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Conclusions

Technical considerations

The survey on household consumption and budgets is a very useful tool for the decision-makers responsible for food supply and nutritional planning. It is effective for several reasons.

First, appropriate data are more convincing than qualitative judgements. This was so well understood by the Tunisian government that in 1975 the Council of Ministers decided to repeat the survey every five years. The results are consistent and comprehensive, and are sufficiently accurate to permit an assessment of the changes that occurred during that period. Such surveys have shown that it is possible to evaluate ex post facto the size of the population below the poverty line and to define their socio-professional profile. They have been used to quantify the economic and social impact of food subsidy policies, and the nutritional and economic effects on the diet of regional development projects. Furthermore, survey results enabled the Service of Agricultural Planning to project a model of food demand divided into two distinct types of diets, urban and rural, with specific income elasticities for each. This model is far better and more sensitive than the previous one based on food balance sheets.

Second, the data on heights and body weights cast new light on the results of the household-consumption survey. On the condition that such data are not limited to children between birth and six years of age, as is now the case in many countries, weight and height distribution patterns may provide inexpensive and objective indicators of changes in the food situation. Such surveys are inexpensive, provided they are not conducted independently but are combined with food-consumption and budget surveys.

Finally, the use of energy-requirement data as a basis for qualitative assessment of nutritional intake leads to inconsistencies in the results and does not give researchers the expected outcomes. More sophisticated algorithms using variables depicting the profile of each consumer, household by household, need to be applied. In this way the variability of requirements could be increased and brought closer to actual living conditions. The variables now available (age, height, and weight) in relation to basal metabolism are adequate for evaluating maintenance requirements, as suggested in the 1985 report.

Food policies

Paraphrasing a famous remark, one might say that urbanization is far too serious to be entrusted to urbanists. In fact, the future of the cities is in the hands of the rural dwellers. Urban over-population is the result of their feeling of frustration. Because small and medium-sized towns constitute an intermediate stage in the process of rural exodus, it seems appropriate to maintain the distinction between their populations and those of large cities in future surveys. It is on those intermediate-stage cities that effort should be focused in order to stem migration toward the larger centres. Results of the 1980 survey showed that the measures taken to liberalize transportation services and develop exchanges in and with the rural areas had a favourable impact on the diet of these medium-sized towns. This policy should be encouraged.

Possible alternatives to a policy of food subsidies are discussed elsewhere. Any policy, however, that accelerates the trend toward the substitution of soft wheat for durum wheat would run counter to the nutritional interests of the poor and of the rural producers. If this substitution proves to be unavoidable and is justified by economic exigencies, it should be accompanied by measures to revise the extraction rate of industrial cereal products.

Data on physical activity are dramatically missing. New surveys of the Tunisian type will need to include a component on the time budgets of household members if the complexity of the various family conditions and their working capacities are to be reflected with any realism, and if hasty and unfounded conclusions are to be avoided in comparing requirements with consumption data. The experience gained with surveys in Côte d'Ivoire and Rwanda is very useful in this respect. Such data could be used to improve our understanding of whether some specific age and sex groups have additional working capacities before new development projects are proposed.

Instead of subsidizing all types of bread, it might be possible to enforce the production and sale at a controlled price of another type of bread that alone would be taken into account for the calculation of the cost-of-living index, as is done in Italy for bread rolls (ciriolo). In Tunisia, such a bread might be made from subsidized flour. To preclude this flour's being mixed with bleached flour and used for other purposes, its extraction rate would be lower; it would then be less white and therefore richer in proteins, vitamins, and minerals. The end product would be a typically shaped loaf, but less attractive because of its brownish colour. Affluent households would neglect this humble loaf for the baguette, made from whiter flour and therefore more enjoyable, but more expensive because it is non-subsidized. In five years, a new survey should make it possible to determine the degree of acceptance of this brown bread in the various population groups, as well as the income categories of persons by whom it is consumed.

If some animal products have to be deleted from the list of subsidized commodities, milk products [except butter) should be maintained. Eggs can be bought one by one and therefore are accessible to persons on a small budget. Milk and acidified milk products (easier to store) are essential for the lowest-income groups, who cannot afford to buy meat. At the lower end of the income distribution it is not uncommon to find households with many children, often headed by widows or divorced women with jobless or handicapped dependents. Such individuals are nutritionally at risk. Subsidized commodities provide help, but a food-stamp programme would be far more efficient. The recent effort made by local authorities to identify those living below the poverty level is a good start in that direction.

One of the good features of the Mediterranean diet is its moderate fat content from good-quality oil. The calorie content of the blended oil, however, is very close to that of cereal products, so that its use results in high calorie intake in the urban low-income groups. It is not desirable to encourage consumption of this oil beyond the present limits, lest it should lead, as in Malta and probably also in Libya, and for the same reasons, to a proliferation of nutritional overweight with a concomitant upsurge of cardiovascular diseases.

Each family has its own unique characteristics and acts as best it can to reconcile two contradictory requirements: securing a maximum calorie intake at a minimum cost, while diversifying the diet to enhance its palatability within the limits of available income. In doing so, the people depend on the instinct for survival rather than a knowledge of physiology; solidarity takes the place of economic accounting. For the time being, Tunisians are doing well, but the patterns of consumption of urban dwellers are accelerating behavioural changes, and such changes are exposing these persons to nutritional risks. This has to be watched. Tunis has proved here to be well equipped for that purpose.

References

1. Périssé J. Kamoun A. The price of satiety: a study of household consumption and budgets in Tunisia. FAD Food and Nutrition 1981;7(2).

2. Fourati H. Identification des populations vulnérables: méthodologie et étude de cas de la Tunisie. In: Les consommation et les politiques alimentaires au Maghreb. Séminaire international FAO-IMA. Tunis, 1986.

3. Kamoun A. L'incidence de la Caisse générale de compensation sur la distribution des revenue et l'équilibre de la ration alimentaire. In: Les consummation et les politiques alimentaires au Meghreb. Séminaire international FAO-IAM. Tunis, 1986.

4. Belhaouane K. Compensation, prix et revenue en Tunisie. In: Les consummation et les politiques alimentaires au Maghreb. Séminaire international FAO-IAM. Tunis, 1986.

Nutrition-related health consequences of urbanization

Fernando E. Viteri, M.D.

Introduction

This paper specifically describes and analyses nutrition-related health problems in urban populations, with emphasis on less-developed countries, anticipates future trends, and places the magnitude of the problems in the context of the total dimensions of the nutritional and health conditions in low-income countries.

The word "urban" may be used in reference to (1) an inhabited place administratively identified as a city and its dwellers, (2) a place with a concentrated population of a certain size living in relatively permanent locations (i.e., a city of a given number of inhabitants whether with a minimal population density or not, or (3) an ecosystem and its population (relatively independent of size) with some or all of the following characteristics: crowding, a cash economy, a low level of occupational physical activity, the predominance of manufacturing, bureaucratic, and service occupations, little contact with plants and animals and their cultivation, and some degree of organized public services. Closely linked to such an ecosystem is the word "urbanism," which refers to a way of life affected by "the consequences, both social and personal, of life in urban environments" [1] (see table 1).

The phenomenon of westernization is defined as the adoption of several characteristics of the Western developed world, particularly life-style and economic, dietary, and health-seeking behaviours. For clarity we must also distinguish modernization from westernization and urbanism. The term modernization is used here to imply the processes and consequences associated with cumulative socio-economic advances, including placing greater social value on women and on children (reducing the demand for children as contributors to the family's economy) [2, 3].

It is evident that these three processes often appear together as societies undergo urbanization, which actually refers to the increase in the proportion of a population living in urban settings. A proportion of urban dwellers may not accept the urban way of life (urbanism) or become westernized or modernized. On the other hand, population groups in non-urban settings may accept these ways of life more effectively. This is particularly true in agricultural areas undergoing industrialization (agro-industrial complexes) and in towns and villages around large cities, especially when, as is often the case in the developing world, one city has absolute primacy.

Dimensions of urban growth

According to a United Nations report [4], the rate of growth of urban populations is close to 4.0% a year in less-developed countries and 1.8% in developed countries. Over two billion persons in less-developed nations will be urban by the year 2000, while slightly over one billion inhabitants of developed nations will be urban. What is more significant in terms of the implications of urbanization for nutrition and health is the 7.7-fold increase of the urban population in underdeveloped countries in the last 50 years (in contrast to a 2.4-fold increase in the rural population) and the appalling fact that in these countries the proportion of households in poverty in urban settings is increasing explosively, so that by the year 2000, 57% of all poor households will be urban in contrast to 34% in 1980 (table 2).

The UN projections of an absolute decline in poor rural households in the last two decades of this century appear optimistic. This may very well be the result of the definition of "urban population," which reclassifies previous rural settings as urban due to rural pert-urban environments being incorporated into the expanding cities.

Also of importance in terms of the dimensions and characteristics of urbanization is the proportion of population growth attributable to the natural increase in the number of city dwellers and that due to inmigration, since the two processes impose different social, economic, health, and nutrition needs and demands on the urban population and on the city environment. The United Nations report [4] estimated that about half the urban growth in emerging countries is due to each of the processes. In Latin America, the proportion of growth due to migration averages 34%. These data are based on the latest information available for the 1980 UN report in a total of 28 countries.

Causes of migration into the urban setting

Several studies 16-101 indicate that people migrate to the cities primarily because of social and economic attraction plus the prestige associated with living in the city. Historically, urban compounds began to form as the agricultural revolution evolved; cities developed further as trading, religio-political, and strategic centres up to mid-eighteenth century, when very rapid urban expansion began in Europe with the industrial revolution and accelerated the demand for labour in production and trading centres.

Urban development in the less-developed countries followed different motives, paths, and rhythms primarily because of their historical, colonial, and neocolonial factors. The cities grew, but essentially as political and trading centres, giving marked primacy to only one or a few. Only lately has the rural environment been incorporated into the urban growth (beginning in the late nineteenth and early twentieth centuries), and industrial development has only more recently sprung up in developing nations. Rural-to-urban migration accelerated in part as a response to these developments, but in many cities immigration and urban growth occurred in the absence of a significant increase in the industrial job market, creating large urban subsistence, commercial, and service sectors. At the same time, substantial declines in mortality with persistent accelerated birth rates in both the urban and rural environments resulted in a rapid population growth. This has been associated with expansion of cash crops, fragmentation of small subsistence plots, and penetration of industrially manufactured goods into the rural areas, displacing less efficient small household and artisan industries and creating a large rural push to the city.

The process of urban growth in less-developed countries is evolving very differently from that in developed countries. Its stages lag about 75 years behind those of developed nations; urbanization is the product of different history and causes, and involves both much greater growth in absolute numbers and much higher rates of growth than in Europe in the late nineteenth century (there is debate on this last issue [9, 11, 12]). An important difference is that in Europe and the developed world in general, industrial growth came before urbanization. In the emerging nations it does not; moreover, even where industrial growth is occurring, it is generating only a very small number of jobs [13].

TABLE 1. Characteristics usually associated with urban in contrast to rural populations

TABLE 2. Poor households in rural and urban areas in less developed countries, 1980 and projections for the year 2000

a. In thousands.

Sources: Refs.4 and 5.

Effects of migration into the urban setting

In less-developed countries the short-term health and nutrition problems exhibited by the migrant poor in the shanty towns are, in large measure, those that were already affecting them as rural poor. These problems may even be exacerbated in the early months of city living by the possible higher degrees of infection and stress. A short-term variant of the well-known phenomenon of circular rural-urban-rural migration is also provoked by the marked concentration of secondary and tertiary levels of health care in the cities, which attract the rural sick in need of medical attention. The sick and those who accompany them move to the city and report themselves as urban dwellers in order to be eligible for free medical care. This has the effect, in terms of health statistics, of diminishing the true urban-rural differentials of ailments that are predominantly rural. In addition, it increases such differentials in the case of chronic "ailments of affluence" that predominantly affect urbanites.

Migration often results in a decline in subsistence agriculture (less technologically developed), which is often the responsibility of women, children, and the elderly. This affects the availability of food for the rural poor, particularly when there are high demographic pressures on land use and where marginal lands are the source of subsistence crops [14, 15]. Urban demands for services, intensified by rapid growth, draw national resources from rural development and deplete the rural sector further [16].

The environment

The diversity and the magnitude of differences of living conditions, demands, and opportunities in the cities are very important as determinants of nutrition and health. The negative effect of rapid and disorganized urban growth on services is well documented. Most poor, marginal areas in rapidly growing cities and other shanty towns lack adequate housing, water, and sewerage services, solid-waste disposal, prevention of environmental contamination, food sanitation control, personal security, and general safety systems (including accident prevention), electricity, communication systems (streets, transportation, mail, telephone), recreational facilities, accessible education and health services, and food outlets [171. This situation is obviously not conducive to physical and mental health. The deterioration that is rather typical of the large cities in less developed countries where economic as well as population growth has taken place without a workable plan, has been described as follows for Lagos:

Chaotic traffic conditions have become endemic; demands on the water supply system have begun to outstrip its maximum capacity; power cuts have become chronic as industrial and domestic requirements have both escalated; factories have been compelled to bore their own wells and to set up standby electric plants; public transport has been inundated, port facilities stretched to their limits; the congestion of houses and land uses has visibly worsened and living conditions have degenerated over extensive areas within and beyond the city's limits, in spite of slum clearance schemes; and city government has threatened to seize up amidst charges of corruption, mismanagement and financial incompetence. Moreover, although employment has multiplied in industry, commerce and public administration, there is no doubt that thousands of in-migrants have been unable to find work, and the potential for civil disturbances has increased [181.

Life in the city is not all bad, however, and according to several authors [1, 19-21 ] the city provides an environment in which individual and group expressions are feasible, where social mobility is a reality, and where conditions are in general better and more attractive than in the poor rural areas. It has been argued that some less-developed countries are over urbanized, but a clear counter-argument has been that such countries are in reality "over-ruralized" [1] and at the same time are fundamentally underdeveloped in the rural sector. The fact is that the poor rural environment appears worse than even the city slums; the constant urban in-migration from the non-urban sector proves it.

Food intake and nutrient adequacy

There is ample evidence that household food purchases and consumption vary by income levels in both developed and developing countries and in urban as well as in rural settings 122-27]. In developing nations, the level of food and nutrient intake, even of the lowest-income rural and urban groups, is enough to prevent widespread, severe deficiency diseases. Exceptions are iodine in some areas and iron in some specific age-sex groups. Mild and moderate deficiencies and temporary shortages of food are, nevertheless, not uncommon among these groups, as evidenced by the better nutritional conditions of low income populations who receive food aid or other social anti-poverty programmes compared to those who do not (e.g., women-infants-children programmes in the United States).

Moderate to severe nutrition deficiencies are common among the lower socio-economic strata in both urban and rural settings. The effect of location on the differential of food availability by income has not been studied properly, but in theory the urban poor are more vulnerable than the rural poor who are engaged in subsistence agriculture. Enough evidence exists, however, to indicate that the rural landless and those in rural areas undergoing modernization are particularly sensitive to economic shortages 128]. In populations involved in agricultural exploitation of marginally productive land, seasonal food scarcity is the rule. The urban poor are subjected to smaller seasonal fluctuations in food availability and intake 129].

By favouring modernization, the urban environment has been fertile ground for the promotion of bottle-feeding at the expense of maternal lactation, particularly among households where the demands of urbanism impose various limitations on adequate breast feeding 15]. On the other hand, weaning and complementary feedings are in general better accomplished among urban populations. In addition, the diets of young children and households in the cities tend to incorporate a greater variety of foods than those in the rural setting.

As the socio-economic level increases in the city, a better-quality diet is established, even though the total macronutrient intake may improve less [30]. These characteristics are significant for adequate child nutrition because of the critical importance of protein quality and energy and nutrient density to children.

When urban and rural diets are compared, it appears that variation in dietary intake depends more on the country and socio-economic group than on urban or rural location. In countries where urban diets are poor, rural diets are poor as well, and often worse. As the general socio-economic condition of a country improves with a factor of equity, the differentials in urban-rural intake (which more often favour the former) tend to disappear.

Even though many comparisons of urban-rural diets do not consider socio-economic rankings (weakening their significance), the intake of urban populations, even of the poor, tends to be better, or at least not significantly worse, than that of the rural poor. It is not rare that, as urbanization proceeds around established cities, dietary intake improves over that in isolated urban areas.

TABLE 3. Prevalence of diarrhoea, fever, and other illnesses (percentages of children) among preschool children in poor urban and rural populations in selected countries

Source Ref. 35

In adults, energy expenditure established by occupation and leisure activities must be taken into consideration in interpreting the possible nutritional consequences of dietary intake. Evidence indicates that urban occupations generally demand less energy than rural occupations. Thus lower energy intake among urban adult populations (and households) does not necessarily mean that these individuals are less well nourished than their rural counterparts. In many countries, the prevalence of obesity is actually higher among urban poor children and adults, suggesting that life-style plays a very significant role in the energy adequacy of diets in the city.

In summary, urban diets, including those consumed by the poor, are commonly more varied than rural diets. Also the poor, whether urban or rural, consume diets that are often deficient. Even though the urban setting may offer some advantage in terms of variety and stability of supply, the more important factor affecting food intake continues to be poverty.

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