ICSE Class 6 Biology Chapter 4 Health and Hygiene

Unit 4: Health And Hygiene

Learning Objectives

Food and its need for the body

Constituents of food: carbohydrates, proteins, fats, vitamins, minerals, water and roughage

Significance of vitamins and minerals

Factors affecting maintenance of good health

The concept of a balanced diet

Personal cleanliness

Community hygiene

Pollution: Air pollution, water pollution and noise pollution

Effects of pollution on health

Measures to control pollution

Our Food

A substance which gives energy and keeps the body in good health is called food. Several types of nutrients constitute our food. Food is one of the basic requirements of all living organisms. We need food for growth, repair, and maintenance of our body and to protect it from illness. Food is necessary for both plants and animals.

Why Do We Need Food?

Food is essential for all living organisms because of the following reasons:

1. It Provides Energy

The food that we eat is digested, absorbed and then oxidised to provide energy. The energy thus released, is utilised by all living organisms to perform various functions of life.

2. It Helps in Growth and Development

Our body is composed of millions of cells and these cells divide to make new cells. Food provides all necessary materials for cell division and helps in the growth and development of our body.

3. It Helps to Overcome Wear and Tear

Food is required to make more protoplasm which is necessary for the repair of damaged cells or for the replacement of worn out tissues and for healing of wounds.

4. It Protects the Body Against Diseases

Food provides resistance to the body against various diseases. Deficiency of food may cause several diseases.

Teacher's Note

Understanding why we need food helps children recognize that eating isn't just about satisfying hunger - it's about giving their bodies the fuel and materials needed to grow, think clearly, and fight off illness every day.

Constituents Of Food

The food we eat consists of the following nutrients:

Carbohydrates

They are compounds of carbon and hydrogen. When they burn with oxygen, they produce energy. Glucose and starch are examples of carbohydrates. It is found in wheat, rice, potato, fruits, etc. If we do not get enough carbohydrates, we feel listless and lethargic.

Proteins

Proteins are very important nutrients of our body. They are compounds of carbon, hydrogen and nitrogen. Few proteins contain sulphur and iron.

Proteins are required for the growth and repair of the damaged cells in our body. There are two sources of proteins: plant proteins and animal proteins. Plant proteins are obtained from pulses, beans, soybeans, etc. Animal proteins are obtained from milk, meat, fish and eggs. Growing children should take lots of proteins for their growth.

Fats

Fats give about twice as much energy as carbohydrates. Fats are found in oil, ghee and butter. Eggs and meats are also a rich source of fat.

Fat gets deposited in the body. Consumption of too much fat is not good for health. It leads to obesity. Obesity leads to many irregularities in the function of body, such as tiredness, hypertension, blood-pressure, sugar, etc.

Water

Water is essential for our body. It makes 70 per cent of our body by weight. It dissolves most of the substances and helps in the transportation of substances. It helps in removal of waste materials from our body. It maintains the body temperature and a specific concentration of salts and minerals.

Beverages like milk, coffee, tea and fruit juice are sources of water. Raw vegetables and fruits contain lots of water. We must drink at least four to five litres of water each day. If the amount of fluid taken fails to replace the amount of fluid lost from the body, it results in dehydration. Dehydration through motion, vomits or any other means leads to weakness, and many other ailments.

Vitamins

Vitamins are required by the body for proper growth and functioning. They are required in small quantity and their deficiencies lead to many diseases. There are many types of vitamins. They are named A, B1, B2, B12, C, D, etc.

Mineral Salts

Minerals are important for the body function. They are required in small quantity. Calcium and phosphorus are required for strong bones and teeth. Iron is required for the formation of blood. Sodium and potassium are required for nervous system. Iodine is required for the proper physical and mental development. The sources of minerals are vegetables, fruits, milk, chewnuts, pulses and eggs. Mineral deficiency can lead to a number of diseases.

Fibres or Roughage

The body also needs enough roughage or fibres to be able to digest the food and prevent constipation. Fibres are found in fruits and vegetables like cabbage salads, fruits and vegetables like cabbage and spinach.

Teacher's Note

When students understand that different foods provide different nutrients, they can make better choices at meals - choosing fruits for vitamins, milk for calcium, and whole grains for fibre rather than just eating whatever tastes good.

A Balanced Diet

Food may not necessarily consist of all the nutrients required for the body. Our body needs all the nutrients in their right proportion in the food for its growth and maintenance. A balanced diet has the required amounts of proteins, carbohydrates, fats, vitamins, fibres, minerals and water.

You take meals which generally consist of rice, dal, vegetables, curd, chapati, etc. These food items consist of all the nutrients required by our body. However the problem arises when we eat only rice or chapatis. No single food item consists of all the essential nutrients required by the body. A person who does not take sufficient amount of nutrients in his diet, becomes undernourished.

A mixed diet that consists of all the required nutrients in their right quantity and proportion is known as a "balanced diet". A balanced diet depends on age, gender and type of work you do. A male needs more energy than a female of the same age. A person doing physical work needs more energy than a person doing an office job.

Teacher's Note

Explaining balanced diets helps students understand that eating a variety of foods - not just their favourites - ensures their bodies get everything needed to be healthy, energetic, and able to concentrate in class.

This is a preview of the first 3 pages. To get the complete book, click below.