Global micronutrient deficiencies in childhood and impact on growth and survival: challenges and opportunities.

Despite numerous advances and improvements in child health, malnutrition still remains as one of the main public health challenges of the 21st century, particularly in developing countries. It undermines the survival, growth and development of children, and is associated with almost 35% of all deaths in children under the age of 5 years worldwide. An estimated 178 million children are stunted globally, and an additional 19 million children have severe acute malnutrition (wasting). These conditions are very often associated with concomitant micronutrient deficiencies, and among these, vitamin A, iron, zinc and iodine deficiencies are the most prevalent in childhood. Vitamin A and zinc deficiency is associated with an estimated 1 million child deaths and 9% of global childhood disability-adjusted life years. Recent data on the timing of growth retardation and stunting in infants suggest that the onset is commensurate with inappropriate complementary feeding and potentially compounded by maternal undernutrition and intrauterine growth retardation, and that the first 24 months represent a critical window of opportunity for intervention. Given the wide prevalence of multiple micronutrient deficiencies in malnourished children in developing countries, the challenge is to implement intervention strategies that combine appropriate infant and young child feeding with micronutrient interventions at scale. Emerging data from community intervention trials now provide evidence that this is both tangible and can lead to alleviation of childhood undernutrition. Some of these recent findings will be discussed.