Sodium

Sodium Sources, Functions and Deficiency

Sodium is essential for life and is chiefly found in extra cellular fluids and very little inside the cells. This is in reverse order as compared to potassium, which is mainly found inside the cells, and very little in the extra cellular fluids.

The total sodium in a body is equal to 0.1% of body weight, i.e. about 100 mg and is present in all body fluids.

Function of Sodium in Our Body



Sodium is necessary for digestion, and elimination of carbon dioxide. It works in the body either as sodium ions, or as sodium compounds.

As sodium ions its functions are:

• It is essential for the normal function of the cells.
• It is essential for the contraction of the muscles.
• It initiates and maintains contraction of heart.
• It excites nerves, being neuro-excitatory as opposed to calcium ions.
• It helps in glucose absorption and for the transportation of other nutrients across cell membranes.

As sodium compounds its functions are:

• It maintains blood reaction, by acting as buffer and phenomenon of chloride shift.
• It controls reaction of urine, by altering the proportion of acid and alkaline phosphates in the kidneys.
• It regulates reaction of pancreatic juice and bile due to sodium carbonate.
• It maintains osmotic pressure, as sodium chloride is the chief regulator of the pressure of the body fluids.
• It helps in the formation of hydrochloric acid of gastric juice, since sodium chloride takes part in various reactions in the stomach.
• It rectifies defective fat absorption.
• It maintains water balance.

Natural Sources of Sodium


Sodium occurs in many foods like milk and vegetables, and is added as common salts during cooking. It is present in whole meal flour, bread, celery, bananas, water, milk, lotus, dry stem, pulses, and legumes, green and leafy vegetables; beetroot, fruits, fish and meat.

Daily Requirement of Sodium

The daily requirement as sodium chloride is 10-15 mg but normally the consumption is much above this. The requirement of sodium chloride depends upon climate, occupation and physical activity. People engaged in hard work will need more.

Sodium Deficiency

• The sodium deficiency shows reduction in fat deposit, atrophy of muscles and testis, lung infection, retarded bone growth, and reduction in osteoid tissue.
• Depletion of sodium chloride causes muscular cramps, nausea, mental apathy, oedema, and heat exhaustion in hot weather and exertion.

Sodium in Excess

• If taken in excess, it can raise blood pressure, liver cirrhosis, and congestive cardiac disorders, and renal diseases, water retention, even stomach ulcers.