urban nutrition in developing countries

Special Article April 1995: (1)90-95

Urban Nutrition in Developing Countries Noel W. Solomons, M.D. and Rainier Gross, Ph.D.

In developing countries, the past decades have seen a marked demographic shift from rural to urban. By the year 2000, 40% of the population of the Third World will live in urban areas. We have limited specific knowledge of the similarities and differences in diet, nutrition status, and health effects of diet and lifestyle between the traditional rural populations and the emerging urban poor. Such information will be useful for basic descriptive information as well as for assistance in the design and execution of health and nutrition projects for the urban poor.

Introduction

Among the research paradigms relevant to urban nutrition research are issues of migration, changes in family structure, food contamination, changing food habits and lifestyle, increased consumption of street foods, and access to medical care. All of these are expected to affect the urban poor profoundly and present a series of opportunities for urban nutrition research. However, pitfalls and limitations in the investigation of the urban poor must be recog- nized. These include the selective and differential nature of populations that migrate to the city and those that remain in the countryside. The age at migration and the duration of life in the city are also important covariables. Differential access to populations or acceptance by potential subjects may produce a participation bias that distorts the representation of the sample.

It is not mere coincidence that the term “peasant,” which literally refers to a rural agriculturalist, is also used colloquially in reference to a poor person. Subsistence farmers or landless rural people are a paradigm for poverty, and poverty carries with it a relative risk of a substandard intake of nutrients.

Dr. Solomons is at CeSSlAM Hospital de Ojos y Oidos, Guatemala City, Guatemala, and Dr. Gross is at the SEAMEO-TROPMED-GTZ Regional Commu- nity Nutrition Training Program, Jakarta, Indonesia.

Rural and traditional lifestyles, however, also imply higher intakes of substances such as dietary fiber and lower consumptions of cholesterol, animal fat, food additives, and total calories. The affluent are generally urban and have a lower risk for deficiency of most nutrients. At the same time, overconsump- tion and conditions of excess are associated with the process of becoming affluent.

In most countries of the developed world, the agrarian way of life has given way to agro-business, whereby more than 80-90% of the residents live in populations of more than 20,000 that would be clas- sified as “urban.” Selecting out the urban populations in a survey such as the U.S. National Health and Nutrition Examination Survey (NHANES) as “special” would be redundant. However, just as “peasant” is the paradigm for poverty, in tropical and developing countries “rural” is the traditional focus of interest for studies in human biology from anthropology to public health. The image of so- called preindustrialized or developing nations as corroborated by tourist manuals and National Geo- graphic photographic portraits may lead one to be- lieve that the Third World populations are largely peasants, pastoralists, or tribal groups. In fact, the research publications in nutrition and other fields have reflected a similar picture,’ with a predominant focus on rural populations. The current demographic reality, however, would not support the classical image. City and township dwellers are a growing sector in poor and tropical nations, and in many regions, they are the clear majority. The United Nations projected demographic data for the distribution of population between rural and urban resi- dences for industrialized and developing countries in the aggregate and for the five regions of the Third

While less than 20% of the population lived in urban areas in 1950, 40% of the developing world’s population will be living in cities 50 years later. In Latin America and Oceania, the majority of the population is already urbanized.

Once, the world was indeed almost completely agrarian, pastoral, or tribal. The cities of today have grown up around ports, forts, communication hubs, ceremonial centers, and seats of government. This

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is as true of Timbuktu and S5o Paulo as it is of Paris or New York. One should then ask whether the phenomenon of urbanization in countries of the Third World will simply be an extension of what has transpired in First World cities, or whether dif- ferent and specific characteristics exist that are related to climate, social history, and widespread poverty.

Public health nutrition tries to prioritize the most severe dietary and deficiency problems. It may have been the commonly held belief that general nutrition status is improved in the city compared to the countryside. Some surprising exceptions to this rule of thumb can be found in a survey of trace elements in breastmilk: in which rural lactating mothers often produced milk with a superior amount of zinc or iron as compared to their urban peers in some of the developing countries surveyed. On the other hand, there is abundant evidence to substantiate a general trend of urban nutrition ~uperior i ty .~ Survey data from metropolitan areas, however, are not rou- tinely disaggregated into the elite and the middle class as contrasted with the poor. It is well known that there are marginal and destitute persons in large numbers in most of the Third World’s towns, cities, and large metropolises. The nutrition problems that affect this growing sector and the types of research approaches that best serve the new knowledge in this area are the subject of this review.

Growing Interest in Urban Nutrition in Developing Countries

Urban nutrition has only recently become a specific, identified, and distinct concern in international nutrition. In 1984, the coauthors were sitting on the ornate sidewalk of the Copacabana Beach in Rio de Janeiro, planning the curriculum for a local univer- sity nutrition course, when we looked up into the hills behind us. We saw the favelas, the notorious poor slums of Brazil, and wondered how much the international nutrition community really knew of the situation in these neighborhoods, or of poor urban populations throughout the Third World. A year later, an impromptu and informal workshop on urban nutrition was organized in Brighton, England at the XI11 International Congress on Nutrition.6 Within the International Union of Nutritional Sci- ences (IUNS), the issue has taken on momentum with the formation of a Committee on Urbanization and Nutrition. The topic has been the subject of formal workshops at the International Congress of Nutrition (ICN) XIV in Seoul and the Congress XV in Adelaide, and i t will also be featured in a major symposium at an upcoming Congress. The responsible IUNS committee, meanwhile, has organized workshops on Nutrition and Health in Metropolitan

Areas in Asia (Kuala Lumpur, Malaysia), Latin America (Mexico City, Mexico), and Africa (Co- tonou, Benin), with publications issued from each. The IUNS Committee has also coordinated the development and initiation of an eight-nation, multi- center research collaboration on the project “Nutri- tion Situation of Rural and Urban Elderly from Se- lected East Asian and Latin American Developing Countries” encompassing Brazil, China, Guatema- la, Indonesia, Malaysia, Mexico, Philippines, and Thailand.

The primary mandate of nutrition science is to explore and explain the interrelationship between nutrition and biology. In the context of underprivi- leged populations, i t has additional responsibilities in the development of policy. To paraphrase the principles cited by G. Andrew as they relate to the urban poor, “data collected should contribute to developing a general profile of the population, to de- scribing the problems and needs affecting the population, and to determining the unmet needs and the services available to meet them. Data should also set a basis for obtaining feedback on the operation, quality, and impact of policies and programs in urban nutrition.”’

To a certain extent, both basic and applied research can be called to the service of the policy, planning, and executive agencies that serve developing countries. United Nations agencies such as the Food and Agriculture Organization (FAO), the World Health Organization (WHO), and the United Nations International Children’s Emergency Fund (UNICEF) could all be assisted in their goals by the investigative results of nutrition scientists. Although each of the aforementioned UN dependencies has been associated with an emphasis on rural areas, one sees the emergence of applied interest in the urban situations. The F A 0 has supplied food to the urban centers and has a growing concern about the microbiologic safety and nutrition quality of street- vendor foods. WHO is stimulating interest in urban health initiatives for all of the cities’ age groups that include issues of both deficient and imbalanced di- ets in the urban milieu. The urban nutrition interests of UNICEF involve projects of sanitation, the welfare of street children, and child survival in the context of Third World cities.

Common Paradigms in Urban Nutrition

The. institutional and academic interactions outlined above led to our compiling a series of paradigms that urban areas throughout the developing world have in common. These are outlined in Table 1 and briefly discussed below.

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Table 1. Prominent Paradigms in Urban Nutrition Research

-Rural-urban migration -Nuclear families and internal migration --Chemical contamination, noise pollution, and stress -Processed foods, novel foods, fast foods, and nutrient

-Sedentary life pursuit -Street vendors and street foods -Access to Western medicine in health care

supplement

Rural-Urban Migration Since urbanization in developing countries is rela- tively recent and decidedly a post-World War I1 phenomenon, the migration of population from rural areas to the towns and cities has been an accelerated process. Natural growth-births in excess of deaths from both the pre-existing residents and new migration-often contributes to the growth of an urban area in equal segments. However, after natural or man-made disasters such as crop failures, earth- quakes, insurrections, floods, etc., there are often periods of rapid rural-to-urban migration. One ge- neric phenomenon that occurs throughout the world is an abrupt change in cultural norms, including dietary habits. Moreover, the new arrivals often oc- cupy the least desirable areas of the urban or metropolitan zone.

The cultural sharing is not unidirectional, however. In efforts to preserve cultural traditions such as dance, art, or culinary arts, the “country cousins” may establish businesses that attract the larger population, so that a staid urban culture may be re- opened to diversity. For the purposes of research, selective migration to the cities is an important issue. Within the same family, those who migrate and those who stay in the countryside may have differ- ent characteristics. Aside from the classical issue of the nonheirs (younger children) leaving the land, questions exist as to whether the more motivated and innovative of the family members opt for a chance to modify their life and lot, whereas the less adventurous remain behind.

Money management in a monetary economy is one new skill that must be mastered. Whereas the rural population’s food supply comes from its own production, the urban population’s food supply has to be purchased, providing new options and new norms and values. Several studies have evaluated spending behavior for poor urban populations,8,’ including the choices people make based on monetary income and food prices and the consequences of these choices on the quality of the diet.

Nuclear Families and Internal Migration The extended multigenerational family is the norm in traditional rural areas, while the nuclear family

consisting of a young adult couple and their children is the norm in cities. Another departure from the rural family pattern is the proliferation in some Third World cities of female-led households. On the other hand, male heads of household may often leave their family in the rural sites and travel to work in cities, returning on weekends or just once a month to their families in the countryside.

The changing structure of the family, new de- mands on women’s time, and cultural differences and altered availability of foods may all have implications for the distribution of food within the household. Particularly affected may be the most traditionally vulnerable age groups-infants, tod- dlers, and preschool children, as well as the mothers themselves.I0

Whenever one member of a family unit be- comes isolated or dispossessed in a rural area, col- lective efforts are generally made to sustain the in- dividual. For the urban poor, the social safety nets are less evident and less secure. The plight of urban elderly living outside of the extended family unit is a specific concern. Their economic welfare, food security, and nutrition health may all suffer in the context of the isolation of living alone or within nuclear families in the metropolis.

Street Children and Homelessness In poor nations, the problem of the homeless is magnified in large, expanding cities if there are growing segments of urban populations of developed countries that cannot find or maintain a stable dwelling. Street children have received the greatest notoriety as an unstable population. These children are subject to vices of all natures, to aggression and violence, and to deprivation, but also may be a selected population of increased intelligence and in- genuity among the juvenile poor. Street children may actually be less poor than their siblings and cousins living in shanty towns and slums.

Processed Foods, Novel Foods, Fast Foods, and Nutrient Supplements With a monetary economy come more store-bought foods and the introduction of processed foods, rath- er than fresh animal products and garden produce. Additives, including sodium salts and simple sug- ars, become an increased dietary reality. Salt-sen- sitive hypertensive disorders that may not have been expressed on a traditional diet may become mani- fest. The rural migrant is exposed to novel foods, unknown in the rural community. The dispersion of the family to various corners of the city at mealtime promotes the use of fast foods, including street foods. Not all novel foods are necessarily exotic dishes and may include such basic items as white


bread. Because maize tortillas and tamales are the staple cereal items in Guatemala, Krause et al.'I ex- amined the factors that lead to a substitution of white bread for corn. The existence of a bakery or a bread truck route was a principal factor, but this was associated with a greater level of urbanization.

Given the cost and cultural aloofness that may characterize the interaction with a licensed physi- cian in a Third World city, the pharmacist often re- places the traditional shaman or midwife as the primary care provider. In the pharmacopeia one can find concentrated vitamin and mineral supplement products. The use of supplements would generally be associated with better nutrient reserves than pro- vided by the diet alone, except where nutrient-nutrient interactions could lead to depression of status of another vitamin or mineral. Conventional wis- dom would suggest that urbanization increases a person's susceptibility to both the beneficial and the adverse consequences of nutrient supplement use.

Sedentary Life Pursuits Another feature of dietary change in the processed foods of the urban environment is the consumption of energy-dense items. This can combine with a more sedentary lifestyle in the urban environment to produce changes in body composition, such as overweight and obesity. Forty years ago, Costa Rica was similar in its economic and social pattern to its neighbors, Honduras and Guatemala. Four decades of rapid evolutionary change have produced a tran- sitional nation that has replaced undernutrition with overnutrition. Today, in a survey of suburban elderly women outside of San Jose, 25% have a body mass index of >28 m/kg.'* In Guatemala, elderly men in a rural village were, on average, 20% lighter in weight than periurban men living in the capital city. In both Costa Rica and Guatemala, a high per- centage of the elderly have total cholesterol levels over 220 mg/dL.I2."

Chemical Contamination, Noise Pollution, and Stress Fecal contamination of the household environment has been documented in rural regions in which nei- ther intradomiciliary water for hand and dish wash- ing nor latrines for human waste disposal are available.I4 Rates of intestinal infections and parasitism often vary between rural and urban-poor communities but are still prevalent in periurban areas,I5 with the consequent effects on nutrition status. De- pending upon the type of agricultural practices, residues of herbicides, fungicides, insecticides, and other pesticides may be in all levels of the food chain in rural areas of developing countries. The shift from rural to urban is at best a shift of the

contamination paradigm. Chemical pollution is still a factor, but particulate matter from automobile ex- haust, volatile fumes from industry, and liquid and solid wastes from industrial plants have all become new chemical hazards in the environment. While rural agrarian settings are noted for their quietness, noise pollution is the reality in most metropolitan areas, combining vehicular noise, low-level aircraft operations, high-intensity loudspeakers, etc. Stress is hard to define, and one would imagine that poverty and recurrent illness would be stressful for the rural poor. However, the rapid pace, crime and in- security, and crowding of the mechanized environment can produce a distinctly urban version of stress.

In the final analysis, the greater burden may fall on the urban poor of developing countries. In ad- dition to the new contaminants of urban life, the "old" issues of fecal microbes and agricultural chemical residues may persist. Eventually, the plumbing and sanitary practices in the city may be little improved over the countryside in that the fish and game in the market stalls come from the same streams and woods as that consumed in the interior.

To date, little attention has been paid as to how pollution specific to the urban milieu interacts with human nutrition.I6 This question may require inquiry and cooperation of both the nutrition and tox- icologic sciences.

Street Vendors and Street foods The fast-food restaurants of the urban poor around the world are the mobile carts of street vendors, and street foods are the fare of the urban working class. There has been a moderate amount of hysteria and comparatively less examination of the nutrition and microbiologic quality of the food sold in the streets, with street foods having been declared responsible for a host of public health offenses. If the point of reference is the cuisine of the five-star restaurants in the tourist zones of Nairobi or Jakarta, then the food stands of the central market or the construction projects may not fare well. But let ,us look at the microbiologic safety and fecal contamination of the foods that these same urban poor would consume in their homes or in food brought from their homes to the workplace. We suspect that, despite the lack of hot running water and disposable paperware, chances of becoming ill with food poisoning after any given meal would be comparable. The concern should be for the potential for large numbers of in- dividuals to become sick from a single point source. Clearly, the Shiga bacillus or the Vibrio cholerae found in the fruit drink of a street stand will produce many more primary and secondary victims than the same microbes in a cold soup in a periurban shanty.

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Table 2. Opportunities in Urban Nutrition Research

-Basic description of diet and nutrition in selected

-Rural-urban comparisons -Role of family and household relationships --Influence of rural-to-urban migration on nutritional

-Universality and generalizability of dietary factors

townships and metropolises

status and dietary status

and degenerative diseases

Access to Western Medicine in Health Care Urban life generally means greater access to the concepts of allopathic Western medicine in health care. Hospitals, clinics, and doctors’ offices are concentrated in cities. The rural population generally has one or more systems of traditional healing ad- mixed with concepts of Western medicine and the use of chemical pharmaceuticals. The ‘degree to which the parallel system of traditional healing sur- vives and thrives among the urban migrants is not known for all sites, but it is substantial in many capitals and large cities of Third World countries.

Obviously the rational use of antibiotics, timely surgical interventions, and modern rehabilitation techniques can represent an improvement over the traditional approaches to pneumonia, appendicitis, and hip fractures. However, there may be adverse nutrition costs to hospital birthing practices compared to traditional midwifery in terms of the amount of iron that is transferred from the placenta to the infant in the process of the delivery. In the latter, with delayed clamping and cutting of the um- bilical cord, a greater quantity of blood passes into the newborn during the birth process. Also, to what- ever degree Western medicine discourages breast- feeding or proposes feeding formats that reduce the exclusivity of maternal nutrition in early life, it may be doing a disservice to infant nutrition compared to what would have been the practice in a rural set- ting.”

The Academic and Research Challenge

Emerging from this brief survey is a demographic imperative to apply the interest of nutrition scientists to issues of the Third World cities. This appli- cation should be undertaken because of both the gravity of the deficiency problems and the growing numbers of urban residents. If poverty and deprivation are a common denominator of the developing world’s masses in both the metropolitan areas and the countryside, distinct paradigms seem to be in- volved in the cause and characterization of the problems of diet and nutrition. Knowing the pattern of nutrition epidemiology in the rural population is of-

Table 3. Pitfalls and Limitations in Urban Nutrition Research

-Selective rural-to-urban migration -Timing of (age at) migration -Duration of residence in the urban area -Participation bias -Accessibility and stability of target populations

ten “old news” and not applicable to the new issues confronting the urban poor.

A series of opportunities for research on urban nutrition present themselves, as listed in Table 2. The first opportunity is descriptive, and this has both scientific merit and policy implications for the countries under investigation. It is obvious that comparisons must be made with the “original” populations, the rural inhabitants. Of contemporary rel- evance are the nutrition epidemiology possibilities. We need to determine whether the dietary and en- vironmental factors we associate with chronic dis- easeI8.l9 are valid and viable beyond the urban population of the industrialized nations in which they have largely been conducted.

We can anticipate a series of pitfalls and limitations both in conducting research on urban nutrition and in interpreting the findings (Table 3). The most important interpretative issue relates to the selective rural-to-urban migration discussed above. One cannot determine whether differences are due to location of residence or to results of differential migration. If our hypothesis is to impute changes in diet and nutrition to the urban environment, we treat life in the city as an “exposure” in the epidemio- logic sense. Hence, two covariables-the age at migration and duration of residence in the urban area-must be considered. Finally, aspects of urban life may determine who gets studied. There may be selective characteristics as to who participates in studies in poor urban populations, governed by the willingness of potential subjects to be studied, and by the willingness of the investigators to visit certain neighborhoods. Hence, participation bias is an ever present threat to the representation of the urban populations studied and to the validity of the con- clusions drawn.

Only a few are drawn to research in international nutrition. Some of those few attracted to the field, moreover, are interested in the rural populations. The Third Worldwide demographic trends and the area of major gaps in our knowledge, however, both point to urban nutrition as a justifiable priority for research investment in developing countries. The limited experience points to some deviation from our experience in rural poverty in the findings from the urban poor. To the extent that this under- standing can be used to tailor and adjust public


health programs and surveillance, i t may be well worth the shift i n emphasis from rural to urban i n international nutrition investigation.

1. Solomons NW. Urban nutrition in the tropics: a ne- glected subject of scientific inquiry. In: Gross R, Sol- omons NW, eds. Tropical urban nutrition. Eschborn, Germany: Agency for Technical Cooperation (GTZ), 1 987: 1 5-30

2. United Nations, Department of International Econom- ics and Social Affairs. Patterns of urban and rural population growth. Population studies no. 68. New York: United Nations, 1980

3. Popkin BM, Bisgrove EZ. Urbanization and nutrition in low income countries. Food Nutr Bull 1988;10:3- 23

4. Parr RM, DeMaeyer EM, lyengar VG, et al. Minor and trace elements in human milk from Guatemala, Hungary, Nigeria, Philippines, Sweden and Zaire. Results from a WHO/IAEA joint project. Biol Trace Elem Res 1991;29:51-75

5. Viteri FE. Nutrition-related health consequences of urbanization. Food Nutr Bull 1987;9:33-49

6. Gross R, Solomons NW, eds. Tropical urban nutrition. Eschborn, Germany, Agency for Technical Co- operation (GTZ), 1987

7. Andrew G. Health and ageing in the developing world. In: Evered D, Whelan J, eds. Research and the ageing population. Ciba Foundation Symposium 134. Chichester: John Wiley and Sons, 198837-31

8. Alarcon JA, Andrino FJ. Diferencias urbano-rurales en la ingesta de alimentos de familias pobres de Guatemala. Arch Latinoamer Nutr 1991 ;41:327-35

9. Alarcon JA, lmmink MD. Elasticidad ingreso de la de- manda de alimentos y otros bienes en grupos de poblacion marginal urbana de la ciudad de Guate- mala. Arch Latinoam Nutr 1990;40:518-32

10. Nieves I, Engle PL. Conductas de distribucion intra- hogarena de alimentos en comunidades periurbanas de Guatemala: lecciones para 10s programas de distribucion de alimentos. Arch Latinoam Nutr 1989;39: 339-56

11. Krause V, Tucker KL, Kuhnlein HV, Lopez-Palacios CY, Ruz M, Solomons NW. Rural-urban variation in limed maize use and tortilla consumption by women in Guatemala. Ecol Food Nutr, in press

12. Llanos G, ed. Estudio de la Tecera Edad en Coro- nado, Costa Rica. Pan American Health Organization Monograph 90-01. San Jose: PAHO, 1990:53-74

13. Ramirez I, Mendoza ME, Romero ME, Valdez C, Vasquez A, Haskell K, Breuer K, Solomons NW. Fac- tores de riesgo en enfermedad cardiovascular en an- cianos guatemaltecos de una comunidad urbano- marginal. Rev Med lnterna 1992;3:61 (abst)

14. Schneider RE, Shiffman M, Faigenblum J. The potential effect of water on gastrointestinal infections prevalent in developing countries. Am J Clin Nutr

15. Kaminsky RG. Parasitism and diarrhoea in children from two rural communities and marginal barrio in Honduras. Trans R SOC Trop Med Hyg 1991;85: 70-3

16. Gross R. Urbanization and nutrition from a thermo- dynamic and cybernetic point of view. In: Gross R, Solomons NW, eds. Tropical urban nutrition. Esch- born, Germany: Agency for Technical Cooperation (GTZ), 1987:31-60

17. Wray J. Breast-feeding: an international and histori- cal review. In: Falkner F, ed. lnfant and child nutrition worldwide: issues and perspectives. Boca Raton, FL: CRC Press, 1991:61-116

18. Willett W. Nutritional epidemiology. New York: Oxford Press, 1990

19. National Research Council. Diet and Health. Wash- ington, DC: National Academy of Sciences, 1989

1978;31:2089-99

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urban nutrition in developing countries

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