( Originally Published 1938 )
Contrary to most person's belief, the amount of water in the tissues proper of the body remains quite constant. Moreover, any deviation from the total amount, no matter how slight, is very serious and may result in death if the condition is not remedied.
We all know stories of the agonies of men lost on a desert when their water supply has given out. We have seen them depicted in the movies, too, dying a slow, tortuous death. Such exhaustion and death is due principally to the decrease in the water content of the tissues. While occasionally we hear fantastic tales of persons who have gone nearly three weeks without water, ordinarily a man cannot survive more than three days at the most without water.
To increase the amount of water in the tissues, you will recall, is almost impossible. Observe that we say, in the tissues, and not in the body, which is an entirely different matter. The total amount of water that enters the body through the alimentary canal has nothing to do with the amount within the tissues. Whatever water is not needed by the tissues is either immediately cast off in the kidneys or is cast off by the skin or in respiration. Tissue water is not concerned with this excess water in the blood or excretory organs.
The amount of water we need depends upon a number of factors physical activity, external temperature, the amount of perspiration given off and the depletion of the tissue water by salty foods and saline cathartics. If you have ever tried to shake salt from a salt cellar on a damp summer's day you know what a great attraction salt has to water.
Ordinarily it is not necessary to pay much heed to the tissues' need for water as this need is most delicately regulated by the sensation of thirst. Thirst is the best indicator that Nature has given us of the water content of our tissues. And it is a far more reliable indicator than hunger is for food. Hunger pangs soon pass away in an adult, leaving only disagreeable sensations scarcely recognized as originating in the body's need for food. On the other hand, thirst becomes ever more persistent and uncomfortable, and is always recognized as a need for water.
We have three sources of water. All our foods contain water in a greater or less amount. Cucumbers, for example, contain about 95 per cent water and meat is about half water. The oxidation of food material for energy produces some water. But our greatest source is from beverages, and first and foremost among them is water itself.
Climate is an important factor, you will recall, in determining the daily intake of water. In a temperate climate the average adult consumes from one and one-half to three quarts of water daily. Or to put it in terms of the usual way of drinking water itself from six to twelve full glasses a day. In the tropics, or working under conditions similar to the English miners we mentioned, this amount may go up to thirteen or fourteen quarts a day.
The question of drinking water with meals and the influence of water on digestion has not been settled as yet. Some people drink a great deal of water with their meals without any apparent ill effect and others, equally healthy, drink very little. Europeans drink very little water if at all, with their meals, but their food is inclined to be moister than much of ours, and besides, they do drink plenty of wine and beer. Here in America observation seems to point to the fact that the majority drink water with their meals, or perhaps coffee or tea; and the minority shun water at such times as if it were a poison and look upon water drinkers as dissipators who will justly come to an early end.
Much of this attitude is due to a misconception of the fate of water in the alimentary canal. Water leaves the stomach almost immediately upon entering it. It goes in the upper end and out the lower almost as if it were running down a trough. The stomach may be. empty or it may be full no matter what its condition this rapid emptying of water takes place. And, more-over, when the stomach has food in it, the other foods do not leave it with the water. In other words, the water has no influence on the passage of food from the stomach to the' intestines.
Therefore, it would seem that water has no influence upon the rate or completeness of digestion. Such is the case: experiments by eminent scientists on digestion have proved that water has no influence.
When one stops to think of the meals which non-water drinkers consume, the inconsistency of their arguments that water hinders digestion by diluting the digestive juices, that it hastens the food through the stomach and out through the intestines, etc. is evident. An advocate of waterless meals will probably preach against the evils of water with meals while eating a bowl of soup which he follows with a meat course with plenty of gravy and tender vegetables floating in their own juice and tops off with a dish of ice cream. Ali of these foods contain a large amount of water and your stomach certainly isn't going to say to itself, "Ah-ha! This water surely comes from a glass that held nothing else. I refuse to work under such circumstances. Come, all you other members of the Alimentary Union, we are going to strike for only soup and gravy water."
No, indeed! The stomach continues to work, water or no water, and in all probability will work all the better for a little drink.
In addition to supplying the tissues with their quota of water, water helps the absorption of foods after they have been digested. It also helps to keep the bowels toned and the feces soft, thereby rendering evacuation easier. Many mildly constipated persons find that drinking one or two glasses of water upon rising helps to remedy the condition.
Water also helps the kidneys to eliminate the exeess nitrogen in the body.
Therefore, we believe that you can safely drink a moderate amount with your meals, the amount depending upon the dryness of the food. But, of course, the water should never be used to actually wash down the food that has not been thoroughly masticated, and moreover, it should not be iced.