Experimental Investigation Of The Influence Of Mastication And Cooking Of Food, Etc - In The Laboratories Of The Battle Creek, Michigan, Sanitarium, Under The Direction Of Dr. J. H. Kellogg.

From Modern Medicine

The table clearly shows the effect of cooking and the effect of mastication upon the salivary digestion of food. Column I shows the results obtained after an ordinary test meal consisting of 1 1/2 ounces of water biscuit to 8 ounces of water; column 2, 1 1/2 ounces of water biscuit ground fine, mixed with water and swallowed without chewing; column 3, test meal consisting of 1 1/2 ounces of raw wheat flour and 8 ounces of water; column 4, test meal consisting of 1 1/2 ounces of unground pearled wheat with 8 ounces of water.

Several points of interest are to be noted in the above table, the first and most conspicuous of which is the fact that the saliva did not act at all upon the raw flour and raw wheat, as shown by the total absence of maltose in the cases represented in columns 3 and 4. The small amount of dextrine and soluble starch shown was, perhaps, already present in the raw grain, but this point I have not investigated. It is clear, however, that no sugar was produced when raw starch was taken, whereas the amount of sugar produced after the ordinary test meal was more than I gram in each 100 c.c. of stomach fluid; in other words, the stomach fluid contained more than one per cent of sugar without taking into account the amount which had been absorbed.

The figures for maltose in column 2 represent a test meal in which little or no saliva was mixed with the test meal, the food being swallowed without chewing, indicating very slight action of the saliva, the amount of maltose found in the stomach fluid being but a trifle more than one-fourth the amount obtained after an ordinary test meal. The amount of soluble starch and dextrine was less than half the normal amount in the case of the raw flour, and but little more in the case of the raw wheat.

Another point of interest is the increased amount of lactic acid found in the test meal taken without chewing, represented in column 2. The coefficient of fermentation which represents the number of milligrams of lactic acid (as expressed in terms of HC1) found in 100 c.c. of stomach fluid was more than double that found after the same kind of test breakfast properly masticated, represented in column I. The results of this experiment distinctly associate acid fermentation with imperfect mastication and imperfect salivary digestion.

Another fact noted in a comparative study of the results of the analysis of over 5000 stomach fluids, which very strongly confirms this idea, is that starch conversion is usually complete in cases of apepsia, while lactic acid is conspicuous by its absence. In nearly all cases of apepsia which I have encountered, numbering about forty cases in all, the most delicate tests for lactic acid have failed to show its presence except in the most minute quantities; in most cases it was entirely absent.

There are a number of other points of interest in the above table in addition to those which relate particularly to starch digestion. One of the most noteworthy of these is the fact that the digestion of albumen was not unfavourably influenced by the neglect to masticate the food, the coefficient of digestion, in fact, being raised from .82 to .97. This coefficient is a qualitative and not a quantitative index. The higher coefficient indicates a more perfect elaboration of proteids and a close approach to an absolutely perfect proteid digestion.

Another fact of perhaps even greater interest has relation to the digestion of albumen when the wheat was eaten raw, in the form of either flour or wheat. The coefficient of proteid digestion in both cases, as shown in columns 3 and 4, was 1.00, indicating perfect elaboration of the albuminoids. From this it appears that raw gluten, or the proteids of wheat, is digested more perfectly when taken in a raw state than when cooked, the very opposite of which we have seen to be true of starch. The digestion of raw starch may take place in the intestines, by the action of the pancreatic juice, but cannot take place in the stomach, for the reason that the saliva has not the power to penetrate the cellulose envelope of the starch granule, and hence cannot digest raw starch.

This fact coincides in a most interesting manner with the biological fact that man is by nature a frugivorous animal. In the process of ripening, the starch of fruits undergoes a hydration similar to that which takes place in cooking and in pancreatic digestion, whereby the insoluble starch is converted into soluble starch, dextrine, and sugar. This explains, also, why well-ripened fruit may be eaten raw with impunity, while unripe fruit and farinaceous food of all sorts require cooking. In his diet, man, like his nearest relative, the monkey, being naturally a frugivorous animal, may eat fruits in the state in which Nature has provided them; but when he introduces other natural products into his bill of fare, he must adopt artificial means for securing the preparation for digestion which Nature makes in the ripening process of fruits.

The coefficient of chlorine liberation (m) is very nearly uniform, indicating that the mastication of food and the cooking of food have little influence upon this digestive function.

The coefficient of salivary activity (c) was determined independently for each test breakfast. Its practical uniformity indicates that there was no essential change in the character or quality of the saliva to account for the differences shown by the totals in relation to the stomach digestion of starch.