- The components of food are: Carbohydrates, Fats, Proteins, Minerals, Vitamins, Water and Roughage.
- If all the components are present in optimum proportions and quantity for maintaining the body in perfect state of health, activity and development than the food is called balanced diet.
CARBOHYDRATES
- Constitutes 3 elements: Carbon, Hydrogen and Oxygen.
- Daily requirement is 500 gms. 1 gm gives 17 KJ of energy.
- The carbohydrates of the food eaten, after being processed in the alimentary canal and liver, are supplied to the tissues mainly as glucose, often called blood sugar.
- Sources: 3 main cereals (wheat, rice and maize), sugar cane, milk, fruits, honey, beet, etc.
- They are 3 types: Cellulose, Starch and sugar.
- Structrually, carbohydrates are of 3 types: Monosaccharides, Disaccharides and Polysaccharides.
- Excess carbohydrate is stored in the liver in the form of glycogen.
FATS
- Provides twice the energy of carbohydrates (1 gm provides 37 KJ of energy).
- Acts as the reserve food material because excess fat is stored in the liver and as adipose tissue.
- An enzyme called Lipase digests fats. It breaks down into fatty acids and glycerol.
- Daily requirement: 50 gms.
PROTEINS
- Made up of Carbon, Hydrogen, Oxygen and Nitrogen.
- Important for growth and repair of the body.
- Made up of amino acids.
- Kwashiorkar and Marasmus are the diseases which occur due to deficiency of protein.
MINERALS
| Mineral
MACRO ELEMENTS |
Sources | Signiflcance | Effects of deficiency |
| Calcium (Ca)# | Milk, cereals, cheese, green vegetables | Required for formation of teeth and bones, blood clotting, functions of nerves and muscles | Weak teeth and bones: retarded body growth |
| Phosphorus (P) | Milk, meat, cereals | Required for formation of teeth and bones and acid-base balance: component of ATP, DNA,RNA | Weak teeth and bones: retarded body growth and physiology |
| Sulphur (S) | Many proteins of food | Component of many amino acids | Disturbed protein metabolism. |
| Potassium (K) | Meat, milk, cereals, fruits and vegetables | Required for acid-base balance, water regulation and function of nerves | Low blood pressure, weak muscles: risk of paralysis |
| Chlorine (C) | Table salt | Required for acid-base balance: component of gastric juice | Loss of appetite, muscle cramps |
| Sodium (Na) | Table salt | Required for acid-base and water balance and nervous functions | Low blood pressure, Loss of appetite: muscle cramps |
| Magnesium (Mg) | Cereals, green vegetables | Co-factor of many enzymes of glycolysis and a number of other metabolic reactions dependent upon ATP | Irregularities of metabolism principally affecting nervous functions |
| Iron (Fe) | Meat, eggs, cereals, green, vegetables | Component of haemoglobin and cytochromes | Anaemia, weakness and weak immunity |
| Iodine (I) | Milk, cheese, sea food, iodized salt | Important component thyroxine hormone | Goitre, Cretinism |
- The salt of Ca required by our body is Ca3 (PO4)2
VITAMINS
- Necessary for normal growth, good health, good vision, proper digestion, etc. They do not provide energy to our body.
- Vitamins can be divided into two categories.
- Water-soluble: Vitamin B-complex, Vitamin C.
- Fat-soluble: Vitamin A, Vitamin D, Vitamin E, Vitamin K.
TYPES OF VITAMINS
| Vitamin | Chemical Name | Properties | Deficiency Disease |
| A | Retinol | General health giving vitamin, can be stored in liver | Night blindness |
| B1 | Thiamine | For growth, carbohydrate metabolism, functioning of heart | Beri-Beri |
| B2 | Riboflavin | For keeping skin and mouth healthy | Cheilosis |
| B5 | Niacin | For healthy skin, sound mental health | Pellagra |
| B6 | Pyridoxine | Processing of proteins and for nervous system | Convulsions in child |
| B12 | Cynacobalamin | Required for formation and maturation of RBCs | Pernicious anaemia |
| C | Ascorbic Acid | For keeping teeth, gums and joints healthy. Gets destroyed on heating | Scurvy |
| D | Calciferol | For normal bones and teeth, can be stored in liver | Rickets |
| E | Tocopherol | For normal reproduction, removes scars and wrinkles | Sterility |
| K | Phylloquinone | For normal clotting of blood | Haemophilia |
WATER
- Important in digestion, transportation, excretion and to regulate body temperature (body contains 65% water).
ROUGHAGE
- Fibrous material present in the cell wall of plants.
- Mainly contains cellulose.
- It doesn’t provide energy but only helps in retaining water in the body.
- One of the common source is Daliya, Which we eat in our homes.