Nutrition Diet: Understanding What is SAM in Malnutrition?

October 8, 2025 •

5 min read

Globally, severe acute malnutrition affects an estimated 19 million children under the age of five, with devastating consequences for their health and survival. It is a life-threatening condition, so understanding what is SAM in malnutrition? is crucial for public health and emergency response efforts.

Quick Summary

Severe acute malnutrition is the most dangerous form of undernutrition, defined by severe wasting, nutritional edema, or very low weight-for-height.

Key Points

Definition: SAM is the most severe form of undernutrition, defined by severe wasting, nutritional edema, or a very low weight-for-height score.
Diagnosis: It is diagnosed through anthropometric measurements like Mid-Upper Arm Circumference (MUAC) and weight-for-height, along with clinical assessment for bilateral pitting edema.
Two Types: Historically classified as marasmus (severe wasting) and kwashiorkor (edema), though treatment is now standardized for both conditions.
Causes: Key factors include poverty, food insecurity, inadequate feeding practices, infections, and poor sanitation.
Treatment Pathways: Treatment is divided into outpatient care for uncomplicated cases using Ready-to-Use Therapeutic Foods (RUTFs) and inpatient care for complicated cases using the WHO's 10-step protocol.
High Mortality: SAM significantly increases the risk of death, especially in children under five, and requires urgent intervention.
Long-Term Impact: Survivors can face lasting effects, including impaired cognitive development and an increased risk of chronic diseases.

Defining Severe Acute Malnutrition (SAM)

Severe Acute Malnutrition (SAM) is the most severe and fatal form of undernutrition. It is primarily identified using anthropometric measurements and clinical signs, with the World Health Organization (WHO) providing the universally accepted definitions. The condition results from an insufficient intake of energy, protein, and other vital nutrients, leading to serious medical complications and compromised immunity. For children, especially those under five, SAM is a leading cause of mortality and morbidity globally.

Key diagnostic features of SAM include:

Low weight-for-height/length: A weight-for-height/length measurement more than three standard deviations ($<-3 ext{SD}$) below the median WHO child growth standards.
Low Mid-Upper Arm Circumference (MUAC): A MUAC measurement less than 115 mm, typically used for children aged 6–59 months.
Bilateral Pitting Edema: The presence of swelling in both feet, a distinct clinical sign of nutritional origin.

The Two Principal Types of SAM

Historically, SAM was categorized into two clinical types: marasmus and kwashiorkor. While their specific treatments are now aligned under a single, phased approach, understanding these manifestations is still important.

Marasmus: The Appearance of Severe Wasting

Marasmus is characterized by severe wasting, where the child's body appears visibly emaciated. This results from a significant loss of both muscle mass and subcutaneous fat, as the body uses its own stores for energy. Children with marasmus may have a characteristic 'old man' face, loose skin folds, and a very low weight-for-height measurement.

Kwashiorkor: Edema and Water Retention

Kwashiorkor is defined by the presence of bilateral pitting edema, or swelling, in the legs and sometimes other parts of the body. This swelling can mask the true extent of wasting, and its presence alone is enough to diagnose SAM. The condition is complex and is thought to involve a combination of insufficient protein and micronutrient intake, oxidative stress, and gut microbiota imbalances. Other signs can include skin and hair discoloration.

Causes and Risk Factors of SAM

The causes of SAM are multifactorial, stemming from a combination of underlying social, economic, and environmental issues, particularly in low- and middle-income countries.

Poverty and Food Insecurity: Limited access to nutritious and sufficient food is a primary driver.
Inadequate Feeding Practices: Poor breastfeeding practices, improper timing for introducing complementary foods, and low-quality diets are significant risk factors.
Infections and Diseases: Frequent episodes of infectious diseases, such as diarrhea, can hinder nutrient absorption and exacerbate malnutrition.
Poor Sanitation and Hygiene: Unsanitary living conditions increase the risk of infections, creating a vicious cycle of malnutrition and illness.
Political and Environmental Instability: Emergencies like conflict, famine, and natural disasters can disrupt food systems and healthcare, leading to spikes in SAM cases.

Diagnosing SAM

Diagnosis requires a clinical assessment by a trained health worker. The key steps include:

Clinical Examination: The child is assessed for signs like bilateral pitting edema.
Anthropometric Measurements: The child's weight-for-height and MUAC are measured and compared to WHO growth standards. For children 6–59 months, a MUAC strip is a simple and effective screening tool.
Appetite Test: For children with no medical complications, an appetite test using Ready-to-Use Therapeutic Food (RUTF) determines if they can be managed as outpatients.

How is SAM Treated? A Phased Approach

The treatment for SAM is organized into two main pathways based on the child's clinical condition: outpatient for uncomplicated cases and inpatient for complicated cases.

Outpatient Treatment (Community-Based Management of Acute Malnutrition, CMAM): This approach is recommended for the majority of uncomplicated SAM cases (approx. 85-90%) who have a good appetite and no severe medical issues. The child is treated at home with regular follow-ups at a health facility. A core component is the use of Ready-to-Use Therapeutic Food (RUTF), a high-energy, nutrient-dense paste that does not require water, reducing the risk of contamination.

Inpatient Treatment (Facility-Based Care): Children with complicated SAM—those with bilateral pitting edema (+++), a poor appetite, or medical issues like hypoglycemia, hypothermia, or severe infections—require hospitalization. The WHO outlines a 10-step protocol for inpatient management, which is divided into two phases.

The WHO 10-step inpatient protocol:

Treat/prevent hypoglycemia.
Treat/prevent hypothermia.
Treat/prevent dehydration.
Correct electrolyte imbalance.
Treat infection.
Correct micronutrient deficiencies (excluding iron initially).
Start cautious feeding (with F-75 therapeutic milk).
Promote catch-up growth (with F-100 therapeutic milk or RUTF).
Provide sensory stimulation and emotional support.
Plan for follow-up.

SAM vs. Moderate Acute Malnutrition (MAM)

Understanding the difference between SAM and Moderate Acute Malnutrition (MAM) is critical for effective diagnosis and management. Both are forms of acute malnutrition, but they differ in severity, risk, and treatment intensity.


Feature	Severe Acute Malnutrition (SAM)	Moderate Acute Malnutrition (MAM)
Definition (WHO)	Weight-for-height/length < -3 Z-scores, MUAC < 115mm (6-59m), or bilateral pitting edema.	Weight-for-height/length between -2 and -3 Z-scores, or MUAC between 115mm and <125mm (6-59m).
Severity	The most life-threatening form of malnutrition, with a high risk of death.	Less severe than SAM, with a lower, though still significant, risk of complications.
Associated Risks	High risk of mortality, severe medical complications, infections, organ failure.	Increased susceptibility to illness but typically fewer severe complications than SAM.
Treatment Setting	May require inpatient care for complicated cases, or outpatient care with RUTF for uncomplicated cases.	Usually managed through outpatient programs using fortified supplementary foods (RUSFs).
Therapeutic Foods	Ready-to-Use Therapeutic Food (RUTF) and therapeutic milks (F-75, F-100).	Ready-to-Use Supplementary Food (RUSF).

The Long-Term Impact of SAM

Even for survivors, SAM can leave a lasting legacy on a child's health and development. The long-term consequences include impaired physical and cognitive development, stunting, and an increased susceptibility to chronic diseases later in life. This is because SAM can reduce learning ability and overall intellectual performance. The effects can extend across generations, perpetuating a cycle of undernutrition.

Preventing Severe Acute Malnutrition

Preventing SAM requires a multi-pronged approach addressing nutrition, sanitation, and healthcare access. Key strategies include:

Optimal Breastfeeding: Promoting and supporting exclusive breastfeeding for the first six months of a child's life is crucial.
Complementary Feeding: Ensuring access to age-appropriate, nutrient-dense complementary foods from six months of age is vital.
Disease Prevention: Implementing strategies like improved sanitation, hygiene practices, and vaccination programs can help break the infection-malnutrition cycle.
Addressing Social Determinants: Tackling root causes such as poverty, food insecurity, and poor maternal health through social protection and education can have a significant impact.

Conclusion

Severe acute malnutrition is a grave public health issue with devastating short- and long-term consequences, particularly for children. The answer to what is SAM in malnutrition? is complex, involving not just a lack of food but also underlying social, economic, and health-related factors. Effective management relies on prompt and accurate diagnosis, followed by a strategic approach that ranges from community-based outpatient care with RUTF to hospital-based inpatient care for complicated cases. Ultimately, preventing SAM requires a comprehensive approach that focuses on improving feeding practices, sanitation, and overall healthcare, especially in vulnerable communities. Organizations like the WHO and UNICEF have provided clear guidelines to combat this critical challenge.

For more information on the guidelines for treating acute malnutrition, consult the WHO documentation on the management of severe acute malnutrition.

Frequently Asked Questions

The primary causes of SAM are multi-faceted and include poor access to nutritious food (food insecurity), inadequate feeding practices, and recurrent infections exacerbated by poor sanitation and hygiene.

SAM is the most severe form of malnutrition, characterized by specific clinical signs like severe wasting or edema. General malnutrition covers a broader spectrum, including moderate and chronic forms like stunting and being underweight.

The Mid-Upper Arm Circumference (MUAC) tape is a simple, colored measuring strip used by health workers to assess a child's nutritional status. For children 6–59 months, a measurement less than 115mm indicates SAM and requires immediate attention.

Yes, uncomplicated SAM, where the child has a good appetite and no other medical complications, can be effectively treated at home using Ready-to-Use Therapeutic Foods (RUTFs) under a Community-Based Management of Acute Malnutrition (CMAM) program.

RUTFs (Ready-to-Use Therapeutic Foods) are high-energy, nutrient-dense pastes used for treating uncomplicated SAM. They are effective because they are safe, palatable, do not require water, and are fortified with essential vitamins and minerals.

Complicated SAM cases with severe edema, poor appetite, or other medical issues like hypoglycemia, infections, or dehydration require inpatient hospitalization. This ensures close medical supervision and treatment of underlying complications before nutritional rehabilitation can begin.

Surviving SAM does not mean a full recovery without risk. Long-term consequences can include impaired cognitive development, stunted growth, and a higher risk of developing chronic diseases in adulthood, perpetuating a cycle of poverty and poor health.