This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Global Public Health. Please check back later for the full article.
Malnutrition is caused by consuming a diet with either too little or too much of one or more nutrients, such that the body malfunctions. These nutrients can be the macronutrients protein, carbohydrates, and fats that provide the body with energy, or the micronutrients, including vitamins and minerals, that help the body to function. Infectious diseases, such as diarrhea, can also cause malnutrition through decreased nutrient absorption, decreased intake of food, increased metabolic requirements, and direct nutrient loss. A double burden of malnutrition (both over and under) often occurs across the life course of individuals and can also coexist in the same communities and even the same households. While about a quarter of the world’s children are stunted, due to both maternal and young child undernutrition, overweight and obesity affects about one in three adults and one in ten children. Anemia, principally due to iron deficiency, also affects about a third of women of reproductive age and almost half of preschool children. At least 88% of countries face a serious burden of either two or three of these forms of malnutrition.
Malnutrition is one of the principal and growing causes of global disease and mortality, affecting at least half of the world’s inhabitants. Programs for tackling maternal and child undernutrition have gained impetus since the early 21st century with a consensus developing around a package of effective interventions. The nutrition-specific interventions, mostly delivered through the health sector, are directed at immediate levels of causality, while nutrition-sensitive interventions, directed at the underlying and basic levels of causality, are delivered through other sectors such as education, agriculture, water and sanitation, and social welfare. Less consensus exists on the interventions needed to reduce overnutrition and reduce the non-communicable diseases (NCDs) associated with it, including diabetes, high blood pressure, and coronary heart disease. Prevention is certainly better than cure, however, and creating enabling environments for healthy food choices seems to be the most promising approach. Public health nutrition capacity to manage such nutrition programs is still widely lacking. Achieving “healthy diets for all” by reducing consumption of meat and of ultra-processed foods as well as increasing consumption of fruit and vegetables would help control rising rates of obesity and reduce NCD mortality. Adopting such diets would also greatly contribute to reducing greenhouse gas emissions, which the agriculture sector is responsible for producing over one third of current levels of, and so also reduce global warming.