Fat Soluble Vitamins

Fat soluble vitamins:

 They are classified into four types :
1. Vitamin A
2. Vitamin D
3. Vitamin E
4. Vitamin K
         Fat soluble vitamins are soluble in fat, contain antioxidant properties and reduce the free radical damage the unwanted substance produced in our body due to disturbance in the metabolism.

1. Vitamin A (or) Antixeropthalmic Vitamin:

 History- Elmer MC collum first recognized it as a nutritional factor.Later Holmes isolated it from fish liver oil.
 Chemical name- is Retinol.Also called as Anti infective Vitamin due to its role in visual cycle.
 Functions- Plays an important role in vision.Vitamin A aldehyde is essential for the formation of rhodpsin, a factor sensitive to light of low intensity.Deficiency of it leads to impaired adaptation to darkness.It also helps in Tissue growth, helps in maintaining the integrity of the epithelial membranes.
     It helps top improve the Immune response hence called as a Anti infective vitamin.It also improve the bone development and helps in remodelling. It is an Antioxidant and Anti cancer agent.
Deficiency- It leads to Night Blindness- The person can't see in dim light. Conjuctival  xerosis- The conjunctiva becomes dry. Bitot's spot- Greyish scar develops on conjunctiva.Follicular hyperkeratosis- The skin becomes dry and scaly leading to ulcers and bleeding.
Sources- Liver, Kidney, Fish, yellow and green leafy veggies and all the dairy products.

2. Vitamin D (or) Anti rachitic Vitamin:
Chemical name- is calciferol.Also called sunshine vitamin as it is formed by the action of U.V rays on the precursor sterols present beneath the skin.

Functions- Through the action of precursor sterols it enhances the calcium, phosphorus absorption from the digested food, helps in the calcification process of the osteoblast cells present inside the bones which carry out the deposition process of calcium. It also helps to maintain the calcium serum levels in blood.
Deficiency- Leads to bone deformities such as curved legs, swelling of wrist , knee and ankle joints. Rickets in children and osteomalacia in adults leading to growth failure. In adults, the progressive decalcification of the bones leads to the replacement of bony substances with soft  osteoid tissue. 
Sources- The best source is sunlight, Cod liver oil and organ meat.

3. Vitamin E  (or ) Anti sterility Vitamin:
Chemical name- Tocoferol

Functions - Neutralize the free radicals and prevent the free radical damage, Acts an Anti aging agent which reduce the aging process, Helps to prevent the dryness. Increases the arterial blood flow and prevent intermittent claudication ( improper blood flow).
Deficiency- Leads to reproductive failure and R.B.C destruction leading to haemolytic anemia.
Sources- Vegetable oils, nuts, rice bran oil, milk, meat, egg, fish and poultry.

4. Vitamin K (or) Anti haemorrhagic Vitamin:
 History- Mc Farlance isolated the Vitamin k deficiency in rats.
Chemical name- Napthquinone.

Functions- It helps in clotting process, growth and development, synthesis of DNA and RNA, Helps in electron transport chain and thus helps in the production of energy.
Deficiency- In newborns, a condition called haemorrhagic disease develops if the mother is deficient in Vitamin k. The capillaries of the newborn will be very fragile leading to internal rupture which can even cause death of the child.
Sources- Green leafy vegetables, all the dairy and animal foods.