Malnutrition: Concept, Classification and Magnitude
J. Ngo, ... L. Serra-Majem, in Encyclopedia of Food and Health, 2016
Severe Acute Malnutrition
SAM was previously known as PEM, or protein–calorie malnutrition, and is an important nutritional condition in developing countries due to its high prevalence and its association with high rates of infant mortality, changes in growth and development, and decreased ability to work, altogether leading to inadequate social and economic development.
SAM occurs when the diet does not provide sufficient protein, energy substrates (calories), or both, to satisfy the body's nutritional needs. It is usually also associated with a deficiency of vitamins and minerals and essential micronutrients needed for growth and tissue renovation. The term SAM includes severe clinical syndromes of kwashiorkor (edema), marasmus (without edema), marasmic–kwashiorkor (edema and the combination of chronic energy deficiency and chronic or acute protein deficiency), and mild and moderate cases that are much more numerous than severe forms. The term ‘malnutrition’ is generally used in common vernacular to refer to SAM.
SAM may be of primary or secondary origin. Primary SAM is caused by inadequate nutrient intake. Secondary SAM results from disorders or drugs that interfere with nutrient use, such as cases of diseases accompanied by low food intake, inadequate nutrient absorption or utilization, increased nutritional requirements, increased nutrient losses, or any or all of these factors. Although SAM is mainly an issue in early childhood, it may also occur in older children and adults, particularly the elderly. This article focuses on primary SAM of gradual onset, with predominance of metabolic disorders and clinical features of protein and energy deficiency.