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Malnutrition is a medical condition caused by an improper or insufficient diet.[24] Malnutrition is technically a category of diseases that includes undernutrition, obesity and overweight, and micronutrient deficiency (known as 'hidden hunger') among others.[25] However, it is frequently used to mean undernutrition from either inadequate calories or inadequate specific dietary components for whatever reason.[26] People who are malnourished may: not consume adequate calories and protein for growth and maintenance, such as undernutrition or protein–energy malnutrition (PEM)[3] consume too many calories (overnutrition)[3] have abnormal nutrient loss (due to diarrhea or chronic illness) or increased energy expenditure (secondary malnutrition)[3][27] Undernutrition encompasses stunting, wasting, and deficiencies of essential vitamins and minerals (collectively referred to as micronutrients). The term hunger, which describes a feeling of discomfort from not eating, has been used to describe undernutrition, especially in reference to food insecurity.[28] The term "severe malnutrition" is often used to refer specifically to PEM.[29] PEM is often associated with micronutrient deficiency.[29] Two forms of PEM are kwashiorkor and marasmus, and they commonly coexist.[24] Kwashiorkor (‘displaced child’) is mainly caused by inadequate protein intake resulting in a low concentration of amino acids.[24] The main symptoms are edema, wasting, liver enlargement, hypoalbuminaemia, steatosis, and possibly depigmentation of skin and hair.[24] Kwashiorkor is identified by swelling of the extremities and belly, which is deceiving of actual nutritional status.[30] Marasmus (‘to waste away’) is caused by an inadequate intake of 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.[24] Marasmus can result from a sustained diet of inadequate energy and protein, and the metabolism adapts to prolong survival.[24] It is traditionally seen in famine, significant food restriction, or more severe cases of anorexia.[24] Conditions are characterized by extreme wasting of the muscles and a gaunt expression.[30] Gomez[edit] In 1956, Gómez and Galvan studied factors associated with death in a group of malnourished children in a hospital in Mexico City, Mexico and defined categories of malnutrition: first, second, and third degree.[31] The degrees were based on weight below a specified percentage of median weight for age.[27] The risk of death increases with increasing degree of malnutrition.[31] An adaptation of Gomez's original classification is still used today. While it provides a way to compare malnutrition within and between populations, the classification has been criticized for being "arbitrary" and for not considering overweight as a form of malnutrition. Also, height alone may not be the best indicator of malnutrition; children who are born prematurely may be considered short for their age even if they have good nutrition.[32] Degree of PEM % of desired body weight for age and sex Normal 90%-100% Mild: Grade I (1st degree) 75%-89% Moderate: Grade II (2nd degree) 60%-74% Severe: Grade III (3rd degree) <60% SOURCE:"Serum Total Protein and Albumin Levels in Different Grades of Protein Energy Malnutrition"[30] Waterlow[edit] John Conrad Waterlow established a new classification for malnutrition.[33] Instead of using just weight for age measurements, the classification established by Waterlow combines weight-for-height (indicating acute episodes of malnutrition) with height-for-age to show the stunting that results from chronic malnutrition.[34] One advantage of the Waterlow classification over the Gomez classification is that weight for height can be examined even if ages are not known.[33] Degree of PEM Stunting (%) Height for age Wasting (%) Weight for height Normal: Grade 0 >95% >90% Mild: Grade I 87.5-95% 80-90% Moderate: Grade II 80-87.5% 70-80% Severe: Grade III <80% <70% SOURCE: "Classification and definition of protein-calorie malnutrition." by Waterlow, 1972[33] These classifications of malnutrition are commonly used with some modifications by WHO.[27] |
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