While the consumption of sugars in all civilized nations is rapidly increasing, there can be no question that, irrespective of fruits, they are, of all foods, the most frequent causes of digestive disturbances. It is only within comparatively recent times that mankind has possessed means of separating sugars in any great bulk from the plants containing them, and as a consequence they have only entered prominently into our every-day diet for a relatively short period of time. Before this, it is true, they were consumed to a greater or less extent in various fruits, but the quantity was insignificant as compared with the amount now universally eaten. As a result of this we are now confronted with a new dietetic problem. For ages the human stomach has been accustomed to deal with only small quantities of these substances, and developed accordingly a capacity to digest them proportionate to the amounts then eaten. Now, however, we constantly call upon our digestive organs to deal with large quantities of such foods, and it is not strange that there has been more or less rebellion on their part.
Experiments have shown that a small amount of sugar assists in the normal chemical changes that go on in the body, and it is, therefore, obvious that nature intends us to take a certain quantity of it. Moreover it is true that sugars while being burned in the body give off much energy—mainly manifested in muscular power; where then we are taking active physical exercise foods of this kind are peculiarly appropriate. It would, therefore, not be wise for us to leave this food entirely out of the dietetic list, but to use it only in small amounts—particularly where we lead sedentary lives. Sugar and alcohol play a more or less similar rôle in the animal economy. It is well known that those who do not use alcohol are peculiarly prone to consume considerable quantities of sugar; and it is equally a matter of common observation that those who habitually take alcohol rarely eat sweets to any extent.
When sugar is properly assimilated, as seems to be done most easily by children, it is an excellent food, but where sweets are over-eaten, and not properly digested, they give rise to a great accumulation of gas in the intestine, and produce in many persons a marked acidity of the stomach, frequently accompanied by severe insomnia. Nothing so quickly relieves such sleeplessness, caused by a “sour stomach,” as allowing ten or fifteen grains of ordinary cooking-soda to slowly dissolve in the mouth and swallowing the saliva rendered alkaline in this way.
Milk.—Milk may be looked upon as an ideal food, it being composed of water carrying in solution the three great natural foods—albumins in the form of casein, carbohydrates as milk-sugar or lactose, and fat. Mixed in the proportion in which they here occur, they are most admirably adapted to the delicate digestive apparatus of the infant—the relative proportion of the different substances even gradually changing as the assimilative powers of the youthful organism increase; it is thus seen that milk itself is not of constant composition, even in the same animal, and that it alters in such a manner as to meet best the needs of the delicate being depending upon it for proper sustenance. It is also the case that the composition of milk varies in different animals—showing again how admirably nature exerts its powers in meeting desired ends.
The lesson of practicable importance that we learn from this is that the milk of one of the lower animals is not in its natural state quite suited to the delicate stomach of the growing infant, and that if it be substituted for the mother's milk it must be more or less altered, depending upon the age of the child. It is particularly important that sweet milk be taken slowly, as otherwise large curds, difficult of digestion, form as soon as it gets into the stomach.
CHAPTER VIII
FOOD-VALUE OF VEGETABLES
In recent times we hear much of vegetarianism, which has its advocates among many highly intelligent people, and which, as a consequence, has achieved a certain vogue throughout the civilized world. It is rarely the case, however, that those who affect to practice this cult in reality live exclusively on a vegetable diet. As a rule it will be found that they are milk-drinkers, and not infrequently add eggs to their dietary. It is, of course, absurd to regard as vegetarians those who simply avoid meat, since it is true that the nitrogenous substances contained in milk and eggs differ in no essential particular from similar substances found in flesh of all kinds.