Nutrition: prospects for the 1990s.

ANNUAL REVIEWS

Further

Quick links to online content Annu. Rev. Public Health.

Annu. Rev. Public Health 1990.11:53-68. Downloaded from www.annualreviews.org by University of Texas Southwestern Medical Center on 01/23/15. For personal use only.

Copyright © 1990

1990. 11:53--68

by Annual Reviews Inc. All rights reserved

NUTRITION: PROSPECTS FOR THE 1990s Nevin S. Scrimshaw United Nations University, Food and Nutrition Program Office, Harvard Center for Population Studies, Cambridge, Massachusetts 02138

INTRODUCTION There are two main kinds of malnutrition, one associated with absolute or relative nutritional deficiencies and the other resulting from dietary excesses. As a result of advances in knowledge, prospects for nutrition in the 1990s appear quite different from those in past decades for both kinds of malnutri tion. After years of controversy, a remarkable degree of consensus has developed regarding the kind of nutritional goals most likely to' promote good health. Concurrently, focus on a child survival and development strategy within a broader concern for implementing the 1978 WHO Alma Ata Meeting concept of nutrition and primary health care has been having a remarkable degree of success in a growing number of countries. These developments are giving new hope that the World Health Organization (WHO) goal of "health for all by the year 2000" will be achieved by a large number of developing countries. This review summarizes briefly the current status of public health nutrition problems of both developing and industrialized countries and ex trapolates to developments in public health nutrition that can be anticipated in the 1990s.

NUTRITIONAL DEFICIENCY DISEASES AND THEIR CONTROL

Chronic Energy Deficiency The dietary energy intakes of the low-income populations in many developing countries presently average 10 to 20% below estimated requirements for a desired level of activity. For example,

41% of the population in a high53

0163-7525/90/0510-0053$02.00


54

SCRIMSHAW

altitude zone of Northwest Rwanda consumed less than 80% of presumed requirement levels in the hungry season (61). Nevertheless, these individuals are not dying of starvation but rather have adapted, primarily by a reduction in physical activity, although a reduction in basal metabolic rate (BMR) makes a small contribution (less than 15%) to reduced energy expenditure (3). The potential consequences of energy deficiency are illustrated by the report of a 41% productivity increase when a group of calorie-restricted industrial workers in Germany during World War II were given an additional 500 calories (30). More recently, a 12.5% increase in the productivity of workers in Kenya was reported after an average of 53 days of caloric supplementation (67). Although he could not measure productivity because payment was made for a fixed amount of work rather than by the hour, Viteri (60) observed an increase in energy intake and in discretionary activities when male Guatemalan plantation workers were given food ad libitum for lunch. Research in the Philippines (M. P. De Guzman, unpublished report, 1989) showed that supplementary food for impoverished families resulted in an increase in the amount of time spent in moderate activity and in energy expenditure per unit time in some activities. For children, physical interaction with their environment is essential for normal cognitive development. Torun & Viteri (59) observed the activity patterns and growth of young children consuming 2 gm of protein per kg and dietary calories ad libitum for one month. When caloric intake was reduced by 10% for a second month, the children reduced their physical activity suf ficiently to come into energy balance in a few days and continue uninterrupted growth. When it was reduced 20% for a third month, there was some further decrease in activity, but not sufficient to prevent reduced growth as a further adaptation. In response to the need for further studies of the social and economic consequences of adaptation to chronic energy deficiency, a United Nations University workshop has developed several appropriate research designs (15) and convened the first of a series of the International Dietary Energy Con sultative Group (lDECG) workshops to analyze and report available informa tion (47). IDECG in the 1990s will promote additional research on the significance of chronic energy deficiency, will develop further scientific and policy reports on the problem, and will identify and promote practical means of corrective action (Secretariat address: P.O. Box 501, Lausanne, Switzer land). Iron Deficiency In the majority of developing countries, iron deficiency is found in one third to two thirds of the population, and it is the most common single nutrient deficiency in the world today. Moreover, its consequences are multiple and

NUTRITION FOR THE 1990s

55

serious for the individuals affected. The first stage of iron deficiency is the


loss of storage iron, indicated by low serum ferritin values. Next is a decrease in circulating iron, identified by a decrease in serum iron and a rise in iron-binding capacity, expressed as a ratio between the two, the transferrin saturation. The development of anemia due to insufficient iron for hemoglo bin synthesis was formerly the only recognized consequence of iron de ficiency. Over the past two decades, however, information has gradually accumulated confirming that iron deficiency, even when it is not severe enough to cause anemia, can reduce resistance to infection, lower work capacity, and, where it can be measured, decrease work productivity. In addition, behavioral studies show that infants, preschool children, and school children who are iron deficient may have impaired performance on cognitive and behavioral tests. Pollitt et al (43) demonstrated both in Cambridge, Massachusetts and Guatemala that �he observed effects were rapidly revers ible with iron supplementation in mild to moderate anemia and also in iron deficiency too mild to cause anemia. For children with moderate to severe anemia in Guatemala, however, the effect was usually not reversible within the 11-12 weeks of the study. These findings were confirmed in Egypt and Indonesia

(44) for both preschool and school children and in Costa Rica (31a)

and Chile (62a) for infants. One of the most important benefits of correcting iron deficiency is de creased morbidity from infectious disease in popUlations with a high in cidence of infectious disease (2, 23, 24). Experimentally, it can be demon strated that iron deficiency interferes with the killing power of phagocytes, decreases T-cells and killer T-cell activity, complement formation, and de lays cutaneous hypersensitivity

(50). Impaired antibody formation has also

been described in iron-deficient rats (39), but not in human populations. It still is not clear which of the mechanisms of cell-mediated and nonspecific immunity is of greatest significance in the increased susceptibility of human populations to infection. The 1990s should see substantial progress in un derstanding the mechanisms whereby iron-deficient individuals are less resis tant to infection and in implementing programs to prevent iron deficiency.

Iodine Deficiency Disorders Endemic goiter occurs wherever populations depend on local food supplies grown on iodine-poor soil. Under these circumstances, the thyroid gland enlarges and becomes more efficient in removing iodine from the blood stream. Iodine-poor soils are found in mountainous and glaciated areas and hence are global in distribution. In endemic areas, some pregnant women are unable to compensate sufficiently for iodine lack and give birth to cretins feeble-minded dwarfs who are often deaf mutes.


56

SCRIMSHAW

It was suggested in the 1920s that endemic goiter was associated with an increase in hearing impairment even without cretinism. Not until more recent studies in Ecuador (56) and China (32), however, was it fully recognized that in endemic goiter areas there is a range of disorders from mild degrees of mental and/or hearing impairment to cretinism, and that an appropriate term would be Iodine Deficiency Disorders (IDD) (32). The result may even be an adaptation of the social structure of a community to accept affected in dividuals as normal (18). An International Committee on Iodine Deficiency Disorders (ICIDD) has been formed in cooperation with WHO to promote the elimination of IDD in those countries in which it is a public health problem (Secretariat: CSIRO, Adelaide, Australia). These include a number of countries in the Andean region of South America, the Asian subcontinent, the mountainous regions of Indonesia, and the countries of Central Asia, among others (20, 49). The most effective means of preventing IDD is the addition of iodine to all salt for human consumption. The compound of choice is potassium iodate because it is stable even in crude, moist, unpackaged salt. When iodated salt is in troduced into a country, endemic goiter disappears as a public health problem in one or two years (45, 48) and with it the risk of other sequelae of IDD. For isolated, hard-to-reach areas that are difficult to provide with iodized salt, a large intramuscular dose of iodine in oil will provide protection for several years (56). Preliminary studies indicate that similar oral doses may also be effective.

A vitaminosis A Vitamin A deficiency is a serious concern, particularly for many Asian countries, because it can lead to permanent blindness. Although in early stages, Bitot's spots and xerophthalmia are reversible with vitamin A therapy, once the cornea has softened and necrosed (keratomalacia), impairment of vision is permanent. It is most often seen in children suffering from severe protein malnutrition as well as low vitamin A intake who often have superim posed infections. Because of the difficulty of preventing vitamin A deficiency through dietary change, despite the vitamin A activity of green and yellow vegetables, WHO and UNICEF as well as some bilateral and private voluntary agencies are supporting the administration of a large oral dose (200,000 LU.) of vitamin A palmitate every six months to children from six months to two years of age in populations at risk (64). This is the weaning period in most societies and the time of greatest risk of eye damage. Since measles is particularly likely to precipitate eye lesions in children whose vitamin A status is borderline (65), measles immunization is another important preventive measure.



57

In a massive dose administration program in Indonesia, lower morbidity and mortality from infectious disease was noted in participating villages compared to others without the program (58). In Guatemala, an age-specific drop in mortality was noted after a nationwide fortification of sugar with vitamin A palmitate (37). This has given added impetus to the campaign to eliminate vitamin A deficiency in child populations in which it is still a problem, and has stimulated a number of studies to determine the effects on morbidity and mortality of vitamin A supplementation in other populations (57, 65). If the WHO/UNICEF vitamin A administration and immunization programs continue to be successful and can be extended to all countries in which vitamin A deficiency is a problem, this disorder should be eliminated in most countries early in the 1990s. The International Vitamin A Consultative Group (IVACG) is playing a valuable role in this effort (Secretariat: The Nutrition Foundation, Washington, D.C. 20006). Protein-Calorie Malnutrition in Children Until relatively recently, a review on protein-calorie malnutrition in children would have given considerable emphasis to the global occurrence of Kwashiorkor in young children and the importance of preventive measures. There has been sufficient social and economic improvement in Asia and Latin America for this condition to have become relatively uncommon. In many African countries, however, a combination of drought, civil war, and other political factors have caused it to recur. Although conditions remain desperate in some of these countries, in most kwashiorkor can be expected to decrease in importance or disappear in the 1990s. Marasmus has been a serious problem among refugees in the 1980s and will continue to occur whenever early weaning and insufficient knowledge and resources result in an in adequate replacement of breast milk. Nonetheless, marasmus has also de creased markedly in recent decades and should cease to be a serious public health problem in the 1990s, except where political and economic chaos persist. Despite the gradual disappearance of these severe forms of protein-energy deficiency (PEM), retarded physical growth and development with mild to moderate PEM continue to affect a majority of young children in developing countries. The problem does not lie in reduced body size per se but in the correlation of growth retardation with increased morbidity and mortality from infectious disease and adverse effects on learning and behavior. Pioneering studies of Cravioto et al (12) in Mexico showed an impairment in intersensory integration among children in the lower quartiles for weight and height-for age in one Mexican village but not among children in more affluent groups. This finding has since been confirmed in many different underprivileged populations (7).


58

SCRIMSHAW

The other consequence is that retarded growth occurring in the weaning period is not made up, and these children become small adults. There is no doubt that persons who have been stunted in childhood and survive to adulthood can work very hard and develop endurance, but they are still at a disadvantage in the performance of manual labor. In Guatemala, the physical capacity of stunted individuals has been found to be less as judged by both treadmill performance and field observations of sugar cane cutting (16). Similar findings have been reported from Colombia (55), Brazil (14), and India (46). NUTRITION AND INFECTION Any infection worsens nutritional status and most nutritional deficiencies are capable of increasing susceptibility to infection. The interactions between malnutrition and infection in human populations are synergistic because the combined result may be greater than would occur from either alone (53). Infections, even as mild as immunization with attenuated virus strains, result in reduced food intake due to anorexia and increased metabolic losses of nitrogen, vitamin A, ascorbic acid, and other vitamins and minerals (4). The internal diversion of essential nutrients in response to infection for the synthesis of a wide variety of metabolites adds significantly to the depletion from an episode of infection and to the need for extra retention of nutrients during the recovery period. Repeated episodes of infection not only impair growth and development of young children (34, 35, 38), but also are the precipitating cause of nutritional deficiency diseases in individuals already in borderline status for the specific nutrient involved (53). It follows that any reduction in infection contributes to improved nutritional status. The coverage achieved by programs of immunization, environmental sanitation, and im proved personal hygiene to reduce infections will continue to increase im portantly in the 1990s. There are a variety of mechanisms of biological resistance to infections, and each of these may be impaired by nutritional deficiency under some circumstances. These include maintenance of epithelial and mucosal integri ty, humeral and secretory antibodies, delayed cutaneous hypersensitivity, phagocytic function, complement activity, lysozymes, and other nonspecific resistance factors. Mortality from infectious diseases fell dramatically with improvements in nutrition in Europe in the last century (36). Similarly, mortality decreases in developing country populations after nutritional im provement. The extensive evidence for the decrease in resistance to infection with most kinds of nutritional deficiency has been extensively reviewed (9, 53), and some of the evidence for the effects of iron and vitamin A deficiency was described above. The continuing nutritional improvement in developing


59


country populations in the 1990s will contribute significantly to falling mortality rates, particularly for infants and preschool children. Nutrition and AIDS It is not possible to provide up-to-date figures for HIV infection and AIDS in Africa because the figures are changing so rapidly. Unpublished infonnation supplied by WHO (1989) indicates 20% HIV positive for women in antenatal clinics in Kampala, 8.7% in Lusaka, Zambia, and 30% for a general popula tion survey in Rwanda. The number of HIV-infected mothers in Africa is estimated to exceed one million, with transmission rates to their offspring ranging from 12 to 65% in five cohort studies. HIV-infected infants usually die of AIDS in the first year, and the problem will be compounded by the early deaths of HIV-infected mothers. The impact on the young adult working population will be catastrophic and is bound to be reflected in agricultural and other economic activities, to the detriment of the overall nutritional and health status of heavily infected populations. NUTRITION AND CHRONIC DISEASE Diet plays a significant role in six of the ten leading causes of death in the United States, including cardiovascular disease, cancer, cerebrovascular dis ease, diabetes mellitus, and atherosclerosis. The relationships between nutri tion and infections, including respiratory diseases that are also among the top ten causes of death, have been described above. Heart Disease An overwhelming body of evidence associates the incidence of coronary heart disease with elevated serum cholesterol and low-density lipoprotein. The latter are strongly influenced by the amount and kind of fat in the usual diet. The evidence has now become so strong for this relationship between diet and heart disease (11) that emphasis in the 1990s will be on the accurate dis semination of information and promotion of a favorable change in dietary habits. Hypertension Hypertension is of concern because it is such an important risk factor for coronary heart disease and stroke (11). From 15 to 20% of a population will have high blood pressure with sodium intakes equivalent to 5-10 g of salt, with an increasing proportion of individuals affected as sodium intake in creases further. A comparison of mean population blood pressures in 27 populations has provided convincing evidence of this (33). In Europe and the United States, the relatively large amount of salt added to processed food is a


60

SCRIMSHAW

serious concern (26). In Asia, the sodium intake from soy sauce, monosodium glutamate, and sea food and vegetables preserved with salt is a serious factor. The 1990s should see increasing recognition of the hazards of excessive salt intake and an overall reduction in the sodium content of commercially pro cessed foods. Other significant risk factors for hypertension are the amount of fat, particularly saturated fat (25), and obesity (28). For most persons with mild to moderate hypertension, a reduction in salt and saturated fat intake combined with exercise and weight reduction, if indicated, is sufficient to return blood pressure to normal levels. There is already an increasingly effective national campaign in the United States for detection of hypertension. What is required for the 1990s is a linkage of this effort in the US with diet modification and exercise as the first recourse in the management of hypertension. Type II Diabetes The only dietary factor consistently related to the prevalence of type II diabetes is total caloric intake and associated obesity (63). Diabetes trends and prevalence rates in the 1990s will depend, therefore, on the success of ongoing efforts to reduce the amount of obesity among populations in which it is a significant health problem. Cancer As other causes of death have been reduced, cancer mortality has increased in both absolute and relative importance, and the search for preventable factors contributing to it has intensified. One result has been growing evidence that dietary factors influence positively or negatively the occurrence of some forms of cancer. For example, societies with a high intake of smoked and salted foods have a higher prevalence of cancer of the esophagus and stomach (10). Excessive alcohol intake is associated with stomach cancer and possibly also with liver cancer. The incidence of breast and colon cancer is low among Japanese consuming a traditional diet, but much higher in ethnic Japanese living in California (8). The principal differences identified were in the amount of animal fat and dairy products consumed (8). This was also true for differences in breast cancer rates among different ethnic groups in Hawaii (29). Quite apart from its role as a precursor of retinol, beta-carotene and other carotenoids may have a further role in preventive health (31). The blood level of carotenoids is primarily regulated by the amount ingested, whereas that of retinol remains remarkably constant because its level is limited by the amount of retinol-binding protein. Carotenoids are linked with vitamin E and ascorbic acid in their ability to quench free radicals and their oxidative products that adversely affect the proliferation of both B- and T-Iymphocytes. There is evidence that these compounds can enhance several aspects of


NUTRITION FOR THE

1990s

61

immune function, including macrophages, cytotoxic T-lymphocytes, and natural killer cells, linked to tumor cell destruction (5). At least 13 human intervention studies with over 100,000 participants are under way to test the potential chemopreventive action of beta-carotene on various kinds of can cers, but it will take another decade to obtain definitive results (31). The evidence for a favorable effect of dietary fiber on cancer of the gastrointestinal tract is less convincing, particularly since diets low in fiber are also apt to be low in vitamins A, E, and C that are thought to be important for reducing the risk of cancer (19). Research on diet and cancer is at least a decade behind that for diet and heart disease, and the 1990s are likely to see a firming of evidence for several different diet and cancer interactions. This will lead to increased efforts at diet modification, particularly a lowering of saturated fat intake and an increase in green and yellow vegetable consump tion, to reduce cancer risk. Perhapse there will be evidence of a reduction in incidence similar to that observed for heart disease in the United States in the past decade (13). Smoking Interactions Despite the fact that smoking is a greater risk factor than dietary fat for the development of coronary heart disease and several types of cancer, it has not been customary to include it in discussions of the effect of diet. A recent study in Scotsmen, however, suggests that smoking affects dietary intakes in ways that add to their adverse effects. The smokers consumed substantially less polyunsaturated fat and fiber and had a much less favorable saturated-to polyunsaturated fatty acid ratio in their diets (42). Smokers have also been reported to add nearly twice as much salt to their food, suggesting that smoking influences taste (17). Dental Caries The reduction in dental caries wherever water supplies have been fluoridated, bolstered by fluoridated toothpaste and topical fluoride applications, is an outstanding success story (40). Nonetheless, fluoridation is far from univer sal, primarily because of misguided local opposition. The 1990s will see a continued slow increase in the proportion of children receiving protection and a resulting further fall in dental caries. NUTRITION AND THE ELDERLY Although the elderly are generally at increased risk of nutritional deficiency in both industrialized and developing countries, this risk varies greatly with geographic and socioeconomic group as well as with individual circum stances. Although physiological changes occur over time, chronological age is a relatively poor predictor of an individual's physiologic status. Many other


62

SCRIMSHAW

factors also affect the health of the elderly, including physical and mental illness or disability, social isolation, bereavement, and the correlates of poverty. A major determinant of the health of the elderly is nutrition, both past and current. As discussed above, dietary habits strongly influence the occurrence of chronic diseases associated with the aging process, including heart disease, hypertension, and various kinds of cancer. A diet adequate in calcium prior to and during puberty is essential for adequate bone density. Adequate calcium intake during this period and throughout life is important for the prevention of osteoporosis in the elderly. The growing recognition of the role of diet in the prevention of disease will result in further improvements in the health and longevity of the elderly. Much of what is currently being written about geriatric nutrition is still largely extrapolation of the knowledge gained from studies of younger age groups. The importance of attention to diet for maintenance of health in the elderly is only beginning to be appreciated. Failure of elderly persons to consume an adequate diet because they are poor, depressed, crippled, or frightened, or because they fail to receive sufficient stimulation to eat is a greater threat to morbidity and mortality than the aging process per se. The appearance of at least four books on nutrition and aging in little over a decade (1, 21, 66, 68) attests to the growing recognition of this relationship. With an increasing proportion of elderly in their populations, the United States and other industrialized countries are beginning to pay more attention to the role of nutrition in maintaining the health and extending the working years of the elderly. The WHO regional office for Europe has initiated major studies of this topic (27), and developing countries are also beginning to be concerned, because they, too, are experiencing an increase in the proportion of the elderly at a time when traditional support systems are breaking down as the result of urbanization and smaller families. Latin American nutritional goals and dietary guidelines (6) devote more space to nutrition in the elderly than to any other age group. Despite all of the interest and the large number of recent publications, much of the information is not specific to the elderly and almost no reliable information is available on those aged 80 and beyond. The 1990s will see a quantum increase in nutritional studies of the elderly, in their nutritional improvement, and in the evaluation of intervention programs to benefit their nutritional and health status. NUTRITIONAL GOALS AND DIETARY GUIDELINES FOR HEALTH

A remarkable degree of consensus on nutritional goals for health now exists. By using the recommendations of the new and massive US National Research



63

Council (NRC) report (11), the WHO proposals for Europe (27), and recom mendations for Latin America (6), Australia (62), and Japan (22), other countries in these regions can be expected to develop and vigorously promote dietary guidelines adapted to the food availability and food preferences of their populations. This is occurring already in the United States and some other countries, and health benefits have already been observed. The refer ences cited give the quantitative goals on which dietary guidelines should be based. The principal difference between the two most recent comprehensive pub lished dietary goals (6, 11) is in the daily percentage of calories from fat. The US recommendations suggest 30% or less and the Latin American ones less than 25%. Both recommend a balance between polyunsaturated and saturated fat, limitation of cholesterol intake to 300 mg and salt intake to 5 g daily. Increased consumption of green and yellow vegetables as sources of vitamins and dietary fiber is recommended, as is a caloric intake that will maintain a suitable weight. More general but important recommendations include a variety of food groups as the best assurance of a good diet, the importance of physical activity for weight control and cardiovascular fitness, abstention or moderation in alcohol consumption, and total avoidance of tobacco. Fish, soybean oil, and greens furnish omega-3 methyl fatty acids or their de rivatives as essential precursors of prostaglandins and other biological regula tors. Coconut oil is to be avoided because it is largely saturated fat. The 1990s should see continuing modifications of diets and life-styles in response to national nutritional goals and dietary guidelines and further health im provements can be anticipated to result. EFFECTS OF ADVANCES IN FOOD PRODUCTION AND PROCESSING Food Production It is now well recognized that the world as a whole, and nearly all countries individually, have the capacity to produce the food they require for the foreseeable future. For all principal crops there are still large discrepancies between crop yields in the most advanced countries and those in less de veloped ones, and between the most advanced agriculturalists in developing countries and the great majority of farmers. In some cases, changing to more appropriate crops and associated technologies could make large differences in total food production. In addition, advances in biotechnology and genetic engineering will continue to shorten the time needed to develop improved plant cuitivars. The technological possibilities for adding to food supplies from aquaculture can also benefit many countries.

64

SCRIMSHAW

Processing of More Healthful Foods


Over the past several decades, plant and animal breeders have faced consider

able uncertainty and controversy over nutritional goa ls . As discussed above, there is now reasonable consensus regarding dietary goals for lipid intake. This consensus can lead to revised feeding practices of domestic animals and to selective breeding that will significantly improve the healthfulness of foods of animal origin by reducing fat content (41). Price structuring that penalizes rather than rewards breeding for high fat content will thus benefit health. More attention is also lik ely to be given to vegetable sources of beta carotene, both for their vitamin A activity and because of the growing interest in the possible protective role of carotenoids against both cancer and impaired immune function. Changes in food processing and marketing will contribute increasingly to

more healthful diets in the industrialized countries and bring benefits to the growing middle and upper income groups in the developing countries as well. The processing and marketing of dairy products has already changed. Re duced-fat milk is now outselling regular milk in the United States, and the marketing and use of low-fat and nonfat yogurts, low-fat cottage cheese, and modified butter and margarine spreads is growing steadily.

The increased use of artificial sweeteners has been much less of a health advantage. Although some may have benefited by this relatively easy way of reducing total caloric intake, the high consumption of sugar-free carbonated beverages that are also nutrient-free is not good nutritional practice. In moderation, the emphasis on products with enhanced dietary fiber can be beneficial for their contribution to the total diet, but fiber alone is not recommended. However, developments that make available fat-free nutritious

foods that would otherwise be undesirable sources of saturated fat would have positive health value. Two new products have the functional properties of fat without contributing any fat calories to diet. Simp1esse by Monsanto is made from protein of high quality (soy and egg-white) whose fat-like properties depend on its small particle size. It can replace fat in any product that is not heated, such as icecream, "whipped cream," and many cheeses. Olestra TM, developed by Proctor and Gamble, also has the properties of fat and will withstand heating. It is a non-absorbable sucrose-polyester. As discussed above, a further de crease in the percentage of calories from fat, and particularly in the amount of saturated fat consumed, will have substantial health benefits. ™

FAMINE AND HUNGER

Although drought has contributed to the recent famines in Africa, civil war, political incompetence and venality, and extreme social inequity have been



65

the real culprits (51, 54). For this reason, improvements in agricultural production, even with the assistance of modem agricultural research and the successful application of biotechnology to various aspects of agriculture, will not be enough to banish famine in the 1990s. The conquest of famine will

require satisfactory settlement of the civil wars currently raging in Ethiopia and the Sudan and political and economic reforms in these countries as well as in Mozambique and other African countries currently experiencing chronic hunger and periodic famines. The prospects for this are guarded but hopeful f or many of the countries that have experienced f amine i n the 19 80 s. The abolition of chronic hunger also req uires approp ria te political actions,

but the problems of poverty, rapid population growth, and illiteracy will make it difficult for the worst-off countries to achieve this in the 1990s. Overcom ing world h unger will require improvement of every step in the food chain, including agricultural produc tion, reduction of field losses, postharvest food conservation, improved storage and distribution, as well those measures that will give everyone an opportunity to acquire food by producing it or purchas ing it (52).

For most developing countries, satisfactory improvements in food produc tion will require not only improved agricultural research and extension ser vices but also more equitable land tenure policies, availability of rural credit for necessary agricultural inputs, fair agricultural purchase and trade policies,

and increased resources devoted to the agricultural sector. For those families not in the food production sector, policies and programs will be needed that will give them a chance to acquire food through increased employment, better wages, and, for the most vulnerable, appropriate entitlement programs.

SUMMARY AND CONCLUSIONS

For many decades there has been adequate information for the elimination of acute dietary deficiency diseases. Scurvy, beri-beri, and pellagra, once serious scourges, are now seen only rarely. The severe forms of protein energy malnutrition, kwashiorkor and marasmus, have also decreased greatly. Nonetheless, m il d to moderate forms of pro tei n e ne rg y deficiency, ex acerbated by infection, co ntin ue to im pair growth and d ev elopm ent in a -

majority of the low-income pre-school age populations of most developing co untri es. Deficiencies of iron, iodine, and vitamin A are still widespread in developing countries. Fortunately, the success of the WHO/UNICEF "Child Survival and De velopment Revolution" in persuading most developing countries to introduce exp anded programs of immunization, growth monitoring, and appropriate feeding of young children, control of diarrheal disease, and specific cam pa igns against avitaminosis A, iodine deficiency disorders, and the functional

SCRIMSHAW


66

consequences of iron deficiency, will accelerate the decline of acute de ficiency diseases in the developing world. Diets are changing among the more affluent in these countries, however, and it is time for them to stress dietary goals for the health of rich and poor alike. For the first time there is enough information regarding dietary risk factors for chronic disease to provide an opportunity in the 19908 to accelerate the dietary changes that have already brought significant health benefits to some populations in North America and Europe. The changes, which include a lower dietary intake of fat, particularly saturated fat, less salt, and more green and yellow vegetable and whole grain cereals, can be expected to influence favorably morbidity from cardiovascular diseases and some kinds of cancer. For maximum benefit, these measures need to be combined with the avoid ance of obesity, reasonable physical activity, abstention from, or moderate use of, alcohol, and avoidance of tobacco in any form. Since there is already considerable momentum toward these changes in North America and some European countries, the 1990s are likely to see substantial further progress in the reduction of chronic diseases known to be influenced by diet. Literature Cited I. Armbrecht, H. J., Prendergast, J. M. ,

2.

3.

4.

5.

6.

7.

8. 9.

Coe, R. M. 1984. Nutritional lnterven tion in the Aging Process. New York: Springer-Verlag Basta, S. S., Soekirman, Karyadi, D. , Scrimshaw, N. S. 1979. Iron deficiency anemia and the productivity of adult males in Indonesia. Am. J. Clin. Nutr. 32:916-25 Beatun, G., Taylor, L. E. 1981. The uses of energy and protein requirement estimates. Report of a workshop. Food Nutr. Bull. 3:45-53 Beisel, W. R., Sawyer, W. D., Ryll, E. D., Crozier, D. 1967. Metabolic effects of intracellular response in infections in man. Ann. Intern. Med. 67:744--79 Bendich, A. 1988. A role for carotenoids in immune function. Clin. Nutr. 7:113-22 Bengoa, J. M., Tomn, E. B. , Behar, M. , Scrimshaw, N. S. 1988. Guias de alimentacion: Bases para su desarrollo en America Latina. Guatemala. INCAP. 54 pp. Brozek, J., ed. 1977. Behavioral Effects of Energy and Protein Deficits. Wash ington, DC: US Dept. Health, Educ. Welfare, NIH Publ. No. 79-1906. 669 pp. Buell. P. J. 1973. Changing incidence of breast cancer in Japanese-American wo men. J. Natl. Cancer Inst. 51:1479--83 Chandra, R. R. , Newberne, P. M. 1977.

Nutrition, Immunity, and Infection: Mechanisms and Interactions. New York: Plenum. 246 pp. 10. Cummittee on Diet, Nutrition, and Can cer. 1982. Diet, Nutrition and Cancer. Washington, DC: Natl. Acad. Press. 496 pp. 11. Committee on Diet and Health. 1989. Diet and Health: Implications for Reducing Chronic Disease Risk. Wash ington, DC: Natl. Acad. Press. 768 pp. 12. Cravioto, J., De Licardie, E., Birch, C. 1966. Nutrition, growth and neurointe grative development: An experimental and ecologic study. Pediatrics 38:319--72 13. Dept. Health and Human Services. 1987. Monthly Vital Statist. Rep., Vol. 36, Adv. Rep. Final Mortal. Statist. 1985. Hyatt sville, Md: DHHS Publ. No. (PHS) 871120. Natl. Cent. Health Statist. , Public Health Serv., US DHHS. 48 pp. 14. Desai, I. , Waddell, D. S. , Dutra de Oliveira, J., Duarte, E., Robazzi, M. 1984. Marginal malnutrition and re duced physical work capacity of migrant adolescent boys in Southern Brazil. Am. J. Clin. Nutr. 40:135-45 15. Durnin, J. V. G. A. 1987. Investigating the biological and social consequences of chronic nutritional energy deficiency. Food Nutr. Bull. 9:49-- 6 1 16. Flores, R., Immink, M. D. C., Tomn, B. , Diaz, E., Viteri, F. E. 1985. Func tional consequences of marginal


NUTRITION FOR THE 1990s malnutrition among agricultural workers in Guatemala. Part I. Physical work capacity. Food Nutr. Bull. 6:5-11 17. Fulton, M., Thomson, M., Elton, R. A., Wood, D. A., Oliver, M. F. 1988. Cigarette smoking, social class and nutrient intake. Relevance to coronary heart disease. Lancet 1: 1243-46 18. Greene, L. S. 1977. Hyperendemic goi ter, cretinism, and social organization in highland Ecuador. In Malnutrition, Be havior, and Social Organization, L. S. Greene, ed. pp. 55-99. New York: Aca demic 19. Greenwald, P., Lanza, E. 1986. Role of dietary fiber in the prevention of cancer. In Important Advances in Oncology, ed. V. T. DeVita, S. Hellman, S. A. Rosen berg, pp. 37-54. Philadelphia: Lippin cott 20. Hetzel, B. S. 1988. The prevention and control of iodine deficiency disorders. Geneva: Nutr. Policy Discuss. Pap. No. 3. Admin. Comm. Coord., Subcomm. Nutr. 123 pp. 21. Horwitz, A., MacFadyen, D. M., Mun ro, W., Scrimshaw, N. S. , Steen, B., Williams, T. F. 1989. Nutrition in the Elderly. Geneva: WHO 22. Hosoya, N. 1985. Diet for health pro motion\ Jiruyo 67:413-17 23. Husaini, M. A. 1982. The use of forti fied salt to control vitamin A deficiency. PhD thesis. Bogor Agricultural Univ., Bogor, Indonesia 24. Hussein, M. A. , Hassan, H., Abdel Ghaffar, A. A., Salem, S. 1988. Effect of iron supplements on the occurrence of diarrhoea among children in rural Egypt. Food Nutr. Bull. 10(2):35-39 25. Iacono, J. M., Dougherty, R. M. 1987. Dietary polyunsaturated fat and blood pressure regulation. In AlN Symp. Proc. Nutrition '87, pp. 105-9. Bethesda, Md.: Am. Inst. Nutr. 26. James, W. P. T. 1987. The dominance of salt in manufactured food in the sodium intake of affluent societies. Lan cet 1 :426-29 27. James, W. P. T. 1988. Research relating to energy adaptation in Man. In Chronic Energy deficiency: Consequences and Related Issues, ed. B. Schurch, N. S. Scrimshaw, pp. 7-36. Lausanne: Nestle Found. 28. Kannell, W. B. , Brand, N., Skinner, J. J., Dawber, T. R. , McNamara, P. M. 1967. The relation of adiposity to blood pressure and development of hyperten sion. The Framingham Study. Ann. In tern. Med. 67:48-59 29. Kolonel, L. N., Hankin, J. H., Lee, J., Chu, S. Y., Nomura, A. M., Hinds, M.

67

W. 1981. Nutrient intakes in relation to cancer incidence in Hawaii. Br. 1. Can cer 44:332-39 30. Kraut, H. A., Juller, E. A. 1946. Calo rie intake and industrial output. Science 104:495-97 31. Krinsky, N. I. 1988. The evidence for the role of carotenes in preventive health. Clin. Nutr. 7:113-17 31a. Lozoff, B. 1989. Methodologic issues in studying behavioral effects of infant iron-deficiency anemia. Am. J. Clin. Nutr. 50:641-54 32. Ma, T., Lu, T., Tan, Y., Chen, B., Zhu, X. 1982. The present status of endemic goitre and endemic cretinism in China. Food Nutr. Bull 4:13-19 33. MacGregor, G. A. 1985. Sodium is more important than calcium in essen tial hypertension. Hypertension 8:62840 34. Martorell, R. , Habicht, I.-P., Yarbor ough, C. , Lechtig, A., Klein, R. E., Western, K. A. 1975. Acute morbidity and physical growth in rural Guatemalan children. Am. J. Dis. Child. 129:12961301 35. Mata, L. J. 1978. The Children of Santa Maria Cauque: A Prospective Study of Health and Growth. Cambridge, Mass: MIT Press. 395 pp. 36. McKeown, T. 1976. The Modern Rise of Population. New York: Academic. 168 pp. 37. Mejia, L. A., Arroyave, G. 1982. The effect of vitamin A fortification of sugar on iron metabolism in preschool children in Guatemala. Am. J. Clin. Nutr. 366:87-93 38. Morley, D. , Woodland, M. 1979. See How They Grow: Monitoring Child Growth for Appropriate Health Care in Developing Countries. LondoniBas ingstoke: MacMillan. 265 pp. 39. Nalder, B. N. , Mahoney, A. W. , Ramakrishnan, R. , Hendrics, D. G. 1972. Sensitivity of the immunological response to the nutritional status of rats. J. Nutr. 101:535-42 40. Natl. Inst. of Dental Res. 1981. The prevalence of Dental Caries in Uni ted States children: 1979-80. US Dept Health Human Services Pub!. 22-2245 41. Natl. Res. Council. 1988. Designing Foods, Animal product Options in the Marketplace. Washington, DC: Natl. Acad. Press. 324 pp. 42. Oliver, M. F. 1989. Cigarette smoking, polyunsaturated fats, linoleic acid, and coronary heart disease. Lancet 1:124146 43. Pollitt, E. , Viteri, F. E., Saco-Pollitt,


68

SCRIMSHAW

C., Leibel, R. L. 1982. Behavioral effects of iron deficiency anemia in chil dren. In Iron Deficiency: Brain Bio chemistry and Behavior, ed. E. Pollitt, R. L. Leibel, pp. 195-208. New York: Raven 44. Pollitt, E., Soemantri, A. G., Yunis, F., Scrimshaw, N. S. 1985. Cognitive effects of iron-deficiency anemia. Letter to the Editor. Lancel 1;58 45. Rueda-Williamson, R., Tellez, F. P., Hoyos, F. P. M. J. A., Naranjo, L. U. 1966. La efectividad de la yodacion de la sal en la prevencion del bocio enedmi co en Colombia. Arch. Lalionamer. Nutr. 16:65-88 46. Satyanarayana, K., Naidu, A. N., Chat terjee, B., Rao, B. N. 1977. Body size and work output. Am. 1. Clin. Nutr. 30:322-25 47. Schurch, B., Scrimshaw, N. S., eds. 1987. Chronic Energy Deficiency: Con sequences and Related Issues. Lau sanne: Nestle Found. 201 pp. 48. Scrimshaw, N. S., Ascoli, W. 1960. Endemic goiter in Latin America. Public Health Rep. 75:731-37 49. Scrimshaw, N. S. 1964. The geographic distribution of thyroid disease. In The Thyroid, ed. J. J. Hazard, D. E. Smith, pp. 100-22. Baltimore: Williams & Wil k in s 50. Scrimshaw, N. S. 1984. Functional con sequences of iron deficiency in human populations. J. Nutr. Sci. Vitaminol. 3 0: 47-63 51. Scrimshaw, N. S. 1987. The phenom enon of famine. Annu. Rev. Nutr. 7:121 52. Scrimshaw, N. S. 19 89. Completing the Food Chain: From Production to Con sumption, ed. P. M. Hirchoff, N. G. Kotler, pp. 1-17. Washington, DC! London: Smithsonian Inst. 53. Scrimshaw, N. S., Taylor, C. E., Gor don, J. E. 1968. Interactions of Nutri tion and lrifection. 57. Geneva: WHO. 329 pp. 54. Sen, A. 1981. Poverty and Famines: An Essay on Entitlement and Deprivation. Oxford: Clarendon. 257 pp. 55. Spurr, G. B. 1988. Effects of chronic energy deficiency on stature, work capacity and productivity. In Chronic Energy Deficiency: Consequences and Related Issues, ed. B. Schurch, N. S. Scrimshaw, pp. 95-134. Lausanne: Nes tle Found. 56. Stanbury, J. 1985. Iodine deficiency dis orders: Clinical presentations and con tinuing problems. Food Nutr. Bull.

7:64-72

57. Subcommittee on Vitamin A De ficiency. 1987. Vitamin A supplementa tion: Methodologies for Field Studies. Washington, DC: Natl. Acad. Press. 91 pp. 58. Tarwotjo, I., Tilden, R., Satibi, I., Ned rawti, H. 1986. Vitamin A deficiency in Indonesia. In Vitamin A Deficiency and Its Control, ed. J. C. Bauernfeind, pp. 444-60. Orlando, Fla: Academic 59. Torun, B., Viteri, F. E. 1981. Energy requirements of preschool children and effects of varying energy intakes on pro tein metabolism. In Protein-energy Re quirements of Developing Countries: Evaluation of New Data, ed. B. Torun, V. R. Young, W. M. Rand, Food Nutr. Bull. Suppl. 5:229-41 60. Viteri, F. E. 1976. Definition of the nutrition problem in the labor force. In Nutrition and Agricultural De velopment-Significance and Potential for the Tropics, ed. N. S. Scrimshaw, M. Behar, pp. 87-98. New York! London: Plenum 61. Von Braun, J., de Haen, H., Blanken, J. 1988. Commercialization of agriculture under conditions of population pressure: A study in Rwanda on production, con sumption and nutritional effects, and their policy implications. Washington, DC: IFPRI. 230 pp. 62. Wahlqvist, M. L.. King, R. W. F., McNeil, J. J., Sewell, R. 1987. Food and Health: Issues and Directions. Lon don/Paris: Libbey. 119 pp. 62a. Walter, T. 1989. Infancy: Mental and motor development. Am. J. Clin. Nutr. 50:655-66 63. West, K. P. 1978. Epidemiology of Di abetes and Its Vascular Lesions. New York: Elsevier/North-Holland. 579 pp. 64. West, K. P., Pettis, S. T. 1986. Control of vitamin A deficiency by the vitamin A periodic oral dosing approach. In Vita min A Deficiency and Its Control, ed. J. C. Bauemfiend, pp. 324-57 . Orlando, Fla.: Academic 65. West, K. P., Howard, G. R., Sommer, A. 1989. Vitamin A and infection: Pub lic health implications. Annu. Rev. Nutr. 9:63-86 66. Winnick, M., ed. 1976. Nutrition and the Elderly. New York: Wiley. 208 pp. 67. Wolgemuth, J. c., Latham, M. C., Hall, A., Chester, A., Crompton, D. W. T. 1982. Worker productivity and the nutritional status of Kenyan road con struction laborers. Am. J. CUn. Nutr. 36:68-78 68. Young, E. A., ed. 1986. Nutrition, Ag ing, and Health. New York: Liss

Prospects for cancer control in the 1990s.

Child health in the United States: prospects for the 1990s.

Prospects for ancillary treatment of sinusitis in the 1990s.

Injury prevention and control: prospects for the 1990s.

Challenges for public health nutrition in the 1990s.

Prospects for better nutrition in India.

The future of public health: prospects in the United States for the 1990s.

Hospital cost containment in the 1980s. Hard lessons learned and prospects for the 1990s.

Setting objectives for public health in the 1990s: experience and prospects.

Animal nutrition to human nutrition: achievements and prospects.

Substance use disorders: predictions for the 1990s.

Expanded programme on immunization for the 1990s.

Public health policy for the 1990s.

The biliary tract: imaging for the 1990s.

Asylum for psychiatric patients in the 1990s.

Separation techniques for biotechnology in the 1990s.

FK 506: an immunosuppressant for the 1990s?

Toxicology in the 1990s.

Primary nursing for the 1990s and beyond.

Prospects for the future.

The challenge of the 1990s.

Asthma in the 1990s.

Photopheresis in the 1990s.

Hysterosalpingography in the 1990s.