Vitamin B1 or Thiamine- Chemistry, Sources, Daily Requirement, Biochemical Functions And Deficiency Symptoms

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Vitamin B1 or Thiamine is also known as anti beri-beri and anti neuritic vitamin. It is water soluble. It has a specific coenzyme Thiamine pyro phosphate TPP, which is mostly associated with carbohydrate metabolism.


Thiamine contains a pyrimidine ring and a thiazole ringheld by a methylene bridge. Also it is the only compound in nature with thiazole ring. The coenzyme thiamine pyro phosphate is formed by the esterfication of alcohol group of thiamine by phosphate.this reaction is catalysed by the enzyme ‘Thiamine pyro phosphate transferase’.

Biochemical functions:

The conenzyme of thiamine the TPP is very much essential for the carbohydrate metabolism. The reactions dependant on TPP are,

The irreversible conversion of pyruvate to acetyl CoA catalysed by pyruvate dehydrogenase. This a oxidative decarboxylation reaction.

Transketolase is an enzyme of Hexose Mono Phosphate shunt also is dependant on TPP

Alpha keto dehydrogenase of citric acid cycle  also requires TPP.

TPP also plays an key role in the transmission of nerve impulse.

Recommended dietary allowance RDA:

The daily requirement for adults is about 1 – 1.5 mg/daily. For children the RDA is 0.7 – 1.2 mg/daily.  The RDA increases in pregnancy and lactation..

Dietary sources:

Cereals, pulses, oilseeds, nuts, and yeast are good sources of thiamine. Polishing of rice removes thiamine as it is present in the outer bran in high concentration.

Animal sources like milk, meat , liver, kidney also contain thiamine. While cooking thiamine is extracted to the water hence use that water to avoid the loss of thiamine and other water soluble vitamins.

Deficiency symptoms:

Loss of apetite(Anorexia)







Beri-beri is the name of the deficiency syndrome


There are two types of beri-beri

Wet beri-beri:

·        Oedema of legs, face and trunk are present.

·        Dyspnea and palpitations present

·        Heart becomes weak

·        Death may result from heart failure.

Dry beri-beri

This is associated with neurological symptoms

·        Oedema not common

·        Muscular weakness present

·        These symptoms may be mixed up.

·        Infantile beri-beri:

·        This occurs in infants whose mother has thiamine deficiency

·        Sleeplessness, restlessness, vomiting, convulsions may occur.

·        Death may occur due to cardiac failure

Thiamine antagonists:

Pyrithamine and oxythamine are two important antimetabolites of thiamine.


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