Diet in diseases of the lungs is of importance, not so much from its curative effect as from the point of view of mitigating the symptoms and relieving the discomfort of the patient. In other words, much harm may be done through a wrong or an excessive diet. The guiding principle should be to regulate the quality and the quantity of the food in such a way as to avoid throwing an increased amount of work on the lungs, which are already overtaxed. For example, if through unsuitable feeding the intra-abdominal pressure is raised by flatulent distension, the free action of the lungs will be impeded. Again, the excretory action of the lungs is interfered with in most pulmonary affections, and if by overfeeding and improper feeding the excretion of CO2 is increased, the work of the lungs will be rendered still more difficult. The circulation of the blood through the lungs must also be considered. In pulmonary disease this is always interfered with, more or less obstruction being present. As healthy blood flows more easily than unhealthy, it is clear that if the blood is loaded with an excessive amount of food products and if it is increased in amount, the circulation through the lungs will be still further impeded. These conditions of the blood must be avoided if possible, for they tend also to bring on the chief danger in all pulmonary affections, namely, cardiac debility and exhaustion. For these reasons the regulation of the feeding - the amount of the food at each meal, the regularity of the meals, and the food materials - is of great importance in all acute pulmonary affections. In chronic affections, where a state of equilibrium has been established between the lungs and the other systems, the diet does not as a rule prove such a disturbing factor. In many of the chronic conditions more direct benefit can be produced through the diet than in the acute diseases.
The chief disease of the lungs, namely, pulmonary tuberculosis, has been fully considered in another section (vide Tuberculosis) and will not be referred to here.