PYRIDOXIN (VITAMIN B6)
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- It is white crystalline substance soluble in water, quite stable to heat and acid. In an alkaline medium it is easily destroyable.
Functions
- Vitamin B6 acts as a co-factor for several enzymatic reactions in all the three metabolisms. In protein metabolism, transamination takes place with the help of this enzyme system. In carbohydrate and fat metabolisms, there are intermediary reactions where vitamin B6 acts as a co-factor.
- Tryptophan conversion to niacin has a series of biochemical reactions. In pyridoxine deficiency this conversion step will not materialize and niacin is not formed.
- Removal and transfer of sulphur groups from sulphur containing amino acids like cysteine requires pyridoxine.
- In carbohydrate metabolism pyridoxal phosphate is essential for the action of phosphorylase enzyme which converts glycogen to glucose
- Vitamin B6 helps in energy transformation in brain and in nervous tissues. In its deficiency, convulsive seizures occur in animals and in human beings. Especially infants fed on evaporated milk develop nervous irritability and convulsion seizures.
Deficiency
- As a part of general deficiency of B complex, vitamin B6 deficiency also occurs otherwise Vitamin B6 deficiency is highly uncommon in humans.
- In experimental cases anorexia, nausea, restlessness, lethargy, seborrhea, hyperpigmentation, pellagra like dermatitis, cheilosis, glossitis and angular stomatitis were observed.
- Changes in the periphery of nerves with sensory impairment and motor abnormalities were also observed.
- In infants convulsion are seen. Immune response is impaired in B6 deficiency
Sources
- Good sources: Dried yeast, liver and rice polishing
- Rich to fair source : sorghum, bajra, pulses, beetroot, cabbage and fleshy foods
Table RDA of vitamin B6
| Age Group
|
Category
|
Body weights
kg
|
Vitamin B6
mg/d
|
| Man
|
Sedentary
Moderate
Heavy
|
60
|
2.0
|
| Woman
|
Sedentary
|
55
|
2.0
|
| Moderate
|
| Heavy
|
| Pregnant
|
55
|
2.5
|
Lactation
0-6m
6-12m
|
55
|
2.5
2.5
|
| Infants
|
0-6 m
|
5.4
|
0.1
|
| 6-12m
|
8.4
|
0.4
|
| Children
|
1-3y
4-6y
7-9 y
|
12.9
18.0
25.1
|
0.9
0.9
1.6
|
| Boys
|
10-12y
|
34.3
|
1.6
|
| Girls
|
10-12y
|
35.0
|
1.6
|
| Boys
|
13-15y
|
47.6
|
2.0
|
| Girls
|
13-15y
|
46.6
|
2.0
|
| Boys
|
16-17y
|
55.4
|
2.0
|
| Girls
|
16-17y
|
52.1
|
2.0
|
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Last modified: Tuesday, 5 June 2012, 5:41 AM
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