Other environmental risks
Clinically, malnutrition is characterized by inadequate intake of protein, energy and micronutrients and by frequent infections or disease. Nutritional status is the result of the complex interaction between the food we eat, our overall state of health and the environment in which we live.
Many people in the developing world, particularly women and children, continue to suffer from undernutrition. The poor especially often suffer from a basic lack of protein and energy, the adverse health effects of which are frequently compounded by deficiencies in micronutrients, particularly iodine, iron, vitamin A and zinc. Another important risk factor is lack of breastfeeding.
Undernutrition, defined in public health by poor anthropometric status, is mainly a consequence of inadequate diet and frequent infection, leading to deficiencies in calories, protein, vitamins and minerals. Underweight remains a pervasive problem in developing countries, where poverty is a strong underlying determinant, contributing to household food insecurity, poor child care, maternal undernutrition, unhealthy environments, and poor health care. All ages are at risk, but underweight is most prevalent among children under five years of age, especially in the weaning and post-weaning period of 6--24 months. WHO has estimated that approximately 14% of children under five years of age were underweight in 2015. However, in 2015, 156 million children under five years of age were stunted, and 50 million children were wasted. Underweight children are at increased risk of mortality from infectious illnesses such as diarrhoea and pneumonia (Rice et al 2000). The effects of undernutrition on the immune system are wide-ranging, and infectious illnesses also tend to be more frequent and severe in underweight children.
Rice AL, Sacco L, Hyder A, Black RE. Malnutrition as an underlying cause of childhood deaths associated with infectious diseases in developing countries. Bulletin of the World Health Organization 2000; 78: 1207-21.