November 26th, 2009
Calcium is the most common cation in the human body, and a very important mineral for the maintenance of neuromuscular function. It represents 2% of body weight and 26% of the dry weight of bones and teeth, such as phosphates and carbonates. Approximately 0.5 g of serum calcium must be replaced with bone calcium daily.
ABSORPTION
The absorption of calcium depends on the factors listed below.
1. Body needs. In a normal person, only 30% of the calcium is absorbed, but in aLack person is included, the share higher.
2. Concentration. Other factors are equal, the higher the concentration of calcium in the diet, the greater the absorption.
3. Motility. Haste gut reduces the absorption of calcium. With chronic diarrhea, and prolonged use of laxatives, is significantly reduced calcium absorption.
4. Fat. When fat intake is deficient, as in steatorrhoea, calcium. Combined with fatty acids in the intestinal lumenShape
insoluble calcium soaps. Reduced fat intake also reduces the absorption of vitamin D.
5. Recorded food. The absorption of calcium from the diet is similar, whether it is taken as whole milk, chocolate, yogurt or
Cheese. The absorption is similar, if calcium is taken with milk or calcium acetate, lactate, gluconate, citrate or carbonate.1 The amino acid L-Iysine helps positive calcium balance, not only because it enhances calcium absorption, but alsobecause it improves the conservation of the absorbed calcium. Lactose (milk sugar) and amino acids such as arginine and tryptophan, improve calcium absorption. When co-administered with glucose polymer, increased the absorption of calcium chloride 1.5 to 5-fold in vitamin D-deficient patients.
Cereals contain phytic acid (inositol hexaphosphate), which combines with calcium to form insoluble calcium phytate, which is not absorbed, too. Even foods containing oxalate, such as spinach, combinewith calcium to form insoluble calcium oxalate. An excess of magnesium increases evidently absorption of calcium. Intestinal lactase deficiency leads to reduced milk (and calcium) intake and if possible also reduces calcium absorption.
6. Is vitamin D. The most important factor in promoting the absorption of calcium vitamin D, which stimulates the formation of an enhanced calcium-binding protein, the calcium absorption. When vitamin D is not consumed, as with a strict vegetarian(vegan)
Diet (which also includes milk than assumed to be of animal origin), or if the skin is not sufficiently exposed to sunlight, severe vitamin D deficiency leads to poor absorption of calcium.
Vitamin D3 (calcitriol: 1,25 Dihydroxy-vitamin-03) 400-800 IV may be useful in ensuring your calcium intake. At high doses of vitamin 0, the absorption of calcium from food are almost completed and it is possible to maintain a positive calcium balance, even at a lowRecording.
Glucocorticoids and alcohol reduce intestinal absorption of calcium.
7. Calcium-phosphorus ratio. The ratio of calcium to phosphorus in the diet has an important influence on absorption. Most of the food
that a proper ratio of calcium and phosphorus. Milk, eggs and certain leafy vegetables such as lettuce offer these elements in the required proportions.
Blood levels
Calcium is present in plasma, but not in the red blood cells. The serum levels of approximately] 0 mgper 100 ml (2.4 mmol / l), about half
one of which is ionized and the remainder is bound to plasma proteins. Ionized calcium is diffusible. His normal serum level is obtained by the parathyroid glands. Alkalosis reduces the level of ionized serum calcium levels. Reduction of calcium ions leads to an increased muscular irritability and tetany.
The rest of the serum calcium is bound to proteins, primarily albumin, so that when the plasma albumin is the level of serum
Calcium is low, but since theseDecrease is only in the form of non-diffusive, not develop tetany.
Regulating factors
Parathyroid hormone (PTH), mobilizes calcium and phosphorus from the bones to hold the blood.
Hyperparathyroidism causes absorption of minerals together. bone matrix, so that an X-ray appearance of cysts in the
Bones (osteitis fibrosa cystica), most clearly in the skull. It can also be used as kidney without demonstrable bone disease. PTH also stimulates theMitochondria of the kidney to increase the conversion of Calcifediol to calcitriol, which improves
intestinal absorption of calcium.
Calcitonin is a peptide hormone that is produced by the C cells of the thyroid. After a very short half-life is excreted
continuously. Secretion with increasing serum calcium. It helps to increase blood levels of calcium to prevent release from the bone and urinary excretion obtained.
Therapeutically used when serum calcitoninCalcium is high, as in Paget's disease (where it decreases bone resorption),
and hyperparathyroidism and breast cancer (where it increases urinary calcium excretion). Estrogen raises the levels of calcitonin and prevents bone loss. Postmenopausal bone loss is attributed to decreased estrogen, calcitonin, therefore more
as estrogen therapy for prevention of postmenopausal bone loss suggested, as well as for the treatment of
Osteoporosis.
STORAGE
Most of the body calcium (99%) is stored in bones and teeth. The skeleton is the dynamic memory, where calcium is continuously stored and resumed. This dynamic activity is high in the young and declines with age. About one percent
of total body calcium is in the circulation and soft tissues.
An episode of mild to moderate malnutrition, during the first years of life, is linked to many years later with
increased dental caries in both deciduous and permanent teeth.
At puberty, under the influence of sex hormones, girls gain about 200 mg and 400 mg of boys, calcium per day. Positive calcium balance occurs only if the calcium intake above 1000 mg per day.
Excretion
About half of the daily calcium intake is excreted in the feces, which unabsorbed calcium and calcium from endogenous
Sources. If a high dose of vitamin D is taken in the calcium content of theChairs from.
About half of the total daily calcium intake is excreted through the urine. Urinary excretion of calcium is the result of
glomerular filtration and tubular reabsorption from. The urinary excretion of the parathyroid gland is under the control and
usually represents endogenous calcium. The normal range of calcium excretion in adults on a normal diet is 100-300 mg (2.5-7.5 mmol) per day for men and 100-250 mg (2.5-6.5 mmol) per day for women. The kidneys receiveCalcium deficiency in.
With normal renal function, which is excreted about eight percent of the filtered calcium. With the administration of diuretics
Furosemide or ethacranic acid, the absorption of calcium through the kidneys is inhibited and increases the urinary loss of 12%.
Thiazides, on the other hand, the conservation increases renal tubular reabsorption of calcium, urinary tract and the loss is only three
Percent. Therefore, especially in elderly patients with high blood pressureWomen's bone loss and osteoporosis occur with furosemide. Thiazide is recommended for the prevention and treatment of osteoporosis. By reducing calcium excretion,
Thiazide is also helpful in preventing a recurrence of kidney stones.
High-protein diet reduces absorption of calcium through the kidneys and increased urinary calcium excretion.
FUNCTIONS
Calcium and phosphorus are necessary for bone formation.
Bone consists of a protein matrix (frame), whereCalcium phosphate is deposited. Protein, vitamins A and C, and gender
Hormones are necessary for the formation of the matrix. The calcium in the bones is always switched over to using calcium
Blood and other tissues, with a rate of 0.5 g (12.5 mmol) per day.
Ionic calcium affects neuromuscular excitability of both voluntary and involuntary muscles. If the serum calcium ion
Concentration. is reduced significantly increased neuromuscular excitability, asin tetany.
Calcium is also necessary for blood clotting and maintenance of the permeability of the capillaries.
SOURCE
Milk and milk products are the best sources of calcium. Calcium in milk is received better than in other foods, because improving lysine and lactose (milk sugar), calcium-recording. Fatty preparations such as butter, cream and ghee are poor in calcium, however, contain a sufficient amount of vitamin D, which aids in calcium absorption.
The daily calcium requirements of a mancan easily be supplied by a cup of buffalo milk. Molasses, and vegetables such as peas, beans, legumes, potatoes, cauliflower, and dried figs, also supply calcium. Pumpkin leaves have a calcium content of 240,300 mg (6-7.5 mmol) per 100 g. The chewing of betel leaves with lime (calcium hydroxide) increased food calcium. Hard water contains calcium, which can be better absorbed in tropical countries with vitamin D obtained from sunlight. Those who chew bones are also assured adequateCalcium intake. A solution of bone soaked in vinegar for several weeks, is a practice of the Indo-Chinese, a good source of calcium.
The tropical diet of rice, wheat or millet lack of calcium, but the body Sunlight produces vitamin D, which
improves the absorption and tends to compensate for the low intake. In the west of the mandatory addition of calcium (fortress) of wheat-flour ensures adequate calcium intake.
Calcium carbonate is the cheapest commercialSource of calcium.
REQUIREMENTS
People have a remarkable ability to adapt to low calcium intake, it is due to the decreased renal excretion and balance
increased intestinal absorption.
The daily requirement of calcium intake depends on factors are positive or negative, in the recording. In
Tropics, with exposure to sunlight, a positive balance of calcium is maintained at a lower calcium intake than is generally
recommended. TheRequirement increases with physical activity, and is greater among athletes.
The current calcium intake of American girls during the pubertal growth period is not appropriate, and increased intake was
recommended.
Pregnancy increases the demand, as well as the absorption of calcium. An infant at birth more than 20 g (500 mmol) of calcium, most of it is a whole during the last three months, when the bones are formed of the fetus. Even if extra calcium is notby the mother claimed, the fetus is more calcium from the bones of the mother. For severe shortage of calcium may be the mother suffering from osteomalacia. About 1.2 g (30 mmol) of calcium per day is adequate for the
Mother during the last trimester.
Lactation involves loss of calcium in human breast milk contains 20-30 mg of calcium per 100 ml (5-7.5 mmol / l). When 1000 ml of milk
isolated, 300 mg (7.5 mmol) of extra calcium to be absorbed by the mother. Even "if the motherCalcium intake is not
is sufficient, the concentration of calcium in the milk to the required level by mobilizing obtained from the bone. In order for loss and daily needs, a nursing mother requires 1.2 g (30 mmol) of calcium daily.
Infants are breast fed will need 50 mg (1.25 mmol) of calcium per kg of body weight daily. Artificially infants need two to three times that amount of calcium, since the absorption is not from artificial sources as efficiently as from motherMilk.
Deficiency (hypocalcemia)
Low serum calcium levels seen listed fn situations.
1. Hypoparathyroidism and pseudohypoparathyroidism.
2. Vitamin D deficiency (i) due to poor nutrition, (ii) in regions where women put themselves to sunlight, or (iii) by
diminished absorption in steatorrhoea.
3. Low serum protein (hypoproteinemia), in which the non-diffusing portion is reduced bound to albumin.
4. Kidney diseases in whichThere is retention of phosphate or non-acidified the urine, resulting in a systematic and acidosis
Loss of calcium.
5. Acute pancreatitis, where the pancreatic enzyme lipase in the abdominal cavity and blood, releasing fat breakdown in
Glycerol and fatty acids, soaps, the latter combination with calcium to form.
6. Taking drugs and toxins such as sodium, fluorine, and viomycin.
7. After hypothermia for cardiac surgery.
8. After gastric surgery,probably due to insufficient vitamin D absorption. These patients respond to daily oral dose of 32.5 micrograms or weekly injections of 25 micrograms of vitamin D. Some cases of hypocalcemia after gastrointestinal surgery may be replaced by hypoproteinemia.
9. High-protein diet, urinary calcium excretion increased.
10. Rheumatoid arthritis, in which calcium is a significant early loss of the disease.