Beriberi is a peculiar disease resulting from disorder of nutrition owing to the absence of certain unknown ele ments, or vitamins, in the food.
Vitamins are substances existing in food and essential to growth and life. Certain disorders, as rickets and scurvy in children, scurvy in adults, softening of the bones in pregnant women, pellagra, and beriberi are caused by food deficient in these substances. Grains when deprived of their germ and outer coating, as wheat, rice, barley, and oats, will produce beriberi in many birds and animals. Vitamins are also destroyed by heat and by drying and pickling.
In the case of beriberi experience and experiments show that a diet of rice, from which the outer coat and germ have been removed, is the more common cause. This is called white rice or polished rice, and is what we ordinarily use. In preparing white rice it is steamed, the outer red covering bursts, the grain is dried, the hulls, with germ, removed, and the rice is polished in milling. Red rice, covered by its natural coats, will not induce beriberi. The most interesting experiments have been tried, as in the case of the inmates of the insane asylum at Singapore, where formerly half died of beriberi. It was found that the disease could be produced or cured at will by feeding first polished rice and then unpolished rice.
In India a group of men was given polished white Siam rice and developed beriberi in sixty days, while another group living under the same condition, but eating only unpolished rice, remained free from the disease. But when this second group was fed polished white rice beriberi developed within two months. By exchange of clothing and contact of the well with the sick it was shown that the disease was not infectious or contagious.
The same results have been obtained in Japan and the Philippines. As many as 50,000 cases of beriberi arose from the feeding of polished rice to the Japanese during the Russian War, but recent knowledge of the cause of the disease has enabled the authorities to stamp it out. Osler states that "there has been no more remarkable triumph of modern hygiene than Takagi's dietetic reforms in the Japanese navy." Schaumann and others went further, and concluded that deficiency in phosphorus, as it occurs in combination in vegetable or animal tissue, is the true cause of the disorders of nutrition above mentioned. He and others found that rice which contained less than 0.4 of 1 per cent. of phosphorus is likely to produce beriberi. This conclusion has not been wholly accepted, since Funk claims to have isolated a new substance, or true vitamin, the deficiency of which in food is the cause of beriberi and which does not contain any phosphorus. It is unques tionably a fact that the feeding of the polishings (germ and bran) of rice will cure beriberi, and it seems probable that food contains often more than one vitamin - some for growth and others for proper nutrition. Thus in milk there is a vitamin destroyed by heat or boiling, and pasteurized or boiled milk may cause scurvy. But other vitamins in milk survive heat, for in dried milk the vitamins are still present that will cure beriberi and that are essential for growth of young animals. When there is a deficiency of vitamin in food the animal or man must use up that already in the body, so that some of the tissues are damaged. In the case of beriberi it is the nervous system which is in volved. At present we must confess our ignorance of the precise nature of vitamins, although evidence points to either phosphorus or nitrogen as being their most likely chemical constituents. But we do know that there are essential unknown substances in many foods which are destroyed by removal of the germ and outer hulls of grains, or by boiling, heat in any form, drying, canning and pickling, and that deficiency of these bodies in food gives rise to the diseases already enumerated. That while rice germs and hulls contain the essential vitamin curing beriberi, the vitamin curing scurvy resides in fresh vegetables and fruits, as in fresh onions, potatoes, cab bage, lemons, limes, oranges, apples, etc.
White bread (deprived of the bran and the embryo or germ of wheat) is the most important food from which vitamin is removed, but all sorts of prepared foods in which the hulls are taken from grains or in which heat is used, as condensed and dried milk, dried eggs, infant and invalid foods, vegetable and meat extracts, and canned food or dried or pickled meat, are deficient in vitamins and instrumental in causing the diseases noted above. This explains the reason for beriberi developing on ships where the crew live on pickled meat, dried potatoes, rice, white flour bread, and biscuit.
Beriberi has occurred most extensively in the Orient, the Chinese and Japanese subsisting largely on a rice diet. The disease has existed in the Philippines, India, and South America, among fishermen in Europe and on the New foundland Banks, on shipboard, and in this country in camps, mines, and asylums. It does not develop in per sons living on a varied and mixed diet and in good surround ings and circumstances. The lack of vitamins is only felt by those on a restricted diet, usually from poverty. Poor children are stunted from being fed largely on white bread. The poor of the South develop pellagra from a diet of starch and sugar. Babies fed on heated milk have scurvy (see p. 303). Starch and sugar contain no vitamins. Fresh meat, milk, eggs, vegetables, fruits, and germs of grain abound in them.
Symptoms. Beriberi is from twenty days to two to four months in developing and may last many weeks or months. The death-rate varies tremendously - from 2 to 50 per cent. The disease is essentially an inflammation of the nerves throughout the body (polyneuritis). It begins like a bad head cold, with pains, swelling, and loss of sensation in the limbs. There may be complete loss of sensation and power in the arms and legs, although pain, crawling sensations, and other peculiar feelings are common in the limbs. The muscles are tender and may waste away or there may be extreme dropsy and the whole body swells. The breath ing becomes difficult, the heart is weak, and the pulse rapid.
Prevention consists in change in the diet depending upon the cause. In most cases this has been the extensive use of polished white rice, and the substitution of this for unpolished rice is usually sufficient.
The government in the Philippines has forbidden the use of polished rice among the native troops and in its institu tions. Thus, in the leper colony there were 309 deaths in 1910 from beriberi, but after changing the diet from pol ished to unpolished rice not a single case of the disease de veloped in the following year. There is also a duty of 21 cents a kilo (2.68 pounds) on polished rice imported into the Philippines to discourage the natives from using it. Improvement in the general hygienic conditions is essen tial in the treatment of beriberi and the use of tea made from rice hulls or polishings, or when a liberal diet is pos sible this may be given without rice. It is a very chronic disease and treatment in hospitals is advisable. There is dropsy or fluid in the cavities of the chest and belly, so that rest in bed and saline cathartics tend to drain away the fluid, while heart stimulants are often required.