Realising the potential human development returns to investing in early and maternal nutrition: The importance of identifying and addressing constraints over the life course

Abstract

The benefits of interventions which improve early nutrition are well recognised. These benefits, however, only accrue to the extent that later life circumstances allow. Consequently, in adverse contexts many of the benefits will never be realised, particularly for the most vulnerable, exacerbating inequality. Returns to investment in early nutrition could be improved if we identified contextual factors constraining their realisation and interventions to weaken these. We estimate cost and impact of scaling 10 nutrition interventions for a cohort of South African children born in 2021. We estimate associated declines in malnutrition and mortality, and improvements in years of schooling and future earnings. To examine the role of context over the life-course we estimate benefits with and without additional improvements in school quality and employment opportunities by socio-economic quintile. Scale up reduces national stunting (height for age < = -2SD) rates among children at 24 months by 3.18 percentage points, implying an increase in mean height for age z-score (HAZ) of 0.10, and 53,000 years of additional schooling. Quintile 1 (the poorest) displays the largest decline in stunting, and largest increase in mean HAZ. Estimated total cost of increasing coverage of the interventions for the cohort is US$90 million. The present value of the additional years of schooling is estimated at close to US$2 billion. Cost-benefit ratios suggest the highest return occurs in quintile 5 (1:23). Reducing inequality in school quality closes the gap between quintile 5 and the lower quintiles. If school quality and labour force participation were equal the highest returns are in quintile 1(1:31). An enabling environment is key to maximising human development returns from investing in early nutrition, and to avoid exacerbating existing inequality. Therefore, particularly for children in adverse conditions, it is essential to identify and implement complementary interventions over the life course.

Fig 1. The determinants and consequences of nutritional status in the first 1000 days plus.

The immediate and short-term biological consequences of unmitigated poor early nutrition include impacts on cognitive development and physiological health, including mortality, with some variation associated with child level differences, such as genetics [6,8,9]. The long-term implications of these consequences are largely dependent on whether, and how quickly, children access appropriate interventions [10,11]. Without intervention, the cognitive consequences of poor nutritional status can make school more difficult, often leading to early drop-out, and consequent lower earnings [12]. Positive caregiver responses such as accessing appropriate services, and providing adequate child stimulation can compensate for nutritional deficits, thus limiting negative biological consequences of poor early nutrition [13,14]. Conversely, caregivers attempting to protect a child they perceive as weak because of their nutritional status may inadvertently worsen biological outcomes through under-stimulation [–17]. Early interventions have the greatest potential to reverse the consequences of early malnutrition, but many later-life interventions, such as quality schooling, can mitigate the effects of early malnutrition on health, education and associated earnings, and wellbeing [–20]. The later life outcomes of adults who experienced poor early nutrition are shaped by their socio-economic context, such as the labour market. These later life outcomes shape the family circumstances of the next generation of children. This leads to intergenerational consequences of poor early nutrition [8,21].

Fig 2. Human development framework.

The framework focuses on human development, rather than intermediary outcomes. It includes three interacting types of influence on human development: The protection of potential; the realisation of potential; and the utilisation of potential. To be realized, potential must be protected, and to be utilized, potential must be realized. Influences which protect potential are concentrated in early life, those which lead to the realisation of potential cluster in mid-childhood and adolescence; and those which determine the possibility of utilising potential are concentrated in adulthood. While concentrated in particular periods, influences of each type can be found at every life stage. This framework is an adaptation of Nussbaum’s work on basic, internal, and combined capabilities [22]. Nussbaum focused on the interaction of individual development and the contexts in which people live, this framework deviates from Nussbaum in its treatment of biological development which she assumed was essentially automatic [22].