Vitamins can be defined as organic compounds occurring in small quantities in different natural foods and are necessary for growth and maintenance of good health. Vitamins can also be defined as essential food factors, which are required for the proper utilization of food such as carbohydrates, lipids and proteins.
The discovery of Vitamins started from an observation of deficiency manifestations, such as beriberi, scurvy, rickets, etc. The theory was suggested by Hopkins in 1912 and which led to the term “vitamine”, meaning vital + amine, since the earlier identified ones had amino groups.
Other researches showed that most of these vitamins lack amino groups, so the “e” from vitamin last letter was dropped in the modern term to Vitamin. Although vitamins are nutritionally important, their role in clinical practice has been over-emphasized.
Vitamins are very useful in correcting deficiencies but the intake of higher doses will not boost up the health. Vitamins are usually present in our daily diet.
Classification of Vitamins
They are mainly classified into two category:
- The fat soluble vitamins ( A, D, E and K )
- Water soluble vitamins are named as B complex and C. (Thiamine, Riboflavin, Niacin, Pyridoxine, Pantothenic acid, Biotin, Folic acid, Vitamin B12 and Ascorbic acid)
Differences between Fat Soluble and Water Soluble Vitamins
|Features||Fat soluble vitamins||Water soluble vitamins|
|Solubility in fat||Soluble||Not soluble|
|Water solubility||Not soluble||Soluble|
|Absorption Along with lipids||Absorption simple||Requires bile salts except Vitamin B12|
|Carrier proteins||Present||No carrier proteins except Vitamin B12|
|Storage||Stored in liver||No storage except Vitamin B12|
|Deficiency||Manifests only||Manifests rapidly when stores are as there is no depleted storage except Vitamin B12|
|Toxicity||Hyper-vitaminosis may result||Unlikely, since excess is excreted|
|Treatment of deficiency||Single large doses may prevent deficiency||Regular dietary supply is required|
|Major vitamins||A,D,E and K||B and C|
Deficiency due to Vitamins
The following could be as a result of vitamins deficiency
- Reduced intake
- Impaired absorption
- Impaired metabolism
- Additional requirements
- Increased losses.
Textbook of Biochemistry – For Medical Students, 6th Edition