Organs and Processes of Digestion : Part 7

Physiology and Hygiene for Secondary Schools
by Francis M. Walters

(Page 16 of 31)

Quantity of Food. - Overeating and under eating are both objectionable from a hygienic standpoint. Overeating, by introducing an unnecessary amount of food into the body, overworks the organs of digestion and also the organs of excretion. It may also lead to the accumulation of burdensome fat and of harmful wastes. On the other hand, the taking of too little food impoverishes the blood and weakens the entire body. As a rule, however, more people eat too much than too little, and to quit eating before the appetite is fully satisfied is with many people a necessary precaution. The power of self-control, valuable in all phases of life, is indispensable in the avoidance of overeating.

Frequency of Taking Food. - Eating between meals is manifestly an unhealthful practice. The question has also been raised as to whether the common habit of eating three times a day is best suited to all classes of people. Many people of weak digestive organs have been benefited by the plan of two meals a day, while others adopt the plan of eating one heavy meal and two light ones. Either plan gives the organs of digestion more time to rest and diminishes the liability of overeating. On the other hand, those doing heavy muscular work can hardly derive the energy which they need from less than three good meals a day. Though no definite rule can be laid down, there is involved a hygienic principle which all should follow: Meals should not overlap. The stomach should be free from food taken at a previous meal before more is introduced into it. When this principle is not observed, material ferments in the stomach, causing indigestion and other disorders. It should be noted, however, that the overlapping may be due to overeating as well as to eating too frequently.

Dangers from Impure Food. - Food is frequently the carrier of disease germs and for this reason requires close inspection. Typhoid fever, a most dangerous disease, is usually contracted through either impure food or impure water. One safeguard against disease germs, as stated above, is thorough cooking. Too much care cannot be exercised with reference to the water for drinking purposes. Water which is not perfectly clear, which smells of decaying material, or which forms a sediment on standing is usually not fit to drink. It can, however, be rendered comparatively harmless by boiling. The objections which many people have to drinking boiled water are removed when it is boiled the day before it is used, so as to give it time to cool, settle, and replace the air driven off by the boiling.

Care of the Bowels. - In considering the hygiene of the alimentary canal, the fact that it is used as a means of separating the impurities from the body must not be overlooked. Frequently, through lack of exercise, negligence in evacuating the bowels, or other causes, a weakened condition of the canal is induced which results in the retention of impurities beyond the time when they should be discharged. This is a great annoyance and at the same time a menace to the health.

In most cases this condition can be relieved, and prevented from recurring, by observing the following habits: 1. Have a regular time each day for evacuating the bowels. This is a most important factor in securing the necessary movements. 2. Drink a cup of cold water on rising in the morning and on retiring at night. 3. Eat generously of fruits and other coarse foods, such as corn bread, oatmeal, hominy, cabbage, etc. 4. Practice persistently such exercises as bring the abdominal muscles into play. These exercises strengthen indirectly the muscles of the canal. 5. Avoid overwork, especially of the nervous system.

Alcohol and Digestion. - Though exciting temporarily a greater flow of the digestive fluids, alcoholic drinks taken in any but very small quantities are considered detrimental to the work of digestion. Large doses retard the action of enzymes, inflame the mucous lining of the stomach, and bring about a diseased condition of the liver. It may be noted, however, that the bad effects of alcoholic beverages upon the stomach, the liver, and the body in general are less pronounced when these are taken as a part of the regular meals.

Effects of Tea and Coffee. - In addition to the stimulating agent caffeine, tea and coffee contain a bitter, astringent substance, known as tannin. On account of the tannin these beverages tend to retard digestion and to irritate the lining of the stomach - effects that may be largely obviated by methods of preparing tea and coffee which dissolve little of the tannin. (They should be made without continued boiling or steeping.) The caffeine may do harm through its stimulating effect upon the nervous system and through the introduction of a special waste into the body. In chemical composition caffeine closely resembles a waste, called uric acid, and in the body is converted into this substance. If one is in a weakened condition, the uric acid may fail to be oxidized to urea, as occurs normally, or to be thrown off as uric acid. In this case it accumulates in the body, causing rheumatism and related diseases. It therefore happens that while some people may use tea and coffee without detriment, others are injured by them.

Summary. - The main structure in the digestive system is the alimentary canal. This provides cavities where important dissolving processes take place, and tubes for joining these cavities, while glands connecting with the canal supply the necessary liquids for changing and dissolving the foods. The general plan of digestion is that of passing the food through the canal, beginning with the mouth, and of acting on it at various places, with the final result of reducing most of it to the liquid state. The digestive fluids supply water which acts as a solvent and carries the active chemical agents, or enzymes, that convert the insoluble foods into substances that are soluble. The muscles in the walls of the canal perform the mechanical work of digestion, while the nervous system controls and regulates the activity of the various organs concerned in this work.

D.C. Heath and Co. - Publishers
Original copyright 1909