Diet in beri-beri has to be considered mainly as to its effect in causing any embarrassment of the heart. The nerve supply to the stomach is usually impaired, and there is a great tendency to dilatation of that organ. This may occur however carefully the patient is fed, and will increase the tendency to the cardiac failure which is the usual cause of death in this disease.
Therefore, bulky food and any food which is likely to remain long in the stomach and be slowly digested must be avoided. In serious cases milk, mixed with barley-water in equal parts and given in small quantities at a time, is the safest diet. Soda-water should not be given with the milk. Egg and milk is a good mixture. Strong soups or broths given in small quantities are also permissible. Bulky farinaceous foods, such as rice and potatoes, should not be given, even when the acute stage appears to have been passed. Milky puddings, custards, and bread may be added to the diet as the acute symptoms pass away; when convalescence sets in fish, eggs, meat and small quantities of potatoes (mashed) may be added. Even for a convalescent the total amount of food or fluid taken at a time must be carefully regulated, seeing that some impairment of the innervation both of the heart and the stomach may still be present.
As the actual bulk of ingested material is so important in serious cases of beri-beri, the restrictions as to the amount taken must be extended to fluids as well as solids, even to water. The patient must never be allowed free access to food or fluid of any kind. An additional reason for restriction of fluid lies in the circumstance that in all cases there is more or less oedema, and in some an excess of fluid in the serous cavities, slight it may be in some cases but excessive in others. Some authorities attach much importance to the restriction of the total amount of fluid, as well as to the amount given at a time. One pint of fluid in twenty-four hours is by them considered to be sufficient.
Vomiting in this disease is usually a sign of a fatal termination. It is not so, however, from anything special about the vomiting, but as an indication of the extent of the nerve lesions, especially as regards implication of the pneumogastric.
In many cases there is marked congestion of the mucous membrane of the stomach and intestines, and also of all the abdominal viscera and particularly of the liver. The degree of congestion is greater than can be attributed merely to back pressure from cardiac dilatation and failure; it is probably due to a combination of this and of vasomotor paralysis. The condition, however, renders the restriction of diet and the avoidance of any irritating foods, stimulants or drugs, still more necessary.
A further reason against the use of rice as an article of food in beri-beri, is that there is some reason to suspect that the poison which causes the neuritis is contained in certain kinds of rice, and that the injurious effects in acute cases are not due merely to the bulkiness of this food.
In the case of Europeans it is mainly on board ship that beri-beri occurs. Usually, under such circumstances, there is little choice of diet.
As compared to Europeans beri-beri is much more common amongst the coloured races, and particularly amongst rice eating natives, such as the Chinese. Economical considerations, as well as the craving that such people have for rice, may render it impossible to prevent its use to some extent after the acute symptoms have subsided. Under such circumstances, it is better to allow only freshly husked rice or such rice as has been previously treated in the Indian manner by boiling or steaming on garnering and before husking. In these forms it is considered by some that rice does not contain the toxin of beri-beri. Cheap bread and biscuits are sometimes made in part with rice instead of wheat flour, and must therefore be viewed with some suspicion when they become a staple of diet, as on board ship and in large institutions. In beri-beri countries the dietaries in fleets, military camps, gaols, mining camps, schools and charitable institutions must be so arranged that they shall include an adequate amount of nitrogenous and fatty material and fresh vegetables.