The properties of food stuffs to which a laxative influence is due may be briefly enumerated as follows:
1. Sapid qualities to which flavor or tastes are due.
2. Bulk, or rather the presence of cellulose, which is capable of forming an indigestible residue.
3. Moisture, that is, a necessary amount of liquid taken at meals or between meals, especially in connection with cellulose which by absorbing water holds it in the intestine.
4. Chemical properties which result from the presence of sugars and organic acids in the food, including the sugars formed by the digestion of starch, and the lactic acids formed by the fermentation of sugar in the intestine. Fats are also somewhat laxative.
In the regulation of the diet for the relief of constipation, the aim must be to make such selection of food stuffs as will furnish these various laxative properties in the measure required by the individual case. This is by no means a simple matter, and requires, first a very thorough knowledge of food values and second, a most thoroughgoing investigation of each individual case, so that not only the particular form of constipation from which he is suffering may be known, whether it is simple, cumulative, or latent constipation, but also at what point or points in the intestinal track the delay occurs, and the cause of the delay. The force of this statement will be fully appreciated if the chapter on "Causes of Constipation" has been read with care.
In addition to the laxative properties of food stuffs, there is another quality of equal importance, which must be duly considered in the treatment of constipation, because of the prolonged stay of undigested food remnants in the alimentray canal in constipation, and of the tendency to delay which will always remain, even under the best conditions which can be supplied. It is of the highest importance that the food should be of such a character as to prevent as far as possible the putrefactive changes which are always increased, and often to an extraordinary degree, whenever there is delay.
Of the three essential food elements, carbohydrates (starch, sugars and organic acids), fats, and proteins, the last named only is capable of undergoing putrefaction. Foods rich in starch and sugar do not undergo putrefaction, either outside the body or within the intestine, and hence, are properly termed atoxic foods.
Fats in excess encourage putrefaction, while starch and sugar in excess produce the opposite effect. By the fermentation of starch and sugar in the intestine, acids are formed, which, as has already been pointed out, by interfering with the growth of putrefactive bacteria, prevent putrefaction. Fats ferment, when taken to excess, forming butyric acid, an irritant poison.
Fruits, starch in vegetables like the potato, and green vegetables of all sorts, which contain little or almost no protein, together with certain sugars, especially milk sugar, maltose or malt sugar, and the sugar of fruits, and to a less degree, cereals, particularly rice, which are very rich in starch, are not only atoxic, being incapable of putrefactive changes, but are also highly antitoxic, since they in a high degree promote the formation of acids in the intestine.
A most important point in connection with this subject, which appears to have been overlooked by writers on dietetics, is the antitoxic value of uncooked foods. Man is the only "cooking animal." To the primitive man cookery was not only unknown, but was as unnecessary as for any other member of the animal kingdom. The only really valuable purpose served by cookery is to enable man to make use of dried grains and certain coarse vegetables, which would otherwise be unavailable as food. Experience has proved that food is often by cookery deprived of certain elements which are essential to human nutrition. The argument made by certain faddists who advocate the exclusive use of a raw diet, that by cookery the life principle is driven out of the food so that its nutritional value is lost, has no scientific basis; nevertheless, it is true that cookery destroys the life of the cells of vegetable foods, and in so doing, deprives the food of certain properties which are useful in the intestine. Living cells resist the attacks of the microbes which produce fermentation and putrefaction. A raw apple or potato remains intact for months, while a cooked apple or potato is in a few days covered with mould, and is in an active state of fermentation and destructive change. Under favorable' circumstances such changes may take place within a few hours, as is seen in the moulding of bread over night if kept in a warm place. In other words, raw food resists the destructive changes which are produced by bacteria, while cooked food makes no such resistance.
An experiment made by the writer some years ago gave very positive evidence of this fact. Two equal portions of cabbage were taken. One portion was cooked. Both portions were then inoculated with equal quantities of putrefactive bacteria, by mixing with each a portion of fecal matter. The two portions of cabbage were then placed for twenty-four hours in an incubator in which the temperature of the body was maintained. Examination showed that the bacteria in the cooked cabbage had increased enormously in numbers, whereas in the uncooked cabbage the number of bacteria had not increased, but had actually diminished.
Many persons have thought themselves benefited by the use of raw grains, such as wheat and oatmeal. While it would be impossible for a person to live on a diet consisting exclusively of raw grains, it is possible that some benefit may be derived from the use of such food to a moderate extent, through the fact that uncooked starch digests slowly. Cooked starch, as well as sugar and other carbohydrates, is normally wholly absorbed in the small intestine, or practically so, and therefore furnishes no resistance to the growth of bacteria; but raw starch, if taken in more than minute quantities, as has been shown by experiment by the writer, finds its way in considerable quantities into the colon. Here, digestion slowly proceeds, producing dextrin and sugar, which furnish to the acid-forming bacteria just what they require for their growth in a section of the intestine where the help of these friendly organisms is most needed. Man's natural dietary comprises food containing a sufficient amount of raw starch to prevent extensive putrefaction in the colon; and therefore the art of cookery, while essential under the conditions of modern civilization, is not altogether free from disadvantages, which, however, may easily be obviated by a proper selection of foods or, in special cases, by including in the ordinary bill of fare partially cooked foods containing a certain portion of uncooked starch, such as oatmeal or other grains cooked six to ten minutes.
Fruits are the most highly antitoxic of all food stuffs. They possess in a high degree all the antitoxic properties of food.
1. They are most acceptable in an uncooked state, both to the palate and to the digestive organs. They are completely prepared for human sustenance in the great laboratory of Nature, "cooked in the sun," as they say in Mexico. "Cocido en el sol?" asked a native fruit seller of the writer, who was seeking to purchase some tropical fruit in the market place of a town in Old Mexico.
2. With very rare exceptions, fruits contain a considerable amount of organic acids - citric, malic or tartaric, - all of which possess antitoxic properties. Even many sweet fruits contain a considerable amount of these acids, which are disguised by the sugar, but which are not neutralized or destroyed by it.
3. The sugars of fruits promote to a high degree the growth of acid-forming bacteria in the intestine, and thus lead to the formation of lactic acid, which, like the acids of fruits, is antitoxic.
The antitoxic properties of fruits, though not understood until revealed by bacteriological researches of recent years, have long been utilized in a practical way in what is known as the "fruit cure," the value of which in the treatment of chronic bowel disorders has been well understood for centuries. The grape cure of Switzerland and certain parts of Germany, the cherry cure advocated by Linnaeus, the great botanist, and similar "cures" through the use of apples, peaches, and other fruits, practised in several countries, owe their value to the antitoxic properties of these choicest of Nature's products.