Why is it difficult to solve?

Challenges in identifying stunting exist in almost every geographical area. In low-resource settings, stunting is particularly hard to recognize. In such settings, children often have poor access to the health care required to assess stunting. Newborns may not be measured, or their birth date may not be documented, complicating later efforts to measure their growth.

Even when a child is born in a health facility with a skilled health care provider, precisely measuring the length of a newborn at birth can be difficult. Greater importance is often given to weight because of the risks of low birth weight.

Beyond the difficulty of measuring newborns and children, governments often measure other key drivers of stunting inconsistently, if at all. Important underlying factors, including maternal and household-level diet (both quality and caloric intake) and food security, household-level disposable income, women’s empowerment, and complementary feeding habits are subject to poor measurement or lack of measurement. Indicators around dietary intake and feeding frequency are especially challenging to measure in multipurpose surveys, but more recent Demographic and Health Surveys have begun to do so.² Accurate, representative data on coverage and quality of nutrition-specific interventions, such as education around breastfeeding, complementary feeding, micronutrient supplementation, and fortification, is lacking even more.³

An effective government will typically excel at both developing evidence-based strategies (e.g., incorporating the latest scientific findings into policy, and adapting global recommendations for local epidemiology, population dynamics, and cultural features) and executing those strategies. Effective implementation requires the following features:

• Communication, continuity, and incentives across various levels of government and in remote areas
• Prioritization and targeting of particularly vulnerable population subgroups and regions
• Regular and frequent monitoring and evaluation, and adaptation of tactics based on new information or changes on the ground
• Sustained and adequate funding

Because child stunting is driven by a wide array of disparate factors, addressing it successfully demands strong governance capabilities, political commitment, and collaboration across sectors. In practice, because most governments do not have ministries dedicated to nutrition, they must forge partnerships and structures for collaboration across multiple ministries (e.g., education, public works, agriculture, health, and sanitation) to develop and implement effective responses to stunting. Collaboration of this sort has rarely been governments’ strong suit (with some exceptions as seen in the Peru Exemplars work).

Multisectoral programming also presents financial challenges. Government funding is often earmarked by ministry rather than policy priority, and in resource-limited settings, it can be difficult to designate nutrition spending in the annual budget. In addition, sharing and tracking funding across departments, along with coordinating donor funds, comes with significant management challenges.

While overcoming these challenges through operational excellence alone is possible, high-level political commitment, ideally supported by a head of state, can galvanize a national government to further reduce child stunting. In Peru, for instance, the president’s commitment to reducing stunting prevalence by 9 percent within five years compelled ministries to work together and provincial and local governments to implement national-level policies.⁴ Similarly, Senegal’s Cellule de Lutte Contre la Malnutrition (Coordination Unit for the Fight Against Malnutrition), housed within the prime minister’s office, had the political backing to convene key stakeholders and generate support across sectors for a national nutrition strategy.⁵

A well-functioning food system plays a foundational role in providing food security and proper nutrition. The food system is a large, abstract concept—it factors in the food supply chain, retail and commercial markets, the biophysical environment, and other social components including, the politics and demographics of populations.⁶

The central role of a food system is to ensure that an adequately diverse and nutritious diet is available to all people.⁷ Meeting the distinct dietary needs of mothers and their children, however, is extremely difficult in places where resources are limited, conflicts are ongoing, or geography precludes access.

Conceptual framework of food systems for children and adolescents

As it relates to stunting, the food system’s impact is felt at multiple points in time. Beginning with the nutritional needs of mothers and continuing to the diets of children, having access to healthy and nutrient-dense foods, either by growing or buying them, is crucial to minimizing risks factors like anemia and intrauterine growth restriction that predispose a child to be stunted.⁸ Animal source foods (e.g., meat, eggs, and milk) alongside general diet diversity (e.g., micronutrient-rich fruits, vegetables, and grains) promote healthy linear growth and cognitive development, but they can be some of the most difficult items to access in areas where stunting burdens are high.

On the supply side, challenges to thriving food systems include environmentally inhospitable growing conditions, difficulty with management of disease in homestead production (as is the case with poultry and Newcastle disease), and lack of cold-storage facilities. On the demand side, challenges include cultural familiarity with healthy foods and the ability to properly prepare and store foods.

One of the most difficult challenges in low- and middle-income countries is what is known as the nutrition transition.⁹ First seen in high-income countries, the proliferation of cheap, nutrient-poor, processed foods in transitioning economies has contributed to a wave of obesity in sub-Saharan Africa and South Asia.

There are opportunities to address these challenges. For example, minimally processing foods (e.g., fermentation and smoking meats) reduces the post-harvest loss of products and when educated about nutrition, mothers often show a willingness to incorporate new foods into their diets.^{10, 11}  Further upstream, investments in electrification and transportation and higher household wages can lower the costs of nutritious food. Without a conscientious reshaping of food systems, however, equitable access to the critical foods mothers and children need cannot be guaranteed.

One of the most significant implications of child stunting is its association with cognitive development. Stunted children often suffer from delayed mental development, which eventually leads to reduced cognitive abilities.¹³ At the individual level, stunted cognitive development correlates with poorer educational outcomes, lower wages, and a higher risk of living in poverty. For a country, high stunting prevalence could mean reduced GDP (as much as 11% annually) and diminished ability to compete in the knowledge economy of the future.¹⁴

While there is still more work needed to further understand the specific relationship between stunting and cognitive development, an association clearly exists. Difficulty measuring cognitive development, particularly in low-resource settings, hinders further research. In addition, tracking cognitive development alongside accurate linear growth measurements is an even bigger challenge.

Still others caution the global community against focusing on the fire alarm, rather than the fire by conflating stunting and other key health outcomes. While linear growth restriction is a causal driver of difficult births and poor birth outcomes, it is associated with delayed child development, reduced earnings in adulthood, and chronic diseases. While the association between child stunting and other outcomes make it a useful marker, it is important to note that in some cases reducing stunting is neither necessary, sufficient, nor the most cost-effective means to holistically improve the well-being of children.

In the late 2000s, global evidence clarified the link between reduced fertility, increased birth spacing, prevention of adolescent births, and reduced intergenerational transfer of child stunting.¹⁵ As a result, fertility-related interventions remain underrepresented in nutrition policies today.

However, we now know that 20 to 30 percent of stunting occurs in utero. This intrauterine growth restriction accounts for the intergenerational aspect of stunting (and increases other health risks, including low birth weight).¹⁶

The Cycle of Stunting

This intergenerational cycle starts in the mother’s childhood when she becomes stunted and does not reach her full growth potential. As she grows into a teenager and then an adult, often still poorly nourished, she is more likely to give birth to babies that are small and poorly nourished. Years of slow and delayed growth follow, and the cycle of stunting begins once more.

Each year an estimated 10 million girls below the age of 18 are married.¹⁷ Pregnancy in adolescence exacerbates intrauterine growth restriction; teenage girls who become pregnant stop growing as nutrients are diverted to their fetuses. Reducing the number of adolescent pregnancies thus represents a significant opportunity to prevent stunting. Adolescent pregnancies are also associated with other health complications beyond stunting, including a 50 percent increase in the risk of stillbirth and neonatal death and an increased risk of low birth weight.^18, 19  Low birth weight is in turn associated with a greater risk of stunting.

Even in adulthood, decreased fertility and increased birth spacing can reduce stunting and interrupt the intergenerational cycle of stunting (although more evidence is needed). Both factors diminish the toll that pregnancy and childbirth take on women’s bodies. Women with fewer children more widely spaced in age have more energy and resources to devote to each child, both in the womb and after birth. Other interventions in maternal health—antenatal care and attendance at birth by skilled providers, for example—increase contact between women and health workers, thereby increasing the likelihood they will learn and adopt best practices in health and nutrition for themselves and their children.

Many governments and health care providers continue to underestimate the importance of family planning, maternal health, and maternal nutrition during pregnancy and the postpartum period. Part of the challenge is that addressing these drivers—access to birth control, reducing child marriage, improving pregnant and lactating women’s access to good quality foods, and women’s access to prenatal care—often involves reshaping deeply held customary beliefs that are difficult to change but are key to improving health and nutrition.

Our research on Exemplar countries has revealed many lessons learned and has provided a better understanding of how countries have addressed stunting. These lessons fed into the development of a guided ten-step framework to reduce stunting. Such knowledge is part of a growing larger body of evidence that reinforces the importance of increasing education for women, targeting the most vulnerable populations, and securing political commitment to reduce stunting burdens.

The 2021 Lancet Maternal and Child Nutrition Series adds to this body of evidence as it highlights 11 direct nutrition interventions that when scaled effectively can work in tandem with multisectoral efforts to reduce stunting.²⁰ Even with all of this knowledge, how best to deliver the interventions at scale remains an open question and may vary depending on the country context. Some countries have successfully implemented interventions in concert with broad social programs while others have targeted programs to specific geographies. Different approaches have yielded varying results. The still-developing evidence base around both direct and indirect nutrition interventions has left policy makers with some uncertainty about the most effective interventions for improving childhood growth.

Waiting until children were old enough to attend school to intervene meant missing the critical “first 1,000 days” from before conception to a child’s second birthday.

ADDITIONAL READING: Effective interventions to address maternal and child malnutrition: an update of the evidence >>>

Water, Sanitation, and Hygiene

The correlation between water, sanitation, and hygiene (WASH) and child stunting, though well documented across several large-scale studies, continues to puzzle researchers.

While WASH conditions are regularly cited as strong independent risk factors for poor linear growth, they might also be confounded by other household indicators, or elements of the study (e.g., contact frequency and habit adoption). As a result, it is challenging to draw causal inferences around WASH effects on child stunting.

Decomposition analysis of research from Exemplars in Global Health and the International Food Policy Research Institute suggests that nearly 17 percent of stunting reductions can be attributed to WASH initiatives.^{21, 22}  In analyses of cross-sectional data and observational data, significant correlation has been identified between poor WASH and child stunting.²³ At the same time, when WASH intervention trials have been evaluated, they have not demonstrated a positive impact on linear growth.

Conceptual impact of WASH on nutritional status

Poor hygiene can serve as a pathway to stunting in many ways. It increases the likelihood of infection, which demands a higher caloric intake to power an active immune system. Fecal-oral infection can cause diarrhea, which impedes the ability to fully digest food and extract vital nutrients. Finally, repeated diarrheal infection can inflame the small intestines, which chronically inhibits nutrient absorption. The condition, called environmental enteric dysfunction or environmental enteropathy, is widespread among children and adults in low- and middle-income countries.²⁴

Three randomized control trials conducted in Zimbabwe ²⁵ , Bangladesh²⁶ , and Kenya²⁷ assessed the impact of WASH interventions on linear growth, but none of them found an association, stumping researchers.²⁸ The rigorous trials tested large numbers of children in rural areas and included both nutrition interventions (e.g., supplementation, counseling on breastfeeding and complementary feeding) and WASH interventions (e.g., improved pit latrines, handwashing stations, and chlorine water treatment). Findings from all three trials showed a significant association between nutrition interventions and increased growth among children but showed no impact from WASH interventions.

 

	Zimbabwe	Bangladesh	Kenya
Sample size	3,686 children	4,584 children	6,583 children
Primary outcomes	Height and hemoglobin at 18 months	Height and diarrhea at 24 months	Height and diarrhea at 24 months
Measurement timepoints	12 and 32 weeks gestation;  1, 3, 6, 12, 18 months postnatal	12 months, 24 months	12 months, 24 months
Nutrition intervention	Daily lipid-based nutrient supplement 6–18 months + counseling on improved complementary feeding (breastfeeding counseling in all four arms as standard of care)	Daily lipid-based nutrient supplement 6–24 months + counseling on improved breastfeeding and complementary feeding practices	Daily lipid-based nutrient supplement 6–24 months + counseling on improved breastfeeding and complementary feeding practices
Uptake of nutrition interventions	High	High	High
Impact of nutrition interventions on child height	Statistically significant improvement	Statistically significant improvement	Statistically significant improvement
WASH interventions	Improved pit latrine (built to government of Zimbabwe standards), handwashing stations, chlorine water treatment, child play area	Improved pit latrine, handwashing stations, chlorine water treatment, child potty and scoop	Improved pit latrine, handwashing stations, chlorine water treatment, child potty and scoop
Uptake of WASH interventions	High	High	Moderate
Impact of WASH interventions on child height	None	None	None

Despite the findings of these three studies, the debate over the impact of WASH interventions on growth continues. One hypothesis is that because the trials followed participants for only 18 to 24 months after the interventions, they may have missed any impacts that showed up later. Another is that the effectiveness of WASH interventions is limited by the high-frequency contact needed to achieve adherence. At scale, these interventions are not feasible because frequent monitoring (e.g., daily to biweekly) is unsustainable. Researchers have also posited that WASH interventions may require more widespread geographic implementation to take effect or a longer timeline to evaluate impact. Finally, only a limited set of WASH interventions (e.g., improved pit latrine, handwashing stations unconnected to a water source, chlorine water treatment) was used; the study therefore did not evaluate the impact of different and possibly more effective interventions, such as improved food hygiene. Further research is needed to determine the impact of WASH interventions and how they might be implemented differently.

Micronutrient Supplementation

Micronutrient supplementation for women and children and/or fortification of food could be effective in preventing and reducing stunting. The following interventions are included in the Lancet’s 11 priority direct nutrition interventions:

• Maternal balanced energy protein supplementation (for fetal development) for undernourished women
• Maternal calcium supplementation in low-intake populations
• Small-quantity lipid nutrient supplementation (for fetal development and continued child growth)
• Multiple micronutrient supplementation in pregnancy (for fetal development)
• Vitamin A administration in deficient contexts
• Preventive and therapeutic zinc supplementation in children ages 6 months to 59 months

The effectiveness of these micronutrient interventions at scale has varied widely, with some interventions (e.g., vitamin A supplementation) achieving high coverage and effectiveness, and others having mixed results (e.g., iron/folic acid). Still others have failed to scale up effectively (e.g., zinc, calcium). Although evidence for the use of multiple micronutrients versus only iron-folic acid in pregnancy is now clear, even better results are seen with the use of supplements that include sufficiently diverse micronutrients (such as the 15 included in the United Nation’s International Multiple Micronutrient Antenatal Preparation).²⁹

An assessment of the impact of micronutrient supplementation has proven difficult, largely because of the lack of large-scale effectiveness studies and related studies on implementation. WHO recommendations to use multiple micronutrients only in the context of rigorous implementation research presents a barrier to reducing an important health burden.³⁰

The impacts of the COVID-19 pandemic are ongoing and far-reaching across all aspects of child development and nutrition. While the disease itself poses a direct risk, the bigger risk in terms of malnutrition is food insecurity as a result of supply chain shocks, increases in food prices, the end of social protection programming such as school feeding, and job loss.³³

As United Nations Children’s Fund (UNICEF) Executive Director Henrietta Fore said in 2020, “It’s been seven months since the first COVID-19 cases were reported and it is increasingly clear that the repercussions of the pandemic are causing more harm to children than the disease itself.” ³⁴

The most pressing malnutrition challenge as a result of COVID-19 will be an increased prevalence of children with severe acute malnutrition (also known as wasting). However, there is also an expected increase in other forms of malnutrition including stunting, micronutrient deficiencies, and obesity. In conjunction with a disruption in health and social services, an increase in malnutrition can lead to compounding health ailments, making it more difficult to treat individual conditions.

Development partners are working to respond to the crisis, but because of the concurrent economic fallouts from COVID-19, donor and domestic resources have been slow to mobilize and are falling short of the need. To address these shortfalls, UNICEF³⁵  has called on governments, donors, and the private sector to prevent further malnutrition by:

• Safeguarding access to nutritious, safe, and affordable diets as a cornerstone of the response to COVID-19 by protecting food producers, processors, and retailers; discouraging trade bans; and designating food markets as essential services.
• Investing decisively in support for maternal and child nutrition by protecting breastfeeding, preventing the inappropriate marketing of infant formula, and securing children and women’s access to nutritious and diverse foods.
• Investing decisively in support for maternal and child nutrition by protecting breastfeeding, preventing the inappropriate marketing of infant formula, and securing children and women’s access to nutritious and diverse foods.
• Reactivating and scaling up services for the early detection and treatment of child wasting while expanding other life-protecting nutrition services.
• Maintaining the provision of nutritious and safe school meals by reaching vulnerable children through home delivery, take-home rations, cash or vouchers when schools are closed.
• Expanding social protection to safeguard access to nutritious diets and essential services among the poorest and most affected households, including access to fortified foods.

It is also important to note that disruptions to the education sector will be linked to stunting. In short, the long-term impact of COVID-19 on nutrition is almost certainly harmful and widespread but not yet fully comprehensible.