Kwashiorkor is a type of malnutrition with controversial causes, but it is commonly believe 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.