INDUSTRIAL A N D ENGINEERING CHEMISTRY
Nutrition and Health’ By H. C. Sherman C o r r - ~ UXI-RSITY, ~~a NEWYORK,N. Y.
HE grain crop is the staff of life of mankind. Complete failure of grain crops over any large area means famine. It is because the grains areless subject to coni.pletefailure than most other crops and are relatively productive and nonperishable that they have come to bulk so largely in the food supply of the people. But nutrition and health cannot be maintained on grain crops alone, however abundant. A diet consisting too largely of grain products undermines health in two ways: by furnishing so little of some of the mineral elements and vitamins as to lead to deficiency disease, and by weakening the body’s defenses against infections and thus increasing its susceptibility to infectious diseases. Relatively recent researches in the chemistry of food and nutrition have shown the nature of the nutritional deficiencies of the grains and how they may be corrected by use of other foods and also make it plain that merely to prescribe a varied diet is by no means to deal adequately with the question of how to adapt the food supply to the best interests of nutrition and health. The economics of the food supply, the nutritional characteristics of the different types of food, and the direct and indirect effects of the nutritional character of the diet upon the health of the body must all be considered and in somewhat technical detail, before one is in position to form conclusions regarding nutrition and health which shall safely summarize the best present knowledge. If any of the statements in this paper seem a bit dogmatic it is hoped that this will be realized as due, not to lack of adequate evidence, but to the difficulty of making clear the nature and extent of the evidence while a t the same time reducing the results of much scientific research to a very brief and nontechnical form.
dependent upon the grain crops for their food because these furnish the most food value for what they cost in money to buy or in labor to produce. But this very fact increases the danger that people may depend too largely upon the grains and their mill products as food, or that they may vary the food supply to please the palate without fully providing for all their nutritional needs. Grain products which have been refined by the milling processes now common in nearly all countries are deficient in the mineral elements, calcium, phosphorus, and iron (so important to muscles, bones, and blood), as well as in the vitamins. With the use of whole-grain products the supplies of phosphorus, iron, and vitamin B would be much improved; but the deficiencies of calcium, of vitamin which is needed to prevent scurvy, and of the fat-soluble vitamins would still continue. When poverty forces too great a dependence upon grain products, these nutritional deficiencies lead to impairment of health. Unfortunately, it does not follow that economic freedom to choose foods which please the palate and satisfy the traditional demand for variety will always avoid these same nutritional deficiencies. Meat is well liked by most people, and in the past it has been thought, since the grain products are starchy while the meats are rich either in protein or fat, or both, that therefore the meats mere well fitted to “balance” the breadstuffs or other grain products of the dietary. This is still believed by many people, but we nom know that it is a mistaken impression, for the meats show, in general, about the same mineral and vitamin deficiencies as do the grains and therefore have but little supplementing value in the directions in which supplementing of the grain products is most needed. Requirements for an Adequate Diet Contrary to the supposition of former times, we now know The nutritive requirements may be grouped under four main that a food supply consisting largely of grain products is more heads: (1) fuel foodstuffs sufficient to supply the energy effectively supplemented by fruits and vegetables than by needed to support the work of the body, which energy is meats and fish. The richness of fruits and vegetables in vitamin C, which usually expressed in terms of calories; ( 2 ) protein; ( 3 ) mineral prevents scurvy and increases the ability of the body to resist elements; (4)vitamins. The energy requirement of the body is the most constant infectious disease, is much more important to nutrition and and insistent of its nutritional needs. All the properties which health than is the richness of meats and fish in protein. In distinguish the living body from nonliving things involve some addition, the green vegetables are fairly good sources of calform of expenditure of energy, such as warmth, movement, or cium and of vitamin A; but not so good in either of these muscular tension. Such expenditures of energy can never respects as is milk. The experience of those parts of the stop during life, and if the food does not have sufficient fuel Orient in which milk is very scarce but green foods are very value to supply the n.eeded calories of energy the deficit is met abundantly used shows that it is very difficult to make the by burning of body material. For this to go on must, of diet fully adequate when green foods replace milk in the food course, mean the emaciation of the body. Starvation, as we supply. P V I i k is rich in calcium and in fat-soluble vitamins, the commonly use and understand the term, is primarily the result of a deficiency of the total calories or total energy value of the factors which in the average dietary are most in need of refood. Correspondingly, “enough food” or “enough to eat” enforcement. Milk, vegetables, and fruits should preferably means primarily a supply of food sufficient to furnish the all be well represented in the food supply in order to insure its needed number of total calories or t o meet the energy re- nutritional adequacy. It has been well said that “the dietary (or its equivaquirement of the body. In most countries the grain crops should be built around bread and &”-bread furnish the most constant and economical forms of body fuel, lent in other grain products) being usually the most economand at the same time an important protein supply. The ical and generally satisfactory food so far as it goes, and milk grain crops furnish, in different countries, from two-fifths to being the most efficient of all foods in supplying what the four-fifths of the total calories consumed by the population bread does not supply. And even a varied assortment of breadstuffs, meats, sweets, as a whole, the people of lower incomes being the more largely and many fats may still show about the same nutritional Presented a t the Round Table Conference on “The Role of Chemistry deficiencies as do the grains alone. in the World’s Future Affairs” a t the Sixth Session of the Institute of Politics, Williamstown, Mass., August 24, 1926. As McCollum has frequently emphasized, dietaries freely
INDUSTRIAL AND ENGINEERING CHEiUISTRY
chosen and meeting all the desires of the consumer may yet fail to meet all his nutritional needs because of containing too little of what he calls the protective foods-fruits, green vegetables, and especially milk in its various forms-which are the most important means of insuring against the common dietary deficiencies. Anything which leads to a larger production and consumption of fruits, green vegetables, and especially milk makes for the improvement of the public health through better insurance of adequate nutrition. Optimal Nutrition
Thus far we have spoken chiefly in terms of making the diet adequate and have stated as a fact hardly requiring argument that adequate nutrition is essential to health. Inadequate nutrition leads directly to the so-called deficiency diseases such as scurvy, and indirectly to a vast additional amount of ill-health through increased susceptibility to infectious diseases such as tuberculosis and certainly many others. But recent research has shown us that we need not stop with the adequate, as if havirig found it there were nothing more to seek. By feeding experiments with rats which live their lives about thirty to forty times as rapidly as do human beings and mature so early that successive generations are obtained a t the rate of about four each year, it is possible in a laboratory research of a few years’ duration to study the effect of nutritional or other conditions over a long span of family history. Certain rat families in the writer’s laboratory have now been upon the same known diet for twenty generations or an approximate equivalent of six hundred years of experience in human history. Thus what started as an extension of chemical analysis in the study of food values has developed to the point where it might now be employed for the experimental study of some types of historical and economic questions-an unexpected and as yet unexploited contribution of chemistry to the humanities! But let us return to the particular question in hand. Starting with a food supply already adequate it has been found possible by increasing the proportion of milk in the dietary to improve the condition of nutrition and thus raise the standard of health to a very impressive degree. We now see clearly that not merely adequate but rather optimal nutrition should be our aim. Perhaps it will add to the interest and significance of our discussion of the actual improvements in nutrition and health induced by changing an already adequate diet so as to make it still better, if we first make clear that it is economically entirely feasible for the people as a whole to command the means of making this improvement in their dietaries if and as they become educated up to the point of desiring to do so. We must remember, what so many writers seem to forget, that the food crops produced by a country are not a fixed feature of its geography, but are determined by the relative demand for the difYerent things which the same farm can produce. In the long run, the farmer will employ his land and labor and dispose of his crops in whatever way he finds most profitable, and this in turn will depend upon what the consumer demands in the market and the relative prices which he is willing to pay. As fast as consumers come to know and to act upon the knowledge that fruits, vegetables, and milk are really worth more, and meats and sweets less, as food, than has hitherto been supposed, the shifting of the emphasis of their demands from meats and sweets to fruits, vegetables, and milk will tend to make these latter the crops that pay the farmer best ‘and thus stimulate his production of them. For instance, when an average American corn crop has been harvested and all the demands of human consumption of grain, of the manufacturing industries, of seed for the next crop, and of feed for the farm’s draft animals have been met,
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there remain in the hands of the farmers of the United States about a billion bushels of grain to be turned into meat and milk in whatever proportions “the market”-that is, the consumer-makes it more profitable for the farmer to produce. The increased production and consumption of milk, which all competent students of the subject now regard as highly important to the advancement of health through nutrition, need not be brought about entirely a t the expense of a decreased meat production, but even assuming this to be the case, it need cause no serious anxiety, for about one-third of the grass and grain which now go into meat production would suffice to double the production of milk and the shifting of one-third of what consumers now spend for meat to the purchase of additional milk instead would enable them to buy twice as much milk as they now do. Probably two-thirds of our present high rate of meat consumption would be as much as is best for most of us; certainly, the doubling of the present rate of milk consumption would mean very great advance in the well-being of the people. Even if our present milk ’supply be regarded as adequate, we nom have ample evidence that a more liberal supply results in improyed nutrition and thus induces a higher degree of health. Effect on Health and Efficiency
In human experience so many factors may enter to influence health in the course of a lifetime that it may not be possible to separate and measure the effect of food alone upon the whole durat on and efficiency of life. But this can be, and has been, done with laboratory animals of rapid growth, early maturity, and short life such as the rat, and it has been possible to determine, under conditions uniform in all other respects, the influence of an improvement, in this case an increase in the proportion of milk, in a food supply which was already adequate. Such improvement has resulted in several distinct evidences of a higher degree of health and vigor, such as more rapid and efficient growth, earlier maturity, greater ~ i g o r and , longer life with lower death rates both in infancy and among adults, and conspicuously an extension of the pr me of life in both directions, old age being deferred in the same individuals in which earlier maturity had been induced. These evidences of higher health through improved nutrition owing to the betterment of a food supply already adequate have been studied statistically in sufficiently large numbers of cases to establish with certainty the fact that all these differences are real and due to the improvement in dietthat they cannot be accidental nor due to chance or physiological variability of the animals. Moreover, the improvements are even more noticeable in the second generation than the first. There is no reason to doubt and every reason confidently to believe that all these findings, in the general terms here stated, will apply equally in human experience and that longer life with a higher degree of health will follow an improvement in the dietary of an individual or the food supply of a community, even where the original dietary or food supply was already adequate according to current standards. It is yet too early to say whether we should expect that improved nutrition will result in human beings of superior efficiency to any hitherto known. Until the experimental investigation has been carried further and there has been more time for observation of human experience in the light of the newer knowledge of nutrition, we may well hesitate to predict advances over the most illustrious cases of individual efficiency. We may, however, expect with entire confidence that the average of health and efficiency, and the health and efficiency of the great majority of individuals, will be greatly advanced through the application of the new
ISDCSTRIrlL A S D ENGINEERING CHEXISTRY
knowledge of foods and nutrition gained through the chemical research of recent years, and that this mill bring to a much larger proportion of all people that full measure of health and efficiency which only the mo3t fortunate now enjoy. Perhaps deserving of special emphasis is the fact that, under the guidance of our present knowledge of foods and nutrition, it is entirely feasible so to improve the utilization of the primary crops now produced as t o make them pro7Tide both better nutrition and for larger populations than at present Of course, this is not true to so great an extent in the older and more thickly populated countries as in the younger countries which are not yet thickly settled; but the difference is only one of degree Everywhere it is true that the grass and grain which are being turned into meat would yield several fold more human food if turned into milk instead. The energy and protein of the material eaten is much more economically converted into human food by the milch cow than by the animal which is fed merely for slaughter, and what is now seen uith special force is that the conservation of the vitamins and mineral elements so important to the human food supply is incomparably more efficient in the conversion of feed into milk than into meat.
This is not to suggest anything like a cessation of meat production, but only its intelligent moderation. I n a paper recently read before the British Association for the Advance ment of Science, this resource is recognized, but in what seems to be too reluctant and pessimistic a way. As reported in the daily press, the English speaker linked this suggestion with that of the saving of the waste now incurred in the use of grain to produce alcoholic beverages and added: “I feel that the race, noi the individuals, which cuts our meat and alcohol in order to multiply is of a permanent slave type, destined to function like worker bees in the ultimate community.” But is the drone a higher ensample than the worker? And as to slavery, might it not be a t least equally logical to hold that a people who would deny existence to descendants yet unborn rather than moderate the consumption of alcohol and meat are perhaps making themselves slaves to their palates? Is there not more to commend the more optimistic view that as people come to understand the possibilities opened by our present knowledge of foods and nutrition they will find satisfaction in acting upon them, both for their own and for the public good?
The Present and the Future of the Food Supply’ By E. B. Forbes INSTITUTB OF ANIXALNUTRITION, PENNSYLVANIA STATE COLLEGE, STATE COLLEGE, PA.
OOD is the most urgent requirement of life, and the food supply the basic problem of Civilization. From our American point of view, one aspect or another of the food problem has been to the fore, in our public consciousness, from the first winters spent by our European ancestors on this side of the Atlantic to the winter just past, in which the economic status of the food producer was one of the most insistent problems before Congress. Especially during the last quarter-century has our attention been called to matters of food and nutrition. Greatly stimulated by the revelation of conditions within the food industries which led in 1906 t o the passage of the national pure food law, our interest has grown apace through a revolution in our understanding of the principles of nutrition, through vast extension of mass production, marketing, manufacture, preservation, and transportation of foods, and particularly through the prominence recently given the subject of food in war, and of “a place in the sun”-that is, a place to produce food, as a cause of war. It will be readily understood that the food problem is in reality two-one having to do with kinds of foods, and the other with amounts.
Qualitative Aspect of Food Problem
I n a critical sense there are no essential foods. Only specific nutrient constituents of foods are essential. I n dietary terms, therefore, there are many roads to correct nutrition; in d ~ i c hsense, in spite of the differing food customs of the peoples of the world, the food problem is fundamentally and universally but one and the same. I n this light x e have come to understand that, from the point of view of the natural selective determination of nutritive requirements, during the evolution of the human 1 Presented a t the Round Table Conference on “The Role of Chemistry in the World’s Future Affairs,” at the Sixth Session of the Institute of Politics, XVilliamstown, l f a s s . , August 18, 1926.
species, the most important changes which man has made in his diet have been, first, the cooking of his food, and second, since yesterday he became a farmer, the adoption of cereals and cereal foods (including sugar) as the foundation of his ration. These two innovations have been prominent factors in the development of civilization, but have brought in their train a group of physical afflictions comprising the great qualitative food problem. We know something of the effects of cooking, both desirable and undesirable-to make foods easier to masticate; to make foods more palatable; to make some foods more digestible; to sterilize foods; but also to reduce the vitamin contents of foods; to develop in many foods a pasty condition resulting in adherence to the teeth, and the development of injurious acid fermentations on the teeth. Honeever, in spite of some important contributions, comparatively little scientific study has been given this problem of fundamental effects of cooking. A great flood of new scientific evidence, however, has shown in detail the nutritive deficiencies of the cereals and cereal foods, and has shown, especially in view of their quantitative predominance, that they constitute a distinctly disturbing and unbalancing element of the diet of most, a t least, of civilized mankind. Milk, meats, nuts, eggs, fruits, and leafy vegetables are each notable as contributing factors of safety-of nutritional insurance-to the diet. Some authorities on nutrition do not list meats with the protective foods, but the recent evidence on the protein values of foods, and on their effectiveness to support reproduction, lactation, and blood regeneration, requires that we consider meats, especially the glandular organs, as characterized by important protective qualifications. The common deficiencies of cereal foods-possessed by individual products, of course, in varying degree-are especially in mineral nutrients, vitamins, and the quality of the proteins. Sugar is characterized by all these deficiencies,