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Future research directions

In addition to perfecting the analyses reviewed here and to testing other outcomes not yet considered, future research will focus increasingly on analyses of the different responses to supplementation in subgroups of the population. The first task has rightly been to focus on main effects. Next on the agenda are interactions. Also, there will continue to be strong emphasis in the analysis on the assessment of the long-term significance of growth and development during early childhood on adult performance. For example, what are the long-term functional implications of stunting? What does low intellectual performance in the preschool period mean?

In terms of new research, it is hoped that at some future date it will be possible to obtain occupational and economic data to make more appropriate the links to productivity mentioned earlier.

Finally, an ambitious proposal for a longitudinal study of the children of the subjects of the follow-up study has recently been submitted to the US National Institutes of Health. The proposed study is intended to test the notion that malnutrition in little girls affects the growth and development of the future generation. It also will permit examination of the role of maternal education in attenuating these risks.


Until recently, the nutrition community has had few data to offer those who demanded to see results on the impact of nutrition programmes. An exhaustive review of the literature of supplementary feeding programmes aimed at mothers and children [10] is a case in point. The authors concluded that the impact on growth was small. They went on to list the many reasons why larger effects were not found, including that often too little food was provided to make a difference. They also raised the possibility that growth may not have been the only or even the most important health benefit. This study has been widely quoted but is often misinterpreted. Many have abstracted from it the gloomy view that one should not invest in nutrition because it will not make much difference.

Fortunately, the situation has changed. Better-designed evaluations from around the world provide a more positive outlook [26]. Programmes are also more effective because much has been learned about management and design features. New research, including the present follow-up study, has contributed to a growing consensus that, when nutrition interventions effectively increase dietary intake in those who need it, they do indeed result in appreciable effect. It should be stressed that these dietary improvements may be achieved through many types of programmes and not only through targeted supplementary feeding.

Another development is that, whereas the nutrition community used to worry about justifying the economic returns to nutrition programmes, many economists have come to accept the value of the programmes even before they have been provided with conclusive results. In the 1960s and 1970s one often read about the problem of trade-offs between development and social services. Allocation of resources to social services was frequently seen as occurring at the cost of more immediately productive investments in rural areas [27]. For this reason, many saw the provision of these social services as self-defeating in the long run.

The rhetoric has changed. For example, the World Bank's current strategy for reducing poverty adopts a two-part approach [28]. The first component is to seek broadly based economic growth. The second involves the provision of social services in order to increase the capacity of the poor to respond to opportunities arising from economic growth. Rather than a problem of trade-offs, services, including better nutrition, are implicitly recognized as necessary for economic development.

Some have suggested that the follow-up study, by examining the links between nutrition and productivity, is pursuing issues that should best be left alone. If economists and planners seem already convinced of these relationships, why bother? Advocates of nutrition also fear that the proposition that good nutrition is a human right will be weakened by reference to other arguments, such as those about productivity. None of these views deter us. Fashions come and go, and this would seem to apply to development policies as well. It is possible that the World Bank strategy will differ in ten years. It remains important to study whether or not nutrition in early childhood contributes to human capital formation and to economic productivity. To the degree that these linkages can be demonstrated, they offer a powerful counter-argument to those who might view nutrition programmes as competing with economic development. If these links exist, nutrition may be seen a necessary and important component of economic development. Nutrition programmes would then be more appropriately viewed as long-term economic strategies. Demonstration of these linkages would provide support to those politicians and planners who have come to accept the importance of nutrition as a human right and for its contributions to economic development. It is also hoped that this demonstration would strengthen their resolve to improve the nutrition status of needy populations.


The INCAP follow-up study was supported by NIH grant HD22440 and was a collaborative effort involving investigators at several institutions: R. Martorell (principal investigator, originally at Stanford University, now at Cornell University), J. Rivera (INCAP, Guatemala), E. Pollitt (University of California at Davis), and J. Haas (Cornell University).


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