COMPONENTS OF FOOD
The main components of foods are carbohydrates, protein, fats, vitamins and minerals. These are called nutrients.
(i) Carbohydrates: Carbohydrates are also called energy giving food. It is the main sources of energy. It is made up of carbon, hydrogen, and oxygen. There are three types of carbohydrates.
Fig: Types of Carbohydrate
(a) Sugars: It is a simple carbohydrate having sweet taste. Sources of sugar are glucose, Sugarcane, milk and fruits; such as banana, apple, grapes, etc.
(b) Starch: It is a complex carbohydrate. It is a tasteless, colourless, white power. Sources of starch are: Wheat, maize, potato and rice.
(c) Cellulose: It is present in plant cell wall. It is a complex carbohydrate. Humans cannot digest cellulose.
(ii) Protein: Protein helps in body growth and repairs the tissues so it is also called body building food. We get protein from milk, eggs, meat, fish and all kinds of pulse. Protein is made of a large number of smaller molecules called amino acid. The daily requirement of protein for adults is 1 gram per kilogram of the body weight. When the body is building new tissue, more proteins are required, so growing children and pregnant lady need more protein.
Fig: Food rich in proteins
(iii) Fat: Fats are made up of carbon, hydrogen and oxygen. Butter, ghee, milk, egg-yolk, nuts and cooking oils are the major sources of fat in our food. An adult needs about 35 g fat everyday. Our body stores the excess energy in the form of fat. This stored fat is used by the body for producing energy as and when required so fat is considered as energy bank in our body. Fats are essential for the absorption of vitamins A, D, E and K in the body. Fats in our body also prevents heat loss from the body surface.
(iv) Vitamins: Vitamins are complex organic compounds which are essential for the growth and maintenance of our body. It does not provide energy. Our body requires vitamins A, C, D, E, K and B-complex. Our body can make only two vitamins, Vitamins D and K so other vitamins must be present in our food. The B complex vitamin is a mixture of several water- soluble vitamins. The important vitamins of this group are the vitamin B1 B2 B3 B4 B6 B9 and B12.
(v) Minerals: Minerals are required by our body in very small quantities. Iron, Iodine, calcium, phosphorus, sodium and potassium are common minerals. The sources of these animals are plants and animals.
Some diseases caused by deficiency of vitamins and minerals:
Dietary Fibers: The fibrous indigestible material present in any food is termed as dietary fibre or roughage.
It helps in preventing constipation. It adds bulk to the food and gives a sense of completion after the meal. Salad, vegetables, sprouted grains and fruits are the sources of roughages.
Balanced Diet: The diet which contains all the essential nutrients in the right proportion is called a balanced diet. The food we eat must have all the nutrients. It should provide the required energy. Deficiency of one or more nutrients in our food for a long time may cause certain diseases or disorders.
Fig: Food Pyramid