This section is from the book "Practical Dietetics With Special Reference To Diet In Disease", by William Gilman Thompson. Also available from Amazon: Practical Dietetics with Special Reference to Diet in Disease.
The general principles of the dietetic treatment of the condition of fever which accompanies many different diseases are conveniently studied collectively, while the special modifications of diet required for certain infectious fevers will be considered under their several headings.
The cardinal principles of feeding the sick involve, first, the avoidance of all articles that disagree with the condition present, and second, the giving of the food best adapted to relieve the digestive organs of unnecessary labour and to maintain nutrition. In addition, for certain special diseases there are classes of foods which have distinctly curative value - for example, the use of fresh fruits and vegetables in scurvy, fats and oils in scrofula and tuberculosis. Although there is no curative food for fevers, it should be remembered that there is nothing so easily assimilated as water, and advantage must be taken of this fact to introduce other foods into the body with it, giving them therefore in fluid form.
The former treatment of fevers by starvation and depletion, on the theory that the poison of the disease was soonest conquered by withholding all food and drink upon which it might thrive, and starving out "a devouring flame of inflammation," has long been superseded by more scientific methods. This early treatment culminated in France in the first part of this century, and was first combated in England by Graves and his successful followers.
It is now known that in fevers by supplying the patient with abundant nitrogenous food the tissues of the body are spared from consumption - in other words, that the proteid matter of the food is burned up or oxidised instead of the proteid matter of the patient's muscles and other structures. The animal food thus given does not add to the substance of the tissues, but saves them from wasting and combustion.
Bauer believes that "the gravest possible injury to the organism of the fever patient may be brought about by a diet too rich in albuminates," and to some extent carbohydrates and gelatin may be substituted for them, yet he adds that while " an exclusive use of albuminates is undesirable.... In fever a larger relative proportion of albuminates is requisite than in health, and so much larger as the albuminous metabolism is greater".
Fever patients commonly excrete much more nitrogen than they take in as food. In so doing it is believed that they first exhaust whatever reserve supply may be on hand in the food proteids previously absorbed and circulating in the blood, and subsequently draw upon the tissues, just as is the case in starvation. The urea daily eliminated during fever may exceed by forty or fifty grammes the normal amount voided in the urine during health, and this may be the case even when no food is given; hence the waste increase is mainly nitrogenous (Bauer). In chronic fevers with remissions, like tuberculosis, there is less rapid waste than in the continuous forms such as typhoid. If the digestion remains fairly good in any fever, the loss of body weight is proportionately checked.
Voit suggested the theory that the tissues act somewhat after the manner of gland cells, and normally attract such albuminous substances as they need without themselves undergoing any serious change, and Bauer believes that this hypothesis may be applied to the consumption of proteids in fever, "that under those conditions which the febrile processes bring with them the tissues yield up to the circulation a larger proportion of their own albumin, and that an abnormal amount of materials for metabolism is thus presented to the cells." The organs meanwhile lose proteids faster than in ordinary starvation, but by the same processes. A single albuminous meal adds more protein to the circulation, which in starvation would aid in restoring equilibrium; but in fever it fails to do so, and the loss continues because the inflamed cells have for the time being lost their power of assimilation. Emaciation therefore proceeds.
Another theory which has been strongly advocated, but which, on the whole, has less to recommend it, is that the inflamed cells consume and destroy proteid material from the blood at a much faster rate than in health, and supplying a purely proteid diet does not check the waste. The entire question is exceedingly intricate and difficult of solution. The experiments which have been made in febrile metabolism are somewhat contradictory, and it is undoubtedly better to be guided at present by the results of clinical experience in feeding fever patients than by theoretical formulae.
This subject is physiologically very closely related to the parenchymatous and fatty degenerations of organs which attend many diseases, but it is impossible within the practical limitations of this work to enter into this discussion, and the reader is referred to a very able presentation of these theories in the chapter upon Consumption in Febrile Disease by Bauer in his Dietary of the Sick (Handbook of General Therapeutics, v. Ziemssen).
Leyden and Frankel believe that in fever more fat as well as more albumin is consumed than in health, but other authorities think that fat destruction does not keep even with albuminous waste.
In fever the secretion of hydrochloric acid is diminished or suspended in the stomach, and its peristaltic action is so lessened that the food is apt to remain longer than it should and undergo mal-fermentation, causing oppression or pain, nausea, and vomiting. Absorption also is much reduced in fevers. The stomach may wholly give out, and, as Roberts observes, it becomes merely a conduit, so that the intestine must carry out the work of digestion unaided.
The conditions to be met in the dietetic treatment of fever are as follows:
1. To save tissue waste by supplying sufficient nourishment.
2. To give semisolid or fluid nourishment in a form which will not overtax the enfeebled digestive apparatus or leave a large residue for decomposition.