Class 6 Science Notes
Chapter 1: Components of Food
Overview: Different food items contain components needed by our body to grow, perform daily activities, and stay healthy. These chemical substances present in food are called Nutrients.
1. Major Nutrients in Food
The main nutrients required by our body are divided into five primary categories:
a) Carbohydrates
- Function: Provide energy to the body (energy-giving foods).
- Forms: Mainly found as Starch and Sugars in our food.
- Sources: Rice, wheat, maize, potato, sweet potato, sugar, papaya, mango.
b) Fats
- Function: Provide more energy compared to the same amount of carbohydrates. They also keep our body warm.
- Plant Sources: Groundnuts, mustard oil, coconut oil, nuts, sunflower oil.
- Animal Sources: Butter, ghee, milk, cream, eggs, fish, meat.
c) Proteins
- Function: Required for the growth and repair of our body (body-building foods).
- Plant Sources: Gram, moong, beans, soyabeans, peas.
- Animal Sources: Milk, paneer, fish, meat, eggs.
d) Vitamins
Help in protecting our body against diseases and keep our eyes, bones, teeth, and gums healthy.
- Vitamin A: Keeps skin and eyes healthy. (Sources: Milk, fish oil, papaya, carrot)
- Vitamin C: Helps body fight against many diseases. (Sources: Amla, orange, lemon, tomato, guava)
- Vitamin D: Helps body use calcium for bones and teeth. (Sources: Milk, butter, eggs, fish, sunlight)
- Vitamin B-Complex: Essential for cell health and energy metabolism. (Sources: Whole grains, liver, wheat)
e) Minerals
Needed by our body in small amounts for proper growth and maintaining good health.
- Iodine: Salt, fish, ginger, spinach.
- Calcium: Milk, eggs, cheese.
- Iron: Spinach, apples, liver, pulses.
- Phosphorus: Milk, banana, wheat, rice.
2. Dietary Fibres and Water
Besides nutrients, our body needs dietary fibres and water to function properly.
Dietary Fibres (Roughage)
- Do not provide any nutrient to our body, but are essential components of our food.
- Function: Helps our body get rid of undigested food and prevents constipation.
- Sources: Whole grains, pulses, potatoes, fresh fruits, and vegetables.
Water
- Helps our body absorb nutrients from food.
- Helps in throwing out some wastes from the body as urine and sweat.
3. Tests for Nutrients
| Nutrient |
Test Chemical / Reagents |
Positive Result Color |
| Starch |
2-3 drops of dilute Iodine solution |
Blue-Black color |
| Protein |
Copper Sulphate solution + Caustic Soda solution |
Violet color |
| Fats |
Rub food item on a piece of paper |
An oily patch (translucent) appears |
4. Balanced Diet
A diet that contains all the essential nutrients (carbohydrates, fats, proteins, vitamins, minerals) along with adequate amounts of roughage and water in the right proportion is called a Balanced Diet.
Important Note on Cooking: Overcooking or washing peeled vegetables/fruits repeatedly can destroy nutrients. Vitamin C easily gets destroyed by heat during cooking.
5. Deficiency Diseases
Diseases that occur due to the lack of nutrients over a long period are called Deficiency Diseases.
| Vitamin / Mineral |
Deficiency Disorder |
Symptoms |
| Vitamin A |
Loss of vision (Night Blindness) |
Poor vision, loss of vision in darkness |
| Vitamin B1 |
Beriberi |
Weak muscles and very little energy to work |
| Vitamin C |
Scurvy |
Bleeding gums, wounds take longer to heal |
| Vitamin D |
Rickets |
Bones become soft and bent |
| Calcium |
Bone and Tooth decay |
Weak bones, tooth decay |
| Iodine |
Goitre |
Glands in the neck appear swollen, mental disability in children |
| Iron |
Anaemia |
General weakness, tiredness |