Human body contains more than 50 chemical elements. These minerals are obtained mainly through food. Minerals make up l/20th of body weight.

Functions of minerals

1. They are the constituents of bone and teeth and required for their growth e.g. calcium and phosphorus.

2. They are the constituents of various body tissues e.g. iron, phosphorus.


3. They maintain electrolyte balance in body fluids e.g. sodium, potassium and chloride.

4. They maintain tone and functions of muscles e.g. sodium and calcium.

5. They stimulate digestive secretions.

6. They are necessary for growth.


Classification of minerals

1. Major minerals’. Calcium, phosphorus, sodium, potassium and magnesium.

2. Trace elements with known functions: iron, iodine, fluorine, zinc and copper.

3. Trace elements with no known functions, lead, mercury, barium and aluminium.


CALCIUM _________________________

It forms 1.5 to 2 per cent of body weight. An average adult body contains 1200 grams of calcium. Of this 98 per cent is present

in bones.



1. It is necessary for growth of bones and teeth.

2. It is required for the clotting of blood.

3. It regulates the contraction of muscles.

4. It is required for cardiac action and milk production.


5. It transforms light into electrical impulses in the retina.

6. It forms a component of several enzymes.


1. Milk and milk products like cheese, curd and butter milk. They arc the best natural sources of calcium.


2. Green leafy vegetables like spinach.

3. Millets like ragi.


Deficiency of calcium leads to rickets in children and osteomalacia in adults. Also it leads to delayed blood clotting.

Requirement: 400 to 500 mg per day.