Chapter 2: Components of Food (Class VI NCERT Science)

We eat different types of food at different times of the day, and call them our meals. A meal might include dal, rice, chapatis, eggs, salad, any vegetable or curries.

The food that we eat, provides our body with the nutrients that we need. Nutrients are the most important substances that are required by an organism to provide energy for daily activities, to grow and survive.

COMPONENTS OF FOOD

There are six main nutrients or components present in our food. They are carbohydrates, proteins, fats, vitamins, minerals and roughage or dietary fibres.

Besides these nutrients, water is also an essential part of our daily needs.

1. Carbohydrates:

  • It is an energy giving component.

  • It includes starch and sugars.

  • Lesser than the required amount of carbohydrate depletes energy and excess of carbohydrate is stored as fat in our body, this condition is known as obesity.

  • Sources of carbohydrates: potatoes, cereals (rice, wheat), grains, dairy products.

2. Fats

  • Fats are also energy giving components of food, but the energy is present in stored form.

  • When our body falls short of energy, these stored fats are used.

  • Fats keeps our bodies insulated.

  • Excess of fat consumption causes weight gain and risk of heart diseases.

  • Sources of fats: oil, ghee, butter, cheese, milk, nuts.

3. PROTEINS

  • Proteins are body building nutrients. They build and maintain body muscles.

  • They come from both plant and animal sources.

  • Sources of proteins: meat, fish, eggs, milk, pulses, soy beans, gram.

4. VITAMINS AND MINERALS:

  • Vitamins and minerals are helpful in proper functioning of the body.

  • They help us to stay healthy and protect our body from diseases.

  • Vitamins keep our eyes, bones, teeth and gums healthy.

  • Minerals help in the formation of bones, teeth and blood cells.

5. ROUGHAGE / DIETARY FIBRES:

  • Roughage is that portion of plant food that is not digested by humans and it also not provide any nutrients as such.

  • However, it plays an important role in our body because it helps in removal of any undigested food from our body.

  • Lack of roughage in food makes the stools hard and difficult to pass.

  • Sources of roughage: apple, strawberry, whole grains, cabbage, spinach.

6. WATER:

  • Water constitutes almost 70% of our body weight.

  • Lack of water in the body causes dizziness, headaches, poor blood circulation and other associated problems.

  • It is advisable to drink at least 8 glasses of water per day to avoid dehydration.

BALANCED DIET

A diet that comprises sufficient amount of necessary nutrients required by our body for its healthy growth and development is called as Balanced Diet.

DEFICIENCY DISEASES

Diseases that occur due to lack of certain nutrients, in our body, for a long period of time are called deficiency diseases. All deficiency diseases can be prevented by taking balanced diet.

1. Deficiency of carbohydrates: As carbohydrates are a source of energy, people with its deficiency can have reduced stamina and weakness.

2. Deficiency of proteins: Protein deficiency leads to swelling of stomach, face and limbs, stunted growth, skin diseases, diarrhea and discoloration of hair. 

3. Deficiency of proteins and carbohydrates (in combination): The person suffering from combined deficiency of proteins and carbohydrates becomes very weak and lean. The growth might stop completely.

4. Deficiency of minerals:

5. Deficiency of vitamins:

TESTS FOR IMPORTANT NUTRIENTS IN OUR BODY

A. Test for starch (carbohydrate):

  • Take a small amount of food item or raw ingredient.

  • Then, put 2 – 3 drops of dilute iodine solution in it.

  • Observe the color change. If the color changes to blue black, it confirms the presence of carbohydrate in the given food item.

  • This test is also known as Starch iodide test.

B. Test for Protein:

  • Take a small quantity of ground or mashed food item, put it in test tube.

  • Add 10 – 15 drops of water to it and shake the test tube.

  • Add 2 drops of copper sulphate solution and 10 drops of caustic soda solution in the test tube using droppers.

  • Shake well and let the test tube stand for a few minutes. Then observe the colour change.

  • If the color changes to violet, it indicates the presence of protein in given food item.

C. Test for Fats:

  • Take a small quantity of food item.

  • Wrap it in a paper and crush it carefully.

  • Straighten the paper and observe it.

  • Hold the paper against the light and observe again.

  • If an oily patch is visible on paper and light is also faintly visible, then it indicates the presence of fat in given food item.

  • If oily patch is not visible then the food item lacks fat content.

Keywords:

1. Balanced diet: A diet that comprises sufficient amount of necessary nutrients required by our body for its healthy growth and development is called as Balanced Diet.

2. Beri Beri: It is a deficiency disease caused due to lack of Vitamin B1 in our body. Its symptoms include weakness, lack of energy to work and shortness of breath.

3. Carbohydrates: Carbohydrate is an energy giving component of food. It includes sugars and starch. Carbohydrate rich sources of food includes potatoes, milk, wheat, rice, etc.

4. Energy: The ability of a person to do work is known as energy.

5. Fats: Fats are the nutrients that provides energy. They are present in stored form in our body. Oil, ghee, butter, cheese are some fat rich sources of food.

6. Minerals: Minerals are the nutrients required by our body to build bones, teeth and muscles.

7. Nutrients: Nutrients are the most important substances that are required by an organism to provide energy for daily activities, to grow and survive.

8. Proteins: These are the body building nutrients as they build and maintain muscle growth.

9. Roughage: Roughage is that portion of plant food that is not digested by humans and it also not provide any nutrients as such. It plays an important role in our body because it helps in removal of any undigested food from our body.

10. Scurvy: It is the condition caused due to deficiency of Vitamin C in the diet. The symptoms include swelling and bleeding gums.

11. Starch: Starch is a type of carbohydrate that is found majorly in vegetables. It is one of the products formed during photosynthesis.

12. Vitamins: Vitamins are the nutrients that keeps our eyes, bones, gums and teeth healthy.