Sodium daily intake

Sodium, like potassium and chloride, is an electrolyte. Electrolytes are dissolved substance that maintain the human body’s fluid balance both inside and outside the cells.

The value of salt has been recognized for centuries. The common expressions of “salt of the earth” and even the word “salary” all derive from high value placed upon salt throughout history.

The requirement for sodium is not well defined, but human dietaries generally contain more sodium than necessary. In both normal individuals and people with CRF only about 1 to 3 mEq per day of sodium are excreted in the feces and in the absence of visible sweating, only a few meq per day of sodium are lost through the skin.

Tissue formation, as in growth, requires about 1.1 -1.2 mg/kg of tissue gained; the requirement for maintenance should be considerably less. Intakes vary widely; about 10 gm NaCl/day appears to be usual for most Americans, whereas intakes of 30 – 40 gm/day are not uncommon in Oriental countries where soy sauces and sodium glutamate are flavored as flavoring agents.

The American Heart Association and JNC 7 guidelines recommend a dietary sodium intake of no more than 2.4 g or approximately 100 mEg sodium per day. This translates to 6 g sodium chloride per day.

The RDA for sodium is 2.3 g daily for women and men aged 19 to 50 years, or the equivalent of about teaspoon of stable salt daily. The human body contains about 1.8 gm Na/kg at free bodyweight, most of which is present in extracellular fluids.

The content of serum normally is about 140 mEg/liter. Since sodium is the chief cation of the extracellular fluid, the control of the body fluid osmolarity and therefore body fluid volume is largely dependent on sodium ions and the ratio of sodium to other ions.
Sodium daily intake

Salt in human diet

The introduction of salt in significant quantities to the human diet is probably linked to two of its properties:
*Its ability to remove moisture from foods, thus increase their osmotic pressure and making them less likely to spoil,

*Its ability to increase the palatability of savory foods.

The substance we call salt is the chemical compound sodium chloride. Salt also contains small amounts of other trace elements including calcium, magnesium and iodine.

Human evolved in a low sat diet of no more than 20 to 40 mmol sodium per day, and became adapted to the physiologic conservation of the limited salt naturally present in foods and not for excretion of a sodium load some 10 to 20 higher than the physiologic need.

Adults usually consume about 10g of salt a day, but there are enormous variations. A high intake of salt may contribute to the development of hypertension or high blood pressure in some individuals.

Salt in the diet comes mainly from processed foods such as crisps, nuts, cheese, pickled vegetables, sauces and smoked foods.

It is also added to food during preparation, cooking and at the table. Small quantity occurs naturally in some foods. Nobody is quite sure exactly how much salt we need to eat, but it is relatively small amount.

Most of the salt in the diet of contemporary industrialized populations is found in processed foods, added by manufacturers during production for a range of reasons, including taste enhancement, texture and preservation.
Salt in human diet