| Resumo: |
Calcium binders are water- soluble substances whose anionic part can possibly react with calcium cations present in any part of the human body. Some examples of calcium binders are phosphoric, oxalic and phytic acids and their alkaline salts present in many natural foods, in some foods containing additives, and in some medicines. There are also uric and lactic acids that are the result of normal metabolism. The first negative action of calcium binders takes place in the intestinal tract when they react with calcium of dairy food. The latter produces a combination of calcium binder anions with calcium cations, and then an insoluble salt that precipitates as small solid particles that cannot be assimilated and which are eliminated in the faeces. The second negative action of calcium binders takes place when soluble calcium binders are assimilated into the blood circulatory system and get in contact with the free ionized calcium in serum, which gives rise to complexed calcium with inorganic and organic anions. Immediately the free ionized normal level of calcium in blood serum decays, and the parathyroid hormone comes into action (secondary hyperparathyroidism) extracting free ionized calcium from bones (bone resorption). The soluble complexed calcium circulates in the serum through the whole blood circulatory system, and because it is ultrafiltrable, it freely filters through the glomerulus and is excreted in urine. The final result is the formation of the corresponding salts in a metastable state, concentrated near the point where the precipitation of these salts occurs. This special condition is due to the fact that certain proteins are inhibiting the precipitation. In some soft tissues with chronic inflammation, the above-mentioned metastable state is affected because the inhibitory mechanism is blocked, causing the formation of calcium phosphate salts nuclei in the tissue and the build up of calcium phosphate crystals. This triggers causes many serious diseases. Finally, it is suggested that a start can be made on preventing the action of calcium binders by controlling diet, especially by avoiding high intakes of phosphates, oxalates and phytates.
|
