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Food Quality as Physiology Demands It
Published in Let’s Live, October 1956
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The old saying, “The proof of the pudding is in the eating thereof,” is challenging the scientists to give us the values of what we eat in more specific characterizations than those of that simple–and usually pleasant–experience. Eating gives proof in terms of taste, but that is not yet specified by any standard, or reproductible, units of common agreement. We cannot report scientifically all that food does for us. We do not comprehend all the services of it, much less all the body functions in which it may play some vital roles.
Chemical analyses of the ash of vegetables or field crops are not highly informative. The very analysis destroys by ignition the organic compounds for which we eat food in the main. Vitamin assays, specifying these catalytic compounds, are more suggestive. Feeding tests, measuring the food quality by gains in body weight of animals, or by shifts in rates of body processes–of both animal and human–are more widely used to measure the nutritional qualities of food crops in relation to the inorganic fertility of the soil growing them. Though they are laborious procedures, assays of the rat, the Guinea pig, and other animals are about the only accurate measure of food quality now at our command.
An illustration
Visible properties may be appealing, but they are not proof. The tomatoes serve as an illustration. The British market offers the housewife–and she seems to prefer it–a small tomato with fewer sections in it, with more acid and more juice. The American market has large, fleshy, many-sectioned, less juicy and highly flavored tomatoes. But what of the nutritional values, and what evidence thereof can we specify after the eating?
Food quality is arousing more concern in other countries under higher press of population than in ours. That may well emphasize nutrition and good health, as the reason for purchase of groceries for ourselves with decreasing tillable acreage of productive soil per person and declining fertility of those remaining areas under continued cultivation and higher costs. In Germany, and other European sections, a growing number of scientists, of magnitude sufficient for an international society, have concerned themselves in research in the nutritional qualities of different foods.
Apples vary
As an illustration of some of their work, there was reported a study of the qualities of apples used in feeding the children of two comparable orphanages. While the health of the children was studied and examinations of them made regularly, the apples were also put under bioassay by Guinea pigs for measure of vitamin C content.
Some of these results in summary (see accompanying chart) for a feeding test–from November through January–show that two, four, and six grams of one variety of apple, Ontario, were the equivalent in vitamin C content of 20 and 30 grams of another variety, Oldenburg, when used as supplement to a diet free of this essential nutrient.
Average growth (wt. gms.) of young Guinea pigs fed a Vitamin C-free ration which was fortified by different amounts of two varieties of apples, viz. Geh. Oldenburg and Ontario. The control group (no apples) died from scurvy as indicated by the lower sample graph.
Proof
Here proof is given to us in vital characterizations by the Guinea pigs. No apples meant their death; 10 grams of Oldenburg were but little more than survival; and as little as two, four, and six grams of the variety, Ontario, were the equivalent of from 5 to 10 times those weights of the former variety. If once we assay as accurately as this, not only the varieties of foods we grow, but each in relation to the inorganic fertility of the soil producing it, and if we specify the results as life and death for Guinea pigs, we shall no longer be indifferent to nutritional qualities of what we eat. Instead, we shall also be in position to improve and control nutritive values in what foods we grow.