This organ is subject to several degenerative changes, as fatty degeneration, fatty infiltration, cirrhosis, etc. It not infrequently happens that there is a tendency to the accumulation of biliary concretions in the gall-bladder or ducts leading from it. This condition of biliary calculus, or gall-stones, is among the diseases of the liver. The liver is too far from the main line of traffic in the alimentary canal to be directly influenced by the diet. There are, however, certain general principles through whose help we may be able indirectly to ameliorate the condition and assist the system in its struggle to regain the regular normal condition.

In an earlier chapter, under Metabolism, the function of the liver in its relation to metabolism was rather fully discussed. We may recall here how the liver, among its various functions, is called upon to oxidize toxic substances absorbed from the intestines; such substances, for example, as result from overdigestion or fermentation of protein foods, also ethyl alcohol and other toxic substances ingested with the food. When these are absorbed they pass through the liver and are oxidized by that organ as a defensive measure to protect the general tissues of the body against their toxic action. Now, if the liver is diseased by any of these degenerative processes mentioned above, its oxidative action will be interfered with. This fact makes it a matter of very great importance that in all cases of diseased liver care be taken that no alcohol or other toxic substances be ingested with the food. Furthermore, the proteins of the diet should be reduced to a minimum. This reduction of proteins will not only decrease the tendency to protein fermentation in the intestines, but will decrease the amount of the midproducts of protein metabolism that come back from the muscles to the liver to be prepared for excretion.

Regarding carbohydrates, these are elaborated in the liver, being deposited as glycogen, then later changed back to sugar, as described under Liver Metabolism. There is no doubt that in extreme cases of liver degeneration, carbohydrate metabolism in the liver is interfered with. From these general principles, it is evident that, in cases of liver degeneration, the proteins and the carbohydrates of the diet should be distinctly decreased in quantity; in fact, decreased to the minimum compatible with the proper nutrition.

In the case of gall-stones, however, a somewhat different set of conditions confront us. Here there is no interference with the oxidative action of the liver, nor with its glycogenic and glycolytic action. The diet, then, for the gall-stone case need have no great reduction of protein and carbohydrates. With fats, however, the situation is different. The presence of fat in the duodenum stimulates a more copious secretion of pancreatic juice, and this, in turn, stimulates a more copious secretion of bile. If the passage of bile from the gall-bladder or bile vessels is interfered with, the pain and other disturbance will be increased with an increased volume of the secretion. It is, therefore, universally recognized that in all cases of gall-stones the fats should be eliminated from the diet. Another rational reason for their elimination is that decrease of the bile in the small intestine will decrease the efficiency of digestion and absorption and lead to a loss of considerable portions of fat. Therefore, ingestion of fat would be from an economic standpoint useless. In cholecystitis increased volume and decreased viscosity of bile is advantageous; therefore, fat may be used.