Malnutrition

Malnutrition is caused by consuming a diet with either too little and/or too much of one or more nutrients, such that the body malfunctions. These nutrients can be the macronutrients, including proteins, carbohydrates, and fats that provide the body with its building blocks and 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 overnutrition and undernutrition) 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, most commonly due to iron deficiency, is also affecting about a third of women of reproductive age and almost half of preschool children. Around 90% of nations have a serious burden of either two or three of these different 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 in the last decade 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 agriculture, education, social welfare, as well as water and sanitation. Less consensus exists around the interventions needed to reduce overnutrition and the associated non-communicable diseases (NCDs), 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. Achieving “healthy diets for all,” by reducing consumption of meat and 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 healthy diets would also greatly contribute to reducing greenhouse gas emissions: the agriculture sector is responsible for producing a third of emissions, and a reduction on livestock farming would contribute to reducing global warming. Public health nutrition capacity to manage such nutrition programs is still widely lacking, however, and much still needs to be done to improve these programs and their governance.