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 periodic daily evacuations of the bowels are determined by peristaltic contractions of the muscular wall of the intestines excited by their contents. The thick fluid condition of the food (chyme) which enters the small intestine from the stomach is gradually altered by absorption of water and soluble ingredients in the small intestine. This process is accomplished by rhythmical vermicular contractions of the intestinal wall which are reflex in character and stimulated in different degrees by the bulk and chemical combination of the food and by the various digestive secretions, namely, the intestinal and pancreatic juices and, especially, the bile. The peristalsis is more active in the small than in the large intestine, for it has the triple function of (1) mixing the food and digestive fluids; (2) bringing the whole mass into contact with a large surface for absorption; and (3) propelling the residue towards the large intestine.
Simultaneously the local blood current is increased. The vessels and lymphatics in the intestinal wall and mesentery become greatly distended by absorption of food products. The increase in volume and flow of the blood also stimulates peristaltic contractions.
Towards the lower end of the small intestine the food is found diminished in volume by absorption, and the mass is consequently somewhat drier. The ileo-csecal valve is periodically relaxed by reflex mechanism, and the peristalsis of the small intestine propels the food onward into the large intestine, where further absorption takes place, and the residue is more slowly moved towards the sigmoid flexure. Here it remains and accumulates until a certain bulk is gathered, which by pressure or distention excites the reflex mechanism of defecation. This mechanism employs a large number of muscles, and hence the need of a controlling nerve centre, which is found in the lumbar region of the spinal cord.
Constipation, when not due to intestinal obstruction, is dependent upon lack of peristalsis, as diarrhoea is due to excessive peristalsis.
Many persons are wholly ignorant of what constitutes a normal stool. The custom of using patent water closets often prevents them from seeing the stool, and they are unable to correctly estimate its amount or character. A little accumulation of residue left over each day will presently cause very uncomfortable constipation. The normal stool should weigh about five or five and a half ounces, of which only one and a half ounce is solid matter. It should constitute a sausage-shaped mass, in all about six inches in length.
Constipation may result from one or more of the following causes, which are related to diet: I. Insufficient quantity of solid food. 2. Too highly nutritious or concentrated food. 3. Insufficient fluid. 4. Astringent food and drinks. 5. Indigestible food. 6. Lack of digestive fluids. 7. Irregularity in diet. 8. Obstruction from overeating. 9. Lack of peristalsis. 10. Lack of exercise.
1. Insufficient food is one of the most common causes of constipation. In prolonged starvation the bowels cease to move entirely. Persons who eat but sparingly have too little bulk of food to excite the normal peristaltic motion of the intestines, and the waste products accumulate in consequence.
2. Too highly nutritious or concentrated food, such as richly seasoned meats, milk, meat extracts, peptonised fluids, etc., when almost completely absorbed, leave insufficient residue of waste matter. Peristalsis is therefore either not excited or the contracting intestinal wall has insufficient bulk of material to seize upon and propel.
3. Insufficient fluid often causes constipation, and for three reasons: (1) The chyme is not kept liquid enough to be thoroughly mingled with the digestive juices. (2) The intestinal walls become too dry and friction over the hardened fecal masses is increased, making it difficult to propel them. (3) There is less fluid absorbed by the blood, and consequently the digestive juices and intestinal mucus are reduced in amount and altered in quality.
4. Astringent food or drinks, such as tea, brandy, or claret, constipate by checking the mucous and other secretions, thereby increasing friction within the intestinal wall.
5. Indigestible food may be so hard and bulky as to be imperfectly acted upon by peristalsis and incompletely mingled with the digestive juices, or it may give rise to abnormal fermentation and production of substances which inhibit absorption and peristalsis.
6. Lack of digestive fluids in normal proportion or serious alterations in their composition retard digestion and lessen peristalsis.
7. Irregularity in diet or in the intervals of taking food, eating too hastily, imperfect mastication, and great variations in the quantity of food eaten, all tend to disorder digestion by disturbing the natural rhythm of its various stages, and especially the periodicity of defecation.
8. Obstruction from overeating, particularly in children, may cause constipation from the accumulation of larger quantities of waste matter than the intestinal muscles have power to propel.
9. Lack of peristalsis occurs through enfeebled intestinal muscles or imperfect nerve stimulation.
10. Lack of exercise fails to stimulate the circulation, both general and local, and to secure the abundant oxygen supply needed for complete oxidation of the food. It also fails to stimulate peristalsis by the natural movements of the body, especially of the abdominal muscles, and by increasing the flow of bile.
Constipation is not infrequently a constitutional habit or family peculiarity, running through several generations. It is provoked by sedentary habits and neglect of the calls of Nature, and it is the usual accompaniment of impoverished conditions of the blood and malnutrition, and especially anaemia, neurasthenia, hysteria, and chronic diseases of the liver and stomach. It is also frequently present in connection with acute fevers, and the habit of the perpetual consumption of drugs of many varieties may occasion it.
Weakness of the muscles of the intestinal and abdominal wall are common factors in the production of constipation. This symptom is therefore present in obesity, overdistention of the abdominal wall during pregnancy, and in atony of the large intestine and chronic diseases of its mucous membrane. It is also produced by obstruction from the pressure of tumours, accumulation of scybalae from impaction of foreign bodies in the bowel, stricture, and localised atony of the sigmoid flexure.
In all common cases the symptoms accompanying constipation are debility and lassitude, while more or less mental depression is present in persons of nervous or hypochondriacal temperament. When it occurs in the course of chronic insanity it increases languor, moroseness, and irritability of temper, and not seldom excites acute and violent symptoms. As a result of the accumulation of waste matter in the lower bowel, internal misplacements may occasionally result, or, if they already exist, they may be increased. Sacral neuralgia is sometimes produced, and hemorrhoids from congestion of the rectal veins may occur. Occasionally constipation may result from malformations of the intestine - adhesions which bind loops and coils of the intestine in abnormal positions and interfere with peristaltic movement. The impacted feces accumulate in the colon and are found chiefly in the sigmoid flexure, but they may also form large tumours in the hepatic or splenic flexure, or even in the right inguinal region. In aged persons sacculi of the colon may become permanently distended, and scybalae become calcified as enteroliths. A channel is sometimes bored through the impacted masses of fecal material, and the long-continued constipation will give rise to diarrhoea.
The fecal mass acts as a local irritant, and diarrhoeal stools pass through the channel.
Chronic constipation may sometimes give rise to acute attacks of localised pain and considerable fever (1040 F.). These attacks may simulate appendicitis, localised peritonitis, or other acute abdominal diseases.
Before ordering the diet for chronic constipation, the patient must be minutely interrogated as to his daily habits of life, such as occupation, hours for meals and for exercise, recreation, and sleep, the kinds of foods and quantity usually eaten, the amount and kinds of fluids drunk, hour for going to stool, the use of stimulants and tobacco, and presence of mental worry or anxiety.
The principles of dietetic treatment of chronic constipation are based upon supplying digestible food, which will excite peristalsis either by its bulk or its physical and chemical properties. Vegetable food in general, as distinguished from nitrogenous diet, furnishes a much larger proportion of waste matter. Herbivorous animals have more abundant evacuations than do carnivores.
Following is a list of common foods discussed in their relation to constipation:
The cellulose of starchy foods is difficult of digestion and of comparatively little nutrient value for man; hence it yields a considerable quantity of waste material. This is true of the starch granules of potatoes, corn, peas, beans, etc.
Other vegetables which leave a large residue after digestion are tomatoes, spinach, lettuce, asparagus, salsify, cabbage, and celery. Tomatoes and spinach seem to possess slight special laxative properties. Spanish onions, boiled, are laxative.
The various cereals used for bread when coarsely ground contain a large proportion of the external envelope of the grains, which is more or less hard and rough, and by its presence in the intestine it stimulates peristalsis through mechanical irritation.
For the above reasons the following articles of diet tend to overcome constipation: Coarse Graham bread, rye bread, wheatena, wheaten grits, cornmeal, Indian meal, oatmeal, brown or "wholemeal" bread, Boston brown bread, shredded wheat.
Molasses and honey added to bread are laxative. Gingerbread, especially for children, is sometimes efficacious. With some persons the substitution of milk sugar (lactose) for cane sugar proves laxative.