Potassium is, like sodium, an electrolyte or ion, carrying a positive electric charge. II is during equilibrator of sodium, and it for this reason plays a fundamental part in the distribution of water in the organization.
DISCOVERY
Claude Bernard (1813-1878) emits in 1865 the concept of the "interior medium", implying a balance between blood and fabrics, l% homeostasis. But it is much later than one will discover than the exchanges between potassium and sodium are essential in this homeostasis and than their imbalance can involve retention of water and sometimes hypertension. The discovery in 1938 of the essentiality of potassium is due to Mac Collum.
CHARACTERISTICS
The organization of a person weighing 70 kg contains of them approximately 140 G, of which 90 % are localized inside the cells. Its rate in the extra cellular liquids is weak. Its concentration is higher in the digestive liquids than in plasma.
The ion sodium is driven back interior of the cell towards the extra cellular liquids in exchange of ion potassium integrated in the cell. It is not thus astonishing to note that sodium is on the quantitative level the principal cation (positively charged ion) extra cellular, potassium being the principal intracellular cation, and that their concentrations on both sides of the cellular membrane are equal.
But potassium does not attract water like sodium, which maintains it mainly in the interstitial liquid bathing the cells, in the liquids circulating like blood, the lymph or the spinal liquid, with regard to the brain and the spinal cord.
II also one of the contributors of acido-basic balance represents. In this function, it is exchanged against a hydrogen ion, still called "proton"' balance between all these ions is particularly important for cardiac fabric.
In the event of lack or excess of potassium in the myocardium, of the disorders of the rate/rhythm or arrhythmias can occur. The lack of magnesium, the lack of oxygen due to a spasm of the coronary arteries or their obstruction by plates of atheroma or of the stoppers of plates, can involve a tiredness of the cells, which, instead of remaking energy, secrete lactic acid.
The local acidosis thus produced leads the cells of the heart then to lose potassium, which worsens the problems.
Potassium is mobilized by the cells at the time of new syntheses, for example those of proteins like muscle fibers, or energy reserves (glycogen); it is released in the situations opposite. The construction of these new molecules is called "anabolism", their destruction "catabolism".
The anabolism dominates during the pregnancy, the growth, at the time of the muscular development; catabolism, at the time of an infection, burns, at the time of ageing.
In these circumstances, the total potassium reserves decrease in proportion of the muscular loss of mass and energy reserves.
NEEDS
The needs are not quantified exactly. A food bringing more potassium than of sodium is associated a reduction of the risk of hypertension. However, in the current situation, it is most of the time the opposite which occurs. The needs are increased at the people sufIroning from vomiting or diarrheas important and/or prolonged, those treated by drugs involving of the potassium losses like the laxatives, corticoids, unquestionable diuretic, and in the children consuming of the excessive quantities of liquorices.
SOURCES
The daily contribution varies between 2 and 6 G per day. The principal sources are the dry fruits, the oilseeds, the banana, the fresh vegetables, the cereals, the leguminous plants.
The majority of rich foods in potassium are low in sodium. One also finds some in certain drinks like the tea and the chocolate.
SIGNS OF DEFICIENCY AND DEFICIENCY
Imbalances of the distribution of potassium between the mediums will intra and extra cellular appear much more frequently than the deficiencies. The majority of the disorders of the distribution appears by retention of water and is associated, as it will be seen, with an excess of sodium entry in the cells, accompanied by an excess of exit of potassium.
This imbalance, noted thanks to the proportioning of potassium will intra erythrocytic (measured inside the red globules) is often related to a lack of magnesium. The potassium deficiency frequently coincides with a magnesium deficit, and the signs and symptoms of the lacks in these two elements are re-cut (feelings of swarming, muscular weakness, tiredness, cramps, hyper reactivity, extra systoles...).
If the cause of acute or prolonged loss caused a severe deficiency, there is risk of paralysis, including intestinal, and of cardiac arrhythmia.
RISKS OF OVERDOSE
Potassium can, taken in medicinal form, to ulcerate the intestinal wall; from where the development of forms which are released in a no aggressive way (Diffu K).
The overdose or accumulation due to diuretic a potassium savior, a renal insufficiency or a massive exit of the cells (burns, traumatisms) represents a danger to the court, on which operation depends on a good ionic balance, and is likely to involve disorders of the rate/rhythm which can go until the heart failure.
PREVENTIVE ROLE
The principal recommendation consists in increasing the frequency of consumption of rich foods in potassium and low in sodium vegetables and fruits, cereals complete, oleaginous, leguminous, in particular.
The supplementation presents a danger and must be given only under medical supervision. It is essential to prevent the deficits pulled by the catch continues certain drugs like corticoids.
At the time of burns, traumatisms or other acute situations, balance between the ions must be strictly controlled thanks to perfusions and with often repeated biological proportioning, the potassium release by the destroyed cells which can have perverse effects.
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Supplementary food
Vitamin A
