Class 6 Science Chapter 2 Components of Food, Deficiency Diseases, Balanced Diet (For CBSE, ICSE, IAS, NET, NRA 2022)

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Components of Food

Components of Food


  • These are also known as the energy giving food.
  • They break down into glucose thereby providing energy to the body.
  • It consists of carbon, hydrogen, and oxygen.
  • Sugars, Starch and Cellulose are the three types of carbohydrates.
  • Deficiency may cause fatigue, weakness, difficulty concentrating, nausea, constipation, etc.


  • These are the high energy nutrients.
  • Major sources of fat include butter, ghee, milk, egg-yolk, nuts, and cooking oils.
  • Excess energy in the body gets stored in the form of fat.
  • These are essential for the absorption of vitamins A, D, E and K in the body.
  • Dry rashes, hair loss, a weaker immune system may occur due to deficiency of fats.


  • These are the bodybuilding nutrients.
  • They also help in growth and repair of our body.
  • Some good sources of protein are Eggs, Meat, etc.
  • Growing children and pregnant lady need more protein.
  • Swelling, fatty liver, skin degeneration may occur due to the deficiency.
  • For adult՚s daily requirement of protein is 1 gram per kilogram of the body weight.


  • Essential nutrients help in maintaining normal body functions.
  • They are complex organic compounds.
  • Major sources of vitamins are fruits and vegetables.
  • They further help in keeping eyes, bones, teeth, gums, and skin healthy.
  • Vitamins obtained from different foods are A, B complex, C, D, E and K.


  • It helps in keeping eyes and skin healthy.
  • Deficiency causes Night blindness.
  • Symptoms include poor vision or complete loss of vision in darkness.
  • Some of the best sources are Cod liver oil, Eggs, Orange and yellow vegetables and fruits, etc.


  • Helps in obtaining energy from the food one eats.
  • Deficiency causes Beri-beri.
  • Weight loss and weak muscle are the symptoms.
  • Some of the best sources are yeast, cereal grains, beans, nuts, and meat, etc.


  • It helps in healing wounds, maintaining healthy gums and blood vessels apart from fighting infections.
  • Deficiency causes Scurvy.
  • Bleeding gums is the symptom.
  • Citrus fruit, such as oranges and orange juice are some of the best sources.


  • It keeps teeth and bones healthy.
  • Deficiency causes Rickets.
  • Soft and weak bones are the symptoms.
  • This vitamin is found in oily fish – such as salmon, oily fish – such as salmon, liver, etc.

Vitamin E

  • It helps in maintaining healthy skin and hair, also slows down ageing.
  • Deficiency causes chronic pancreatitis, cystic fibrosis, Crohn՚s disease, etc.
  • Symptoms are Pale skin and Rapid ageing.
  • This vitamin is found in few foods including cooking oils, seeds, and nuts.


  • Extremely useful in blood clotting, bone healing, etc.
  • Bleeding problem in new borns may occur due to deficiency of Vitamin K.
  • A hemorrhage usually involves a lot of bleeding in a short time.
  • Excessive bleeding with delay in clotting is the symptom.
  • Green leafy vegetables, turnip greens, collards are some of the sources.


  • They are responsible for proper working of the bones, muscles, heart, and brain.
  • They also help in making enzymes and hormones.
  • They are found in foods like cereals, bread, meat, fish, milk, dairy, etc.


  • The body needs iodine to make thyroid hormones.
  • Thyroid hormones are useful for proper bone and brain development during pregnancy and infancy.
  • Deficiency can cause goitre.
  • Enlarged thyroid gland is the symptom.
  • Iodized Salt, Shrimp, Tuna, etc. are some of the sources.


  • It is essential for building strong bones and teeth, keeping a normal heartbeat, clotting blood, etc.
  • Osteomalacia (bones are soft) and osteoporosis (bones are porous and brittle) may occur due to deficiency of calcium.
  • Brittle bones are the symptom.
  • Milk, cheese, and other dairy foods are the major sources.


  • It is an important component of haemoglobin.
  • Body needs iron for proper growth and development.
  • Anaemia may occur due to deficiency of Iron.
  • Low red blood cell count is the symptom.
  • Red meats, fish, and poultry are the main sources.


  • Formation of bones and teeth is the main function.
  • Bad teeth, and Rickets may be caused due to the deficiency.
  • Twisted limbs, unformed teeth are the symptoms.
  • Beans, lentils, and nuts are some of the sources.


  • Keeping the digestive system healthy is the main function.
  • Constipation may occur due intake of foods with lesser or no fibre.
  • Peas, beans, and pulses are some of the sources.
  • Dietary Fibre is the fibrous indigestible material present in any food and extremely useful in preventing constipation.


  • Helps in absorbing nutrients from the food.
  • Waste materials from the body are released in the form of urine and sweat.
  • Cucumber, Tomatoes, Oranges are some of the sources.

Balanced Diet

  • The diet containing all the essential nutrients of a food.
  • Requirement for calories, proteins, minerals, vitamins, and alternative nutrients should be adequate.
  • Deficiency of any such nutrients for a long time may cause diseases.

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