The role of nutrition in integrated early child development in the 21st century: contribution from the Maternal and Child Nutrition journal

Abstract

Even though it is widely recognized that early childhood development (ECD) is one of the most important predictors of future social capital and national productivity, the recently published ECD Lancet Series reports that about 250 million children under 5 years are at risk of not reaching their developmental potential, mainly as a result of poverty and social injustice. So why is this and what will it take to reverse this situation? The purpose of this special issue is to highlight important contributions from previously published articles in Maternal & Child Nutrition to the field of nutrition and ECD. The collection of papers presented in this special issue collectively indicates that although nutrition‐specific interventions are essential for child development, they are not sufficient by themselves for children to reach their full developmental potential. This is because ECD is influenced by many other factors besides nutrition, including hand washing/sanitation, parenting skills, psychosocial stimulation, and social protection. Future research should focus on mixed‐methods implementation science seeking to understand how best to translate evidence‐based integrated ECD packages into effective intersectoral policies and programs on a large scale. In addition to health and nutrition, these programs need to consider and include responsive parenting (including responsive feeding), learning stimulation, education, and social protection. Future studies should also address if and how childhood obesity affects human physical, socioemotional, and cognitive development.

Early child development (ECD) is fundamentally a process of skill development based on physical and neurobiological development that happens in specific socioeconomic and cultural contexts (Black et al., 2015). Child development has multiple dimensions including physical, sensorimotor, social, emotional, language, and cognitive. During the first 5 years of life, children rapidly develop from being unable to speak and walk to having in place fairly advanced motor, social, and cognitive skills. It is well established that maternal–child health and nutrition during the first 1,000 days of life are crucial for helping the child establish a healthy growth. Recent advances in neuroscience have clearly established that the brain develops very rapidly during gestation and the first 2 years of life and that its development continues unfolding between 3 and 5 years of age following a scaffold‐like process with new abilities building upon the foundations set by previous acquired abilities (Black et al., 2015; Black et al., 2016). Even though it is widely recognized that ECD is one of the most important predictors of future social capital and national productivity (Doyle et al., 2009), the recently published ECD Lancet Series reports that about 250 million children under 5 years are at risk of not reaching their developmental potential, mainly as a result of poverty and social injustice (Black et al., 2016). So why is this and what will it take to reverse this situation?

The purpose of this special issue is to highlight important contributions from the field of nutrition to ECD that have been previously published in our journal and to identify lessons learned from them for better understanding how the nutrition sector can contribute to ECD in the context of multisectorial interventions. Given the centrality of ECD indicators as part of the 2015–2030 sustainable development goals, we indeed hope that this special virtual issue will offer important insights toward understanding what will it take to achieve the ECD sustainable development goals. In the selection of papers included, we gave priority to papers published within the last 2 years (to provide a sense of where the field stands) and also to those that help understand complex nutrition–ECD relationship, have tested innovative interventions, or that have generated interesting hypotheses that can influence future research in the field.

2. NUTRITION AND CHILD DEVELOPMENT ACROSS THE LIFE‐COURSE

Aubuchon‐Endsley et al. (2016) found that maternal pre‐pregnancy obesity combined with excess weight gain during pregnancy was associated with poorer neurobehavior in neonates including poorer regulation, lower arousal, and higher lethargy. Potential confounders, such as delivery complications or early medial difficulties, were not found to influence the interaction between maternal weight and infant neurobehavior. Rather the authors suggest that excessive maternal weight and gestational weight gain may program infant neurobehavioural development via hormonal pathways such as dysregulation of the hypothalamic–pituitary–adrenal axis. This study highlights the key importance that periconceptional nutrition, in this instance, excessive body fat, has on infant development. The importance of breastfeeding on ECD is widely acknowledged in the literature. Adding to the debate about the specific mechanisms by which breastfeeding improves ECD, Huang, Vaughn, and Kremer (2015) conducted a prospective study to further investigate the nurturing hypothesis (i.e., that breastfeeding acts as a proxy for family socioeconomic background and parenting behaviors) on the link between breastfeeding and ECD. They found that the positive association between breastfeeding and academic ability at 12 years of age was independent of socioeconomic status and parenting behaviors. Further, the associations between breastfeeding with children's behavioral problems were divergent from those of family socioeconomic characteristics and parenting behaviors, suggesting that the mechanisms behind the observed relationship between breastfeeding and ECD is likely to be different from those by which family socioeconomic background and parenting exert their effects. Their findings therefore question the hypothesis that the relationship between breastfeeding and improved child development is spurious and totally confounded by socioeconomic status and parenting approaches.

Undernutrition has long been associated with poor developmental outcomes in children, but there have been few longitudinal studies that have investigated this relationship. In an attempt to address this knowledge gap, Crookston et al. (2011) assessed the relative impact of early stunting (stunted at 6–18 months of age) and concurrent stunting (stunted at 4.5–6 years of age on the cognitive ability of Peruvian children participating in the Young Lives cohort study. Factors found to put children at greater risk of poor cognitive development included poverty, living in a rural environment, low maternal education and age, more siblings, and failure to attend pre‐school. Notably, concurrent stunting was found to have a greater impact on cognitive skills than early stunting. This finding indicates that it is important to address stunting throughout the first 5 years and not just during the first 1000 days of life. Teivaanmäki et al. (2016) found in their cohort study conducted in Malawi that improved height gain between two and 15 years of age, but not between birth and two years of age, was independently associated with cognitive development. Consistent with Crookston et al. (2011), this study strongly suggests that promoting linear growth post‐1,000 days is very important for long‐term cognitive development and policy.

Although these studies add to the increasing body of knowledge indicating that poor nutritional status during early childhood and beyond has a negative impact on cognitive development, few have investigated the association between nutritional status and social behaviors and what the potential mediators may be. Liu and Raine (2016) found in a large sample of 3‐year‐old children living in Mauritius that malnourished children had impaired social functioning, which exhibited a dose–response relationship whereby increased malnutrition was associated with more impaired social behavior. Neurocognitive ability was found to mediate the nutrition–social behavior relationship. This suggests that malnutrition predisposes children to poorer neurocognitive functioning, which in turn predisposes them to reduced positive social behavior. These findings help illuminate the complex web of relationships that help explain the dire consequences that malnutrition has for multiple human development dimensions including cognitive abilities and social skills.

It is well established that deficiencies in specific micronutrients, such as iron and iodine, have long lasting detrimental effects on child development. There has been increasing interest in the role of other nutrients, such as fatty acids, zinc, and vitamin B12, on child cognitive development. Findings from studies investigating the association between individual nutrient levels and supplementation on ECD however remain inconclusive. In their review of the impact of fatty acids on growth and neurobehavioural development in infants, Makrides and colleagues confirmed that the effect of maternal supplementation on global neurobehavioural outcomes for children born at term remains unclear, although omega‐3 Long‐Chain Polyunsaturated Fatty Acids (LCPUFAs) supplementation of women expressing milk for their preterm infants does appear to improve their performance on tests of global neurodevelopment (Makrides et al., 2011). Likewise, two observational studies published in Maternal and Child Nutrition failed to find convincing evidence of enhanced infant psychomotor or cognitive development related to the LCPUFA content of breast milk or infant DHA status (Engel et al., 2013; Keim et al., 2012). Two micronutrient randomized controlled trails (one maternal vitamin B12 supplementation trial of mothers, the other zinc supplementation of infants) were also unable to provide evidence of a positive effect on ECD (Locks et al., 2016; Srinivasan et al., 2016), suggesting that nutrition silver bullets simply do not exist to improve ECD.

3. SOCIAL AND BEHAVIORAL MEDIATORS

Maternal postnatal depression has been found to affect maternal–infant interactions and is associated with poor cognitive, emotional, and behavioral outcomes in children. Mallan et al. (2015) found in the Australian prospective NOURISH trial that maternal postpartum depression, assessed at 4 months postpartum, had a negative association with the mother's ability to feed responsively of 2‐year‐old children (i.e., greater pressure to eat, restrictive feeding style, and emotional feeding). It has been suggested that such practices may undermine child self‐regulation of intake and could be associated with obesogenic eating behaviors and increased risk of overweight. These findings highlight the strong links between the mental health of the caregiver and the feeding behaviors of very young child, which is the age when food preferences and long‐term dietary habits get established. Thus, addressing postpartum depression should be considered as part of multi‐focal young child nutrition programs.

4. INTERVENTIONS

Interventions to improve nutritional status of young children may have the added benefit of improving ECD in low‐and middle‐income countries. Larson and Yousafzai (2015) concluded from their meta‐analysis that the mental development of children under 2 years in low‐ and middle‐income countries is more strongly influenced by their motor development than their growth status resulting from postnatal nutrition interventions. It is crucial that these important findings are noted by the nutrition community who traditionally have expected growth to be the strongest mediator between nutrition interventions and cognitive outcomes in children. They underscore the importance of integrated nutrition as part of multifocal ECD interventions that also include child psychosocial stimulation and water, sanitation and hygiene interventions (WASH) as illustrated in papers such as the work of Saxton et al. (2016). Pérez‐Escamilla, Martinez, and Segura‐Pérez (2016) concluded from their narrative systematic review that the Baby‐friendly Hospital Initiative (BFHI) Ten Steps have a positive impact on short‐term, medium‐term, and long‐term breastfeeding outcomes. They also found that there is a dose–response relationship between the number of BFHI steps women are exposed to and the likelihood of improved breastfeeding outcomes. Community support (Step 10) was identified as essential for sustaining breastfeeding impacts of BFHI in the longer term. These findings have major implications for ECD as there is strong and consistent evidence supporting the impact of breastfeeding on the intellectual development of children, and this effect is like to carry through adolescence and adulthood (Victora et al., 2016). They also have strong implications for implementation science as they call for better understanding on how to improve the coordination between facility‐ and community‐based breastfeeding services to provide the continuum of care needed to maximize the benefits from BFHI. Dewey and Adu‐Afarwuah (2008) concluded from their major systematic review that there is no single “one size fits all” recipe with regard to the design of effective complementary feeding “packages” in low‐income countries. This is because the local context where the intervention is to be implemented needs to be taken heavily into account when designing such packages. Some contextual considerations include the initial prevalence of malnutrition, the degree of household food insecurity, the energy density of traditional complementary foods, and the availability of micronutrient‐rich local foods. These findings emphasize the need to conduct extensive formative research before finalizing the design and starting the implementation of complementary feeding interventions. Vazir et al. (2013) found from their randomized controlled trial conducted in India that responsive feeding education of caregivers improved dietary intake, growth, and mental development among toddlers. This study confirmed that understanding how to feed children taking into account their individual needs using developmentally appropriate responsive feeding approaches is as important as knowing what it is that children of this age need to be fed to meet their nutritional needs. Again, this study underlies the multifocal nature of interventions needed to advance the ECD agenda as it specifically calls for the integration of parenting interventions as part of nutrition interventions targeting young children. Fabrizio, van Liere, and Pelto (2014) identified the key components of effective behavior change interventions seeking to improve complementary feeding practices in low‐ and middle‐income countries. The two key components identified were (a) context‐specific formative research identifying barriers and enablers and (b) delineation of program impact pathways to understand behavioral mediators of impact. These findings have important implications for the successful design and implementation of behavior change‐based infant and young child feeding nutrition interventions globally. They also call for the need of interdisciplinary partnerships that included experts in program design and evaluation and systems thinking in addition to experts in maternal–child nutrition. Cumming and Cairncross (2016) found in their review that WASH interventions are likely to have a positive impact at improving linear growth during early childhood in low‐income countries. This paper adds to the strong and consistent evidence that malnutrition and infectious diseases are interrelated, and most importantly, that WASH should be part of integrated multifocal ECD interventions seeking to improve linear growth outcomes. The childhood obesity pandemic calls for a better understanding of how to prevent this condition that can be very harmful for both the physical and the socioemotional development of children.

5. POLICY

The need to translate scientific knowledge to relevant ECD policies and programs is highlighted in two papers. Subramanian, Mejía‐Guevara, and Krishna (2016) call for rethinking policies to address child stunting in South Asia, the region more strongly affected by this outcome, taking into account recent multidisciplinary evidence. Their key conclusion is that it is no longer tenable to continue implementing stunting prevention policies and programs that rely solely on the proximal determinants of growth as upstream social determinants of health need to be addressed for stunting to be abated. This conclusion is highly consistent with the paradigm shift presented in the 2013 Maternal and Child Nutrition Lancet Series highlighting the need to address nutrition specific as well as intersectorial nutrition sensitive policies and programs to improve child nutrition outcomes in low‐income countries (Ruel & Alderman, 2013). A similar conclusion has been reached with regard to the intersectoriality needed to address not only physical growth but also other indicators of ECD including psychosocial and cognitive development (Black et al., 2016; Britto et al., 2016; Richter et al., 2016).

6. CONCLUSIONS

Improving ECD is crucial for meeting the 2015–30 Sustainable Development Goals. The collection of papers presented in this special issue of Maternal & Child Nutrition collectively indicates that although nutrition‐specific interventions are essential for child development, they are not sufficient in and by themselves for children to reach their full developmental potential. This is because many non‐nutrition factors—including the social determinants of health, parenting style, and early childhood stimulation—affect both nutritional status as well as other dimension of ECD including psycho‐emotional, cognitive, and academic development. Indeed, nutrition silver bullets simply do not exist to improve ECD and intersectoral multi‐level programs that are needed to address child development challenges. In addition to health and nutrition, these programs need to consider including responsive parenting (including responsive feeding), learning stimulation, education, and social protection (Black et al., 2015; Black et al., 2016; Britto et al., 2016; Richter et al., 2016).

Complex adaptive systems frameworks, such as the ones proposed by Pérez‐Escamilla and Hall Moran (2016) for improving breastfeeding outcomes, are needed to understand how to scale up effective ECD programs. We believe that lessons learned from scaling up of nutrition/stunting reduction policies and programs may be helpful for the overall ECD arena. Future research should focus on mixed‐methods implementation science seeking to understand how best to translate evidence‐based integrated ECD packages into effective policies and programs on a large scale (Britto et al., 2016; Richter et al., 2016). Appropriate ECD is driven by multiple factors including proper nutrition, health care access, psychosocial stimulation, plenty of developmentally appropriate learning opportunities (e.g., structure and unstructured play time), and social protection. Poverty and social exclusion typically limit the access of families to most if not all of these factors. In order to reverse this trend, it is crucial for governments to scale up multisectorial programs that address each of the factors needed in an integrated way (Richter et al., 2016). The interventions that need to be scaled up need to be evidence based taking into account the papers presented in this virtual issue as well as the Lancet Series recommendations (Britto et al., 2016). Research is also needed to better understand if and how childhood obesity affects the different dimensions of ECD. There is no doubt that learning how to integrate nutrition into integrated ECD policies and programs should be a top priority for the 21st century (Black et al., 2015).

Pérez‐Escamilla, R. , and Moran, V. H. (2017) The role of nutrition in integrated early child development in the 21st century: contribution from the Maternal and Child Nutrition journal, Matern Child Nutr, 13, e12387. doi: 10.1111/mcn.12387.