Sodium chloride
Sodium chloride is the chemical name of the most commonly known "table salt"; it is the sodium salt of hydrochloric acid, which is crystalline and colorless at sight, characterized by its typical color and taste.
Kitchen salt is readily available in nature, both as a terrestrial crystal (rock salt) and as an electrolyte in sea water, from which it can be extracted directly (desalination) or indirectly from the crystals deposited on the ground. One of the oldest methods for collecting sea salt from the kitchen is the solar evaporation of sea water, performed in the so-called salt pans; moreover, a certain refining is carried out in the production of sea salt, which involves the separation, therefore the exclusion, of other types of salt from sodium chloride. Artificially, water evaporation can be achieved through the use of electric current.
Types of table salt
The table salt can be classified according to
Origin nature:
- Marine: of marine origin
- Terrestrial: of terrestrial mineral origin
Degree of refining:
- Refined salt: 99.9% NaCl
- Integral salt: natural, without refining; contains: iodine, magnesium, sulfur, zinc, copper, phosphorus, etc.
Ionic composition:
- Hyposodium salt: it is more deficient in sodium (Na) to the advantage of potassium (K); frequently recommended to combat ARTERIAL HYPERTENSION
- Asodic salt: totally sodium-free; it also finds application in the fight against high blood pressure
- Iodized salt: it is added in iodine; it is a widely consumed dietary salt. Its use has been suggested for the fight against iodine population deficiency and for the reduction of related thyroid complications
Elaborate salts
- Gomai: type of oriental salt added in toasted sesame seeds or seaweed.
Nutritional aspects
The kitchen salt, as already exposed, is the result of the crystallization of sodium (Na) and chlorine (Cl) in proportions of 40% and 60%; it can be seen that 0.40 g of sodium and 0.60 g of chlorine are introduced for every gram of table salt.
On a nutritional level, unlike what happens with other micronutrients, both for sodium and chlorine it is quite simple to reach the recommended intake levels (LARN), which are respectively:
- Na + - 575-3500 mg / day for adults (but not less than 69-460 mg / day) equivalent to 1.5-8.8 g of table salt
- Cl- - 900-5300 mg / day for adults (1.5-8.8 g of table salt)
In the event that frequent use is made of whole salt (rich in other ions), hyposodic (containing K) or iodate (containing iodine), the levels of intake of other electrolytes at the expense of sodium chloride are increased proportionately. The minerals of greatest nutritional interest are:
- Potassium (K): main intracellular cation; fundamental for the trans-membrane cellular passage of molecules against concentration gradient, and for maintaining the acid-base balance. The minimum intake is easy to reach (1600 mg / day), while the excess is PHYSIOLOGICALLY improbable; however, it is advised (especially in the presence of renal impairment) NOT to abuse potassium-containing salt as it may be a source of excessive intake.
- Iodine (I): fundamental constituent of thyroid hormones, therefore its function is mainly bio-regulation. The deficiency is widespread and almost ubiquitous among the regions of the Italian peninsula; this, if serious, can determine the "thyroid goitre" and in order to prevent its onset it is advisable to take at least 150 µg / day of iodine. In pregnancy it would be appropriate to reach an additional surplus of 25 µg / day.
- Magnesium (Mg): it is very important in many metabolic processes and also in the energy-dependent trans-membrane cell transport; furthermore, magnesium constitutes more than 300 different enzymes. The minimum magnesium intake can be around 210-320mg / day, but a safe range of 150-500mg / day is recommended.
NB . The intake levels shown above refer to the general population; athletes and athletes may need (depending on the volume, intensity and importance of sweating) significantly higher saline intake.
