Diet and Longevity

By EDWARD E. CORNWALL
Nature’s law of persisting life and its corollary, the law of self-preservation, command us to live as long as possible. How shall we do it? There are many factors in the longevity problem, and among them, the factor of diet. In order to live, we must eat; but in order to live long, we must eat wisely. As long life depends on health, eating to live long means also eating to keep healthy.
To guide us in right eating we have first, instinct. Our instinct is less than that of many of the lower animals; for with man’s higher development, intelligence has to a certain extent supplanted instinct. But our remnant of instinct is considerable.
The we have experience, which teaches us that some foods and ways of eating are better for us than others. The dietetic teachings of instinct and personal experience form the basis of our eating law.
We learn also from the experience of others; but in applying this teaching we have to bear in mind that individuals may differ in their reactions to particular foods and ways of eating.
And we have history which shows us in perspective the effects of particular diets and ways of eating on individuals and on large groups, and enables us to profit by past racial experience.
Finally, we have science which clarifies and systematizes and adds to the knowledge of food and eating which experience and experimentation past and present have accumulated. Science reveals to us as guiding principles in eating, the principle of the adequate diet, that of the balanced diet, that of the easy diet and that of the temperate diet.
Guiding Principles in Eating
The principle of the adequate diet says that we should eat of the essential foods, that is, the so-called food principles, viz., protein, fat, carbohydrates, minerals, vitamins and water, quantities sufficient to satisfy the needs of the organism under various conditions.
The principle of the balanced diet says that the diet should contain all the food principles in proper quantities and proper relative proportions; and also that the food principles themselves should be internally balanced as to their varieties. The protein rations, for example, should consist in large part of the superior varieties of protein, which are those derived from the flesh, milk and eggs of animal. These resemble n their structure our body protein more closely than do the inferior varieties derived from vegetable sources. No diet is well balanced whose protein ration is not largely of animal origin. And the fat ration has to be correlated with the carbohydrate ration to suit the fuel requirements.
In the carbohydrate rations, starch should generally be preferred over sugar, being especially adapted for use as fuel in the human furnace by long habituation. Sugar in large amounts is a recent innovation in man’s diet. While the balanced mineral ration is usually taken care of in the ordinary health diet of civilized peoples, in may on occasion be necessary to make particular additions of curtailments; as in the diet of those living remote from the sea, the addition of iodine may be required; and the excessive amount of sodium chloride in the diet of most civilized peoples requires curtailment.
In the case of vitamins the balanced ration is usually taken care of in the ordinary health diet of civilized peoples, yet deficiency of particular vitamins must be guarded against; and not only the deficiencies due to natural failures to get proper foodstuffs, but also those caused by wrong dietetic habits or customs, which by prematurely satisfying the appetite cause exclusion from the diet of proper vitamin-containing food stuffs; and in diets which are restricted for any reason, special precautions should be taken to insure against vitamin deficiency. While on this subject, it is interesting to speculate on how it was that our ancestors got along as well as they did without knowing about vitamins and without our extensive markets.
The principle of the easy diet says that the diet should be composed of articles of food which can be utilized by the body in its nutritive processes with comparative ease. This principle of the easy diet says that the diet should be composed of articles of food which can be utilized by the body in its nutritive processes with comparative ease. This principle recognizes the fact that different food stuffs which are equivalent as regards their content of food principles, may differ in the ease with which they are utilized in nutrition. This principle is of special importance in conditions of disease, old age and constitutional weakness or inferiority which reduce below normal the functional activity of the mechanisms involved n nutrition. But the best interests of the individual may require that in conditions of health this principle be not too strictly regarded. It may be advisable for the individual to eat a certain amount of the harder foods in order to exercise properly his mechanisms for preparing and utilizing food.
The principle of the temperate diet prohibits us from eating more than we need. The satiety sense should protect us against overeating. But it may happen that special culinary appeals to taste, or fashions, customs or acquired habits of overeating weaken this sense. Then it becomes necessary for intelligence to exercise quantitative control over eating in accordance with the principle of the temperate diet. –Medical World.
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Calcium Deficiency
In the British Medical Journal (January 8th, 1938), Dr. K. H. Coward and co-workers at the College of the Pharmaceutical Society describe a series of experiments carried out on young rats. The animals were fed on the usual diet of poor people, consisting largely of bread, margarine, jam and potatoes, with some meat and a little milk and green vegetables, and in addition cod liver oil. The addition of the oil should have ensured that the calcium and phosphorus present in the diet were absorbed. The bone ash percentage in this group was rather less than four-fifths normal; but in a similar group when a salt mixture containing calcium and phosphorus or milk was added to all the rest, the bone ash percentage was normal. The authors conclude that this proves quite clearly that the ordinary mixed diet of the poorer classes is seriously deficient in the elements required for the calcification of bone. The British Medical Journal adds: “The importance of this conclusion is so obvious that it requires little comment. It is in general accordance with the findings of American authorities such as Sherman, who have contented for many years that calcium deficiency is one of the most serious dangers of improperly balanced diets.” –Dental Record, London, per The Dental Journal of Australia.