NUTRITIONAL ENGINEERING, I:

AGRICULTURE AND HUMAN NUTRITION. BY

HENRY C. SHERMAN,

Chief. Bureau of Human Nutrition and Home Econmnics. Agricultural Research Administration.

United States Department of Agriculture. (On leave of absence from Columbia l 'niversity.l

Every time a farmer grows a really good plant or animal, he is demonstrating a fact and principle that people have been slow in ap- plying to themselves. This is the fact that full health is more than merely freedom from disease; rather, it is a positive quality of life that can be built to higher levels. To generalize this fact, and give it a formal scientific aspect, we may call it the principle of the improvability of the norm.

For a farmer to find real satisfaction in a plant or animal he has grown, it must be better than merely a normal, it must be a superior, specimen of its kind.

Now the farmer builds these superior individuals and so improves the norm of his crop or herd, first by breeding, and second by feeding and otherwise providing a favorable environment.

( ;ore Hambidge has pointed out that the norm of our American population would be improved if all children were reared with as much regard to their at tainments in positive health as are the animals in a good farmyard.

Our present-day view of nutrition does not, in any way whatever, encroach upon the field of the geneticist; we do not believe that we have changed, nor do we aspire to change, the germ plasm by improving an already normal diet. Heredity and environment determine the life history; and in this sense, the word environment, by definition, covers all influences except the genetic. But, in practice, most of us tend to think of environment as that which surrounds the body, and so most ~f us are late in waking up to the importance of differences in that part of our environment which each of us carries within his own skin -the internal environment of the body.

The reason we have hitherto neglected to take due account of the differences in our internal environments is in one sense quite simple. We did not believe in the existence of such differences. We thought we had learned from two great teachers, Liebig in chemistry and Claude Bernard in physiology, that the internal environment is a constant for the normal members of a given species, at least at any given stage in the life history. Liebig taught farmers to fertilize their fields, with phosphate for example, but with the expectation of getting a bigger

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38 H . C . SHERMAN. [J. t". 1,

crop rather than a crop richer in phosphorus. For, aside from such non-essentials as the amounts of stored starch or fat, the chemical com- position (at a given stage of matur i ty) was believed to be specific for the species. And what Liebig had arrived at through agricultural chemistry Claude Bernard formulated in the physiological phrase that it is because of the fixitd of the internal environment tha t organisms are able to cope with new or changeable external environments. These teachings have been of great service to agriculture on the one hand and to physiology and ecology on the other; but they are only first approximations.

With the universally accepted principles of physical chemistry, and with the experimental facts of the newer knowledge of nutrit ion, we now have the means of deeper insights and of more far-reaching scientific concepts which both " render more intelligible the world in which we live," and are turning out to have an unexpectedly great practical im- portance for the development of human health and efficiency, through bet ter use of food.

The fact tha t this new knowledge of nutr i t ion offers unexpectedly great potent ial i ty for the improvement of human efficiency at a t ime when our country so much needs our best efforts, and also offers guidance in the practical food problems which are now so acute in our national and international affairs, natural ly arouses enthusiasm in some people and skepticism in others.

In this situation, agricultural th inking can render a great service. Every thoughtful agriculturist knows- -whe ther he uses these words or n o t - - t h a t a satisfactory plant or animal must have something of tha t higher health tha t is more than merely absence of disease. And he knows that , impor tant as is the genetic heritage, much also depends upon the nutri t ional environment . The skeptical economist who as yet is refusing to believe tha t anything more than slight improvement of human efficiency and welfare can result from a moderate redirection of our present national resources for food production as advised in the government ' s published goals for I944, can reassure himself and move forward out of his skepticism by learning from his farmer friends that what is now "c la imed" for human nutri t ion is just the sane counterpar t of what scientific agriculture has already demonstra ted in the flocks and herds of the progressive farmers of the nation, and tha t both for human beings and for crops and farm animals, there is good prospect tha t further research will point the way to still higher achievements.

Meanwhile, the t rend of 'the food product ion goals has impor tant significances both industrial and nutri t ional which we plan to take up in subsequent instal lments of this paper.

March I8, I944.

(This is the first of a series of articles by Dr. Sherman. Others will appear in future issues of the JOURNAL OF TI-IE FRANKLIN INSTITUTE.)