, but most of it (about 85%) is concentrated in bones and teeth (in the form of calcium phosphate salt).
The main role in the transformation of phosphorus compounds in humans and animals is played by the liver. The exchange of phosphorus compounds is regulated by hormones and.
Functions of phosphorus in the body
● The main function of phosphorus in the body is the formation of bones and teeth. Human bones consist of hydroxylapatite 3Са3(PO4)3 Ca(OH)2. The composition of tooth enamel includes fluorapatite.
● Phosphorus in the form of phospholipids (eg phosphatidylcholine) is the main structural component of cell membranes. Phosphorus is essential for the growth and regeneration of all tissues and cells of the body. Phosphorus also helps reduce muscle soreness after a hard workout.
● Phosphorus, in the form of phosphorylated compounds such as adenosine triphosphate (ATP) and creatine phosphate, plays a critical role in energy and matter metabolism in organisms. These phosphorylated compounds are primarily known as a universal source of energy for all biochemical processes occurring in living systems.
● Nucleic acids (DNA and RNA), responsible for the storage and transmission of genetic information, have long chains of phosphate-containing molecules.
● Phosphorus is also essential for the body's balanced use of vitamins and minerals, including vitamin D, iodine, and magnesium.
● Phosphorus contributes to maintaining a normal acid-base balance (pH)
● Phosphorus-containing molecules 2,3-diphosphoglycerate (2,3-DPG) binds to erythrocyte hemoglobin and facilitates the delivery of oxygen to body tissues.
● Phosphorus helps the kidneys to filter out waste.
● Phosphorus plays an important role in the functioning of the cardiovascular and nervous systems.
The body's need for phosphorus
The daily human need for phosphorus is 800-1500 mg. With a lack of phosphorus in the body, various bone diseases develop.
According to the recommendations (RDA) of the Institute of Medicine of the National Academy of Sciences of the USA
dietary phosphorus intake by age group:
0 to 6 months: 100 mg daily
7 to 12 months: 275 mg daily
1 to 3 years: 460 mg daily
4 to 8 years: 500 mg daily
9 to 18 years: 1250 mg per day
Adults: 700 mg per day
Pregnant and lactating women:
Under 18: 1250 mg per day
Over 18: 700 mg per day
The upper acceptable level of phosphorus intake is 3-4 g per day.
Phosphorus deficiency. hypophosphatemia
Because phosphorus is so abundant in foods, nutritional phosphorus deficiency or phosphorus deficiency (hypophosphatemia) usually occurs only in cases of near starvation. However, certain diseases such as diabetes, Crohn's disease, and celiac disease can lead to a drop in phosphorus levels in the body. In addition, some can lower the level of phosphorus. medicines(antacids and diuretics ()).
Phosphorus Deficiency Symptoms
● Appetite loss, weakness, fatigue, weight change
● restlessness, irritability, irregular breathing
● bone and joint pain, bone fragility, numbness, tingling in the limbs
● rickets (in children), osteomalacia (in adults)
● increased susceptibility to infections,
Interactions that reduce the level of phosphorus in the body
● Alcohol promotes the leaching of phosphorus from bones, thereby causing a decrease in phosphorus levels.
● Antacids - medications, intended for the treatment of acid-dependent diseases of the gastrointestinal tract by neutralizing hydrochloric acid, which is part of the gastric juice. Antacids containing aluminum, calcium, or magnesium (such as Almagel, Maalox, Mylanta, Riopan, and Alternagel) can bind phosphate in the intestines, preventing the body from absorbing phosphorus. Long-term use of these drugs can lead to low levels of phosphorus (hypophosphatemia).
● Some anticonvulsants (including phenobarbital, carbamazepine, Tegretol) can decrease phosphorus levels and increase levels of alkaline phosphatase, an enzyme that helps remove phosphate from the body.
● drugs (cholestyramine (questran), colestipol (colestide)), may reduce oral absorption of phosphate from food or supplements. Therefore, phosphate supplements should be taken at least 1 hour before or 4 hours after taking these drugs.
● Corticosteroids, including prednisolone or methylprednisolone (Medrol), increase urinary phosphorus levels.
● High doses of insulin can lower phosphorus levels in people with diabetic ketoacidosis (a condition caused by severe insulin deficiency).
● The use of phosphorus supplements along with potassium-sparing diuretics (spironolactone (Aldactone), triamterene (Dyrenium)) can lead to hyperkalemia (an excess of potassium in the blood) and as a result to a violation heart rate(arrhythmias).
● ACE inhibitors – medicines used to treat high blood pressure can lower phosphorus levels. They include: Benazepril (Lotensin), Captopril (Capoten), Enalapril (Vasotec), Fosinopril (Monopril), Lisinopril (Zestril, Prinivil), Quinapril (Accupril), Ramipril (Altace).
● Other drugs may lower phosphorus levels. Cyclosporine (used to suppress the immune system), cardiac glycosides (digoxin), heparins (blood thinners), and non-steroidal anti-inflammatory drugs (such as ibuprofen or Advil). Salt substitutes also contain high levels of potassium and long-term use can cause a decrease in phosphorus levels.
High levels of phosphorus in the body
The presence of too much phosphorus in the body is actually a more alarming symptom than its deficiency.
High levels of phosphorus in the blood occur only in people with severe kidney disease or severe dysfunction of calcium regulation, and may be associated with calcification (calcification, deposition of calcium salts in soft tissues).
A high level of phosphorus in the body is possible with excessive consumption of phosphorus and low calcium intake.
Some studies show that higher phosphorus intake is associated with an increased risk of cardiovascular disease. As the amount of phosphorus you eat rises, so does the need for calcium. A balance between calcium and phosphorus is essential for proper bone density and the prevention of osteoporosis.
Food sources of phosphorus
Phosphorus is found in foods of animal origin because it is an essential component of animal proteins. Dairy products, meat, poultry, fish, eggs are especially rich in phosphorus.
Phosphorus in all plant seeds (beans, peas, cereals, cereals and nuts) is present in the form phytic acid or phytates. Phytic acid reduces the bioavailability of total phosphorus, calcium, magnesium, zinc and many other minerals. Only about 50% of phosphorus from phytates is available to humans because the body lacks an enzyme (phytase) that is able to release phosphorus from phytate.
Cereals, like legumes, contain phytic acid in the whole grain, but most of all in its shells. This acid combines with certain minerals present in the gut to form insoluble phytates. This prevents the absorption of minerals in our body (they talk about demineralization). Fortunately, under phytase(an enzyme that is activated in bread sourdough) phytic acid is destroyed. The higher the percentage of flour purification, the greater the content of phytic acid. The more the dough is fermented, the more time the sourdough phytase has to release minerals from its association with phytic acid. In addition, the process of dough fermentation is, as it were, a digestion process that begins outside the stomach. Sourdough bread is easier to digest than yeast bread, which undergoes alcoholic fermentation during the rise of the dough.
Phosphorus is also a component of many polyphosphate food additives and is present in most soft drinks as phosphoric acid.
Fruits and vegetables contain only small amounts of phosphorus.
Phosphorus content in food:
Milk, skimmed, 240 ml glass - 247 mg
Yogurt, plain fat-free, 240 ml glass - 385 mg
Mozzarella cheese, 100 g - 400 mg
Boiled egg, 1 piece - 104 mg
Beef cooked, 100g - 173 mg
Chicken cooked, 100g - 155 mg
Turkey cooked, 100g - 173 mg
Fish, halibut, cooked, 100g - 242 mg
Fish, salmon cooked, 100g - 252 mg
Bread, whole wheat, 1 slice - 57 mg
Bread, enriched white, 1 slice - 25 mg
Cola carbonated drinks, 350 ml - 40 mg
Almonds, 23 nuts (30 g) - 134 mg
Peanuts, 30 g - 107 mg
Lentils, 1/2 cup, cooked 178 mg
Phosphorus and Diet
Balance of calcium and phosphorus
Nutritionists recommend a balance of calcium and phosphorus in the diet. For example, the typical Western diet contains approximately 2 to 4 times more phosphorus than calcium. Meat and poultry contain 10 to 20 times more phosphorus than calcium, and carbonated drinks such as colas contain 500 mg of phosphorus per serving. When the body has more phosphorus than calcium, calcium is washed out of the bones. This can lead to osteoporosis (brittle bones) and to tooth decay and gum disease.
Calcium and Vitamin D
Parathyroid hormone (PTH) and vitamin D are responsible for regulating the balance of calcium and phosphorus. A slight decrease in the level of calcium in the blood (for example, in case of insufficient calcium intake) leads to increased secretion of PTH. PTH stimulates the conversion of vitamin D to its active form (calcitriol) in the kidneys. An increase in calcitriol levels, in turn, leads to an increase in intestinal absorption of calcium and phosphorus. Parathyroid hormone and vitamin D stimulate the resorption (destruction) of bone tissue, resulting in the release of bone tissue (calcium and phosphate) into the blood, increased excretion of phosphorus in the urine. As a result of increased excretion of phosphorus in the urine, the level of calcium in the blood rises to normal.
A diet high in fructose
A study in 11 adult males found that a diet high in fructose (20% of total calories) resulted in an increase in urinary phosphorus and a negative body phosphorus balance (daily loss of phosphorus exceeded the daily intake in the diet). This effect was more pronounced when the diet was also low in magnesium.
Available Phosphorus Supplement Forms
Elemental phosphorus (phosphorus) is a white or yellow waxy substance that oxidizes to a pale green glow (chemiluminescence) when exposed to air. Phosphorus is very toxic (causes damage to bones, bone marrow, necrosis of the jaws). The lethal dose of white phosphorus for an adult male is 0.05-0.1 g. In medicine, elemental phosphorus is used only in.
As food additives of phosphorus, inorganic phosphates are used, which are not toxic at normal doses:
● Monopotassium phosphate or monobasic potassium phosphate KH 2 PO 4
● Dibasic potassium phosphate K 2 HPO 4
● Monobasic sodium phosphate NaH 2 PO 4
● Dibasic sodium phosphate Na 2 HPO 4
● Sodium orthophosphate or tribasic sodium phosphate Na 3 PO 4
● Phosphatidylcholine
● Phosphatidylserine
Most people do not need to take phosphorus supplements, a healthy body gets the required amount from food.
Sometimes athletes use phosphate supplements before competition or hard training to reduce fatigue and muscle pain.
Phosphates are also used as laxative enemas.
Precautionary measures
Due to possible side effects and drug interactions, you should only take nutritional supplements under the supervision of a knowledgeable physician.
Too much phosphate can cause diarrhea, contribute to the deposition of calcium salts in any soft tissues or organs (calcification), affect the body's ability to use, calcium, and magnesium.
Minerals are part of the tissues of the human body, enzymes and hormones. Their concentration in the body is different, respectively, to ensure its normal functioning, a different amount of minerals is also necessary. Most of all in the body is calcium, so a person needs this chemical element most of all.
The role of calcium in the human body
Calcium belongs to the alkaline earth metals and has a high biochemical activity. The body contains about 1.5 kg of calcium. It is the main structural element of bones and teeth, is part of the nails, hair, soft tissues, extracellular fluid and blood plasma. Calcium is also an important component of the blood coagulation system, it maintains the correct ratio of salts in the human body.
Among the most important functions in a living organism is its participation in the work of various enzyme systems, including those that provide muscle contraction and transmit nerve impulses, change the activity of hormones, and so on. Calcium also affects the permeability of tissue cells for potassium and sodium, and has a stabilizing effect on the membranes of nerve cells.
Food is a source of calcium. With food, an adult can get about 10 g of calcium, pregnant women - up to 15 g, nursing mothers - up to 20 g. Calcium comes from food mainly in the form of insoluble salts that dissolve in the human stomach with the help of gastric juice, then exposed to bile acids, converting it into an assimilated form.
What happens when there is a lack of calcium in the body
The human body absorbs about half of the calcium that comes from food. A lack of calcium (hypocalcemia) can cause a number of painful changes in the body, the main of which is tetany.
Tetany is an increased neuromuscular excitability caused by a decrease in the concentration of ionized calcium (Ca ++) in the blood and in the intercellular fluid, which is manifested by seizures of seizures of individual muscle groups. Most often, tetany occurs with a general lack of calcium due to a lack of parathyroid glands. In this case, the production of the main parathyroid hormone (parathormone) decreases, which helps to reduce the calcium content and increase the phosphorus content in the blood, which causes convulsive readiness.
Other causes of hypocalcemia are: lack of vitamin D (for example, with rickets in children), diseases of the digestive system, accompanied by diarrhea (loss of calcium and impaired absorption), insufficient replenishment of calcium in pregnant and lactating women, impaired renal function, congenital disorders of phosphorus- calcium metabolism.
Tetany is associated with a change in acid-base metabolism to the alkaline side, which occurs with indomitable vomiting (diseases of the gastrointestinal tract, toxicosis of pregnant women, and so on), with the introduction of a large amount of soda solution to patients, with poisoning with oxalic acid (in this case, insoluble salts are formed calcium) etc.
How does tetany manifest itself?
Distinguish between explicit and latent tetany. A typical attack of tetany begins with precursors in the form of paresthesias - sensory disturbances (for example, goosebumps or numbness), after which muscle twitches begin, and then tonic (prolonged) convulsions of individual muscle groups.
The so-called carpopedal spasm is characteristic: convulsive contractions of the muscles of the lower extremities and flexor muscles. With convulsions in the region of the upper limbs, the arms are brought to the body, bent at the elbows, the hands are lowered down, the thumb is brought to the bent IV and V fingers ("obstetrician's hand"). If cramps begin in the lower extremities, the feet and fingers are in a state of plantar flexion, the sole takes the form of a gutter. With convulsions of the muscles of the face, it takes on a characteristic expression: the lips are parted (“fish mouth”), the eyelids are half-lowered, the eyebrows are brought together, the reduction of the masticatory muscles causes a sardonic smile. In severe cases, seizures may spread to the muscles of the trunk and diaphragm, causing bronchospasm and respiratory failure. In children, such a spasm can cause respiratory arrest and death.
The latent form of tetany is characterized by the absence of seizures. But at the same time, paresthesias and arching pains in the muscles of the limbs can occur.
Treatment of tetany due to calcium deficiency
An attack of tetany is removed by intravenous administration of 10 ml of a 10% solution of gluconate or calcium chloride. At the same time, drugs are prescribed that relieve nervous excitability (for example, Relanium). Further treatment is the treatment of the underlying disease that caused the lack of calcium in the body.
Since calcium has a relatively low bioavailability (only half of it is absorbed from food), in order to maintain normal metabolic processes, it needs additional intake in the form of dairy products, dietary supplements, and so on.
Unlike more common clinical and biochemical tests, electrolytes are not as well known to most patients, especially since they make up only 0.9% of the total plasma volume. In fairness, it is worth noting that some of them are mainly located inside the cells, and some in the extracellular space, namely in the vascular bed. Moving on both sides of the cell membrane, electrolytes maintain an electrical potential. To a greater extent, this applies to potassium, sodium and chlorine. However, a blood test for the level of phosphorus and calcium, an increase or decrease in their amount also carries a colossal information load.
What role does calcium play
It is generally accepted that the mineral calcium is strong bones and healthy teeth. Part of the statement is true. In the body of an adult, neither more nor less than 1-2 kg of this chemical element and 98% are in the skeleton. But this is only a depot, a kind of calcium warehouse, it constantly moves from bones to blood and back, depending on the needs of the whole organism, and they are very diverse:
- calcium regulates the work of the cardiovascular and endocrine systems;
- is one of the blood coagulation factors;
- provides contraction of skeletal muscles;
- catalyzes many biochemical transformations, regulating metabolism;
- structural function is expressed in the formation of the skeleton.
Total calcium consists of 3 types - ionized or in ionic form, in the form of cations, non-ionized or associated with albumins and in the form associated with anions, that is, in the form of salts of phosphates, carbonates, lactates and citrates.
This mineral is so important that in order to maintain its homeostasis, nature has created a mechanism to control the movement of calcium. Indeed, in addition to removing the element from the bones, if necessary, a person gains it from food (milk and dairy products, cottage cheese, hard cheese, beans, seafood, leafy greens, nuts) and even with water (in 1 liter up to 500 mg). Absorption depends on many factors. Foods rich in magnesium and potassium, tea and coffee, alcohol, fatty foods, dietary fiber prevent full absorption. Ca\P imbalance also impairs absorption.
The regulation of calcium levels schematically looks like this. The product of the parathyroid glands PTH (parathyroid hormone) reacts to a decrease in the mineral in the plasma. An increase in PTH serves as a signal for osteoclasts to release calcium from the bones. At the same time, the kidneys also receive a signal to increase the reabsorption of calcium in the tubules of the kidneys, thus, its amount in the blood increases. When calcium in the blood rises, another substance, calcitonin, comes into play. Increasing its secretion is a command for osteoblasts to take calcium back into the bones. Bone modeling is carried out in the presence of vitamin D.
The output occurs through the intestines, slightly excreted by the kidneys. Maximum excretion in the morning, enhanced in the presence of carbohydrates.
The daily need for calcium is greatest in children, expectant mothers and breastfeeding women. An adult needs 0.8 - 1.2 g per day, this group needs 2 times more.
Why do we need phosphorus
Compared with the previous element of phosphorus, the body contains less, 600-700g, that is, approximately 1% of body weight. Of this amount, 90% is found in bones and teeth, 9% in cells, and only 1% in serum.
The main role of phosphorus will immediately become clear to anyone who remembers what ATP is - adenosine triphosphate. Advanced in biochemistry will recall ADP and creatine phosphate. Energy transfer is what phosphorus is for. Of course, his role does not end there. Without it, the metabolism of carbohydrates and fats is not complete, it is part of DNA and RNA, its presence helps the "partner" to be absorbed in the small intestine, it is needed for the work of muscles, the heart muscle, during the phosphorylation of vital amines. Biochemists can find phosphorus in plasma in different forms:
- organic phosphoric esters;
- inorganic orthophosphates;
- free nucleotides;
- phospholipids.
Regulation is carried out by the same PTH and calcitonin. An increase in PTH triggers a mechanism to reduce the level of phosphorus derivatives in the blood by inhibiting reabsorption in the kidneys and activating excretion through the urine. Calcitonin works in a similar way. Insulin promotes the transition of phosphorus into the cell, while reducing the concentration in the serum. Also, as in the case of calcium, there is a direct and reverse skeletal-serum transition. Hypercalcemia decreases PTH levels and increases phosphate reabsorption.
Food sources of this mineral of various origins are legumes, meat, fish. Absorption is also carried out in the 12-colon, the most successful ratio for the maximum absorption of both minerals P \ Ca 1: 1 - 1.5.
It is excreted from the body through the intestines and kidneys in the form of Ca, K and Mg phosphates.
An adult needs 0.9 g per day, some authors argue that the real need for phosphorus with food for adults is 1.6, and a child needs 1.5 - 1.8 g. Of course, the need increases in expectant mothers and lactating women.
Who should take a blood test
A biochemical blood test for calcium and phosphorus must be taken in a pair of P and Ca. Total calcium is determined, more accurate data is obtained by determining ionized calcium. It is advisable to examine patients in preparation for a surgical operation, if a malignant neoplasm, peptic ulcer and urolithiasis are suspected, if deviations from the norm are suspected.
Common symptoms are headaches, weakness, fatigue.
Hair splits and falls out, teeth collapse, nails peel and break, skin dries and cracks, leg cramps torment, blood clotting is disturbed - all this indicates a calcium deficiency.
With an increase - increased reflexes, loss of orientation up to immobility, cardiovascular problems, nausea and vomiting.
An increase in phosphorus can be suspected in case of renal failure, a decrease in the function of the parathyroid gland, the decay of tumors, and various types of acidosis.
A slight decrease in phosphorus has no clinical signs. A pronounced decrease manifests itself as muscle weakness, impaired function of erythrocytes and leukocytes, loss of appetite, paresthesia, and bone pain. A decrease is observed in people who abuse alcohol, after overeating or leaving a starvation diet, burns, ketoacidosis.
Signs of rickets and softening of the bones are also a reason for examination.
Preparation for a blood test involves the exclusion of physical and emotional stress, alcohol, fast food, overeating of fatty meat foods and calcium-rich foods on the eve of blood sampling. Blood is taken from a vein, on an empty stomach, on the day of the examination, before blood donation, fluorography, radiation diagnostics, intravenous drip injections of drugs are prohibited. You should inform the doctor about the drugs taken on a regular basis. For example, taking vitamins A and D, progesterone, diuretics can show an increased result, and taking tetracycline, insulin, magnesium preparations, estrogens, and infusion of glucose - on the contrary.
Norm and interpretation of the analysis
The analysis form usually contains normal performance for different age groups. The norm is given for total calcium and for ionized.
The adult norm is considered from 17 years. Total calcium in the blood is in the range of 2.15 - 2.5 mmol / l.
Ionized calcium 1.13 - 1.32 mmol / l.
The age norm in persons over 60 years of age shifts upwards of 2.2 -2.75 mmol / l. This is explained by the fact that physiologically, with age, the processes of calcium leaching from the bone prevail over the processes of its accumulation in the bones.
In newborns, the norm is 1.8 - 2.8 mmol / l, up to a year 1.75, over 2 years 2 - 2.6 mmol / l.
The phosphorus rate also has some fluctuations depending on age:
- Up to 2 years 1.45 - 2.16
- From 2 to 12 years 1.45 - 1.78
- Adults - 0.87 - 1.45, all indicators are given in mmol / l.
After 60 years, the norm for the sexes varies: women 0.9 - 1.32, men 0.74 - 1.2 mmol / l.
Deviation from the norm, even in the absence of symptoms, is a reason for an in-depth examination. After evaluating the results, the doctor prescribes biochemical tests, a study of hormones, densitometry and other examinations. The goal is to find out the cause of the increase or decrease and prescribe nutritional and drug correction.
Hypercalcemia is caused by diseases of the thyroid and parathyroid glands, excess vitamin D, kidney damage with chronic renal failure, leukemia, sarcoidosis, cancer of various localizations, osteoporosis, post-traumatic period, and hereditary factors.
Hypocalcemia occurs with a lack of vitamin D, a decrease in the function of the parathyroid glands, pancreatic necrosis, chronic liver and kidney failure, conditions of acidosis - alkalosis.
Phosphorus increases with kidney disease, starvation, excessive dieting, gastrointestinal disorders, malnutrition of foods containing calcium, bone problems. There is a low level of phosphorus in anorexia, alcoholism, diabetes mellitus, Crohn's disease. A decrease in children is the cause of slow growth.
Where to take a blood test
With the current development of the private sector of services, including clinical diagnostic laboratories, the question of the place for taking a blood test does not arise at all. You can use the KDL INVITRO network. Work experience since 1995, offers more than 1700 blood tests in 900 offices opened on the territory of Russia and neighboring countries. You can book an examination online.
Prices are available. Total calcium 275 rubles, ionized calcium 450 rubles, inorganic phosphorus 285 rubles.
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