STARCH DIGESTION—COOKED AND UNCOOKED
Comparative digestion of cooked and uncooked grain
The student will remember the reference made in Lesson V to experiments concerning the digestibility of starch when taken in various forms. In these experiments, though conducted for the purpose of demonstrating the supposed advantage of excessive cooking, the results showed that at the time the contents of the stomach were removed, all the proteids of the uncooked grain had been digested, while the percentage of proteid digested from the various forms of cooked grain grew less as the cooking was increased. As the chief function of the gastric juice is the digestion of proteids, the real significance of the above experiments was exactly the opposite from that which was intended to be proved.
Reasons given for cooking starch
The statement is frequently made that the starch of grain cannot be digested without cooking, because the cells enclosing the starch grains have indigestible or insoluble cellulose walls. The old theory is that cooking expands the starch and ruptures or tears down these walls, freeing the contents so that the digestive juices may act upon the enclosed starch granules. This is a theory unsupported by facts. The cell walls on the interior of the grain kernel are very filmy, and in the mature grain scarcely exist at all. The analysis of wheat flour shows only a trace of cellulose fiber. Were these cellulose walls within the wheat grain, as this theory commonly teaches, flour would show a liberal quantity of cellulose. The cellulose wall theory, as a necessity for cooking starch, is an excellent illustration of the ease with which a groundless statement or theory may be used to prove or to explain some popular prejudice.
In the process of cooking, the tendency is to render the organic salts contained in food entirely inorganic. This change from organic to inorganic salts is measured by the temperature to which the foods are subjected. Many of these salts are combined with the nitrogenous constituents of food, therefore when subjected to certain degrees of heat they are of little value in the construction of the proteid molecules within the body. This is especially true of fresh or green vegetables.
EXCUSES FOR COOKING OUR FOOD
Ancestral habits not inherited
Inasmuch as the majority of people favor cooking, probably forgetting that about half of the food consumed in the world at the present time is taken in its natural or uncooked state, it may be well to mention some of the views advanced by those who believe that the present diet of cooked grain is better for modern man than an elementary diet, and who attempt to give a natural explanation. One theory is that man has subsisted so long upon cooked foods that his organs have become fitted for a cooked diet, and a cooked diet only. Another view sometimes advanced is, that while cooked foods were originally detrimental, yet by continued use man has become fitted for such a diet and unfitted for a natural diet. These are but other forms of the old belief in the inheritance of acquired characteristics. This belief, however, is steadily losing ground among evolutionists. There is no more reason to believe that a modified function of the stomach would be inherited, than there is to believe that small feet would be inherited among the Chinese women just because these organs are mutilated by local custom.
The best light of scientific knowledge now leads us to believe that the healthy child of today is, in its capacity for nutrition, essentially like the primitive child, and would thrive best upon a varied diet of natural foods.