XIV. NUTRITION PROBLEMS OF THE SOUTH W. D. SAI.MON, ALABAMAPOLYTBCHNIC I N S T I XAWURN, ~, ALABAMA
The nutrition of an animal is reflected in its physical condition. Hence, to ascertain the nutrition problems in a given region it is necessary to know something of the physical condition of the people and their domestic animals. Among the questions that arise in the evaluation of this condition are: What specific deficiency syndromes are peculiar to the region? How prevalent is general malnutrition? Are there indications of a lack of resistance to infections? Are there marked abnormalities of bones or teeth? Is there normal reproduction and rearing of young and do the young grow to the full extent of their hereditary capacity? Then logically follows the query, what factors of climate, soil, dietary habits, or parasitic enemies have either a direct or an indirect relation to the conditions found? These questions should form the basis of our research programs. The writer is aware of only one nutritional disease that may be considered as peculiar to the South; this is pellagra. There were approximately 7400 deaths in the United States in 1928 which were registered as due to pellagra. Only 227 of these were outside the strictly southern states with 53 of this number in California and 12 in Arizona (1). Convincing evidence has not yet been presented that the diet of any class of people in the South is significantlypoorer than that of people representing a comparable economic level in any other section of the country. The determination of the basic factors underlying this regional distribution of pellagra are an unanswered challenge. The available data show that the prevalence of other conditions that may be attributed in part at least to nutritional causes indicate that many dietaries of the South are far from optimum. They do not in general indicate any worse conditions, however, than are found throughout the nation. Studies made in Mississippi (2) show that 30-35 per cent of the groups of rural children examined were underweight, 45-50 per cent had decayed teeth, 57-67 per cent had infected tonsils, and 12-27 per cent showed marked evidence of rickets. Studies in Virginia (3) of 462 white school children show that 85 per cent had defective teeth; the same study shows only 60 per cent with decayed teeth in a group of 323 negro school children. A study of over 5000 negro school children in Atlanta, Georgia ( 4 ) , shows45 per cent in a good state of nutrition as ,judged by clinical evidence; 35 per cent were in a fair state; 2336
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and 20 per cent in a very poor state of nutrition. Two bony evidences of rickets were found in 12 per cent of the children. Enlarged or diseased tonsils were evident in 32 per cent, conjunctivitis in 15 per cent, and defective teethiu 68 per cent of these children; only 35 per cent had teeth that were classed as distinctly "poor." Other studies in this region are in agreement with the data cited. It is apparent that these clinical examinations on the whole do not show findings that are radically different from those conducted in other parts of the country. A summary prepared by Leete in 1921 from statistics on health examinations of 20,000,000 school children in the United States shows 15-25 per cent of malnutrition and 50-75 per cent of defective teeth (5). Of 6000 children examined in a Boston clinic only 11 per cent had perfect teeth (6). The health studies mentioned above emphasize the need for further investigation of the underlying causes of many subnormal conditions of health that are prevalent in the South. Of these perhaps pellagra is the most baffling; while a beginning has been made on this problem, it is only a beginning; its entire solution is not yet in sight. We must also learn more about the causes of decayed teeth, of diseased tonsils, of conjunctivitis, of the various anemias; even the common cold and certain forms of chronic digestive disorders may be included in this category. There is apparently a distinct relationship between these conditions and nutrition. Some of them probably are merely expressions of latent deficiency diseases; others may he the result of secondary infections imposed upon dietary deficiencies of various kinds. The nutrition problems involved in these conditions must be approached through studies on the separate constituents of the diet and the relation of each separate constituent to the diet as a whole. Vitamin Problems It is in the field of vitamin research that the answers to many of our nutrition problems may be found. The relation of diet to such conditions as pellagra, defective teeth, diseased tonsils, and some forms of enteritis may in many cases depend upon the vitamin content of the diet. The exact relationships of the vitamins to such conditions should be determined. It is the opinion of the writer that the most important problems in the field of vitamin research a t the present time are those dealing with: (1) the further resolution of various vitamin-containing fractions into their ultimate active constituents and (2) the determination as far as possible of the chemical niture and the physiologic functions of these constituents. Happily, actual isolation of the pure substances is not an essential prerequisite to many studies of physiologic functions or of pathologic conditions arising from a lack of the known vitamins. Such studies must at present be considered as valuable chiefly in furnishing a basis for
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further work rather than as a basis for final conclusions regarding the nature or action of the pure substances. A most promising phase of this field is a study of the relation of vitamin deficiencies to infectiou. Many cases of lowered resistance to infections of various natures through lack of certain vitamins are reported in the literature (7). There is a general agreement that lack of vitamin A increases susceptibility to infectiou. Jackson and associates (8) presented evidence that lack of vita& C may also decrease resistance to infectiou. More recent work in the writer's laboratory (9) has shown an apparent association of infection with lack of the vitamin G fraction. Matsumura and co-workers ( l o ) ,moreover, have recently concluded that beriberi is an infectious disease in which a dietary deficiency is merely a predisposing factor. The correct evaluation of these findings must await the accumulation of further data. These infections may be purely secondary invaders of damaged tissues and non-pathogenic even to animals weakened by nutritional disturbances; on the other hand, they may markedly alter the ultimate pathologic picture. It is well that as students of nutrition we do not disregard the possible relation of infectious agents to any of the so-called deficiency diseases. Let us give due consideration to every factor that may have even possible influence upon these conditions. There is no unanimity of opinion regarding the factors causing tooth decay. It is logical to expect that vitamin D has a profound influence upon the structure and chemical composition of the teeth. This has been proved to be true. Howe (11) believes, however, that vitamin C has an important relation to quality of teeth, a t least in the guinea pig. It seems probable that several dietary factors have a direct influence upon tooth formation. The relative importance of these various factors should be determined. McCollum has recently emphasized that the only prospect of relief from the present deplorable condition of teeth in America is through increased attention to nutrition during growth, including the prenatal period. Active rickets is a less serious problem in the South than in some parts of the country. It is entirely too prevalent when our long periods of intense sunshine are considered. Studies of the importance of factors other than vitamin D in the prevention of rickets are essential to a complete understanding of rickets in this region. Further investigations of the vitamin content of the foods and feedstuffs produced in this region are of importance. The early tests on the distribution of vitamin B need correcting in the light of the more recent fractionation of the old vitamin B group into vitamins B and G. Before these tests can be conducted, the development of suitable methods is essential. These methods should give proper consideration to the fact that vitamin G is probably complex in nature and that the growth-pro-
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moting properties of this vitamin fraction cannot arbitrarily he taken as a measure of its pellagra-preventive properties. All studies of the vitamin content of any material should as far as possible take into consideration the conditions under which the given substance was produced. I t is far more important to determine the factors that may affect the vitamin content of a food, than merely to determine the vitamin content of a number of samples of this food selected a t random. The effect of soil, fertilizers, season, stage of maturity, and methods of curing, storing, or cooking upon the vitamin content of foods has not been sufficiently studied. I t would be of tremendous interest to know if the low organic matter content of our southern soils tends to produce plants that contain subnormal amounts of water-soluble vitamins. A study of the effect of genetic factors upon the vitamin content of plants may likewise prove of importance in determining whether there is a possibility of increasing the vitamin content of certain plants by selection and breeding methods. The effect of the ration upon the vitamin content of animal products deserves more attention. While the commercial dairymen in this region feed rations that are fair in quality, the average family herd of one to three or four cows is usually very poorly fed; in some cases the sole ration is cottonseed meal and cottonseed hulls in addition to what the cow can gather from so-called pastures; and these pastures are frequently so poor in quality that their contribution to the ration is almost negligible. The quality of the milk produced by such cows should be investigated, for upon the milk from these family herds depends in no small measure the health of a significant portion of our rural population. Mineral Problems The South represents largely a region of soils which are relatively low in soluble bases, particularly calcium, and rather low in readily available phosphorus. Probably the most important mineral problem is the determination whether these properties of the soil are reflected in the inorganic content of the food plants. The available data indicate that such a relationship may exist for calcium and phosphorus (12). That it is similar for iodine is suggested by the high incidence of goiter in regions where the soil contains an insufficiency of this element. If the plants produced in this region fail to supply sufficient inorganic constituents for normal development of animals, suitable sources of the necessary elements must be determined. The relation of the many inorganic elements to growth, bone formation, tooth structure, and lactation offers an almost unlimited field for research. The function of copper and manganese has only recently been recognized. Other rare elements may play
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an important but yet unrecognized r81e in the nutrition of animals as well as of plants. Protein Problems Perhaps the most important protein problems in this region center around studies of the properties and more eflicieut utilization of the protein concentrate, cottonseed meal. Many of the early studies on these problems were conducted before the need for vitamins and minerals was recognized. As a result harmful effects were sometimes ascribed to cottonseed meal, which were in reality deficiencies. Various stations are again undertaking a study of these problems with indications of results much more favorable to cottonseed meal than were formerly obtained. Particular attention is being given to the use of this product in rations for poultry, swine, and young calves. At some stations these studies also include work on soybean meal and peanut meal, although these are available in very limited quantities. Another important problem for study is the nutritive value of legume hays that may be produced on the sandy soils of this region. Many of the leguminous plants cannot be economically grown here. Soybeans, cowpeas, vetch, and kudzu are the most promising. The nutritive value of kudzu particularly should be studied. Selection of Problems I t should be apparent that there is no difficulty in finding problems; the real difficultyarises in determining what is the most important problem to attack. Too frequently the pressure for information is so great that the investigator undertakes too many projects; as a result a study of the basic principles involved in any of the problems is impossible. Research in nutrition is complicated by numerous factors; many of the problems require the cooperation of the biochemist, the physiologist, the pathologist, and the bacteriologist. The activities of these should be centered around a major research project rather than dissipated over a large number of projects. Fortunately, there is an increasing tendency toward such specialization at some of the southern stations. Translating Results of Research into Practice The nutrition problems of the South are by no means research problems entirely. The general adoption of dietary practices that can be recommended in the light of our present knowledge would result in phenomenal improvement in the physical development and health of large masses of people not only in the South but in other parts of the country as well. The modification of dietary habits is a task that is not easily accomplished. Custom, prejudices, economic status, and level of intelligence present
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obstacles t h a t are almost insurmountable. A prolonged program of evolutionary education will be required for achievement of the ultimate object of our research, a n adequately nourished population.
Literature Cited (I) Supplement No. 79, Public Health Reports, U. S. P. H. S., p. 34, 1930. (2) DICEINS, Miss. Sta. Bull. No. 245 (1927). (3) REYNOLDS, Va. Sta. Bull. No. 250 (1926). ( 4 ) STERLING, Public Health Reports, U.S. P. H. S., 43,2713 (1928). (5) LEETE, Mother and Child, 2, 358 (1921). (6) COWAN, Cited by Reynolds in reference 3. (7) McCo~~una and S ~ ~ O N "Newer D S , Knowledge of Nutrition," 4th edition, p. 492, 1929. and MOODY. J. Infect. Dis., 19, 511 (1916). JACKSON and MOORE, (8) JACKSON I6id.. 19, 478 (1916). (9) SALMON, HAYS,and GWRRANT, Ibid., 43,426 (1928). (10) M A T S U ~ RctAal., , Am. Med. Assoc., 92, 1325 (1929). (11) Horn, J. Dental Research, 3.7 (1921); J. Am. Med. Assoc., 79,1565 (1922). et al.. J. Dept. Agr., Union South Africa, May, 1924; GRBAVBS (12) T~EILBR, and HmsT, Utah Sta. Bull.No. 210 (1929); HART,ct al., Wis. Sta. Bull. No. 389 (1927).
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