Global nutrition epidemiology and trends.

In the year 2011, 6.9 million children under the age of 5 years died worldwide, one third of them related to increased susceptibility to illnesses due to undernutrition. An estimated 178 million children under 5 years are stunted, 55 million are wasted, and 19 million of these are severely affected and are at a higher risk of premature death, the vast majority being from sub-Saharan Africa and South-Central Asia. Globally, over 2 billion people are at risk for vitamin A, iodine, and/or iron deficiency. Other micronutrient deficiencies of public health concern include zinc, folate, and the B vitamins. The risk factors for undernutrition include low birth weight, inadequate breastfeeding, improper complementary feeding, and recurrent infections. Infectious diseases often coexist with micronutrient deficiencies and exhibit complex interactions leading to the vicious cycle of malnutrition and infections. Diarrhea along with the poor selection and intake of complementary food are the major contributors to undernutrition. Possible strategies to combat malnutrition include promotion of breastfeeding, dietary supplementation of micronutrients, prevention of protein-energy malnutrition, and improvement in the standard of preparation and hygiene of available weaning foods. The universal coverage with the full package of these proven interventions at observed levels of program effectiveness could prevent about one quarter of child deaths under 36 months of age and reduce the prevalence of stunting at 36 months by about one third. The median coverage rate of interventions along the continuum of care for Countdown countries has however been ≥80% for vaccination and vitamin A supplementation. However, for several interventions, including early initiation and exclusive breastfeeding below 6 months of age and case management of childhood illnesses, the median coverage rate hovers at or below 50%. This suggests that interventions requiring strong health systems or behavior change appear to be stalled and need to be re-examined to find more effective ways of delivery.