Home Science and Home Family – Nutrition, Nutrients & Functions

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Nutrition and Nutrients

  • Food provides nourishment to body and enables it to stay fit and healthy. Food that we eat undergoes many processes, like first the food is digested, then it is absorbed into blood and transported to various parts of the body where it is utilized. The waste products and undigested food are excreted from the body.

  • NUTRITION is the process by which food is taken in and utilized by the Body.

Functions of Nutrients

Food helps that food helps in the nourishment and health of our body. The nourishment is brought about by small units called nutrients present in food.

Nutrients are the chemical substances present in food and are responsible for nourishing the body.

Types of Nutrients

  • Macronutrients

  • Micronutrients

Macronutrients: These are present in large quantities in foods and are also required in large amounts by the body. Carbohydrates, proteins, fats and oils are macronutrients.


  • Carbohydrates are cheapest sources of energy.

  • If there is a short supply of carbohydrates and fats in our body, proteins are utilized for energy production.

  • Functions of proteins is to provide for body building.

  • Therefore, Carbohydrates have to be consumed in proper amounts to spare proteins for body building purpose.

Functions of carbohydrates

  • Carbohydrates provide energy

  • They are main source of energy

  • They are spare proteins for body building function

Food sources of carbohydrates

  • Cereals – wheat, rice, bajra, maize, etc.

  • Pulses- Rajma, channa, all dals

  • Roots and tubers- potatoes, sweet potatoes, beetroot and tapioca

  • Sugar, jaggery


  • Protein are needed in the body for body building.

  • 1 gm of protein gives 4kcal of energy.

  • Proteins are made up of smaller units known as amino acids. There are all together 22 amino acids, out of which are 8 amino acids which our body cannot manufacture.

Functions and sources of proteins


  • Needed for growth, maintenance and repair of tissues

  • Necessary for production of enzymes, hormones, antibodies, hemoglobin, etc.

  • Help in the clotting of blood

  • Provide energy, if necessary


  • Meat, poultry, fish, eggs

  • Milk, cheese, paneer, curd

  • Soybeans, peas, pluses,

  • Cereals, nuts and oilseeds like till, groundnuts, etc.

Fats and Oils

Fats and oils are the concentrated source of energy in our diet. 1 gm of fat gives 9 kcal of energy. Fats are made up of small units called fatty acids. The nature of fats is dependent on the type of fatty acids present. Fatty acids may be saturated or unsaturated. Saturated fatty acids are found in solid fats whereas oils contain more of unsaturated fatty acids. Vegetable oils are rich in unsaturated fatty acids.

Functions and Sources of fats and oils


  • Provide concentrated source of energy

  • Reduce the use of proteins for energy

  • Carry fat soluble vitamins (A, D, E, K) into the body and help in the absorption of these vitamins

  • Help to maintain body temperature. The layer of fat under the skin helps to conserve body heat.

  • Act as a cushion to certain vital organs

  • Help in growth of tissues


  • Cooking oils, ghee, butter

  • Oilseeds, nuts

  • Meat, poultry, fish, eggs

  • Whole milk, cheese

Micronutrients: Other important nutrients which are present in small quantities in foods but are essential for our body are called micronutrients. These are minerals and vitamins and are required in very small quantities. If these micronutrients are not eaten in required amounts, it results in deficiency diseases.

Minerals and vitamins are called micronutrients.

Vitamins: Our body contains very little quantity of vitamins.

Table of Functions and Sources of Nutrients
Title: Table of Functions and Sources of Nutrients




Vitamin A

-Essential for proper functioning of eyes, that is, vision in dim light

-Necessary for healthy skin and linings of nose, mouth, throat, eyes, ears, lungs and other organs

-Liver, eggs, fish liver oils

-Milk and its products

-Green leafy vegetables

-Yellow or orange fruits and vegetables such as pumpkin, carrot, papaya, mango, etc.

Vitamin D

-Necessary for formation and maintenance of strong, healthy teeth and bones

-Helps in the proper absorption and utilization of calcium and phosphorus in the body

- Exposure of skin to sunlight

-Eggs, liver, fish liver oils

- Milk, butter

- Refined oils and ghee fortified with vitamin D

Vitamin E

-Prevents destruction of certain substance in presence of oxygen

-All cereals, pulses, vegetables oils

Vitamin K

-Necessary for clotting of blood

-Green leafy vegetables

-Egg, liver

Minerals: Minerals constitute a very small amount of the total body tissues. These are essential for many vital processes and also for the maintenance of the body. In total, there are about 19 minerals required by the body in various amounts.

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