Underfed - Definition

Definition

Malnutrition is a medical condition caused by an improper or insufficient diet. Malnutrition is technically a category of diseases that includes: undernutrition, obesity and overweight, and micronutrient deficiency among others. However it is frequently used to mean just undernutrition from either inadequate calories or inadequate specific dietary components for whatever reason.

People who are malnourished may:

• not consume adequate calories and protein for growth and maintenance, such as undernutrition or protein–energy malnutrition (PEM)
• consume too many calories (overnutrition)
• have abnormal nutrient loss (due to diarrhoea or chronic illness) or increased energy expenditure (secondary malnutrition)

Undernutrition encompasses stunting, wasting, and deficiencies of essential vitamins and minerals (collectively referred to as micronutrients). The term hunger, which literally describes a feeling of discomfort from not eating, has also been used to describe undernutrition, especially in reference to food insecurity.

The term severe malnutrition is often used to refer specifically to PEM. PEM is often associated with micronutrient deficiency. Two forms of PEM are kwashiorkor and marasmus, and they commonly coexist.

Kwashiorkor (‘displaced child’) is mainly caused by inadequate protein intake resulting in a low concentration of amino acids. The main symptoms are edema, wasting, liver enlargement, hypoalbuminaemia, steatosis, and possibly depigmentation of skin and hair. Kwashiorkor is identified by swelling of the extremities and belly, which is deceiving of actual nutritional status.

Marasmus (‘to waste away’) is caused by an inadequate intake of both protein and energy. The main symptoms are severe wasting, leaving little or no edema, minimal subcutaneous fat, severe muscle wasting, and non-normal serum albumin levels. Marasmus can result from a sustained diet of inadequate energy and protein, and the metabolism adapts to prolong survival. It is traditionally seen in famine, significant food restriction, or more severe cases of anorexia. Conditions are characterized by extreme wasting of the muscles and a gaunt expression.