Components of Food

Components of Food: Complete Guide for Class 6 CBSE Science Chapter 2

Introduction to Components of Food

Food is essential for survival, growth, and maintaining good health. Every food item we consume contains various substances called nutrients that perform specific functions in our body. Understanding these components helps us make informed dietary choices and maintain optimal health.

What are Nutrients?

Nutrients are food constituents required by our body for growth, maintenance, energy production, and protection against diseases. Our body cannot function properly without an adequate supply of these essential components.

Why Do We Need Food?

Food serves six primary functions in our body:

1. Growth and Development - Provides building blocks for body tissues
2. Energy Production - Fuels all physical and mental activities
3. Repair and Maintenance - Fixes damaged cells and tissues
4. Disease Protection - Strengthens immunity against infections
5. Metabolic Regulation - Enables proper body functioning
6. Temperature Regulation - Maintains optimal body temperature

Seven Essential Components of Food 

Our food contains seven major components, each playing a vital role in maintaining health:

Complete List of Food Components

S.No.	Component	Category	Primary Function
1	Carbohydrates	Macronutrient	Energy production
2	Proteins	Macronutrient	Growth and repair
3	Fats	Macronutrient	Energy storage and insulation
4	Vitamins	Micronutrient	Metabolic regulation
5	Minerals	Micronutrient	Body function support
6	Water	Essential component	Medium for reactions
7	Roughage (Dietary Fibre)	Non-nutrient	Digestive health

Classification of Food Based on Function

Food components can be classified into three functional categories:

1. Energy-Yielding Foods

• Components: Carbohydrates and Fats
• Function: Provide energy for daily activities, work, and play
• Examples: Rice, wheat, sugar, oils, butter, ghee

2. Body-Building Foods

• Components: Proteins
• Function: Support growth, repair damaged tissues, and build new cells
• Examples: Pulses, eggs, fish, milk, meat, nuts

3. Protective Foods

• Components: Vitamins and Minerals
• Function: Protect against diseases, regulate body processes, and maintain immunity
• Examples: Fruits, vegetables, milk, eggs

Macronutrients vs Micronutrients: Understanding the Difference

Macronutrients

Definition: Nutrients required by the body in large quantities (grams) to provide energy and support major body functions.

The Three Macronutrients:

1. Carbohydrates

• Required amount: 45-65% of total daily calories
• Primary energy source
• Daily requirement: 250-350 grams (varies by age and activity)

2. Proteins

• Required amount: 10-35% of total daily calories
• Essential for growth and repair
• Daily requirement: 40-60 grams for Class 6 students

3. Fats

• Required amount: 20-35% of total daily calories
• Concentrated energy source
• Daily requirement: 50-70 grams

Micronutrients

Definition: Nutrients required by the body in very small quantities (milligrams or micrograms) but essential for proper functioning.

The Two Categories:

1. Vitamins

• Measured in milligrams (mg) or micrograms (μg)
• Cannot be synthesized by the body (must be obtained from food)
• Examples: Vitamin A, B-complex, C, D, E, K

2. Minerals

• Measured in milligrams (mg) or micrograms (μg)
• Inorganic substances essential for body functions
• Examples: Calcium, Iron, Iodine, Sodium, Potassium

Differences

Aspect	Macronutrients	Micronutrients
Quantity Required	Large amounts (grams)	Tiny amounts (mg or μg)
Primary Function	Provide energy and build tissue	Regulate processes and prevent diseases
Storage	Can be stored in body (especially fats)	Limited storage capacity
Deficiency Effects	Weakness, weight loss, energy depletion	Specific deficiency diseases
Examples	Carbs, Proteins, Fats	Vitamins, Minerals

Detailed Study of Each Nutrient

1. Carbohydrates - The Energy Providers

Chemical Composition: Carbon, Hydrogen, and Oxygen (C, H, O)

Why Called Carbohydrates? The name comes from "carbon" and "hydrate" (water), as they contain hydrogen and oxygen in the same proportion as water (2:1).

Types of Carbohydrates

Carbohydrates are classified into three main types:

a) Sugars (Simple Carbohydrates)

• Glucose - Found in grape juice, blood sugar
• Fructose - Found in honey, fruits
• Sucrose - Common table sugar, sugarcane
• Provide quick, instant energy

b) Starch (Complex Carbohydrates)

• Sources: Rice, potatoes, wheat, corn, sweet potatoes, bread
• Provides sustained, long-lasting energy
• Must be broken down into simple sugars during digestion

c) Cellulose

• Non-digestible carbohydrate
• Acts as dietary fibre/roughage
• Found in plant cell walls

Functions of Carbohydrates

1. Primary Energy Source - Provides 4 calories per gram
2. Quick Energy Release - Especially from simple sugars
3. Brain Fuel - Glucose is the brain's preferred energy source
4. Protein Sparing - Prevents protein breakdown for energy
5. Metabolic Regulation - Helps in fat metabolism

Rich Sources of Carbohydrates

Food Category	Examples
Cereals & Grains	Rice, wheat, oats, maize, barley
Starchy Vegetables	Potatoes, sweet potatoes, yam
Fruits	Bananas, mangoes, grapes, apples
Sugars	Honey, jaggery, sugar, dates
Dairy	Milk (lactose)

Recommended Daily Amount

• For Class 6 students: 250-300 grams
• For adults: 300-400 grams
• For athletes: 400-600 grams

2. Proteins - The Building Blocks

Chemical Composition: Carbon, Hydrogen, Oxygen, and Nitrogen (C, H, O, N)

Special Feature: Nitrogen presence distinguishes proteins from carbohydrates and fats.

Why Are Proteins Called "Building Blocks"?

Proteins are made of smaller units called amino acids. There are 20 different amino acids that combine in various ways to form thousands of different proteins. Our body can make some amino acids, but 9 are essential amino acids that must come from food.

Functions of Proteins

1. Growth and Development - Essential during childhood, adolescence, and pregnancy
2. Tissue Repair - Heals wounds and damaged cells
3. Body Structure - Forms hair, nails, skin, and muscles
4. Enzyme Production - Creates enzymes for digestion and metabolism
5. Hormone Synthesis - Produces hormones like insulin and growth hormone
6. Immune Function - Creates antibodies to fight infections
7. Emergency Energy - Provides 4 calories per gram when needed

Sources of Proteins

Plant Sources (Incomplete Proteins):

• Pulses: Moong dal, masoor dal, chickpeas, kidney beans
• Nuts: Almonds, cashews, walnuts, groundnuts
• Seeds: Pumpkin seeds, sunflower seeds, sesame
• Soybean and soy products (complete protein)
• Cereals: Wheat, maize (contain some protein)

Animal Sources (Complete Proteins):

• Milk and dairy: Milk, cheese, paneer, yogurt
• Eggs (especially egg white)
• Fish: All varieties
• Meat: Chicken, mutton, beef
• Seafood: Prawns, crabs

Recommended Daily Amount

• For Class 6 students: 40-50 grams
• For adults: 50-60 grams
• For athletes: 80-120 grams
• For pregnant women: 70-100 grams

3. Fats - The Energy Reserves

Chemical Composition: Carbon, Hydrogen, and Oxygen (C, H, O) - but different ratio than carbohydrates

Energy Content: Fats provide more than double the energy of carbohydrates - 9 calories per gram compared to 4 calories per gram.

Types of Fats

1. Saturated Fats

• Solid at room temperature
• Found in: Butter, ghee, cheese, meat, coconut oil
• Should be consumed in moderation

2. Unsaturated Fats (Healthy Fats)

• Liquid at room temperature
• Found in: Vegetable oils, nuts, fish, avocados
• Better for heart health

Functions of Fats

1. Concentrated Energy Source - Provides 9 calories per gram
2. Energy Storage - Stores excess energy for future use
3. Insulation - Protects body against cold weather
4. Organ Protection - Cushions vital organs like heart, kidneys
5. Vitamin Transport - Helps absorb fat-soluble vitamins (A, D, E, K)
6. Cell Membrane Structure - Essential component of all cell membranes
7. Flavor Enhancement - Makes food taste better and more satisfying
8. Satiety - Keeps you feeling full longer

Sources of Fats

Plant Sources:

• Oils: Mustard oil, sunflower oil, olive oil, sesame oil, coconut oil
• Nuts: Almonds, cashews, walnuts, peanuts
• Seeds: Flaxseeds, chia seeds, sunflower seeds
• Soybeans and soy products

Animal Sources:

• Dairy: Butter, ghee, cream, cheese
• Egg yolk
• Meat and fish
• Cod liver oil

Recommended Daily Amount

• For Class 6 students: 50-60 grams
• For adults: 60-70 grams
• Note: Fats should constitute 20-30% of total daily calories

4. Vitamins - The Metabolic Regulators

Definition: Vitamins are organic compounds required in very small quantities (milligrams or micrograms) for various metabolic processes.

Main Characteristic: Animals cannot manufacture most vitamins and must obtain them from food.

Classification of Vitamins

Vitamins are classified based on their solubility:

A. Fat-Soluble Vitamins (Stored in body fat)

Vitamin A (Retinol)

Aspect	Details
Essential For	Vision, especially night vision; healthy skin; immune function
Deficiency Disease	Night blindness, dry eyes, rough skin
Rich Sources	Carrots, spinach, mango, papaya, milk, eggs, fish liver oil
Daily Requirement	600-700 micrograms

Vitamin D (Calciferol)

Aspect	Details
Essential For	Strong bones and teeth; calcium absorption
Deficiency Disease	Rickets (in children) - soft and weak bones; Osteomalacia (in adults)
Rich Sources	Sunlight exposure, milk, eggs, fish, fortified cereals
Daily Requirement	10-15 micrograms
Special Note	Called "sunshine vitamin" - produced when skin exposed to sunlight

Vitamin E (Tocopherol)

Aspect	Details
Essential For	Reproductive health; antioxidant protection; healthy skin
Deficiency Disease	Sterility; muscle weakness
Rich Sources	Vegetable oils, nuts, seeds, green leafy vegetables
Daily Requirement	10-12 milligrams

Vitamin K

Aspect	Details
Essential For	Blood clotting; wound healing; bone health
Deficiency Disease	Hemorrhage (excessive bleeding); slow wound healing
Rich Sources	Green leafy vegetables (cabbage, spinach), cauliflower, cereals
Daily Requirement	55-60 micrograms

B. Water-Soluble Vitamins (Not stored, excess excreted)

Vitamin B-Complex (Multiple vitamins)

Vitamin B1 (Thiamine)

Aspect	Details
Essential For	Metabolic activity; nerve function; energy production
Deficiency Disease	Beri-Beri (weakness, nerve damage, heart problems)
Rich Sources	Whole grains, pulses, nuts, pork, yeast
Daily Requirement	1.0-1.2 milligrams

Other B Vitamins Include: B2 (Riboflavin), B3 (Niacin), B6 (Pyridoxine), B12 (Cobalamin), Folic Acid

Vitamin C (Ascorbic Acid)

Aspect	Details
Essential For	Healthy muscles, teeth, and gums; wound healing; immunity; iron absorption
Deficiency Disease	Scurvy (bleeding gums, loose teeth, weakness, slow wound healing)
Rich Sources	Citrus fruits (orange, lemon), amla, tomatoes, green peppers, strawberries
Daily Requirement	40-50 milligrams
Special Note	Destroyed by heat and light; eat fresh fruits

5. Minerals - The Body Function Regulators

Definition: Minerals are inorganic substances required in small quantities for various body functions.

Major Minerals and Their Functions

Calcium (Ca)

Aspect	Details
Importance	Strong bones and teeth; muscle contraction; blood clotting; nerve function
Deficiency Disease	Weak bones; tooth decay; osteoporosis; stunted growth
Rich Sources	Milk, cheese, yogurt, green leafy vegetables, ragi, fish with bones
Daily Requirement	800-1000 milligrams

Iron (Fe)

Aspect	Details
Importance	Formation of hemoglobin in red blood cells; oxygen transport
Deficiency Disease	Anemia (fatigue, weakness, pale skin, shortness of breath)
Rich Sources	Green leafy vegetables, liver, meat, jaggery, dates, dry fruits
Daily Requirement	10-15 milligrams
Special Note	Vitamin C helps iron absorption

Iodine (I)

Aspect	Details
Importance	Production of thyroid hormones; regulates metabolism and growth
Deficiency Disease	Goiter (swelling in neck); mental retardation in children
Rich Sources	Iodized salt, seafood, fish, seaweed
Daily Requirement	120-150 micrograms
Special Note	Use iodized salt to prevent deficiency

Other Important Minerals

• Phosphorus: Bone formation, energy metabolism (sources: milk, fish, meat, pulses)
• Sodium & Chlorine: Fluid balance, nerve function (source: common salt)
• Potassium: Heart function, muscle contraction (sources: bananas, potatoes, pulses)
• Magnesium: Enzyme activation, bone health (sources: nuts, whole grains, green vegetables)

6. Water - The Universal Solvent

Importance: Water constitutes approximately 70% of body weight and is essential for survival.

Functions of Water

1. Medium for Reactions - All chemical reactions in body occur in dissolved state
2. Nutrient Transport - Carries digested food and oxygen to cells
3. Waste Removal - Eliminates waste through urine and sweat
4. Temperature Regulation - Maintains body temperature through sweating
5. Joint Lubrication - Cushions joints and organs
6. Digestive Aid - Helps in digestion and absorption
7. Blood Component - Major component of blood plasma

Water Loss and Requirement

Daily Water Loss:

• Urine: 1-1.5 liters
• Sweating: 0.5-1 liter
• Breathing: 0.3-0.4 liters
• Feces: 0.1-0.2 liters
• Total: 2-3 liters per day

Daily Water Requirement: 8-10 glasses (2-3 liters)

Sources of Water:

• Direct drinking water
• Fruits (watermelon, oranges, grapes)
• Vegetables (cucumber, tomato, lettuce)
• Milk, soups, juices
• Water released during metabolism

7. Roughage (Dietary Fibre) - The Digestive Helper

Definition: Roughage is the fibrous, indigestible part of plant foods that cannot be broken down by human digestive enzymes.

Alternative Name: Dietary fibre (fibre that can be eaten)

How Dietary Fibre Benefits Digestion and Health

1. Digestive Health Benefits

• Prevents Constipation - Adds bulk to stool, making it easier to pass
• Promotes Regular Bowel Movements - Stimulates intestinal contractions
• Prevents Digestive Disorders - Reduces risk of hemorrhoids and diverticulitis

2. Other Health Benefits

• Water Retention - Absorbs water, keeping stool soft
• Blood Sugar Control - Slows absorption of sugar
• Weight Management - Provides satiety without calories
• Cholesterol Reduction - Binds with cholesterol for removal
• Colon Health - May reduce colon cancer risk

3. Mechanism of Action

• Roughage provides bulk to food
• Helps intestinal muscles push food through digestive tract
• Absorbs water like a sponge
• Creates favorable environment for beneficial gut bacteria

Rich Sources of Dietary Fibre

Food Category	Examples
Whole Grains	Whole wheat, brown rice, oats, bran
Vegetables	Broccoli, carrots, cabbage, cauliflower, beans
Fruits	Apples (with skin), pears, oranges, berries
Pulses	All dals, rajma, chickpeas
Nuts & Seeds	Almonds, flaxseeds, chia seeds
Leafy Vegetables	Spinach, lettuce, methi

Daily Requirement: 20-30 grams for children; 25-35 grams for adults

Tests for Nutrients - Laboratory Activities 

Understanding how to identify nutrients in food is an important practical skill in science.

Test for Starch in Food - Class 6 Activity

Preparation of Iodine Solution

Materials Required:

• 5 grams of iodine crystals
• 10 grams of potassium iodide
• 100 ml distilled water
• Glass beaker
• Stirring rod

Procedure:

1. Take 100 ml distilled water in a beaker
2. Add 5 grams of iodine crystals
3. Add 10 grams of potassium iodide
4. Stir thoroughly until completely dissolved
5. Store in a dark glass bottle

Test for Starch Procedure

Materials Required:

• Food samples (bread, boiled potato, rice, banana, etc.)
• Iodine solution
• Dropper
• White tile or plate

Steps:

1. Take a small piece of the food item on a white tile
2. Using a dropper, place 2-3 drops of iodine solution on it
3. Observe the color change
4. Record your observations

Result:

• Blue-black color = Starch is present
• No color change (brown-yellow remains) = Starch is absent

Foods Testing Positive: Bread, potato, rice, wheat flour, corn

Foods Testing Negative: Egg white, meat, cheese

Test for Proteins in Food - Class 6 Experiment

Copper Sulfate and Caustic Soda Test

Materials Required:

• Food sample (crushed/paste)
• 10% copper sulfate solution
• 10% caustic soda (sodium hydroxide) solution
• Test tubes
• Droppers

Safety Warning: Caustic soda is corrosive. Handle with care and adult supervision.

Procedure:

1. Take crushed food sample in a test tube
2. Add 10 drops of water to make a paste
3. Add 2 drops of copper sulfate solution
4. Add 10 drops of caustic soda solution
5. Shake gently
6. Observe color change

Result:

• Violet/Purple color = Protein is present
• No color change = Protein is absent

Foods Testing Positive: Egg, milk, pulses, meat, soybean

Foods Testing Negative: Sugar, potato, oil

Test for Fats in Food - Class 6 Experiment

Paper Spot Test (Grease Test)

Materials Required:

• Food samples
• Plain white paper
• Newspaper

Procedure:

1. Take a small piece of food item
2. Wrap it in plain white paper
3. Press and crush it
4. Unwrap the paper and let it dry
5. Hold the paper against light
6. Observe for translucent (oily) spots

Result:

• Translucent oily spot = Fat is present
• No oily spot = Fat is absent

Foods Testing Positive: Nuts, fried foods, butter, cheese, coconut

Foods Testing Negative: Rice, fruits, vegetables

Activity-Based Questions for Class 6

Activity 1: Food Diary Analysis

• Maintain a 3-day food diary
• List all foods consumed
• Identify which nutrients each food provides
• Check if diet is balanced

Activity 2: Nutrient Detective

• Test 10 different food items for starch, protein, and fat
• Create a chart showing results
• Classify foods based on predominant nutrient

Activity 3: Balanced Meal Planning

• Design a balanced meal for breakfast, lunch, and dinner
• Ensure all seven components are included
• Calculate approximate nutrient quantities

Balanced Diet and Nutrition

What is a Balanced Diet?

Definition: A balanced diet is one that contains all seven components of food (carbohydrates, proteins, fats, vitamins, minerals, water, and roughage) in the right proportions according to the body's requirements.

Key Principles of a Balanced Diet

1. Variety is Essential

• No single food contains all nutrients
• Eat different types of foods from all food groups
• Include colorful fruits and vegetables

2. Proportion Matters

• Not equal amounts, but appropriate amounts
• Based on age, gender, activity level, and health status

3. Individual Requirements Vary

Different people need different amounts based on:

Factor	Nutritional Need
Age	Growing children need more proteins; elderly need more calcium
Gender	Males typically need more calories than females
Physical Activity	Athletes need more carbs and proteins; sedentary people need less
Physiological State	Pregnant/lactating women need more of all nutrients
Health Condition	Sick people may have special dietary requirements

Balanced Diet for Different Groups

For Class 6 Students (10-12 years)

Nutrient	Daily Requirement	Why Important
Carbohydrates	250-300 g	Energy for studies and play
Proteins	40-50 g	Rapid growth and development
Fats	50-60 g	Brain development, energy
Calcium	800-1000 mg	Bone growth
Iron	12-15 mg	Prevent anemia
Water	2-2.5 liters	All body functions

Sample Balanced Meal Plan:

• Breakfast: Whole wheat paratha + milk + banana
• Mid-morning: Fruit/nuts
• Lunch: Rice + dal + vegetable + curd + salad
• Evening: Boiled chickpeas/sprouts
• Dinner: Roti + vegetable + dal + milk

For Manual Laborers

Higher Requirements:

• Carbohydrates: 400-500 g (more energy needed)
• Proteins: 60-70 g
• Fats: 70-80 g
• More water (3-4 liters due to sweating)

For Pregnant Women

Higher Requirements:

• Proteins: 70-100 g (fetal growth)
• Calcium: 1200 mg (fetal bone development)
• Iron: 30-35 mg (increased blood volume)
• Folic acid: 600 micrograms (prevent birth defects)

Signs of Malnutrition

Undernutrition:

• Underweight, stunted growth
• Weakness, fatigue
• Frequent infections
• Poor concentration

Overnutrition:

• Obesity
• Increased disease risk (diabetes, heart disease)
• Joint problems

Quick Reference Tables

Complete Nutrient Functions Table

Nutrient	Chemical Elements	Main Function	Energy Value	Required Amount
Carbohydrates	C, H, O	Energy production	4 cal/g	250-350 g/day
Proteins	C, H, O, N	Growth and repair	4 cal/g	40-60 g/day
Fats	C, H, O	Energy storage	9 cal/g	50-70 g/day
Vitamins	Varies	Metabolic regulation	0 cal/g	mg or μg amounts
Minerals	Inorganic	Body functions	0 cal/g	mg or μg amounts
Water	H, O	Medium for reactions	0 cal/g	2-3 liters/day
Roughage	Complex carbs	Digestive health	0 cal/g	20-30 g/day

Vitamins and Minerals Complete Reference

Vitamin/Mineral	Type	Essential For	Deficiency	Rich Sources
Vitamin A	Fat-soluble	Vision, skin	Night blindness	Carrots, milk, eggs
Vitamin D	Fat-soluble	Bones, teeth	Rickets	Sunlight, fish, milk
Vitamin E	Fat-soluble	Reproduction	Sterility	Nuts, vegetable oils
Vitamin K	Fat-soluble	Blood clotting	Hemorrhage	Green vegetables
Vitamin B1	Water-soluble	Energy, nerves	Beri-Beri	Whole grains, pulses
Vitamin C	Water-soluble	Immunity, healing	Scurvy	Citrus fruits, amla
Calcium	Mineral	Bones, teeth	Weak bones	Milk, cheese, ragi
Iron	Mineral	Hemoglobin	Anemia	Jaggery, liver, spinach
Iodine	Mineral	Thyroid hormones	Goiter	Iodized salt, fish

Food Sources Classification

Food Category	Rich in	Examples
Cereals & Millets	Carbohydrates, some protein	Rice, wheat, bajra, ragi, oats
Pulses & Legumes	Proteins, fibre	Moong, masoor, rajma, chana
Milk & Products	Proteins, calcium, fats	Milk, cheese, paneer, yogurt
Eggs & Meat	Proteins, fats, iron, B12	Eggs, chicken, fish, mutton
Fruits	Vitamins, minerals, fibre	All seasonal fruits
Vegetables	Vitamins, minerals, fibre	Leafy and other vegetables
Nuts & Seeds	Proteins, fats, vitamins	Almonds, walnuts, seeds
Oils & Fats	Fats, vitamin E	Cooking oils, butter, ghee

Conclusion

Understanding the components of food is fundamental to making healthy dietary choices. Each of the seven components carbohydrates, proteins, fats, vitamins, minerals, water, and roughage plays a crucial role in maintaining optimal health, supporting growth, and preventing diseases.

Importants Points:

• Balanced nutrition requires all components in appropriate proportions
• Macronutrients (carbs, proteins, fats) provide energy and building materials
• Micronutrients (vitamins, minerals) regulate body processes
• Water and roughage, though not providing nutrients, are essential for health
• Individual requirements vary based on age, activity, and health status

By applying the knowledge from this chapter, students can make informed food choices, understand nutrition labels, and appreciate the science behind healthy eating. Regular practice of nutrient tests and maintaining food diaries helps reinforce these concepts practically.

Additional Resources

For Further Study:

• NCERT Science Textbook Class 6, Chapter 2
• Multiple Choice Questions for Class 6
• Worksheets for class 6 Science
• Best Home Tutor for Delhi
• home tuition for class 6 near me

Practical Activities:

• Conduct all nutrient tests at home or in lab
• Create a weekly balanced meal plan
• Analyze food labels for nutrient information
• Visit a nutrition counselor for personalized diet advice

About the Class 6 CBSE Science Notes Chapter: This comprehensive guide has been prepared following CBSE Class 6 Science curriculum guidelines, incorporating NCERT textbook content, and enhanced with additional scientific explanations to support student learning. All information is scientifically accurate and educationally appropriate for Class 6 level.