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Chronic malnutrition

  • Page updated onMarch 22, 2025
Chronic malnutrition
Photo: Bruno Abarca

Chronic malnutrition is one of the two existing types of undernutrition, along with acute malnutrition. It manifests in children under five years of age as stunting and is associated with greater vulnerability to infectious diseases and delayed physical, motor, and cognitive development. In the long term, this delay also results in learning difficulties, poorer school performance, and reduced work capacity.

For all the above reasons, this issue has a significant impact on the economy of individuals, their families, and their communities, thereby reinforcing an intergenerational cycle of hunger and poverty. It is estimated to be responsible for the loss of 5%-7% of per capita income in low- and middle-income countries.

Chronic malnutrition is a multi-causal problem

The dimension of the problem

Stunting
UNICEF, WHO and World Bank, 2023.

It is estimated that, in 2022, 22.3% (148 million) of children under 5 years old suffered from stunting. The problem is mainly concentrated in Africa (with a prevalence of 31%), Southeast Asia (30.1%), and the Eastern Mediterranean (25%). These values are considered very low when below 2.5%, low when between 2.5% and 10%, moderate when between 10% and 20%, high between 20% and 30%, and very high when they exceed 30%.

Despite the current rate of 22.3% representing a significant reduction from the 33% prevalence of chronic malnutrition in 2000, this decrease has not been uniform. The decline has been sharp in several densely populated countries in South Asia, which have seen the most economic growth during this period. However, in Latin America, the decrease has been far less pronounced, and in Africa, the number of children with chronic malnutrition has even increased from 61 to 63 million.

The causes of chronic malnutrition have the greatest impact in the first months of life.

Among the causes of chronic child undernutrition is the continued negative effect of hunger and its social determinants during pregnancy and the first two years of life. This period is known as "the 1,000-day window of opportunity". During this time, food insecurity, limited access to health services, infections, deficiencies in water, sanitation and hygiene, or problems in infant feeding and care practices have a major impact on the development of these children's future potential.

Infections by digestive tract pathogens appear to have particularly high relevance in this type of malnutrition. This is due to enteric dysfunction (atrophy and chronic inflammation of the small intestine), which occurs not only in visible cases of diarrhea but also in cases of subclinical infections.

How is chronic malnutrition defined and diagnosed?

Like acute malnutrition, chronic malnutrition is defined by anthropometric criteria: a height-for-age index two standard deviations below the median of the WHO child growth standard. Children with chronic malnutrition have a shorter height than what would be expected for their age.

This method of measuring chronic malnutrition, although seemingly simple, poses many challenges. To begin with, it requires a properly calibrated height measuring device, a trained person, and the cooperation of the child, who must remain still for a few moments. This is often difficult when the child is in an unfamiliar or even frightening environment. Another issue is that diagnosis depends on age, a detail that sometimes isn’t recalled accurately (especially if the birth took place in the community or if there was no proper birth record). However, the main barrier is that chronic malnutrition is not clearly visible. For example, two girls may appear to be in good physical health and not raise suspicions of chronic malnutrition if one doesn't know that one of them is much younger than the other.

The approach to chronic malnutrition is fundamentally preventive

There is no effective treatment for stunting. It’s simply not possible to recover lost growth and cognitive development over months or even years by taking nutritional supplements. For this and other reasons, the fight against this issue has always been sidelined. However, reducing chronic malnutrition could have a tremendous impact on the economy and future opportunities of the poorest households, their communities, and their nations.

To fight chronic malnutrition, we must address the causes of hunger

Preventive action against hunger and its causes makes it possible to reduce the prevalence of chronic undernutrition, detect it and try to slow its progression during early childhood, and attenuate its consequences. These efforts also include action against acute malnutrition, malnutrition in all its forms, food insecurity, poverty, and inequality.

Preventing chronic malnutrition requires a commitment to peace and environmental sustainability, along with advocacy actions that place it among the priorities of duty-bearers and holders of responsibilities. Additionally, programs are needed to ensure access to food, water, sanitation, hygiene, and health services in humanitarian crises, support programs for families and caregivers with a gender perspective, and comprehensive systems of universal social protection for all people, especially the most vulnerable.

Although it is a priority for these actions to focus their effects on pregnant women, children under 2 or 3 years of age and their families, the "thousand days" is not the only window of opportunity. Growth does not stop at age 2. On the contrary, in adolescence there is a second period of accelerated development, which should be used to make up for the previously accumulated delay. In this period, moreover, the risk of developing overweight and obesity also increases, if the diet is not adequate.

Hunger and malnutrition

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