Vitamins-Functions, Types, Characteristics, Chemical Name, Uses and Deficiency Diseases

These essential nutrients are broken up into two groups based on the amount that is needed:
1. Macro nutrients: protein, carbohydrates, fat, and water

2. Micro nutrients: vitamins and minerals

Vitamins: Vitamins comprises micro-nutrients, since these are required in minute quantities. These are necessary for normal growth, good health, good vision, proper digestion of body. etc.  Each vitamin has its own importance for life and the health of the body. It is difficult to replace it by any other thing. If there is deficiency of vitamins in the diet of body, the body suffers from various diseases and ailments. 

Function of Vitamins
Vitamins are helpful for the health and life of the body in the following respects:
(a) They build up the resistance of the body against diseases.
(b) Prevent and cure various diseases caused by deficiency.
(c) Help the digestion and utilisation of mineral salts and Car­bohydrates in the body.
(d) Stimulate and give strength to digestive and nervous system.
(e) Help health protection.
(f) Help maintenance of proper health and normal growth.

Vitamins are classified as 

Water soluble vitamins - Water-soluble vitamins cannot be stored in the body, so you need to get them from food every day. They can be destroyed by overcooking. These are easily absorbed by the body. Human body doesn't store large amounts of water-soluble vitamins. B-complex vitamins and vitamin C are water-soluble vitamins that are not stored in the body and must be replaced each day. These vitamins are easily destroyed or washed out during food storage and preparation. They are eliminated in urine so, body need a continuous supply of them in diets. Examples:  Vitamin B-complex group: Thiamin (vitamin B1), Riboflavin (vitamin B2), Niacin, Vitamin B6, Folate, Vitamin B12, Biotin, Pantothenic acid  and Vitamin C 

Fat soluble vitamins - Vitamin A, Vitamin D, Vitamin E and Vitamin K. Unlike water-soluble vitamins, these vitamins dissolve in fat and are stored in liver and  body tissues. Fat-soluble vitamins are absorbed, together with fat from the intestine, into the circulation. 

• Vitamin D is absorbed in small intestine.
• Vitamin E is stored in liver and adipose tissue. 
• Vitamin A is a generic term for a class of compounds called retinoids. Carotenoids: pigment in fruits and vegetables used in forming vitamin A. Retinoids stored in liver and carotenoids stored in liver and adipose tissue.
• The release of vitamin K and Vitamin E from food requires bile, digestive enzymes from the pancreas and intestinal tract, and integration into micelles
• Vitamin D: Two nutritionally important forms: vitamin D2 (ergocalciferol) which is found in plants and vitamin D3 (cholecalciferol) which is synthesized in the body from cholesterol. Provitamin D (a form of cholesterol) is converted to previtamin D3 is converted to vitamin D3 in Skin. D3 must be metabolized in the liver before becoming the active form of vitamin D. Formation of hormone form (Calcidiol and Calitriol) of vitamin D occurs in the liver and kidneys

Where are Fat Soluble Vitamins stored in Human Body?
Vitamins A, D and K are stored in the liver and vitamin E is distributed throughout the body's fatty tissues.

What is Hyper-Vitaminosis? 
Because fat-soluble vitamins are stored in body, over time they can accumulate to dangerous levels and can lead to a condition called hyper-vitaminosis, meaning excess amounts of a vitamin in the body if taken more than enough.

Vitamins	Chemical Name	Sources	Deficiency Causes	Function in Body
Vitamin A	Rclinol	Animal Fat, Eggs. Carrot Mangoes, Milk, Papayas.	Night blindness. Dermatitis and Xerophthalmia	vision,  growth,  resistance to diseases
Vitamin B1	Thiamine	Cereals, Eggs	Beriberi	energy metabolism (glucides), proper functioning of the nervous system
Vitamin B2	Riboflavin	Fish. Cereals	Ariboflavinosis	metabolism of amino acids and fats
Vitamin B3	Nicotinic Acid	grains, yeast, fish, eggs		tissue integrity (skin)
Vitamin B6	Pyridoxine	Cereals, Eggs	Convulsions in child	metabolism of proteins, fats, glucides and iron
Vitamin-B9	Folic Acid	yeast, liver		protein metabolism, haemoglobin synthesis
Vitamin B12	Cyanocabalamin	Eggs and cereals	Pernicious Anaemia	protein metabolism, haemoglobin synthesis
Vitamin C	Ascorbic Acid	Fruit, Orange. Lenons. Milk	Scurvy
Vitamin D	Calciferol	Fish. Eggs, Milk, Butter	Ricketts and Osteomalacia	balanced metabolism of phosphorus and calcium, improved absorption of calcium
Vitamin E	Tocopherol	Wheat germ. Milk. Eggs. Yolk	Sterility	antioxidant prevention of muscular pathology (strain)
Vitamin K	Phylloquinione	Wheat germ. Milk, cereals. Eggs	Hemophilia	production of coagulants
Vitamin -H	Biotin	yeast,  natural ingredients		integrity of the skin, metabolism of glucides. lipids and proteins.

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