While it is true that the cooking of food in general increases digestibility, experience in the feeding of both infants and adults has clearly shown that a diet consisting exclusively of cooked food is detrimental both to digestion and to general health, and may lead to the most serious results. It has, indeed, been shown that in children a cooked diet, such as sterilized milk, for example, may lead to the development of rickets and general mal-nutrition. Combe, one of the world's greatest authorities on infant feeding, asserts that the symptoms and injury from such a dietary make their appearance within two or three weeks. The writer's observations have fully convinced him that adults as well as infants suffer from this cause. It has long been known that salt is not the exclusive cause of scurvy in sailors, as was once supposed; it is rather the lack of certain elements - enzymes and vitamines found in raw foods, many of which are destroyed by the heat of cooking, and which are essential to good nutrition.
Another objection to the exclusive use of a cooked diet has a special relation to the subject in hand - the fact that it renders the cellulose of the food too readily digestible by the intestinal bacteria, so that the amount remaining is insufficient to give to the intestine the needed stimulus to movement.
The same objection also applies in relation to starch. Raw starch is to a degree digestible in the intestine, but cooked starch is much more readily digestible. For good bowel action, it is necessary that a certain amount of undigestible starch should find its way into the colon. Cooked starch is quickly converted into sugar, and is completely absorbed in the small intestine. When no starch reaches the colon, the acid-forming bacteria which feed upon starch and convert it into lactic and other acids, are not able to grow; acids are not formed, the intestinal contents become alkaline, with the formation of ammonia and the putrefaction of protein. This condition results in a semi-paralysis of the colon, so that the feces are too long retained, and putrefaction proceeds still farther.
Foods containing starch or cellulose should be taken every day, or preferably at every meal. Among foods of this kind to be specially recommended are green corn fresh from the garden (uncooked), lettuce, cabbage, and fresh fruits of all sorts, turnips of the best varieties, and even radishes, if care be taken to remove the acrid rind. Young carrots are also relished by some prepared raw. As a salad Cucumbers and raw tomatoes are excellent.
These raw foods must be thoroughly chewed, as otherwise they may cause too long delay in the stomach or in the small intestine. The universal relish for fresh vegetables, and the intense craving for them, is an evidence of their value. These food stuffs, while supplying very little active nutriment, nevertheless furnish the body with quantities of certain elements which modern research shows to be essential, while at the same time they supply necessary bulk and a sufficient amount of undigested carbohydrates to establish in the colon conditions essential for a normal activity.
Heat relaxes and paralyzes, while cold stimulates. For a muscle in a state of cramp or violent contrac-tion, the application of heat is the most efficient remedy. When food is taken into the stomach active muscular movements at once begin. As we have seen, these movements are essential, not only for churning the food and passing it onward along the digestive tube, but also to move forward the contents of the colon to the sensitive point in the rectum, at which are set up the automatic actions by which the bowels are moved. Heat, whether taken into the stomach by food or drink, or applied externally, has the effect of weakening these movements. It does this by exciting the sympathetic nerves which hinder or inhibit the movements of the stomach or intestine, and so check peristalsis. The practice of eating food as hot as it can be swallowed, and especially of taking hot drinks at meals, is unquestionably a very active cause of constipation. If the food is held in the mouth for a sufficient length of time to permit thorough mastication and the proper admixture of saliva, no harm will result from serving it hot when necessary, as it will be cooled in the mouth to body temperature before swallowing.
Priessnitz, the sagacious peasant doctor of water cure fame, noted the unwholesome effects of hot foods more than a century ago. By experiments upon pigs he demonstrated that hot food produced an unhealthy state of the intestine. He accordingly recommended his patients to take their food at the natural temperature of the air, and the thousands coming from every part of the civilized world who annually ate at his table in the little village of Graefenberg, hidden among the forests of Austrian Silesia, testified to his success in the treatment of chronic constipation' and numerous other ills which were at that time acknowledged incurable even by the best physicians.
Hot foods and drinks produce a sensation of comfort in the stomach directly after they are swallowed. In certain forms of indigestion this effect of heat is particularly noticeable. In these cases, however, temporary comfort is obtained only at the expense of the later serious disadvantages of the constipating effect of such a diet.