Introduction
Despite a recent focus on maternal and child undernutrition, no country is ready to meet all ten of the 2025 nutrition targets set by the World Health Assembly in 2012.1 Globally, there are 149 million children younger than 5 years whose growth is stunted, 49·5 million who are wasted, and 40·1 million who are overweight, with notable disparities between countries and regions.1 The 2008 Lancet Series on maternal and child undernutrition and the 2013 Lancet Series on maternal and child nutrition were important publications that summarised the effect of evidence-based interventions in reducing maternal and child undernutrition.2, 3 Since, many countries and agencies have scaled up the ten core interventions outlined in these Series (preventive zinc supplementation; promotion of breastfeeding; appropriate complementary feeding; periconceptual folic acid supplementation or fortification; maternal balanced energy protein supplementation; maternal multiple micronutrient [MMN] supplementation; maternal calcium supplementation; vitamin A supplementation; management of moderate and severe acute malnutrition). However, there is a need to periodically revisit the evidence-base of these interventions with newer evidence and assess areas that need further investigation.
Maternal and child nutrition research has had a rapid development over the last decade with large-scale effectiveness studies, and developments in innovations and improved commodities. The nutrition programme community now recognises the co-occurrence of conditions (eg, stunting and overweight, or stunting and wasting, in children) and the need for double-duty or triple-duty actions.4 There is also a growing awareness of the importance of targeting certain populations (eg, adolescents and school-aged children) that have been ignored until now. Additionally, the very nature of evidence synthesis is evolving, with emphasis being placed on good quality and effectiveness studies that assess how an intervention will fare in real life conditions that are not optimal.5 The inappropriate inclusion of low-quality studies in systematic reviews has also been highlighted.6
The 2013 Lancet Series showed a conceptual framework that categorised nutrition actions into those that were either nutrition-specific or nutrition-sensitive, depending on the nutrition determinant they addressed.7 This framework has triggered multisectoral planning in many countries, and has posed challenges in terms of coordination and affixing responsibility for nutrition oversight, especially for the traditional health and nutrition sectors.8, 9, 10, 11 We have proposed a revision of the framework, categorising nutrition actions into direct and indirect health and non-health-care sector interventions alongside cross-cutting strategies for nutrition support and integration (figure 1).12 With the revised framework as a guide, this Review builds upon previous research through a comprehensive set of systematic reviews and review updates to provide a new overview of what works to improve undernutrition in low-income and middle-income countries (LMICs; panel 1). We also discuss potential actions that could be taken to mitigate the rising double burden of malnutrition.
Key messages
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Evidence-based interventions for improving maternal and child nutrition continue to be a combination of interventions that are direct (eg, delayed cord clamping, micronutrient supplementation, breastfeeding promotion, and counselling) and indirect (eg, malaria prevention, and water, sanitation, and hygiene promotion)
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Nutritional interventions delivered within and outside the health-care sector are equally crucial for preventing and managing malnutrition
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New evidence supports the use of preventive lipid-based nutrient supplementation for reducing childhood stunting, wasting, and underweight, and the use of antenatal multiple micronutrient supplementation for preventing adverse pregnancy and birth outcomes
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Evidence gaps remain for strategies to address malnutrition among schoolchildren and adolescents
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The drivers of undernutrition are diverse, and novel evidence synthesis methods underscore the need for multisectoral action and coordination