IN the light of our modern knowledge of nutrition, it is interesting to speculate on what form the human body might have assumed if, in its beginnings, it had encountered other food than that which determined its destiny, and whether modifications of racial types might still be made by alterations in dietary habits.

There is much evidence to show that in the evolution from amoeba to the higher forms of animal life the various steps were influenced by nutrition. If this hypothesis is granted, we have at least one explanation for the different physical types of the people inhabiting the earth. Are the Japanese, the Javanese, the Chinese and other Oriental races short in stature because of their preponderating rice diet? Are the Polynesians, the larger types of Africans, or the northern Europeans, taller in stature because they hit upon a dietary that resulted in greater growth? There is testimony that this may be the case.

It has been shown, for example, that the size of a rat, and in a measure its characteristics, may be determined by the chemical constituents of its food. The rat has proved a valuable experimental animal. It is an omniverous feeder in that it takes both animal and vegetable food, and although its life cycle is only about three years many of its metabolic processes have been found to resemble those in man. The effects of food upon the rat are often analogous to those upon man and therefore have thrown much light upon nutritive results. Professor McCollum, of the Johns Hopkins School of Hygiene and Public Health, has demonstrated by experiments, repeated again and again, that if a litter of eight rats is divided into two groups of four each, and one group is fed upon a diet consisting of distilled water and whole wheat, and the other group upon exactly the same quantity of distilled water and whole wheat, with an addition of a few turnip or beet leaves, each rat in the first group will attain only the size of a large mouse, whereas the rats in the second group will attain nearly double the size of those of the first group. Except as to size, so far as can be ascertained, the rats in both groups are normal in all respects.

Notable contributions have been made to this hypothesis by the Japanese scientists who are testing on human beings the knowledge that has been gained in the laboratory. In Tokyo a few other foods are being added to the regular school lunches of a group of children. This trial, extending over several years, has already shown that the school children receiving a diet augmented by food used by the taller races are several inches taller and weigh several pounds more than children on the normal diet of the country. Similar results followed trials with a group of children in Baltimore who were placed on special diets. It is reasonable to infer, then, that the Polynesian's greater stature is due to his having availed himself of food containing substances that are missing in the ordinary Japanese diet. Nor are these isolated instances.

Colonel McCarrison, of the Indian Medical Service, was struck by the fact that the average stature of the Sikhs and Patans was markedly greater than that of the Madrassis and other peoples of India, notwithstanding that all these peoples apparently lived under the same conditions of filth, squalor, and poverty. Further investigation showed, however, that while the diet of the Sikhs and Patans had the same limitations as to quantity, it differed markedly in components. The two former groups took milk in the form of kurds and cheese, leafy vegetables, and a small amount of animal food -- materials which were lacking in the general Indian diet.

In order to ascertain whether diet was responsible for the difference in stature, Colonel McCarrison performed some interesting experiments. He fed half of a litter of rats on Sikh and Patan diet, and the other half of the litter on Madrassi diet. The groups receiving the Sikh and Patan diet attained great size, and the group on the Madrassi diet remained small. He repeated the test many times with similar results. He then enlarged the experiment and had rats serve, so to say, as international representatives. He fed groups of them on the characteristic diet of the less favored and ill-nourished English workman, and other groups on the habitual diets of the Japanese, the Filipino, the Javanese, and a number of other races. Again the individuals of the Sikh and Patan groups were of huge size with smooth coats and gentle demeanor; those of the English group attained nearly the same size as those of the preceding groups, but they had rough coats and were of a combative disposition. The Japanese, the Filipino, and the Javanese groups were small in stature, and displayed many of the characteristics of those nationalities.

While no doubt there may be other factors involved, these experiments naturally raise the question as to whether food is not largely responsible for the varying characteristics of the races of mankind. This leads to interesting speculation as to what the histories of the various races might have been had they chanced on a different dietary, and whether changes in national diets will change national characteristics in the future.

II

Whether definite deductions are warranted from the foregoing facts may be open to debate, but there is no question that nutrition is directly responsible for certain diseases. It is generally conceded that many diseases gain a foothold through lowered resistance. And lowered resistance, in turn, is often produced by malnutrition.

Beriberi, a disease peculiar to the Orient, and one that alone causes annually over 100,000 deaths and makes millions ill, has until very recently been most baffling in its etiology. It is now definitely known to occur among those whose staple article of diet is white rice. It is easily prevented by substituting natural dark rice for the polished variety. The outside of the rice grain contains substances (vitamin B) which are essential for maintenance and repair. When rice is white, it means the outer layers of the grain have been removed through a polishing process. In the absence of this outer layer, needed nutrition is withheld and paralysis and grave circulatory disturbances follow. Experience has conclusively shown that when dark rice is used, beriberi does not occur.

In our Southern States pellagra is a disease which seriously affects the health and lives of thousands. It occurs only in the inadequately nourished and is commonly found among those whose staple article of diet is corn which does not contain all of the substances necessary to nourish the body properly. In the relief work which was done among the victims of the recent Mississippi floods, special precautions have been taken to provide a diet which would decrease the danger of pellagra among the sufferers.

It has been a common observation for ages that the crews of sailing ships making long voyages were subject to scurvy because of the absence of vegetables from their diet. Empirically, lime juice was believed to be a corrective, and all British ships were required to carry it in their stores -- hence the name "Lime Juicers" or "Limeys" as a synonym for British sailors. It is now known definitely that when citrus fruit and vegetables are added to the diet, scurvy does not occur.

Certain forms of ophthalmia, which sometimes manifest themselves in the form of night blindness, have been found to be due to a lack of vitamin A in the diet. In the World War this deficient diet was a serious cause of disability among the Russians. One of the dangers of industrialism in China has recently come to light among a large group of factory operatives who were given subsistence by their employers. Although the food supplied was adequate in quantity, it did not contain the essential components required by the body, and large numbers of cases of partial blindness occurred among the workmen.

Various forms of skin diseases can be experimentally produced by withholding certain nutritive substances from the diet. Skin diseases among children are often due to this cause. Japanese scientists have shown that stones in the gall bladder or kidneys may be caused by omitting certain constituents which go to make up vitamin A. The Japanese have also in their research work produced gastric ulcers by means of deficient diet and have promptly healed these ulcers by substituting an adequate diet. If they persisted with the diet that caused the gastric ulcer, they were able to change the ulcer into cancer. But no corrective diet has had any influence on the cancers so produced.

At the time the World War began, the tuberculosis rate in Germany and Austria compared very favorably with that of other countries. As food became scarce there was great restriction in its variety and it definitely lacked the substances which are known to be essential to human economy. The records show that tuberculosis steadily increased in these countries until 1920, and when the diet again contained the customary nutritive values, the infection rate rapidly declined. By 1925 the rate had reached pre-war figures, yet the German and Austrian authorities point out that the housing conditions were as bad as, or worse than, during the war and that overcrowding had not been relieved.

Laboratory evidence that diet is intimately associated with virulence of infection has been brought forward by Professor Lloyd Arnold of Chicago. He has shown that if mice are fed upon a diet deficient in vitamins, and inorganic salts are then injected with a definite quantity of virulent bacteria, the mortality among them is approximately 50 percent. If mice of the same litter are given an adequate diet and injected with the same quantity of virulent organisms as the first group, the mortality is only 10 percent. This evidence might well explain the high incidence of tuberculosis among the Germans and Austrians following upon the restriction of their food supply.

It may be that the seemingly direct relationship between cause and effect in the instances here cited does not necessarily follow. Many other factors may be involved. For example, rickets is known to be associated with a deficient diet, and it may be prevented or cured by administering cod liver oil. It may occur, too, in a child that has been fed upon milk from a cow that has been kept in a dark stable. In this case the condition may be corrected by the use of milk from a cow that has been exposed to sufficient sunlight. However, milk of the former type, if it is subjected to violet rays or if the cow from which it is obtained is subjected to violet rays, may acquire the desired essentials.

On the whole the foregoing facts would seem to warrant the deduction that nutrition is concerned in producing various types of the human race and in maintaining their health. As knowledge with regard to the effects of food upon man increases, it is more than conceivable that the races that first avail themselves of the new values of nutrition may decrease the handicaps of disease, lengthen their lives, and so become the leaders of the future.

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  • VICTOR G. HEISER, M. D., Director of Health in the Philippines, 1905-1915; now Director for the East, International Health Board
  • More By Victor G. Heiser