Chapter 2: Components of Food
Source: NCERT Class VI Science (English Medium), Pages 8–17 Class: VI
What Are Nutrients? 🌿
Food is made up of ingredients – things we get from plants or animals. These ingredients contain useful components that our body needs. These components are called nutrients.
🔑 The Major Nutrients in Our Food Are:
| Nutrient | Also Known As |
|---|---|
| Carbohydrates | Energy giving food |
| Fats | Energy giving food |
| Proteins | Body building food |
| Vitamins | – |
| Minerals | – |
In addition to nutrients, food also contains dietary fibres (roughage) and water, which are also needed by our body.
Tests for Nutrients 🧪
Simple tests can show whether a food item contains carbohydrates (starch), proteins, or fats.
2.1 Test for Starch
| Step | Action | Result |
|---|---|---|
| 1 | Take a small amount of the food item | – |
| 2 | Put 2–3 drops of dilute iodine solution on it | – |
| 3 | Observe colour change | Blue-black colour = starch is present |
2.2 Test for Protein
| Step | Action | Result |
|---|---|---|
| 1 | Grind or mash the food item into a paste or powder | – |
| 2 | Put some in a test tube; add 10 drops of water; shake | – |
| 3 | Add 2 drops of copper sulphate solution + 10 drops of caustic soda solution; shake well; let stand for a few minutes | Violet colour = protein is present |
2.3 Test for Fat
| Step | Action | Result |
|---|---|---|
| 1 | Wrap the food item in paper and crush it | – |
| 2 | Straighten the paper; hold against light and observe | Oily patch that lets light through = fat is present |
| 3 | If unsure, let paper dry – water from food dries up, oily patch from fat stays | If no oily patch after drying = no fat |
⚠️ A food item may contain more than one nutrient.
What Do Nutrients Do for Our Body? 🌿
| Nutrient | Main Job for Our Body |
|---|---|
| Carbohydrates | Mainly provide energy |
| Fats | Provide energy (much more than the same amount of carbohydrates) |
| Proteins | Needed for growth and repair of the body |
| Vitamins | Protect the body against diseases; keep eyes, bones, teeth and gums healthy |
| Minerals | Needed in small amounts; essential for proper growth and good health |
3.1 Carbohydrates ⚡️
The main carbohydrates found in our food are in the form of starch and sugars.
Sources of carbohydrates: sweet potato, potato, sugarcane, papaya, wheat, rice, bajra, melon, mango, maize
3.2 Fats ⚡️
Fats give much more energy than the same amount of carbohydrates.
| Source Type | Examples |
|---|---|
| Plant sources | Groundnuts, nuts, til, mustard oil, sunflower oil, soybean oil, coconut oil |
| Animal sources | Meat, fish, eggs, ghee, butter, cream, milk |
3.3 Proteins 🌿
Foods rich in proteins are called 'body building foods'.
| Source Type | Examples |
|---|---|
| Plant sources | Gram, moong, tuar dal, beans, peas, soyabeans |
| Animal sources | Meat, fish, eggs, milk, paneer |
3.4 Vitamins 🌿
Types of vitamins: Vitamin A, Vitamin B-complex, Vitamin C, Vitamin D, Vitamin E, and Vitamin K.
| Vitamin | What It Does | Some Sources |
|---|---|---|
| Vitamin A | Keeps skin and eyes healthy | Milk, fish oil, papaya, carrot, mango |
| Vitamin B-complex | – | Wheat, rice, liver |
| Vitamin C | Helps body fight many diseases | Orange, tomato, guava, green chilli, lemon, amla |
| Vitamin D | Helps body use calcium for bones and teeth | Milk, butter, fish, egg, liver |
| Vitamin E | – | – |
| Vitamin K | – | – |
⚠️ Our body also prepares Vitamin D in the presence of sunlight. Nowadays, insufficient exposure to sunlight is causing Vitamin D deficiency in many people.
3.5 Minerals 🌿
| Mineral | Some Sources |
|---|---|
| Calcium | Milk, eggs |
| Iron | Leafy greens, apple |
| Phosphorous | Milk, banana |
| Iodine | Fish, leafy greens, ginger |
Dietary Fibres and Water 🌿
4.1 Dietary Fibres (Roughage)
| Feature | Detail |
|---|---|
| Other name | Roughage |
| Main sources | Whole grains, pulses, potatoes, fresh fruits, vegetables |
| Does it give nutrients? | No – roughage does not provide any nutrient |
| What it does | Adds bulk to food; helps the body get rid of undigested food |
4.2 Water
| What Water Does | How We Get It |
|---|---|
| Helps body absorb nutrients from food | Liquids we drink – water, milk, tea |
| Throws out wastes from body as urine and sweat | Water added to most cooked foods |
| – | Water naturally present in fruits and vegetables |
Balanced Diet 🌿
Diet = the food we normally eat in a day.
🔑 Balanced diet = a diet that has all the nutrients the body needs, in right quantities, along with a good amount of roughage and water.
⚠️ Not too much of one nutrient and not too little of another.
5.1 A Balanced Diet Does Not Need to Be Expensive
The following affordable foods provide many nutrients and help achieve a balanced diet:
pulses, groundnut, soyabean, sprouted seeds (moong and Bengal gram), fermented foods such as idlis, combination flours such as missi roti and thepla (made from cereals and pulses), banana, spinach, sattu, jaggery, and other available vegetables.
5.2 Nutrient Loss during Cooking ⚠️
| Action | What Gets Lost |
|---|---|
| Washing vegetables or fruits after cutting or peeling | Some vitamins |
| Repeated washing of rice and pulses | Some vitamins and minerals |
| Using excess water during cooking and throwing it away | Proteins and minerals |
| Heating food during cooking | Vitamin C gets easily destroyed |
🔑 The skins of many vegetables and fruits contain vitamins and minerals – avoid discarding them.
5.3 Too Much Fat – Obesity ⚠️
Eating too much fat-rich food can cause a condition called obesity.
Deficiency Diseases 🌿
🔑 Deficiency = when a person does not get enough of a particular nutrient over a long period of time.
🔑 Deficiency disease = a disease that occurs due to lack of nutrients over a long period of time.
6.1 Effects of Protein and Carbohydrate Deficiency
| Nutrient(s) Lacking | What Happens |
|---|---|
| Protein (long-term) | Stunted growth, swelling of face, discolouration of hair, skin diseases, diarrhoea |
| Both carbohydrates and proteins (long-term) | Growth stops completely; person becomes very lean, thin, and too weak to move |
6.2 Deficiency Diseases – Vitamins and Minerals 📊
| Vitamin / Mineral | Deficiency Disease | Symptoms |
|---|---|---|
| Vitamin A | Loss of vision | Poor vision; loss of vision in darkness (night); sometimes complete loss of vision |
| Vitamin B1 | Beriberi | Weak muscles; 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 | Goiter | Glands in the neck appear swollen; mental disability in children |
| Iron | Anaemia | Weakness |
🔑 All deficiency diseases can be prevented by eating a balanced diet.
Common Confusions ⚠️
| Confusion | Clarification |
|---|---|
| Both carbohydrates and fats give energy – are they the same? | No. Fats give much more energy than the same amount of carbohydrates. Both are energy givers but fats are more energy-dense |
| Is roughage a nutrient? | No. Roughage does not provide any nutrient to the body. But it is still essential – it adds bulk and helps remove undigested food |
| Does Vitamin D only come from food? | No. The body also prepares Vitamin D in the presence of sunlight. Sunlight is a source, not just food |
| Can someone eating enough food still have a deficiency disease? | Yes. If the food they eat does not contain a particular nutrient, deficiency can happen even without going hungry |
| Is eating only one food – like only rice, or only meat – enough? | No. Rice alone cannot meet all nutritional needs. Meat alone cannot either. A variety of foods is needed for a balanced diet |
Memory Aids 💡
| What to Remember | Memory Aid |
|---|---|
| 5 major nutrients | 💡 C-P-F-V-M – "Cats Play Funny Video Moves" – Carbohydrates, Proteins, Fats, Vitamins, Minerals |
| Starch test – blue-black with iodine | 💡 Think: "Iodine = Midnight Ink" – whenever starch is there, iodine turns as dark as midnight ink |
| Protein test – violet with copper sulphate + caustic soda | 💡 "Two drops of copper + ten drops of soda = Violet for Vita-protein!" – violet colour = protein present |
| Fat test – oily patch on paper | 💡 "Fat leaves its fingerprint – an oily ghost on paper that sunlight shines through" |
| Energy givers | 💡 "Cars need Fuel to GO – Carbohydrates and Fats give the body its GO!" |
| Body builders | 💡 "Proteins are the Painters and Plumbers – they build and repair the body-house!" |
| Vitamin A – eyes and skin | 💡 "A is for Alert eyes – Vitamin A keeps you Alert in the dark!" |
| Vitamin C – fights diseases | 💡 "C for Combat – Vitamin C helps the body fight back, and helps Cuts heal faster" |
| Vitamin D – bones and teeth | 💡 "D from the Day-star (Sun) gives Dense bones – step into sunlight, build strong bones!" |
| 7 deficiency diseases (Table 2.3) | 💡 Think of 7 soldiers: Beriberi, Rickets, Scurvy, Loss of vision, Goiter, Anaemia, Bone decay – "BR SLGAB" |
Exam Corner 🎯
Directly from NCERT Class VI Science, Chapter 2 Exercises (Page 17):
| Question | Topic Tested | Reference |
|---|---|---|
| Q1. Name the major nutrients in our food. | All 5 major nutrients | p. 17, Q1 |
| Q2(a). Nutrients which mainly give energy | Carbohydrates and fats | p. 17, Q2a |
| Q2(b). Nutrients needed for growth and maintenance | Proteins and minerals | p. 17, Q2b |
| Q2(c). Vitamin required for maintaining good eyesight | Vitamin A | p. 17, Q2c |
| Q2(d). Mineral required for keeping our bones healthy | Calcium | p. 17, Q2d |
| Q3(a). Name two foods rich in fats | Groundnut, coconut oil (from Fig 2.4) | p. 17, Q3a |
| Q3(b). Name two foods rich in starch | Rice, wheat (from Fig 2.3) | p. 17, Q3b |
| Q3(c). Name two foods rich in dietary fibre | Whole grains, fresh vegetables (from source text) | p. 17, Q3c |
| Q3(d). Name two foods rich in protein | Gram, soyabeans (from Fig 2.5) | p. 17, Q3d |
| Q4. Tick the correct statements | Statements (b) and (c) are correct | p. 17, Q4 |
| Q5(a). Fill in blank – caused by deficiency of Vitamin D | Rickets | p. 17, Q5a |
| Q5(b). Fill in blank – deficiency causing beriberi | Vitamin B1 | p. 17, Q5b |
| Q5(c). Fill in blank – disease from Vitamin C deficiency | Scurvy | p. 17, Q5c |
| Q5(d). Fill in blank – night blindness caused by deficiency of | Vitamin A | p. 17, Q5d |
Abbreviation Legend
| Abbreviation | Full Form |
|---|---|
| Fig. | Figure |
| p. | Page |
| Q | Question |
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