In developing countries, protein undernutrition occurs predominantly in young children, whereas in developed countries, it is most commonly seen in long-term care. Similarly, isolated vitamin deficiencies, such as pellagra, beri-beri, and Wernicke's encephalopathy, occur in developing countries, whereas these are rare in developed countries, being replaced by vitamin B12 deficiency and hypovitaminosis D and a variety of complex nutritional disorders seen in older persons living in long-term care. In developed countries, there are usually adequate quantities of food, so the development of undernutrition occurs because of disease or poor nutritional choices associated with the anorexia of aging.
展开▼
