4th Class Science Food and Health Food & Digestion, Health & Hygiene

Food & Digestion, Health & Hygiene

Synopsis

• The food we eat gives us energy to live. Food contains substances that are useful to our body.

These are called nutrients.

• Carbohydrates, fats, proteins, vitamins and minerals are different nutrients required by our body.

• Carbohydrates are the main energy giving foods. Sugar and starch are the important carbohydrates. Wheat, rice, potato, etc. are the important sources of carbohydrates.

• Fats give us heat and energy. Fats give more energy than carbohydrates. Butter, ghee and creams are some sources of fats. Excess fats make us fat and lead to many diseases, Proteins are body building foods. They help our body to grow and repair the damaged parts. Egg, fish, meat, pulses, milk and soyabeans are some important sources of proteins.

• Vitamins keep us healthy and protect us from many diseases. Fruits, vegetables and fish are rich in vitamins. The food items rich in vitamins are called protective foods.

• Vitamins are named A, B, C, D, E and Vitamin D can be prepared in our body with the help of sunlight.

• Minerals help us to make our bones and teeth strong. They help to prepare blood. We get minerals from fruits, vegetables, milk and liver.

• The food we eat is chewed in the mouth. Mouth secretes saliva, saliva makes the food like a paste. It also changes starch into sugar with the help of an enzyme. Later, food is passed into the stomach through food pipe.

• Several digestive juices produced from the walls of stomach break down proteins in the food into smaller substances. Then the food is pushed into small intestine.

• More juices secreted in the small intestine make the food into liquid form and it is absorbed by the blood.

• The undigested food goes into large intestine where some water is absorbed and the remaining solid waste goes out through anus.

• Food should be cooked properly. Cooking makes the food more tasty, soft and easy to digest. Cooking is done in various ways. Frying, roasting, boiling, steaming and baking are commonly used methods.

• Food can be preserved in different methods.

e.g., Fruits and vegetables preserved in vinegar (low pH) and salt (dehydrated) do not go bad because the conditions are not suitable for bacteria and fungi to grow.

• Food can be stored at low temperatures in the refrigerators to prevent the growth of germs.

• Preserving food in tight containers keeps away moisture and the harmful insects, rodents, etc.

• Boiling milk kills germs present in it.

• Some substances such as sugar, salt and oil slow down the growth of germs. They are added to food to preserve them for a long time. They are called preservatives.

• Care should be taken so that the food is not exposed to flies and dust.

• Eating uncovered food may cause vomiting, diarrhoea, jaundice, etc.

• Clean and pleasant surroundings keep us healthy. Unclean surroundings may cause various diseases.

• Mosquitoes breed in standing water. It spread various diseases like malaria.

• Soakage pits should be used to dispose off dirty water.

• Flush systems should be used for latrines. It keeps them clean and free from foul smell and prevents breeding of houseflies.

• A thin film of kerosene should be sprayed on standing water to prevent breeding of mosquitoes.

• The solid waste produced in our house is called garbage. Garbage should be kept in closed dust bins and disposed off at regular time intervals. A decaying garbage attracts houseflies which spread diseases.

• Diarrhoea is a common disease. A person suffering from diarrhoea passes loose watery stools resulting in the loss of water and salts from the body. Oral Rehydration Solution (ORS) should be given to such people. It can be prepared from boiled water, adding one spoon of salt and eight spoons of sugar.

• Diseases can be prevented by proper waste disposal and clean habits (proper sanitation).