46. Vitamins - II
The disease beri-beri is commonly attributed to deficiency of this vitamin, although whether this is the sole cause or some other additional factor is necessary has not been finally ascertained. Deficiency of this vitamin also causes lack of appetite and defective movements in the alimentary canal. It has been isolated from yeast and rice polishings. It is soluble in water. It contains carbon, hydrogen, nitrogen, sulphur and oxygen. It is one of the most stable vitamins, is fairly resistant to heat and oxidation. It is destroyed at 120° C but the decomposition at 100° C (the temperature of boiling water) is insignificant. "Continued heating of foodstuffs at 100° C, however, leads to some loss of the vitamin. In preserving and canning foodstuffs the temperatures employed are frequently much higher than 100° C, and canned foods of all description may contain very little or no vitamin B1 and, as a practical rule, should therefore be regarded as free from it, unless they have been specially investigated and found to contain it." Foodstuffs should not be boiled for more time than is necessary to keep this vitamin almost intact. Most people derive their supply of vitamin B1 from cereals and pulses. Different parts of cereals vary widely in their Vitamin B1 content; the largest amount is found in the embryo or germ, the bran (pericarp, and aleurone layer) comes next in order, whereas the endosperm is deficient in the anti-neuritic factor. Hence the inferiority of white wheaten flour or mill-polished rice as diet.
This vitamin is soluble in water; therefore boiling of any foodstuff with excess of water and then decanting to supernatant liquid would deprive the foodstuffs of almost the whole of its vitamin B, content. In Bengal people generally use dhenki-husked rice but they boil that rice with excess of water and after it is well boiled decant the liquid from the solid. Such rice is no protection against beri-beri. The people of Bengal should give up this bad practice. In the preparation of chapati from wheat there is no danger of vitamin B1 content of the wheat being diminished. Yeast is the richest source of vitamin B,. Eggs are also valuable sources of the anti-beri-beri factor. Large deposits of this vitamin in the seeds of plants and eggs of animals (birds and fishes) suggests a due provision made for the wants of the young offspring during the early period of life. The prevalence of beri-beri among pregnant women in countries where the disease is endemic also suggests that they require more of this vitamin for the growth of their yet unborn offspring.
"Of the green vegetables tested, watercress and lettuce proved to be about twice as rich as cabbage and spinach and not inferior to egg yolk or the embryo of cereals, if dry weights are compared." (Vitamins: A Survey of the Present Knowledge). Of the common Bengali foodstuffs the richest source is pooin-shak (Bassela cordifolia), then we have dherosh Bhindi, gima shak and cabbage. Potato contains.a small quantity of vitamin B1, but the large quantities of potato consumed make it a good source the vitamin in an ordinary diet. Milk is poor in this vitamin.
Toddy contains a good quantity of this vitamin, but no one should advocate toddy drinking on this ground. Toddy has its bad effects. "The balance of the pharmacological opinion is in favour of the view that had alcohol been discovered late it would have never been used as a medicine." (Pyman : Synthetic Drugs.)
Deficiency of this vitamin leads to scurvy, a disease characterized by a spongy condition of the gums and a tendency to haemorrhages into the gums, muscles, joints and internal organs. It was for centuries the scourge of the sailor and the explorer who could not get fresh vegetables or fruits. They discovered empirically that an addition of lime juice to the diet would prevent it. But certain animals, such as the rat, mice, pigeons and chickens do not get this disease even when they are kept on vitamin C- free diet. Probably they can synthesize vitamin C from other articles of diet which the human system cannot do.
Vitamin C was first isolated in a crystalline condition in 1928 from the cortex of the adrenal gland. Later on it has been isolated from lemon juice and other substances. It is an acid and it has got anti-scorbutic properties, so it is now known by the name of ascorbic acid. It is a compound of carbon, hydrogen and oxygen. It has been synthesized. Ascorbic acid is exceedingly soluble in water, and of all the vitamins it is most easily destroyed by heat. Human milk contains more of it than cow's or goat's milk. It is the practice in India to take boiled milk which contains still less vitamin C. Therefore, children who do not get sufficient mother's milk but depend on cow's or goat's milk should be given orange, grape or tomato juice to make up for the ascorbic acid deficiency. Very recently ascorbic acid content of many Indian foodstuffs has been analysed and it has been found that Kul (plum), Batabi- Lebu (citrus decumana), guava, marfgo, lichi and green chilli are the richest sources of vitamin C. All the above mentioned fruits are now found to be richer than the Indian lemon and orange, the well-known antiscorbutics (Indian Journal of Medical Research, October 1935, p. 350). We should depend on uncooked foodstuffs for this vitamin. Fruits are as a rule taken uncooked. The above- mentioned fruits are more or less abundant throughout India and in season they become cheap also.
Deficiency of this vitamin is the chief cause of rickets, which is also produced by deficiency of calcium or of phosphate. In the presence of ample D much smaller amounts of calcium and of phosphate are sufficient to prevent rickets than when there is only a small amount of the vitamin present. It conserves these mineral constituents in the body. The vitamin is also growth promoting. But it’s over-dosage is toxic to most species of animals. It has been shown conclusively that continued excessive doses of vitamin D prove fatal to mice, rats, guinea-pigs, rabbits, cats and dogs. Man has greater capacity for resistance against overdose, although fatal cases in children have been reported. Birds are, however, unaffected by the overdose. Death is preceded by loss of appetite, loss of weight, and sometimes marked diarrhoea. Moderate overdosage of the vitamin is, however, without harmful effect. It is soluble in fat and is moderately resistant to heat. It is produced from ergosterol by irradiation or exposure to sunlight. Ergosterol is present in all animal and vegetable fats as well as in human skin. In a sunny country like India no one need, therefore, suffer from deficiency of this vitamin. Rubbing the body with some amount of oil and the exposing it to sunlight for some time is the best way of getting this vitamin. In Bengal villages there is a custom of rubbing the body of infants with oil and then exposing them to sunlight. This is a very good custom. But no one need think that a long continued exposure to sunlight would ensure maximum intake of the vitamin. Ultra-violet rays of sunlight which convert ergosterol into vitamin D also destroy the vitamin. So a moderate exposure which the system also enjoys would be the ideal thing.
It is also an alcohol like ergosterol and it contains the same number of carbon, hydrogen and oxygen atoms and double bonds as ergosterol, and as it has an influence on calcium (metabolism) the name calciferol has been given to it.
Excellent sources of calciferol are the liver oils of the halibut, tarbot and cod and the body oils of certain fishes. Egg yolk is a good source. Excellent sources of calciferol after irradiation are yeast and egg yolk. Good sources are oils and fats.
As a result of the painstaking researches of scientists the importance of vitamins in our diet has been brought to light and some of these substances, which were at one time considered to be mysteries, have also been prepared in a pure state. But as night follows day some evil also followed this very laudable work of the scientists. There came a large number of artificial preparations in the market which brought fortunes to some at the cost of many poor men. These artificial preparations should by all means be avoided. Nature has provided ample amount for us - even for the poorest amongst us.
We can get enough of these vitamins from green leafy vegetables, cereals and pulses, cheap season fruits and sunlight. We need not make any abnormal change in our diet for the vitamins.
P. C. GHOSH