What are wasting and stunting?
Wasting and stunting are both forms of undernutrition affecting millions of children, primarily in low- and middle-income countries. Though often discussed together, they are distinct conditions with different causes, symptoms, and consequences. A clear understanding of the difference between wasting and stunting is vital for effective prevention and treatment strategies.
Wasting: Acute Malnutrition
Wasting, or acute malnutrition, is characterized by low weight-for-height, often stemming from recent, severe weight loss or lack of weight gain. Moderately or severely wasted children face increased mortality risk, though recovery is possible with timely treatment.
- Causes: Inadequate food intake and severe infectious diseases like diarrhea are primary causes of wasting. This leads to the body using energy reserves and rapid weight loss.
- Symptoms: Wasted children appear very thin. Severe cases might show nutritional oedema (swelling) due to protein deficiency.
- Detection: Wasting is detected via weight-for-height z-score (WHZ), mid-upper-arm circumference (MUAC), and checking for bilateral pitting oedema.
Stunting: Chronic Malnutrition
Stunting, or chronic malnutrition, is defined by low height-for-age, meaning a child is too short for their age. It results from long-term or repeated undernutrition and infections that hinder linear growth. Stunting causes irreversible physical and cognitive impairment with lifelong effects.
- Causes: Stunting is linked to poor socioeconomic conditions, inadequate maternal health and nutrition during pregnancy, poor infant feeding, and frequent illnesses, especially in the first 1,000 days.
- Symptoms: Stunted children are shorter than peers. They may not appear thin and can even be overweight due to altered body composition.
- Detection: Stunting is diagnosed by measuring height and comparing it to standards for age and sex using a height-for-age z-score (HAZ).
Comparison: Wasting vs. Stunting
| Feature | Wasting | Stunting |
|---|---|---|
| Type of Malnutrition | Acute (recent and severe) | Chronic (long-term and recurrent) |
| Anthropometric Indicator | Low weight-for-height | Low height-for-age |
| Timeframe of Onset | Rapid onset, often due to recent events | Gradual onset over a prolonged period |
| Primary Cause | Inadequate food intake or recent infection (e.g., diarrhea) | Continuous lack of nutrition, frequent illness, and poor living conditions |
| Physical Appearance | Appears very thin for their height | Appears short for their age |
| Reversibility | Potentially reversible with timely and appropriate treatment | Largely irreversible damage to physical and cognitive development |
| Impact on Body | Loss of muscle and fat mass, impaired immune response | Retarded linear growth and reduced muscle mass, cognitive deficits |
| Mortality Risk | Significantly increased risk of death, especially when severe | Increased risk of mortality, magnified when concurrent with wasting |
Overlap and Co-occurrence
Wasting and stunting often occur together in concurrent wasting and stunting (WaSt). A child experiencing acute malnutrition (wasting) may subsequently become stunted as the body prioritizes survival. This creates a poor health cycle. The mortality risk is significantly higher for children with both conditions.
Addressing the Challenges
Combating wasting and stunting requires integrated strategies addressing immediate and underlying causes. Focus is crucial during the first 1,000 days of life. Interventions should also consider the link between the conditions.
Key actions include:
- Improving maternal health and nutrition.
- Promoting optimal feeding practices.
- Ensuring access to clean water, sanitation, and hygiene (WASH).
- Expanding healthcare access for detection and treatment.
- Enhancing food security and household wealth.
Guidelines on managing wasting and nutritional status assessments are available from the World Health Organization.
Conclusion
Wasting is acute, short-term low weight-for-height, often reversible, while stunting is chronic, long-term low height-for-age with largely irreversible consequences. Both are preventable, and effective programs must target the immediate causes of wasting and the chronic factors of stunting to break the cycle of malnutrition and protect children's potential.
