The nutritional trade-off

Nutrition has always been a key driver of development. It is in fact a key indicator of children's growth and development.  The capacity of an individual to work is intimately connected with nutrition intake - not with food intake per se - as eating is not feeding. Arguably, good nutrition is needed to reduce child mortality as well as to ensure cognitive development and hence of educational successes of young cohort. In fact, both of these two inputs are positive function of labour productivity and economic growth.  The link between nutrition and GDP growth becomes clear when malnutrition affects labour productivity. While nutritional status as a whole comprises a set, and particularly in a regime of scarcity of resources, one has to make a choice among the sub-sets. Which has to be addressed first - underweight or stunting?
The Copenhagen Consensus Center - a think tank on development issues - expresses its concern over growing stunting in developing countries. It also calls for a special attention to reducing stunting. The concern seems to be more deeply rooted in a working paper produced by Susan Horton (University of Waterloo, Canada) and John Hoddinott (International Food Policy Research Institute, Cornell University). Unlike the traditional approaches to nutritional considerations, the researchers take on benefits and costs of food and nutrition intervention (s) required to arrest stunting among children. The perennial premise upon which the exercise is based is that reduction of stunting is more important than under-weight. Thus stunting - low height for age - could be considered an excellent nutrition indicator to be included in the Sustainable Development Goals (SDGs). It improves on the earlier nutrition indicator used in the MDGs. It may be mentioned here that MDG 1 had aimed at halving the number of the 'hungry' where hunger was defined in terms of the number of children who were underweight.
The important question is why there should be a shift of emphasis from slashing underweight to stunting. The World Health Organisation's (WHO) nutrition goals for 2025 stipulate a reduction by 40 per cent of the number of stunted children under-5. Just to illustrate why stunting is a better indicator than under-weight, the researchers referred to bring in an example: imagine a child who is born and grows up in early childhood consuming a diet largely consisting of starchy staples, and whose mother faced the same diet during her pregnancy. Such a diet is devoid of variety of foods needed to provide minerals and vitamins required for healthy growth. This child is likely to end up stunted by age two (short of his /her age), after which catch-up in height is more difficult. The MDG goal (halving underweight) will incorrectly categorise this child as of normal weight, whereas the proposed SDG (stunting) will correctly categorise this child as suffering from long-run under-nutrition.
A few studies have made estimates of the contribution of stunting to GDP, of which Hoddinott and others calculate the cost-benefit ratio of nutrition interventions aimed at reducing stunting. They also point out the channels through which height can affect future income. First, there is a direct effect on wages (taller individuals may earn more, more so in low and middle-income countries where physical productivity matters in some manual occupations). Second, there are also indirect effects through improved cognition and hence wages (individuals with higher cognitive scores earn more, and also via their increased schooling achievements, also earn more). Third, there are potentially increased health costs associated with chronic disease in adulthood for which under-nutrition in childhood can be a risk factor.
The cost-benefit ratio calculated ranges from 3.5:1 (Democratic Republic of Congo) to 42.7 (Indonesia) when a 5 per cent discount rate is sued. The variations depend on the country's current level of income, projected growth rate, the current rate of stunting, and other parameters. Countries which are growing faster and/or have higher incomes have higher cost-benefit ratios, because the absolute dollar value of the benefits (due to higher wages) are greater while there is less variation in costs of the nutrition intervention.
For Bangladesh, the median country in terms of cost-benefit ratio of 17.9, the stunting rate in 1990 was 63.4 per cent which fell to 41.4 per cent in 2010, i.e. a 35 per cent (22 percentage points) reduction in stunting. If the same trend of reduction of 35 per cent (from 1990 to 2010) continues for another 20 years, this should be enough to reduce the proportion of stunting by close to 50 per cent between 2010 and 2030. Bangladesh had 6.3 million stunted children in 2010 (41.4 per cent of 15.3 million children under-5). In 2025, the number of children under-5 is projected to be 14.2 million, and if the proportion of the stunted falls to 20.7 per cent (half of 41.4 per cent), then there will be 2.9 million stunted children in 2025, which achieves the WHO goal. This estimate is reported to be preliminary and awaits further scrutiny. However, this estimate cannot be taken for a generalisation as Bangladesh is an unusual case with a trend rate of reduction in stunting (even without adding nutrition interventions) which is higher than the average for low and middle- income countries. Clearly the gruesome global phenomena of stunting would be largely influenced by that in Sub-Sahara Africa.
By and large, the Copenhagen Consensus Center that investigates and publishes the best policies and investment opportunities based on social good for every dollar spent, campaigns that stunting is a better goal to address than that of underweight. It is an excellent measure of health and diet provided to children during the 1,000 days from conception to age 2. Although it is not quite as predictive of mortality as underweight, it is much more predictive of economic outcomes (cognitive scores, education, and wages). Economic models suggest that the returns to investments in nutrition have high cost-benefit ratios, and that this should be a top development priority.
[The article titled 'Cost and returns in agriculture' by Prof. Abdul Bayes, which appeared in Monday's issue , was, in fact, printed on October  06. The mistake is regretted.]
The writer is a Professor of Economics at Jahangirnagar University.
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