Human body contains more than 50 chemical elements. These minerals are obtained mainly through food. Minerals make up 1/20th of body weight.
Functions of minerals
- They are the constituents of bone and teeth and required for their growth e.g. calcium and phosphorus.
- They are the constituents of various body tissues e.g. iron, pharphorus.
- They maintain electrolyte balance in body fluids e.g. sodium potassium and chloride.
- They maintain tone and functions of muscles e.g. sodium and calcium.
- They stimulate digestive secretions.
- They are necessary for growth.
Classification of minerals
- Major minerals: Calcium, phosphorus, sodium, pottasium and mangnesium.
- Trace elements with known functions: iron, iodine, fluorine, zinc and copper.
- Trace elements with no known functions: lead, mercury, barium and aluminium.
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 bones.
- It is necessary for growth of bones and teeth.
- It is required for the clotting of blood.
- It regulates the contraction of muscles.
- It is required for cardiac action and milk production.
- It transforms light into electrical impulses in the retina.
- It forms a component of several enzymes.
- Milk and milk products like cheese, curd and butter milk. They are the best natural sources of calcium.
- Green leafy vegetables like spinach.
- Millets like ragi.
Deficiency of calcium leads to rickets in children and osteomalacia in adults. Also it leads to delayed blood clotting.
400 to 500 mg per day.
Iron is a very important nutrient. The adult human body contains 3 to 4 grams of iron. Of this 50 to 70 per cent is present in hemoglobin of blood. Each gram of hemoglobin contains 3 to 3.4 mg of iron.
- It is necessary for the synthesis of hemoglobin.
- It is required for brain development and muscle activity.
- It is needed for the regulation of body temperature.
- It has a central function in oxygen transport and call respiration.
Iron is present in liver, meat, kidney, fish, cereals, green leafy vegetables, legumes, jaggery and date fruits.
Deficiency of iron leads to anemia. Also iron deficiency leads to impaired immunity and decreased resistance to infection.
The recommended intake of iron is 15 to 30 mg per day.
Iodine is an essential micronutrient. The total body content of iodine is about 50 mg The blood level is about 8 to 12 micrograms/dl.
- It is required for the synthesis of thyroid hormones.
- Minute amounts are required for growth, development and well being.
The best Sources of iodine are sea foods and codliver oil. Small amounts are present in milk, meat, cereals and vegetables.
Deficiency of iodine leads to iodine deficiency disorders which include
- Goiter and hypothyroidism.
- Retarded physical growth and mental development.
- Spontaneous abortion and still birth.
- Neurological cretinism.
- Myxoedematous cretinism.
150 micrograms per day.
It is the most abundant element in nature. It is highly reactive. So it occurs only in combined form as fluoride. Most of the fluoride in the body(96 per cent) is present in bones and teeth.
- It is required for normal minralisation of bone.
- Also required for the formation of dental enamel.
Drinking water, sea fish, cheese and tea.
Deficiency and excess
Deficiency of fluoride produces dental caries. Excess of fluoride in drinking water leads to dental and skeletal fluorosis.
The recommended fluoride intake in water is 0.5 to 0.8 mg per liter.
It is found in all tissue in traces. Also it is a constituent of several enzymes.
Meat, fish and milk.
Deficiency of zinc leads to growth retardation, sexual infantilism, delayed wound healing and skin disorders.
5 to 10 mg daily.
Copper is required for the synthesis of hemoglobin and also some enzymes. Its deficiency leads to defective formation of elastic tissue and tissue matrix. It is present in common salt, banana, tomatoes and green leafy vegetables.