Sodium – Functions, Food Sources, Imbalance

An adult body contains approximately 120g of sodium of which about 50% of the body’s sodium is present in the extracellular fluid, 40% in bones and 10% or less in intracellular fluid (intracellular fluid refers to fluid inside the cell).


  1. It is required for maintenance of normal osmotic pressure and water balance.
  2. It is also required for maintaining the permeability of cell membrane.
  3. Sodium ‘pump’ helps to maintain the electrolyte difference between intracellular and extracellular fluid compartments.

Food Sources

Common salt or sodium chloride is the chief source of sodium in the diet. One teaspoon of salt provides almost 2000 mg sodium. It is universally used to flavour the food we eat and is also used for preserving food for long periods. Numerous sodium compounds are used in food processing and preparation like baking soda, baking powder, sodium alginate, sodium propionate and sodium citrate. Sodium is a naturally occurring constituent in animal foods, including milk, egg, meat, poultry and fish and in certain vegetables as spinach, celery, beet greens and fenugreek. Most vegetables, fruits, cereals, legumes are naturally low in sodium.

Recommended Dietary Allowance

5-10 gm of salt (sodium chloride) is sufficient for an average healthy adult. An individual doing hard labour may need more.

Sodium Imbalance

Osmotic pressure and the pH are seriously affected when there is a disturbance in the concentrations of sodium in the extracellular fluid of the body tissues. When there is retention of sodium in the tissue, oedema occurs. In cardiac and renal failure sodium excretion gets reduced. Excess sodium losses occur during the hot weather causing muscular weakness, cramps, fatigue, vomiting and loss of appetite. In this case a small amount of salt may be added to liquid intake.

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