Vitamin B1 (Thiamine)
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- It is a white powder which is readily soluble in water. Alkali destroys thiamine. Thiamine is commercially produced as thiamine hydrochloride. It has yeast like odour and it is stable in its dry form.
Functions
- Thiamine combines with pyrophosphate and forms thiamine pyrophosphate, which acts as intermediary metabolism of carbohydrates.
- Transketolase, an enzyme has thiamine pyrophosphate, as a co-factor. It acts as a co-enzyme in the metabolic pathway of carbohydrates at different places.
- Animal experiments showed that thiamine pyrophosphate is essential for protein metabolism
- Thiamine is also required for the synthesis of glycine in the body
- Thiamine pyrophosphate is present in the peripheral nerve cells. It has a specific effect on nerve tissues. In thiamine deficiency the peripheral nerves degenerate
- Thiamine is also required for the maintenance of normal gastro-intestinal tone and motility
- Thiamine seems to help the heart in its normal action
- Thiamine is otherwise known as ‘morale vitamin’ because it helps the transmission of nervous impulses and maintains the stability of nerves
Deficiency
- It is difficult to identify the deficiency earlier. In mild deficiency loss of appetite, loss of weight and strength, fatigue, emotional upsets, irritability, depression, anger and fear are manifested.
- Constipation is common among such people.
- Headache, insomnia and tachycarida with slight exertion occurs during thiamine deficiency.
- Gastrointestinal and cardiovascular disorders with peripheral nervous problems initiate the deficiency state of thiamine.
- Severe deficiency of thiamine causes beriberi. Three forms of beriberi occur in human beings. They are dry beriberi, wet beriberi and infantile beriberi.
Dry beriberi
- The peripheral nerves of the legs and arms are affected first.
- Degeneration of the myelin sheath of the nerves is followed by the degeneration of the axis cylinder.
- Calf muscles become tender.
- Numbness in the toes and ankles takes place.
- The knee and ankle jerk and later on the sensation are lost.
- Tingling and numbness of the legs and hands are followed by wasting of muscles and difficulty in walking.
Wet beriberi
- All the symptoms of dry beriberi are seen in wet beriberi also.
- In addition to these, oedema in legs and in-between cardiac muscle fibre is observed.
- These changes in the heart muscles lead to enlargement of the heart.
- Later palpitation, oliguria and dyspnoea may develop.
- Oedema on the legs will be prominent.
- The patient may be bed-ridden and cardiac failure may take place.
- If untreated it leads to death within hours.
- It affects infants within six months.
- The early symptoms are restlessness, sleeplessness and loss of appetite.
- The affected child is pale, oedematous and ill tempered.
- Vomiting and green coloured diarrhea are common.
- If treatment is delayed it leads to death.
Sources
- Rich sources – Rice polishing (Bran), dried yeast and wheat germ
- Good sources - Wheat, oats, legumes, oil seeds and nuts
- Fair sources - Milled cereals, vegetables, fruits, milk, meat and fish
Requirements
During deficiency state 5mg of thiamine orally three times a day is recommended. It is readily absorbed from the small and large intestines. It is not stored in the body.
RDA of Thiamine for Indians Age
| Group
|
Category
|
Body weights
kg
|
Thiamine
mg/d
|
| Man
|
Sedentary
|
60
|
1.2
|
| Moderate
|
|
60
|
1.4
|
| Heavy
|
|
60
|
1.7
|
| Woman
|
Sedentary
|
55
|
1
|
| Moderate
|
|
55
|
1.1
|
| Heavy
|
|
55
|
1.4
|
| Pregnant
|
|
55
|
+0.2
|
| Lactation
|
0-6m
6-12m
|
55
|
+0.3
+0.2
|
| Infants
|
0-6 m
|
5.4
|
0.2
|
|
6-12m
|
8.4
|
0.3
|
| Children
|
1-3y
4-6y
7-9 y
|
12.9
18.0
25.1
|
0.5
0.7
0.8
|
| Boys
|
10-12y
|
34.3
|
1.1
|
| Girls
|
10-12y
|
35.0
|
1.0
|
| Boys
|
13-15y
|
47.6
|
1.4
|
| Girls
|
13-15y
|
46.6
|
1.2
|
| Boys
|
16-17y
|
55.4
|
1.5
|
| Girls
|
16-17y
|
52.1
|
1.0
|
|
Last modified: Saturday, 2 June 2012, 6:41 AM
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