Weight and diets: low salt diet
Pure sodium, which is one of the two elements in sodium chloride, or common salt, is seldom found except in chemical laboratories. Many combinations of sodium with other elements are used in diet and in industry. Table salt is sodium chloride. Baking soda is sodium bicarbonate.
The average man takes in his diet about half an ounce of sodium chloride every day. It is easy, on a low salt diet, to reduce this to about one fifth as much. This is done particularly when excess of fluid accumulates in the tissues, as in dropsy. No one knows exactly the minimum or maximum of sodium chloride that any one person ought to have, but fortunately the human body is equipped with factors of safety, so that it can get rid of excesses of various substances. The average human body contains at all times about three ounces of sodium chloride. The use of salt by the body and its elimination by the kidney are apparently controlled by the cortex or outer layer of the adrenal gland.
Many vegetables contain another salt with an element similar to sodium, namely, potassium. A person who subsists on a vegetable diet craves salt, because vegetables contain less sodium than meat. The moment the salt in the human body falls below the amount necessary, a craving is set up.
Salt is also important for supplying the chlorine element, since hydrochloric acid is secreted by the stomach regularly as an aid to digestion. Pepsin works as a digestive substance only in the presence of hydrochloric acid. However, hydrochloric acid should not be taken by the average person in that form except on the advice of a physician.
Various diets free from large amounts of sodium chloride have been developed. Most physicians are convinced that there is a definite relationship between salt in the diet and the occurrence of various conditions affecting the blood pressure and the kidneys. However, in the presence of unusual craving for salt, or, in fact, in any disease condition, it is well to be guided by competent advice.