Food Important Notes - Class 5 Science | Fully Solved Notes For Students

Introduction

Food is made up of different substances called nutrients. A nutrient is a substance that is needed to keep a living organism alive and to help it grow and develop. Nutrients provide our body with energy, protect us against some diseases, and help in growth and repair. There are five main types of nutrients in food: carbohydrates, fats, proteins, vitamins and minerals. In addition, our body needs water and roughage. The body requires these substances in the right amounts for good health.

Different Types of Nutrients

1. Carbohydrates

Carbohydrates are the main source of energy for the body. They are used by cells to produce energy for everyday activities and growth. Common foods rich in carbohydrates include wheat, rice, corn, bread, potatoes and sugar.

2. Fats

Fats give more energy per gram than carbohydrates and are important for storing energy, insulating the body and protecting internal organs. Foods that are good sources of fats include milk, oil, ghee, butter, cheese and dry fruits. However, eating excessive fatty foods may lead to obesity and related health problems.

3. Proteins

Proteins are essential for growth, building new tissues and repairing damaged cells. Proteins are especially important for children who are growing. Sources of protein include milk, paneer, pulses, beans, eggs and meat.

4. Vitamins and Minerals

Vitamins and minerals do not provide energy but are needed for the normal functioning of the body and to protect us from diseases. They help chemical reactions inside the body and are necessary for growth and maintenance. Fruits, vegetables and milk are good sources of many vitamins and minerals. For example, vitamin C helps keep gums healthy, vitamin D and calcium help strengthen bones and teeth, and iron is needed to prevent anaemia.

5. Water and Roughage

Water is essential for life: it helps dissolve nutrients, transport them in the body and remove wastes through urine and sweat. Roughage (also called dietary fibre) is the part of plant food that is not digested. Roughage helps in the movement of food through the digestive system and prevents constipation. Fruits, vegetables and whole grains are good sources of roughage.

Balanced Diet

• A balanced diet includes all the nutrients (carbohydrates, fats, proteins, vitamins and minerals), together with sufficient water and roughage, in the right amounts.
• It is important to eat a variety of foods from different food groups so that the body receives all the necessary nutrients.
• A balanced diet helps maintain a healthy weight, provides the energy needed for daily activities and reduces the risk of chronic diseases such as diabetes, heart disease and obesity.

For example, a balanced meal might include a bowl of whole grains (like rice or chapati), a portion of lentils or a lean protein (such as dal, paneer or egg), some vegetables, a fruit and a small amount of healthy fats (like oil or ghee). Drinking enough water and including roughage in the diet helps digestion and keeps the body healthy.

Balanced Diet

Disease

Disease comes from the word "dis-ease", meaning "not at ease" or "uncomfortable". A disease is a condition that causes the body or a part of it to stop functioning normally. When the usual activities of the body are disturbed, we say the person is suffering from a disease or illness.

Types of Diseases

Diseases can be classified into two broad groups:

• Communicable diseases (infectious diseases) - illnesses that can be passed from an infected person to a healthy person.
• Non-communicable diseases - illnesses that do not spread from person to person and may be caused by deficiencies, genetic conditions, environmental factors or lifestyle.

1. Communicable Diseases

Pathogens Causing Diseases

Communicable diseases are caused by tiny disease-causing organisms called pathogens. Pathogens include viruses, bacteria, fungi, protozoa and worms. These organisms are so small that they can only be seen with a microscope and are also called microorganisms or microbes.

Spread of Communicable Diseases

Communicable diseases spread from an infected person to others by several modes. For learning, these modes are described as direct and indirect.
1. Direct Mode  

• Direct contact: Healthy persons touch an infected person or use the same personal items (towels, handkerchiefs, utensils) and get infected. Diseases such as chickenpox, measles and ringworm spread this way.
• Through cuts and wounds: Germs can enter the body via cuts, wounds or sores on the skin and cause infections (for example, tetanus).
• From mother to child: Some diseases can pass from a mother to her child during childbirth or before birth.
  

2. Indirect Mode  

• Through air (airborne): When an infected person coughs or sneezes, germs spread in tiny droplets. A healthy person who breathes the same air can catch diseases like the common cold, tuberculosis or influenza.A Person Suffering from Common Cold
• Through contaminated food and water: Food and water that are not clean may carry germs. Houseflies and cockroaches can carry germs from dirt to food. Consuming such contaminated food or water can cause typhoid, jaundice and food poisoning.Diseases spread through unhygienic food
• Through vectors: Some insects and animals act as carriers or vectors. For example, when a mosquito bites an infected person it may carry the germ and pass it to the next person it bites. Diseases like malaria and dengue spread this way.

Examples of how pathogens spread:

• Through water: Contaminated water can spread diseases such as cholera and typhoid.
• Through Air: Airborne diseases like flu, cough, and cold can spread when an infected person sneezes or coughs, releasing pathogens into the air.
• Through Mosquitoes: Diseases like malaria and dengue are transmitted by mosquitoes. Malaria is caused by a protozoan carried by the female Anopheles mosquito, while dengue is transmitted by the Aedes mosquito infected with the dengue virus.
• Through animal bites: Some animals carry germs that infect humans when they bite. For example, dog bites can transmit rabies. The Nipah virus is another example, where certain animals act as carriers of the virus.

Spread of Disease through Mosquito

Ways to Prevent Communicable Diseases

• Personal cleanliness: Regular bathing and keeping the body clean reduces the risk of skin infections and many other illnesses.
• Hand washing: Wash hands with soap and water before eating, after using the toilet, after touching animals and after coughing or sneezing.
• Cover coughs and sneezes: Use a tissue or handkerchief to cover your nose and mouth while coughing or sneezing and dispose of used tissues properly.
• Avoid sharing personal items: Do not share towels, clothes, spectacles or eye drops with infected persons.
• Remove stagnant water: Do not allow water to collect around homes or in coolers as this helps mosquito breeding.
• Keep dustbins covered: This reduces flies and other pests that carry germs.
• Keep food and water covered: Avoid eating uncovered food and drinking exposed water; handle food with clean hands.
• Use clean public bathrooms: Prefer clean restroom facilities to reduce infection risk.
• Spray disinfectants and insecticides: Regular cleaning and spraying help control germs and vectors in homes.

Important Note: Vaccination

• Vaccination is a safe method to prevent several communicable diseases such as polio, tetanus, typhoid and measles.
• Vaccines contain dead or weakened germs (or parts of germs) and are given by injection or orally.
• When a vaccine is given, the body makes antibodies that protect against the disease in the future.
• Vaccines are given at specific ages so that children develop immunity before they are exposed to the disease.

2. Deficiency Diseases/Non-Communicable Diseases

Non-communicable diseases are illnesses that cannot be passed from one person to another. Some non-communicable diseases are present at birth, some develop because of poor nutrition, and others arise from environmental factors or lifestyle. Examples include asthma, beriberi, goitre, kwashiorkor and marasmus.

Deficiency Diseases

Deficiency diseases are caused by the lack of essential nutrients in the body. Each vitamin or mineral has a role, and the lack of a particular vitamin or mineral leads to a specific disease.

1. Some diseases caused due to the lack of vitamins in our body are:

2. Some diseases caused due to lack of minerals:

Malnutrition

Malnutrition occurs when the diet lacks enough nutrients or has too few calories for normal growth and health. One important type is Protein Calorie Malnutrition (PCM), which happens when there is not enough protein and energy (carbohydrates/fats) in the diet.

1. Some diseases caused due to protein calorie malnutrition:

2. Diseases caused due to carbohydrate malnutrition:

Tips for Good Health

• Wash your hands regularly with soap and water to remove dirt and germs; this helps prevent many infections and diseases.
• Brush your teeth twice a day and clean your tongue with a tongue cleaner to maintain oral hygiene and prevent dental problems.
• Avoid spitting in public places to keep the surroundings clean and reduce disease spread.
• Exercise regularly to strengthen muscles, improve circulation and keep the body fit.
• Get enough sleep so the body can repair cells, recharge and grow properly.
• Eat a healthy and balanced diet that includes foods from all major food groups to supply the body with required nutrients.