Vitamin B1 (Thiamin) – Chemistry, Functions, Food Sources, Deficiency

Chemistry and Characteristics

Thiamine hydrochloride is a white crystalline substance. It has a faint yeast-like odour and a salty, nut like taste. It is readily soluble in water but not in fat solvents or fats. It is readily destroyed by heat in neutral or alkaline solution; in acidic medium it is resistant to heat up to 120oC.

Functions

Thiamine teams up with an enzyme to form a coenzyme. The latter act as a catalyst with the oxidation processes.

  1. It is essential for the utilisation of carbohydrates in the body; in deficiency there is accumulation of pyruvic acid and lactic acid in the tissues and body fluids.
  2. Thiamine is also essential for the maintenance of good appetite and normal digestion.
  3. It has a role in brain metabolism as the deficiency causes neurological and nervous disorder.

Food Sources

All the natural foods contain thiamine, even if in very small amounts. Important sources are dried yeast, whole grain cereals and pulses, oilseeds and nuts especially groundnuts. Meat, fish, egg, vegetables and fruits are relatively poor sources.

Recommended Dietary Allowances

Thiamine requirements are expressed on the basis of energy intake. The recommended dietary allowances is 0.5 milligram/1000kcal.

Deficiency

The clinical manifestations of thiamine deficiency are beri-beri and Wernick’ sencephalopathy. Beri-beri exists in three forms- dry, wet and infantile beri-beri. Manifestations of minor thiamine deficiency are loss of appetite, absence of ankle jerks, knee jerks and presence of calf tenderness.

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