Vitamins: Introduction, Classification, Benefits, Supplements and Deficiencies
Posted on : 25-11-2017 Posted by : Admin



The vitamins are a group of complex organic compounds required in small quantities by the body for the maintenance of good health. They are not normally synthesized in the body and hence are to be supplied through the diet.

Casimir Funk, a Warsaw-born biochemist was the first to coin the word "vitamin" in 1911. While working on effect of poor diet on nerve inflammation in chickens. Chickens raised on diet deficient in a particular compound developed nerve imflammation, and when that particular compound was replaced the chickenswere normal. He isolated and named that substance "vitamine" as this substance was vital for life and it was an amine. Later it was discovered that all vitamins are not amines and the letter "e" was removed from the ending and finally the name VITAMIN was given.

All the vitamins are named so in the order of their discovery. The one exception was vitamin K which was assigned its name "K" from the term "Koagulation" by Henrik Dam. There are 13 different vitamins in the human body. Out of these only vitamin K and D are produced by the human body.

Unlike other groups of nutrients the vitamins are not chemically similar to each other. Each vitamin has a specific chemical structure and a specific function in the living system. Most of the vitamins act as coenzymes in the body. Normally a well-balanced diet will supply all the necessary vitamins in sufficient quantity.


Vitamin Classification

Energy is the primary requirement for performing various activities. We get energy from the food we eat. Apart from the normal food we consume, our body requires other compounds like vitamins in small amounts for the proper body functioning and deficiency of these compounds may cause disorders. Vitamins are generally classified into the following two main groups, based on their solubility.


Fat soluble vitamins

These vitamins are not soluble in water but are readily soluble in fat dissolving organic solvents. They need presence of fats for their transport and metabolism. They are found in foodstuffs in association with lipids. The fat soluble vitamins are absorbed along with dietary fats. Adequate bile flow and good micelle formation favor absorption of fat-soluble vitamins. These vitamins are excreted primarily in the faeces via bile. The following are the characteristics of fat soluble vitamins,

  • Adsorbed with dietary fat in micelles
  • Excreted much more slowly
  • Stored in adipose tissue & liver and hence they pose a greater risk of toxicity when consumed in excess
  • Chylomicrons containing fat-soluble vitamins are transported via the lymph to the bloodstream and eventually to the liver.

The following is the list of fat soluble vitamins,

  • Vitamin A (Retinol)
  • Vitamin D (Calciferol)
  • Vitamin E (Tocopherol)
  • Vitamin K (Phytonadione)


Water soluble vitamins

Water soluble vitamins are are the ones which dissolve in water. These vitamins are sent out of the body through urine. The ups and downs in the fat absorption do not affect the absorption of water soluble vitamins. The following are the main characteristics of water soluble vitamins,

  • Dissolve in water
  • Readily excreted by kidney
  • Function as a coenzyme & in energy metabolism
  • Vitamin C, thiamin and riboflavin are especially susceptible to heat and alkalinity
  • Hydrophilic compounds and water leach them from vegetables
  • Marginal deficiency more common

The following is the list of water soluble vitamins,

1. Vitamin B complex (includes B1, B2, B3, B5, B6, B7, B9, B12)

2. Vitamin C (Ascorbic acid)

Vitamin B Complex

Vitamin B complex has a major role to play in all the metabolic processes of the cell. The vitamins in this comples are all water-soluble vitamins. The B vitamins were initially considered to be a single vitamin and was called vitamin B. Further experiments proved that vitamin B is actually a groups of separate chemicals which existed together in same food material. The complete group of all the vitamins B members are referred to as a vitamin B complex. They are eight in number. Individual member of this group is called by its name for example vitamin B1, vitamin B2...

Importance of Vitamin B complex

  • Energy metabolism
  • Immune system health
  • Nervous system function
  • Hormone balancing
  • Health skin, hair and teeth
  • Antioxidant effects
  • Healthy cholesterol levels
List of B-complex vitamins

  • Vitamin B1 (Chemical name thiamine)
  • Vitamin B2 (Chemical name riboflavin)
  • Vitamin B3 (Chemical name niacin/niacin amide)
  • Vitamin B5 (Chemical name pantothenic acid)
  • Vitamin B6 (Chemical name pyridoxine)
  • Vitamin B7 (Chemical name biotin)
  • Vitamin B9 (Chemical name folic acid)
  • Vitamin B12 (Chemical name cyanocobalamin)
Deficiency of Vitamin B complex

Because vitamins in B complex group acts as coenzymes for key metabolic processes, its deficiency may lead to poor intake of all other vitamins, difficulties with vitamin absorption and conditions causing increased metabolism which deplete vitamin levels at a higher rate than normal. Since the vitamin B complex work in harmony, a deficiency in one type may have broad implications. Poor intake of B vitamins is most often a problem in strict vegetarians and the elderly. People who frequently fast or diet may also benefit from B vitamin supplements.


Benefits of vitamins

  • Vitamins have the ability to prevent and treat various diseases like heart problem, high cholesterol level, eye disorder and skin disorder.
  • Vitamins also facilitate various mechanisms of the body.
  • Vitamins have the ability to perform functions which cannot be performed by any other nutrients.


Vitamin supplements

Vitamins can be ingested by humans in a variety of ways. Generally vitamins are acquired through the foods we eat, but due to variation in our location, culture and food habits, some may take more vitamin or some may take less vitamins. When the intake of vitamins is less than the required quantity, then vitamins must  be supplied from outside.  Vitamin supplements boost the vitamin content in our body. To improve the overall health and maintain a good balance of body multivitamins are often prescribed.

Some vitamins become more usable by the body when subjected to steam or cooking. On the other hand water soluble vitamins like vitamin B and vitamin C leak into the water while boilin or cooking.


Vitamin deficiencies

To avoid deficiencies, humans must often consume vitamins. Also the storage capacity of the human body for various vitamins is different. While vitamin A, D and B12 are stored for quite a significant time in the liver, Vitamin B3 is stored only for a couple of weeks.

Vitamin deficiency can be primary or secondary. Primary vitamin deficiency arises when the body does not get enough vitamins through dietary sources. Secondary vitamin deficiency arises when the absorption of the vitamin is limited by the body due to various underlying disorders.

Moreover, overdoses of vitamins may result in vitamin poisoning with side effects like nausea, diarrhea and vomiting.

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