Notes On Vitamins - CBSE Class 12 Chemistry
The organic substances that we need in small amounts in our diet, and whose deficiency leads to specific diseases, are called “vitamins”. Vitamins perform specific biological functions. They are essential for proper growth.

Classification of Vitamins:
 
Vitamins are typically classified into two groups based on their solubility in fat or water – fat-soluble vitamins and water-soluble vitamins. Fat-soluble vitamins are soluble in fats or oils.
EX: Vitamins A, D, E and K

On the other hand, water soluble vitamins are soluble in water.
EX:  B group vitamins and vitamin C
 
Fat soluble vitamins:

Vitamin A or Retinol:
  • It is present in carrots, butter, milk, Fish liver oil etc.
  • This vitamin is necessary for a clear vision. The deficiency of vitamin A leads to xerophthalmia.

Vitamin D or Calciferol:
  • It is produced when skin is exposed to sunlight.
  • Food sources of vitamin D include fish and egg yolk.
  • This vitamin is required for bone growth and calcium metabolism.
  • Vitamin D deficiency leads to rickets In adults, this is called osteomalacia.
 
Vitamin E:
  • Dietary sources of vitamin E include vegetable oils and cereal grains.
  • Vitamin E deficiency leads to more fragile red blood cells and muscular weakness.
 
Vitamin K:
  • Green leafy vegetables are good dietary sources of vitamin K. 
  • Vitamin K deficiency leads to slower blood clotting.
 
Water soluble vitamins:

Vitamin C (or) ascorbic acid:
  • Dietary sources of vitamin C include citrus fruits, amla and green leafy vegetables.
  • This vitamin is required for the synthesis of collagen
  •  It’s deficiency causes scurvy.

B group vitamins:
  • They are found in meat products, whole grains, milk and yeast.
  • They are essential for metabolism and the proper utilisation of energy sources like carbohydrates, proteins and fats.
  • B group vitamins include vitamin B1, vitamin B2, vitamin B6 and vitamin B12.

Vitamin B1 or thiamine:
The richest source of this vitamin is yeast and the outer layers of cereals like rice, wheat and millets. A deficiency of this vitamin causes beriberi.

Vitamin B2 or riboflavin:
It is mostly found in milk and milk products, eggs, liver, green leafy vegetables, pulses, wheat ... and so on. Insufficient vitamin B2 leads to cheilosis.
 
Vitamin B6 or pyridoxine:
It is found in meat, liver, egg yolk, cereals, grains and vegetables.
Its deficiency causes convulsions.
 
Vitamin B12 or cobalamine:
It is found in meat, fish egg and curd.
Its deficiency leads to pernicious anaemia, that is, RBC deficient in haemoglobin.

Summary

The organic substances that we need in small amounts in our diet, and whose deficiency leads to specific diseases, are called “vitamins”. Vitamins perform specific biological functions. They are essential for proper growth.

Classification of Vitamins:
 
Vitamins are typically classified into two groups based on their solubility in fat or water – fat-soluble vitamins and water-soluble vitamins. Fat-soluble vitamins are soluble in fats or oils.
EX: Vitamins A, D, E and K

On the other hand, water soluble vitamins are soluble in water.
EX:  B group vitamins and vitamin C
 
Fat soluble vitamins:

Vitamin A or Retinol:
  • It is present in carrots, butter, milk, Fish liver oil etc.
  • This vitamin is necessary for a clear vision. The deficiency of vitamin A leads to xerophthalmia.

Vitamin D or Calciferol:
  • It is produced when skin is exposed to sunlight.
  • Food sources of vitamin D include fish and egg yolk.
  • This vitamin is required for bone growth and calcium metabolism.
  • Vitamin D deficiency leads to rickets In adults, this is called osteomalacia.
 
Vitamin E:
  • Dietary sources of vitamin E include vegetable oils and cereal grains.
  • Vitamin E deficiency leads to more fragile red blood cells and muscular weakness.
 
Vitamin K:
  • Green leafy vegetables are good dietary sources of vitamin K. 
  • Vitamin K deficiency leads to slower blood clotting.
 
Water soluble vitamins:

Vitamin C (or) ascorbic acid:
  • Dietary sources of vitamin C include citrus fruits, amla and green leafy vegetables.
  • This vitamin is required for the synthesis of collagen
  •  It’s deficiency causes scurvy.

B group vitamins:
  • They are found in meat products, whole grains, milk and yeast.
  • They are essential for metabolism and the proper utilisation of energy sources like carbohydrates, proteins and fats.
  • B group vitamins include vitamin B1, vitamin B2, vitamin B6 and vitamin B12.

Vitamin B1 or thiamine:
The richest source of this vitamin is yeast and the outer layers of cereals like rice, wheat and millets. A deficiency of this vitamin causes beriberi.

Vitamin B2 or riboflavin:
It is mostly found in milk and milk products, eggs, liver, green leafy vegetables, pulses, wheat ... and so on. Insufficient vitamin B2 leads to cheilosis.
 
Vitamin B6 or pyridoxine:
It is found in meat, liver, egg yolk, cereals, grains and vegetables.
Its deficiency causes convulsions.
 
Vitamin B12 or cobalamine:
It is found in meat, fish egg and curd.
Its deficiency leads to pernicious anaemia, that is, RBC deficient in haemoglobin.

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