Calcium is at the same time a major element of bone and dental tissues, and the activator of many biochemical operations allowing the muscular contraction, coagulation, etc.
discovery
DISCOVERY
The role of calcium in ossification was suspected during centuries. The prehistoric man sufIroned already from osteoporosis. And it is by studying the skeletons of the Egyptian mummies which one had the idea that the exposure to the sun could protect from demineralization
In 1842, the Chossat French shows in the pigeon that a lack of calcium weakens the bones, and consequently that this mineral is essential
Characteristics
CHARACTERISTIC
Calcium is the mineral whose human body is richest. It contains some, in the adult, of 1 000 to 1 500 G according to weight's, of which 98 % to 99 % are in the skeleton and the teeth. It thus constitutes 1,6 % of the total weight of the body. The 1 % no osseous also has an essential importance. It is distributed between the extra and intracellular mediums
roles
ROLES
Calcium plays of multiple physiological roles the construction of the bone and the teeth, of which it ensures, related on phosphorus and magnesium, the growth, solidity and maintenance
The pressures which the body from the station undergoes upright and from the movements which one makes exert on some points of the skeleton. Also, although the bone is carried out starting from an accumulation of solid crystals, it would break very quickly on the level of these points of pressure if it unceasingly were not disassembled and were not reassembled. When that arrives, one speaks about "fractures of tiredness".
Small cells, the osteoclasts, thus demolish unceasingly the bone and others rebuild it behind they are the osteoblasts. It is this permanent renewal which prevents occurred of fractures and tiredness.
In addition to the calcium, which constitutes principal material of these crystals, of many other elements are also necessary.
The vitamin D initially, for absorbing calcium well and fixing it on the osseous screen. The phosphorus and the magnesium, then, which are integrated with calcium.
Magnesium proves also essential with the good distribution of calcium. Indeed, as for potassium or sodium, it takes part in the control of its distribution in fabrics. If magnesium is missed, calcium can enter in too great quantities the cells of soft fabrics and calcify them instead of going to fix itself in the skeleton.
It is one of the factors which carry out to the renal calculi, with the peri-arthritis scapular humeral, the calcification of the arteries. Zinc, the B6 vitamin and the vitamin C also take part in osseous mineralization
Hormonal factors also play an important part. Estrogens, sex hormones principal at the woman, contribute to support osseous mineralization. However, with the menopause, their rate falls. From where the acceleration of a phenomenon of demineralization which, actually, starts in the two sexes as of the 20 years age, and from where interest of a hormonal treatment the menopause
Nevertheless, this treatment has against indications. The question of knowing if it increases the frequency of certain cancers of the woman is still discussed. And it seems that its effectiveness is limited if calcium and the other nutrients necessary to osseous mineralization are not present in sufficient quantity, which is generally the case; and that all the more on the no vertebral bone (least sensitive to estrogens
Otherwise known as, it is especially calcium and its accomplices who allow to reduce the frequency of the fractures of the collar of the femur or the wrist.
The estrogens are not the only ones in question. If one misses of a little calcium in the food to provide his functions other than osseous mineralization, a small gland attached to thyroid gland, the parathyroid gland, secretes the para-thormone which will demolish a little bone to release the missing quantity of calcium
This is why the blood calcium rate remains remarkably fixed, and the quiet calcium deficit during very many years before one does not sufIron from osteoporosis (reduction of the size and pains of vertebral compressing, fractures of the collar of the femur or the wrist).
The other hormones which play a part in the metabolism of calcium and the bone are the calcitonine and the growth hormone.
The functions independent of the mineralization in which calcium intervenes are:
>Muscular contraction and movements of the heart. >The coagulation of blood.
>The detachment of fatty acids of the cellular membrane to produce mediators of the ignition and allergy.
But, calcium balance inside the cell, between each of its parts (membrane, mitochondria, nucleus, …) and its potential link to regulating proteins, like cahnodulin, appear to be more and more important. Excess calcium inside the cell can reduce its energy and possibly lead to its “suicide”, called apoptosis.
WHEN THE NEEDS ARE THEY INCREASED?
WHEN THE NEEDS ARE THEY INCREASED?
In period of growth (infants, children and teenagers), during the pregnancy and, more still, breast feeding, at the old person and at the time of fractures.
SOURCES
They are varied but, in practice, calcium is especially brought currently by dairy produces and, with a less degree, by fresh vegetables.
The champion all categories in contribution of calcium is the Parmesan (undoubtedly Italian to have some with table is systematically necessary it to be, in grated form), then the Gruyere and, at a less rate, the other cooked cheeses in a hurry the blue ones are rather rich too.
DAIRY PRODUCTS
Is this good thing to receive the major part of your calcium of the dairy products? The question is discussed more and more, because:
The calcium of cheeses is associated great quantities of saturated fatty acids which bring many calories, increase the risks of cardiovascular pathologies and certain cancers, and form with the calcium of the molecules connected with those which constitute the soaps, which involves an interrogation on its absorption.
Milk is physiologically designed by mothers for infants; it is artificially that one made a food according to weaning of it.
Milks present compositions in cells, proteins, lipids, minerals and vitamins which are specific of each species. Thus, the milk of woman is very difIronent from the ewe or goat, cow's milk. And precisely, for the development of the baby, as the health of the adult, the cow's milk appears far from being ideal. It has antibodies which want nothing to say, it human being, the proteins most frequently allergenic of all food, more saturated fatty acids, less polyunsaturated fatty acids, more phosphorus, much less vitamin C, which the milk of woman.
Frequent consumption of dairy products seems to be linked with increase risk of diabetes, sclerosis and cataract.
SOLUTIONS
Then, that to make?
The first measure, we have developed in the introduction, is, baring kidney stones or kidney failure, to drink water filled with minerals, rich in calcium. Two great advantages are associated with this: 0 calorie and protective magnésium added.
The second is to eat yogurts, 2 or 3 a day (you can also use yogurts to make sauces, deserts, …) since they are difIronent from other dairy products: Ironmentation modifies their composition and brings new molecules, shown to be favorable to health. You can, from this point of view, be happy that the dairy industry in this area.
Third is to replace the cow's milk by milk of soya enriched with calcium (one finds some now in the great distribution), for the preparation of cereals, sauces, and the majority of the receipts of kitchen. The tofu, even carried out starting from milk of soy not enriched, is richer in calcium than the cow's milk.
Fourth is more frequently to consume of other rich foods in calcium almonds (2 times richer in calcium than the cow's milk), Brazil nut, nut, olives, cruciIrons (cabbage, sauerkraut, broccoli...), fatty fish, in particular whole sardines.
Les rates vary a lot in vegetables, and fresh and dried fruits. Leafy vegetables bring 80 mg for every 100 g on average, but watercress 150 and small salad 20. Root vegetables, 50 mg on average, but beets 150 and carrots 20. Other vegetables about 20 mg.
Spinach contains much calcium, but it is badly absorbed from the presence of oxalate. The same phenomenon affects the calcium of the cocoa and the chocolate. The fruits contain of them little the fresh fruits between 20 and 60 mg/100 G; dry fruits between 100 and 170 mg/100 G, owing to the fact that they contain less water.
In practice, it is necessary to tend to a daily contribution located between 1 G at 1,5 G; 500 calcium Mg being brought by 1 liter of Hépar or Contrex, by 0,5 liter of milk of soy, 100 G of almonds with 2 yoghourts, etc.
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Supplementary food
Vitamin A
