Severe acute malnutrition (SAM), the most extreme form of undernutrition, is responsible for the deaths of a least 1 million children under five years old annually.

Globally, the World Health Organization (WHO) estimates 16 million children suffer from SAM. They are nine times more likely to die than well-nourished children – not only from malnutrition, but also from diseases they are too weak to fight off, including pneumonia and diarrhea.

While often associated with emergency situations, including conflicts and droughts, the United Nations Children’s Fund reports that most cases of SAM actually occur in developing countries that are not experiencing emergencies. The cases appear in settings that are facing endemic poverty, where communities are cut off from access to basic nutrition, clean water and essential health services. Nearly two-thirds of all cases are in Asia.

Researchers have warned that the number of children facing SAM might actually be much higher than estimated. Officials are often unable to capture new cases that can occur when communities experience rapid changes in their nutrition status.

Children suffering from SAM generally have visible signs of wasting and edemas that swell their feet, limbs or other parts of their bodies, but there are several ways health workers can diagnose suspected cases of SAM.

The WHO has set standards for children’s expected weight for their height. If they fall three standard deviations below that weight, they are considered severely malnourished. Children who fall between two and three standard deviations are moderately malnourished. Health officials also use mid-upper arm circumference (MUAC) measurements to measure undernutrition. Children between six and 60 months with a MUAC of 115 millimeters or less are also considered to be experiencing SAM.

Children who cross these limits need intensive nutritional and medical support or they face an extremely heightened risk of death. Untreated, a median of 30 to 50 percent of cases of SAM among children five years old are fatal, according to the WHO.

SAM treatment has undergone a revolution in recent years. Historically, children diagnosed with SAM received therapeutic milks at a hospital or health center, where they could be assured careful monitoring and access to clean water. However, the process of transporting a child to often-distant health centers and then remaining with them through treatment could devastate already-impoverished caregivers.

The situation began to change with the introduction of nutrient-rich ready-to-use therapeutic food (RUTF) in the mid-1990s. The pre-mixed pastes do not require water and have long shelf lives, making it possible to keep large amounts available in remote settings. Because they can be fed to a child straight from the package, sanitation is not a concern.

Their introduction has meant children experiencing SAM no longer need to go to health facilities for treatment after they are diagnosed. In 2007, the United Nations endorsed a strategy of community-based treatment for SAM that utilized RUTF.

The introduction of RUTF has not been without some controversy. Importing RUTF can be expensive, and some countries have complained that the products undercut local therapies that could be used to treat SAM. Many developing countries are now experimenting with producing their own, lower-cost RUTF.

While children are able to recover from SAM with treatment, there is some evidence that episodes of wasting can negatively affect future growth and undermine a child’s development. Researchers are still investigating those links.

Given both the immediate and long-term effects of SAM, experts continue to remain alarmed at the low treatment rates: Fewer than 15 percent of cases of severe wasting received treatment in 2012, according to the WHO and other international bodies. Experts are pushing for better integration of SAM detection and treatment in basic healthcare services, where it is often overlooked, especially in countries that are not experiencing an emergency.