The prescription of a diet in gastric disorder has a scientific basis. In the first place there is required a knowledge of the whole process of digestion and absorption in health. It must be realized that digestion and absorption are chiefly effected in the intestine, and that the functions of the stomach are to prepare the food for intestinal digestion and in some degree to disinfect it. For the performance of these functions food must enter the stomach suitably cooked, and thoroughly divided and mixed with saliva. These elementary points should be impressed on all patients. It is important to remember that scarcely any absorption takes place in the stomach, only alcohol, small amounts of sugar, dextrin, albumoses and salts being taken up, but little or no water. In many cases of impaired gastric digestion, such as chronic gastritis, gastrectasis, and carcinoma of the stomach, it would be extremely useful if we could increase the amount of nutriment absorbed in the stomach. Very little, however, can be effected in this direction. But in most of these conditions intestinal digestion still has its full value, and it is wise, therefore, to aim at giving such food as will be most quickly discharged from the stomach into the duodenum. Only in pyloric obstruction is the increase of absorption in the stomach a real necessity.
In the second place it is necessary to have a knowledge of the secretory, motor, absorptive and sensory powers of the stomach in the particular diseased condition which is under treatment. Opportunities for actual inspection of diseased stomachs are rare, but from a chemical examination of the contents, from estimation of the size of the stomach (preferably by CO2 distension), and from a study of all sources it is possible in most cases to gain a fairly clear idea of the state of the stomach-wall in all its elements. For practical purposes the secretion of hydrochloric acid may be taken as an index of the total secretory power. Of this secretion there may be an excess or a deficiency, and both these alterations can be met with appropriate food. As regards the treatment of an insufficiency of motor power, the mode of preparation is nearly as important as the choice of food. In such conditions the consistence of the food must be considered with the idea of ensuring a quick emptying of the stomach. The sensory power of the stomach requires no estimation. If it is normal, it is not considered. If it is abnormal, it is obtrusive and will not be concealed. Thus in some cases of gastric disorder not necessarily severe in themselves, a secondary hyperaesthesia of the gastric mucosa is engendered. In prescribing a diet we are then hampered by the fact that even easily digested foods produce pain and sometimes vomiting upon their entrance into the stomach. The normal unconsciousness of digestion is lost and it is hard to restore. In neurasthenia the task may be hopeless, unless the general condition can be improved. This hyper-aesthetic state or nervous dyspepsia may develop without any previous illness. The patient, commonly a female, may have reduced herself to a small liquid diet barely sufficient to sustain life although the functions of the stomach are adequately performed. It may be necessary in some cases to resort to enforced administration of food (cp. Diseases of the Nervous System).
The causation also must be appreciated if dietetic treatment is to be complete. The common disorders of the stomach are mostly self-inflicted, and it is quite as important to correct all vices of eating, diet and life as to cure their results. Excess of food and drink, improper food, imperfect mastication through defective teeth or hurry, and a general tendency to quick meals and immediate movement thereafter, play a large part in gastric disturbance. A routine examination of the teeth should always be made. I doubt if the importance of good teeth and a clean mouth is sufficiently recognized. With reference to excess of food and improper food, a preliminary stage of starvation is the first necessity in the treatment of many cases of gastric disorder.
To miss an occasional meal or to pass one day in seven on a meagre diet is good for many people of leisure. Above all it is necessary to estimate correctly the actual amount of food that is being consumed daily by patients after middle life. The nutritional requirements lessen progressively with increasing years, but the appetite is not necessarily adjusted to this decline, or, if it is so adjusted, custom and example prevail and in spite of diminishing appetite the diet of robust middle life is maintained. Sometimes it will be found that the gastric symptoms of an elderly patient depend entirely on this persistence in the habits of his youth. Sometimes, on the other hand, an old and reluctant patient, who has naturally made the necessary change in his diet proportionate to his age, is brought before a physician by over-zealous relatives on the ground that he is eating nothing. For an old man who has done his life's work a supply of 15 calories per pound of body-weight is an ample allowance.
Beyond this point empiricism begins. All articles of food have been divided by Leube into groups of digestibility by the ascertained times within which they leave the stomach in health. This test of digestibility is not a complete guide in the choice of food, as it is concerned chiefly with the motor power of the stomach, and it does not take fully into account the state of the secretory function. Such a grouping, however, may be utilized in framing a diet, but experience shows that it is not entirely applicable to states of disease. Moreover modifications and allowances must be made for the likes and dislikes of patients. These idiosyncrasies are real but they cannot be foretold, and it is never wise to give a rigid diet to a patient without some discussion of details. All diet-lists are merely suggestive, and as regards both kind of food and amount of food they must be adapted to the patient.
Complete rest lying down after meals is, I think, beneficial in all forms of gastric disorder. It is absolutely necessary in all conditions of diminished motor and secretory power, especially in gastrectasis and gastroptosis. I think it is of equal service in hyperacidity, although there is experimental evidence to show that in health the acidity of the stomach-contents is greater at rest than during movement. Sleep, however, should not be permitted.
Examination of the contents of the stomach must be made when possible. A few simple tests are at the command of all. Vomit may sometimes be used for the purpose, but a test-meal is generally necessary. In ordinary practice Ewald's test-breakfast is most suitable, as it involves little discomfort. It consists of 1 1/3 oz. of white bread with 10 oz. of water or weak tea without milk or sugar. In this every class of food is represented, viz : protein, starch, sugar, fat, non-nitrogenous extractives and salts. It should be given in the early morning on an empty stomach, and the residuum should be removed exactly one hour later. The contents of the stomach should then be from 20 to 40 c.c. of clear yellowish fluid when filtered. This test-meal is especially useful when the question of the presence or absence of free hydrochloric acid arises.
For the settlement of questions of delayed digestion and of hyperacidity Riegel's test-meal is more trustworthy. It consists of 12 oz. of soup, 5 oz. of beef, 1 1/2 oz. of mashed potato and a roll, with 8 oz. of water. It should be taken at midday fasting, and after it the patient should remain at rest. Five hours later the contents of the stomach should be acid, and peptones are present with some undigested muscle and starch. Seven hours after this meal the stomach should be empty or contain a little neutral liquid.
The fluid removed after the test-breakfast should be acid. It should show free hydrochloric acid but no lactic acid, and the total acidity should be between 40 and 60 on Ewald's scale (cp. later). It should contain peptone and sugar, pepsin and rennin, but no starch or erythrodextrin.
The reaction may be tested with litmus paper, which is reddened by acid, free or in combination. That the acid is free, is shown if Congo paper is rendered blue or violet (filter paper saturated with a watery solution of Congo red 1-1,000 and dried). But this alteration is produced both by free hydrochloric acid and by organic acids, and the further test of Topfer and Gunzburg is necessary to distinguish between them.
A few drops of a 0.05 per cent solution of this substance in alcohol gives a cherry-red colour to the filtrate or even to the unfiltered stomach-contents if free hydrochloric acid is present. A yellow colour is produced in the absence of free hydrochloric acid. It is true that a red colour is produced if as much as 0.2 per cent of lactic acid is present, but this amount of organic acid is rarely found and the test is generally efficient, and certainly easy.
Gunzburg's Test requires more care. A few drops of the filtrate are evaporated slowly in a porcelain dish with a few drops of Gunzburg's solution (vanillin 1, phloroglucin 2, absolute alcohol 30 parts). As it nears dryness, a red colour quickly appears along the edge. The evaporation must be slow, and care must be taken to avoid charring. This test will demonstrate 005 per cent of free hydrochloric acid and it is not given by organic acids.
The presence of lactic acid, which is the organic acid of most common occurrence, may be shown by Uffelmann's test. If lactic acid above 0.01 per cent is present, the addition of a few drops of the filtrate will change the blue colour of Uffelmann's solution (carbolic acid 5 per cent 10 c.c, water 20 c.c, liq. ferri per-chloridi 2 drops) into a yellow or greenish-yellow. For perfect accuracy, when vomit and not the te3t-residuum is examined, it is necessary to extract the filtrate with ether, evaporate, and U3e a solution of the residue in water.
The total acidity may be thus determined. Ten c.c. of the filtrate with three drops of a saturated alcoholic solution of phenol-phthalein are diluted with distilled water to 100 c.c. This is divided into two equal parts, and each part is placed in a beaker standing on white paper. To one part decinormal solution of sodium hydrate (4 grms. of sodium hydrate dissolved in a litre of distilled water) is added drop by drop until a red colour appears. The unused part serves for comparison. The total acidity may now be expressed by a figure (commonly 40-60) which represents the number of c.c. of the alkaline solution which are required to neutralize 100 c.c. of the filtrate. Thus if 5.5 c.c. are required to neutralize 10 c.c. of the filtrate, the total acidity is expressed by the figure 55 on Ewald's scale.
For examination for organic acids (other than lactic acid), for peptones, starch, sugar, erythrodextrin, and for the methods by which the activity of pepsin and rennin, and the motor and absorptive powers of the stomach are estimated, reference should be made to a systematic work on the subject.