The water soluble vitamins make up a large group, All but one belong to the complex group. For the most part, water soluble vitamins are not stored in the body. Excesses are largely excreted, thus eliminating the possibilities for toxicity that exist with over dosage of fat soluble vitamins ,At least eleven vitamins compose the B-Complex group. Seven of them are essential in human nutrition and they must be provided in our daily meals.
Three of these included in the allowance table; they are thiamine, riboflavin and niacin. They were thought to be one substance but later on their separate identities were established .The fact that each one is soluble in water made it difficult to recognize them. Each one of them has a task of helping to provide energy to the body. They make it possible for carbohydrate to ‘burn’ at body temperature. All three occur in very small amounts in everybody cell.
Thiamine is a component of the enzyme co-carboxylase, which is needed for the production of energy in the metabolism of carbohydrates. This energy is essential for the maintenance of normal appetite, normal muscle tone of the gastro-intestinal tract and a healthy nervous system. The liver, kidney, heart, muscles and brain are richer in thiamine than the blood which contains only traces. During deficiency, thiamine is rapidly lost from the tissue and this leads mainly to muscular and nervous disorder.
The thiamine requirements of the body are roughly proportional to the calorie expenditure of the body. Thiamine is not stored to any appreciable extent and the total reserves in the body last only for a few weeks of normal functioning. Hence a day-to-day supply is essential. The normal requirement of thiamine in daily diet is 0.5 mg/1000 calorie intake.
A very low intake of thiamine for a prolonged period leads eventually to ‘Beri-beri’, a dietary deficiency disease. It is also associated with a low calorie intake and the deficiency of the other factors of vitamin B-complex that are found in the same foods.
Causes of Thiamine Deficiency
There are three factors that cause thiamine deficiency:
(i) Low intake.
Occurs in areas where refined cereals, in the form of polished rice or refined flour are taken as major sources of calories. Milling is cereals remove those portions of grains which are riches in thiamine-the sperm, aleurone layer and the bran. In addition to poor diet, severe alcoholism causes thiamine deficiency because the food intake is very low and the alcohol increases the metabolism and demand for this vitamin.
(ii) Poor absorption.
Patients suffering from various diseases of the gastro-intestinal tract absorb thiamine poorly.
(iii) Excessive Demand
During pregnancy, lactation, pyrexia, hyperthyroidism and hepatic disorders, or diseases which interfere with proper absorption and utilization, there is an excessive demand of thiamine. It is also increased when the basal metabolic rate is high and when large amounts of refined carbohydrates like sugars are taken.