Sodium

Sodium is an essential nutrient having important roles in regulation of blood and body fluids, transmission of nerve impulses, heart activity, and certain metabolic functions.

Sodium participates in the regulation of blood volume, blood pressure, osmotic equilibrium and pH. Sodium is also important in neuron function and osmoregulation between cells and the extracellular fluid.

Sodium is actively pumped out of cells. (Potassium is actively pumped into cells.) So the sodium concentration is low inside cells and high outside cells in the extracellular fluid, where sodium is the most prominent positive ion.

The concentration of sodium in the extracellular fluid is about 140 mmoles/liter. (This is probably a concentration close to that in the primodial ocean where the first unicellular organisms developed.)

In an average human weighing 70 kg the extracellular fluid (including the fluid of blood) amounts to about 15 liters, which carry around 50 grams of sodium or 90% of the body's total sodium content. Here sodium exists as sodium chloride.

Sources

Sodium chloride is the principal source of sodium in the diet. Sodium most sodium comes from processed foods chloride is used as seasoning and preservative, like for pickling and jerky.

Most of the ingested sodium comes from processed foods, including condiments and seasonings such as Worcestershire sauce, soy sauce, and bouillon cubes.

Fast foods are generally high in sodium.

Daily intake

generally we eat too much salt The recommended intake of sodium as sodium chloride is 2.3 grams per day.

The Western diet usually contains too much (about 3-4 grams per day). Here is a list of foods having the highest content of sodium.

Deficiency

The minimum physiological requirement for sodium is 0.5 grams per day.

Since plants contain little sodium a completely plant-based diet will be very low in sodium.

Deficiency will lead to low concentration in the blood (hyponatremia), which can give rise to nausea and vomiting, headache, confusion, lethargy, fatigue, appetite loss, restlessness and irritability.

More serious deficiency can lead to muscle weakness, spasms, or cramps, seizures, and decreased consciousness or coma.

Hyponatremia may occur in individuals competing in very long endurance exercise events, such as marathons, ultramarathons, and Ironman triathlons.

The hyponatremia seems to be related to relative fluid overload suggesting a decreased fluid excretion and/or an overestimation of the fluid needs of these athletes.

Excess

A diet containing more than 3-4 grams per day of sodium chloride promotes development of high blood pressure (hypertension). Hypertension causes 7-8 million premature deaths worldwide.

A high concentration of sodium in the blood (hypernatremia) can result from massive salt ingestion (e.g. by drinking seawater). Most frequently hypernatremia is caused by a relative deficit of water or dehydration due to insufficient intake of water.

Normally even a small rise in the serum sodium concentration will result in a sensation of thirst leading to increased water intake, which will normalize the sodium concentration in the blood.

Therefore, hypernatremia most often occurs in people with insufficient sensation of thirst or insufficient ability or motivation to drink the necessary amount of water (infants, elderly people, people with impaired mental status).

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