NCERT Explained: Class VI Science, Chapter 1 - Components of Food: The Building Blocks of Life

Introduction to the Topic

Have you ever wondered why we feel hungry after playing for a long time? Or why our parents insist on us eating green leafy vegetables and drinking milk every day? Food is more than just a tasty meal; it is the fundamental fuel that keeps our bodies functioning. In the NCERT Class VI Science curriculum, Chapter 1 titled 'Components of Food' takes us on a journey to understand what exactly is inside the food we eat and how these components help us grow, stay active, and fight diseases.

In different parts of India, people eat different kinds of food. A meal might consist of chapati, dal, and brinjal curry. Another may be rice, sambar, and a vegetable preparation of lady’s finger (bhindi). Yet another meal could be appam, fish curry, and vegetables. Despite this incredible variety, all these meals have something in common: they contain certain chemical substances that our body needs. These substances are called nutrients. This guide will break down the complex science of nutrition into simple, digestible concepts for every student.

Key Concepts Explained

To understand food, we must first understand nutrients. Nutrients are the components of food that provide energy, help in growth, and protect us from illnesses. The major nutrients in our food are carbohydrates, proteins, fats, vitamins, and minerals. In addition, food also contains dietary fibres and water, which are also essential for our body.

1. Carbohydrates: The Energy Givers

Carbohydrates are the main source of energy for our bodies. Whenever you run, jump, or study, your body uses carbohydrates to keep going. There are many types of carbohydrates, but the ones we primarily find in our food are in the form of starch and sugars.

• Sources: Rice, wheat, maize, potato, sweet potato, sugarcane, papaya, melon, and mango.
• Testing for Starch: You can easily test if a food item contains starch. Take a small quantity of a food item (like a raw potato slice) and add 2-3 drops of dilute iodine solution on it. If the color of the food item turns blue-black, it indicates the presence of starch.

2. Proteins: The Body Builders

Proteins are often called the 'body-building foods.' They are needed for the growth and repair of our body. Every time you get a cut or a bruise, or as you grow taller, your body uses proteins to build new cells and tissues.

• Sources: Plant sources include pulses (dal), peas, gram, moong, and beans. Animal sources include milk, fish, meat, and eggs.
• Testing for Protein: To test for protein, make a paste or powder of the food item. Put it in a test tube, add 10 drops of water, and shake it. Then, add 2 drops of copper sulphate solution and 10 drops of caustic soda solution. Shake well. If the solution turns violet, it confirms the presence of proteins.

3. Fats: The Energy Reserves

Fats also provide energy to our body. In fact, fats give much more energy compared to the same amount of carbohydrates. However, it is harder for the body to break down fats, so they are often stored as energy reserves.

• Sources: Plant sources include groundnuts, various oils (mustard, coconut, soybean), and nuts. Animal sources include butter, ghee, milk, cream, meat, and eggs.
• Testing for Fats: This is the simplest test. Take a small quantity of a food item and wrap it in a piece of paper. Crush it (being careful not to tear the paper). If an oily patch appears on the paper and makes it translucent when held against light, the food contains fat.

4. Vitamins: The Protectors

Vitamins are required in small quantities, but they are vital for protecting our body against diseases. They also help in keeping our eyes, bones, teeth, and gums healthy. Each vitamin has a specific role:

• Vitamin A: Keeps our skin and eyes healthy. (Sources: Carrots, fish oil, papaya, milk).
• Vitamin B-Complex: Essential for various metabolic functions and energy production. (Sources: Whole grains, liver).
• Vitamin C: Helps the body fight against many diseases and promotes healing. (Sources: Citrus fruits like orange, lemon, amla, and green chilies).
• Vitamin D: Helps our body use calcium for bones and teeth. Our body also prepares Vitamin D in the presence of sunlight. (Sources: Fish, eggs, milk, butter).

5. Minerals: The Growth Regulators

Like vitamins, minerals are needed by our body in small amounts. Each one is essential for proper growth of the body and to maintain good health. Key minerals include:

• Iodine: Needed for the thyroid gland. (Sources: Iodized salt, ginger, fish).
• Phosphorus: Important for strong bones and teeth. (Sources: Milk, bananas, green chilies).
• Iron: Crucial for the formation of blood (haemoglobin). (Sources: Spinach, apples, liver).
• Calcium: Essential for building bones and teeth. (Sources: Milk, eggs).

6. Dietary Fibres and Water

Besides nutrients, our body needs dietary fibres and water. Dietary fibres are also known as roughage. Roughage is mainly provided by plant products in our foods. While it does not provide any nutrient to our body, it is an essential component because it helps our body get rid of undigested food and prevents constipation.

Water helps our body to absorb nutrients from food. It also helps in throwing out some wastes from the body as urine and sweat. We get most of the water that our body needs from the liquids we drink, such as water, milk, and tea, and also from the water added to cooked foods.

7. What is a Balanced Diet?

The food we normally eat in a day is our diet. For growth and maintenance of good health, our diet should have all the nutrients that our body needs, in right quantities. Not too much of one and not too little of the other. The diet should also contain a good amount of roughage and water. Such a diet is called a balanced diet.

A balanced diet does not have to be expensive. One can eat a balanced diet consisting of pulses, groundnut, soyabean, sprouted seeds, fermented foods (like idli), flours (missi roti, thalipeeth), banana, spinach, sattu, and jaggery. Eating the right kind of food is not enough; it should also be cooked properly so that its nutrients are not lost (e.g., repeated washing of rice and pulses may remove some vitamins and minerals).

8. Deficiency Diseases

A person may be getting enough food to eat, but sometimes the food may not contain a particular nutrient. If this continues over a long period of time, the person may suffer from its deficiency. Deficiency of one or more nutrients can cause diseases or disorders in our body. These are called deficiency diseases.

• Vitamin A deficiency: Causes loss of vision (Night blindness).
• Vitamin B1 deficiency: Causes Beriberi (weak muscles and very little energy to work).
• Vitamin C deficiency: Causes Scurvy (bleeding gums, wounds take longer to heal).
• Vitamin D deficiency: Causes Rickets (bones become soft and bent).
• Calcium deficiency: Leads to bone and tooth decay.
• Iodine deficiency: Causes Goitre (glands in the neck appear swollen, mental disability in children).
• Iron deficiency: Causes Anaemia (weakness).

Summary & Key Takeaways

• Nutrients: Chemical components in food required for growth, energy, and health.
• Carbohydrates and Fats: Primarily provide energy; fats provide more energy than carbohydrates.
• Proteins: Necessary for growth and repair of the body.
• Vitamins and Minerals: Protect the body against diseases and maintain health.
• Roughage: Helps in the easy passage of food through the digestive system.
• Balanced Diet: A diet containing all essential nutrients, roughage, and water in correct proportions.
• Deficiency Diseases: Health issues caused by a lack of specific nutrients over a long duration.
• Nutrient Tests: Use Iodine for starch, Copper Sulphate/Caustic Soda for protein, and a paper test for fats.