- A balanced diet is one which contains all principal food factors, i.e., proteins, vitamins, carbohydrates, mineral salts, fats, water, etc., in correct proportion.
- This should be able to give about 3,000 calories of energy per day.
The essentials of good diet are:
- These are the organic compounds of carbon, hydrogen and oxygen.
- These produce heat and energy in the body
- Their deficiency causes loss of weight
- These are found in rice, wheat, sugarcane, potatoes, starch in maize, etc.
- These are complex compounds of carbon, hydrogen, oxygen, nitrogen and sulphur.
- These build tissues of the body and repair them when torn out.
- These are found in eggs, meat, pulses, etc.
- Made up of amino acids.
- Amino acids are of 2 Types :
- Essential Amino Acids : They cannot be synthesised in the body and must be taken in the diet. They include isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.
- Non – Essential Amino Acids : They are synthesized in the body and do not need to be taken from outside. These include Alanine, Arginine, Asparagine, Aspartic Acid, Cysteine, Glutamine, Glutamic Acid, Glycine, Histidine, Proline, Serine and Tyrosine.
Some important Proteins are:
- As Enzymes : As Catalyst in Digestion (Eg. Pepsin, Trypsin).
- As a Hormone : To regulate body functions (Eg. Insulin, Glucogon, ACTH).
- In Transport of different Substances : (Eg. Haemoglobin – Transports O2 in blood, Myoglobin – Stores O2 in muscles).
- As Contractile Proteins for Contraction in Muscles : (Eg. Actin and Myosin).
- Structural Proteins : (Eg. Collagen – Component – of Connective Tissue, Bones, Tendons, Cartilage Keratin – Component of Skin, Feathers, Nails, Hair, Horn).
- Protective Proteins : To fight infections (Eg. Gamma globulins).
- Visual Proteins : Rhodopsin and Iodopsin of rods and cones are proteins only. (Rods and Cones are the cells which are present in Retina of the eye).
Sources : Groundnuts, Soyabean, Pulses, Lean Meat, Fish, Eggs, Milk, etc.
Protein deficiency causes:
- Due to diet deficiency of protein.
- Means neglected child (when mother stops breast feeding).
- Symptoms : Abdomen and feet swells (due to retention of water called oedema), Skin becomes Dark and Scaly, Enlarged Liver, Anaemia.
- In infants under 1 Year of age.
- Deficiency of Proteins, Carbohydrates and Fats.
- Symptoms : Losing of body weight, wasting of muscles, ribs look prominent. (Oedema and skin pigmentation absent).
- In children between 6 months and 3 Years.
- These have carbon, hydrogen and oxygen.
- They are obtained from animal and vegetable kingdoms.
- They also produce heat and energy in the body and build fatty tissues.
Butter, ghee and various vegetable oils are examples of fats.
Types of fats
- liquid at room temperature.
- These are found in plant foods and fish.
- These may be good for heart health.
- Solid at room temperature.
- These fats are found in meat and other animal products, such as butter, cheese, and all milk except skim.
- Eating too much saturated fat can raise blood cholesterol levels and increase the risk of heart disease.
- These are a group of substances that are essential in small quantities for normal functions of the body.
- Their deficiency causes sickness and improper development of body.
- At present six of these are recognised as essential to human nutrition.
- These are A, B, C, D, E and K. The richest sources of vitamins are green vegetables, milk, butter, fruits, eggs, etc.
Vitamins are of 2 Types :
- Water Soluble : Vitamin B–Complex and C.
- Fat Soluble : Vitamin A, D, E and K.
TYPES OF VITAMINS
- 1. Vitamin A:
- It increases resistance to infection and tones up the whole system.
- Its deficiency causes night blindness, disorders of skin, stomach growth and respiratory diseases.
- It is found in milk, butter, egg-yolk, ghee, carrot, cod-liver oil, etc.
- 2. Vitamin B:
- It is present in cereals, peas and beans.
- It protects the body from nerve diseases such as beri-beri, pellagra, etc., and it cures pernicious anaemia, degeneration of sex glands and enlargement of liver and adrenals.
- It is also called thiamine.
It is considered to be a hormone.
- 3. Vitamin C:
- It is also called Ascorbic Acid.
- It ensures healthy teeth, bones and protects the body against scurvy.
- It is present in fresh vegetables, orange, lemon, lettuce, tomato, cabbage, turnip, potato and mango
- 4. Vitamin D:
- It is present in milk, butter, ghee, cod-liver oil, yolk of eggs and it is also produced under the skin by the rays of the sun.
- It promotes bone promotion and prevents rickets.
5. Vitamin E:
- It has vital influence on organs to reproduction.
- Its absence causes sterility.
- It is present in the germinating wheat.
- It is also called Alpha-tecopherol.
- 6. Vitamin K:
- It help in the clotting of blood.
- Its absence cause haemorrhage.
- It is found in fish, oats and wheat.
- (vi) Water:
- It serves to dissolve food when digested and aids absorption.
- It helps in removing waste matters from the body.
- It also helps in circulation of blood.