Kwashiorkor is a type of malnutrition with controversial causes, but it is commonly believed to be caused by insufficient protein intake. It usually affects children aged 1–4 years, although it also occurs in older children and adults. Jamaican pediatrician Cicely D. Williams introduced the name into international scientific circles in her 1935 Lancet article. When a child is nursing, it receives certain amino acids vital to growth from its mother's milk. When the child is weaned, if the diet that replaces the milk is high in starches and carbohydrates, and deficient in protein (as is common in parts of the world where the bulk of the diet consists of starchy vegetables, or where famine has struck), the child may develop kwashiorkor.
The name is derived from one of the languages of coastal Ghana, translated literally "first-second", and means "rejected one", reflecting the development of the condition in the older child who has been weaned from the breast, often as the result of the birth of a sibling.
Symptoms of kwashiorkor include a swollen abdomen known as a pot belly, as well as alternating bands of pale and dark hair (flag sign) and weight loss. Common skin symptoms include dermatitis and depigmented skin.
The swollen abdomen is generally attributed to two causes: First, the appearance of ascites due to increased capillary permeability from the increased production of cysteinyl leukotrienes (LTC4 and LTE4) as a result of generalized intracellular deficiency of glutathione. It is also thought to be attributed to the effect of malnutrition on reducing plasma proteins (discussed below), resulting in a reduced oncotic pressure and therefore increased osmotic flux through the capillary wall. A second cause may be due to a grossly enlarged liver due to fatty liver. This fatty change occurs because of the lack of apolipoproteins which transport lipids from the liver to tissues throughout the body.
Victims of kwashiorkor fail to produce antibodies following vaccination against diseases, including diphtheria and typhoid. Generally, the disease can be treated by adding food energy and protein to the diet; however, it can have a long-term impact on a child's physical and mental development, and in severe cases may lead to death.
There are various explanations for the development of kwashiorkor, and the topic remains controversial. It is now accepted that protein deficiency, in combination with energy and micronutrient deficiency, is certainly important, but may not be the key factor. The condition is likely due to deficiency of one of several type one nutrients (e.g., iron, folic acid, iodine, selenium, vitamin C), particularly those involved with anti-oxidant protection. Important anti-oxidants in the body that are reduced in children with kwashiorkor include glutathione, albumin, vitamin E and polyunsaturated fatty acids. Therefore, if a child with reduced type one nutrients or anti-oxidants is exposed to stress (e.g. an infection or toxin) he/she is more liable to develop kwashiorkor.
Ignorance of nutrition can be a cause. Dr. Latham, director of the Program in International Nutrition at Cornell University cited a case where parents who fed their child cassava failed to recognize malnutrition because of the edema caused by the syndrome and insisted the child was well-nourished despite the lack of dietary protein.
One important factor in the development of kwashiorkor is aflatoxin poisoning. Aflatoxins are produced by molds and ingested with moldy foods. They are toxified by the cytochrome P450 system in the liver, the resulting epoxides damage liver DNA. Since many serum proteins, in particular albumin, are produced in the liver, the symptoms of kwashiorkor are easily explained. It is noteworthy that kwashiorkor occurs mostly in warm humid climates that encourage mold growth, in dry climates marasmus is the more frequent disease associated with malnutrition. This has important consequences for treatment of the patients: Protein should be supplied only for anabolic purposes, the catabolic needs should be satisfied with carbohydrate and fat. Protein catabolism involves the urea cycle, which is located in the liver and can easily overwhelm the capacity of an already damaged organ. The resulting liver failure can be fatal.